Merge branch 'main' into feat/desktop-private-dms

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/bloom/BloomFilter.kt

@@ -23,7 +23,7 @@ package com.vitorpamplona.quartz.bloom
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.utils.RandomInstance
 import com.vitorpamplona.quartz.utils.sha256.Sha256Hasher
 import org.junit.Assert.assertEquals
@@ -135,7 +135,7 @@ class BloomFilterTest {
 
         var failureCounter = 0
         for (seed in 0..1000000) {
-            if (bloomFilter.mightContains(Nip01.pubKeyCreate(Nip01.privKeyCreate()))) {
+            if (bloomFilter.mightContains(Nip01Crypto.pubKeyCreate(Nip01Crypto.privKeyCreate()))) {
                 failureCounter++
             }
         }

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip01Core/Nip01CryptoTest.kt

@@ -23,7 +23,7 @@ package com.vitorpamplona.quartz.nip01Core
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.utils.Secp256k1Instance
 import com.vitorpamplona.quartz.utils.sha256.sha256
 import org.junit.Assert.assertEquals
@@ -33,14 +33,14 @@ import org.junit.Test
 import org.junit.runner.RunWith
 
 @RunWith(AndroidJUnit4::class)
-class Nip01Test {
+class Nip01CryptoTest {
     private val privateKey = "f410f88bcec6cbfda04d6a273c7b1dd8bba144cd45b71e87109cfa11dd7ed561".hexToByteArray()
 
     @Test
     fun testGetPublicFromPrivateKey() {
         assertEquals(
             "7d4b8806f1fd713c287235411bf95aa81b7242ead892733ec84b3f2719845be6",
-            Nip01.pubKeyCreate(privateKey).toHexKey(),
+            Nip01Crypto.pubKeyCreate(privateKey).toHexKey(),
         )
     }
 
@@ -66,7 +66,7 @@ class Nip01Test {
     fun testDeterministicSign() {
         assertEquals(
             "1484d0e0bd62165e822e31f1f4cc8e1ce8e20c30a060e24fb0ecd7baf7c624f661fb7a3e4f0ddb43018e5f0b4892c929af64d8b7a86021aa081ec8231e3dfa37",
-            Nip01.sign(sha256("Test".toByteArray()), privateKey, null).toHexKey(),
+            Nip01Crypto.sign(sha256("Test".toByteArray()), privateKey, null).toHexKey(),
         )
     }
 
@@ -81,10 +81,10 @@ class Nip01Test {
     @Test
     fun testDeterministicVerify() {
         assertTrue(
-            Nip01.verify(
+            Nip01Crypto.verify(
                 "1484d0e0bd62165e822e31f1f4cc8e1ce8e20c30a060e24fb0ecd7baf7c624f661fb7a3e4f0ddb43018e5f0b4892c929af64d8b7a86021aa081ec8231e3dfa37".hexToByteArray(),
                 sha256("Test".toByteArray()),
-                Nip01.pubKeyCreate(privateKey),
+                Nip01Crypto.pubKeyCreate(privateKey),
             ),
         )
     }
@@ -93,18 +93,18 @@ class Nip01Test {
     fun testNonDeterministicSign() {
         assertNotEquals(
             "1484d0e0bd62165e822e31f1f4cc8e1ce8e20c30a060e24fb0ecd7baf7c624f661fb7a3e4f0ddb43018e5f0b4892c929af64d8b7a86021aa081ec8231e3dfa37",
-            Nip01.sign(sha256("Test".toByteArray()), privateKey).toHexKey(),
+            Nip01Crypto.sign(sha256("Test".toByteArray()), privateKey).toHexKey(),
         )
     }
 
     @Test
     fun testNonDeterministicSignVerify() {
-        val signature = Nip01.sign(sha256("Test".toByteArray()), privateKey)
+        val signature = Nip01Crypto.sign(sha256("Test".toByteArray()), privateKey)
         assertTrue(
-            Nip01.verify(
+            Nip01Crypto.verify(
                 signature,
                 sha256("Test".toByteArray()),
-                Nip01.pubKeyCreate(privateKey),
+                Nip01Crypto.pubKeyCreate(privateKey),
             ),
         )
     }

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/Nip01CryptoTest.kt

@@ -33,7 +33,7 @@ class Nip01CryptoTest {
     fun testGetPublicFromPrivateKey() {
         val privateKey =
             "f410f88bcec6cbfda04d6a273c7b1dd8bba144cd45b71e87109cfa11dd7ed561".hexToByteArray()
-        val publicKey = Nip01.pubKeyCreate(privateKey).toHexKey()
+        val publicKey = Nip01Crypto.pubKeyCreate(privateKey).toHexKey()
         assertEquals("7d4b8806f1fd713c287235411bf95aa81b7242ead892733ec84b3f2719845be6", publicKey)
     }
 }

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip04Dm/EncryptionTest.kt

@@ -22,7 +22,7 @@ package com.vitorpamplona.quartz.nip04Dm
 
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.nip04Dm.crypto.EncryptedInfo
 import com.vitorpamplona.quartz.nip04Dm.crypto.Encryption
 import org.junit.Assert.assertEquals
@@ -34,8 +34,8 @@ class EncryptionTest {
 
     val sk1 = "91ba716fa9e7ea2fcbad360cf4f8e0d312f73984da63d90f524ad61a6a1e7dbe".hexToByteArray()
     val sk2 = "96f6fa197aa07477ab88f6981118466ae3a982faab8ad5db9d5426870c73d220".hexToByteArray()
-    val pk1 = Nip01.pubKeyCreate(sk1)
-    val pk2 = Nip01.pubKeyCreate(sk2)
+    val pk1 = Nip01Crypto.pubKeyCreate(sk1)
+    val pk2 = Nip01Crypto.pubKeyCreate(sk2)
 
     val expectedShared = "7ce22696eb0e303ddaa491bdf2a56b79d249f2d861b8e012a933e01dc4beba81"
 

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip04Dm/Nip04Test.kt

@@ -21,7 +21,7 @@
 package com.vitorpamplona.quartz.nip04Dm
 
 import androidx.test.ext.junit.runners.AndroidJUnit4
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.nip04Dm.crypto.Nip04
 import org.junit.Assert.assertEquals
 import org.junit.Test
@@ -33,8 +33,8 @@ class Nip04Test {
     fun encryptDecryptNIP4Test() {
         val msg = "Hi"
 
-        val privateKey = Nip01.privKeyCreate()
-        val publicKey = Nip01.pubKeyCreate(privateKey)
+        val privateKey = Nip01Crypto.privKeyCreate()
+        val publicKey = Nip01Crypto.pubKeyCreate(privateKey)
 
         val encrypted = Nip04.encrypt(msg, privateKey, publicKey)
         val decrypted = Nip04.decrypt(encrypted, privateKey, publicKey)
@@ -46,8 +46,8 @@ class Nip04Test {
     fun encryptSharedSecretDecryptNIP4Test() {
         val msg = "Hi"
 
-        val privateKey = Nip01.privKeyCreate()
-        val publicKey = Nip01.pubKeyCreate(privateKey)
+        val privateKey = Nip01Crypto.privKeyCreate()
+        val publicKey = Nip01Crypto.pubKeyCreate(privateKey)
 
         val encrypted = Nip04.encrypt(msg, privateKey, publicKey)
         val decrypted = Nip04.decrypt(encrypted, privateKey, publicKey)

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip44Encryption/Nip44v1Test.kt

@@ -24,7 +24,7 @@ import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -68,8 +68,8 @@ class Nip44v1Test {
     fun encryptDecrypt() {
         val msg = "Hi"
 
-        val privateKey = Nip01.privKeyCreate()
-        val publicKey = Nip01.pubKeyCreate(privateKey)
+        val privateKey = Nip01Crypto.privKeyCreate()
+        val publicKey = Nip01Crypto.pubKeyCreate(privateKey)
 
         val encrypted = nip44v1.encrypt(msg, privateKey, publicKey)
         val decrypted = nip44v1.decrypt(encrypted, privateKey, publicKey)
@@ -81,8 +81,8 @@ class Nip44v1Test {
     fun encryptDecryptSharedSecret() {
         val msg = "Hi"
 
-        val privateKey = Nip01.privKeyCreate()
-        val publicKey = Nip01.pubKeyCreate(privateKey)
+        val privateKey = Nip01Crypto.privKeyCreate()
+        val publicKey = Nip01Crypto.pubKeyCreate(privateKey)
 
         val sharedSecret = nip44v1.getSharedSecret(privateKey, publicKey)
 

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip44Encryption/Nip44v2Test.kt

@@ -25,7 +25,7 @@ import com.vitorpamplona.quartz.nip01Core.core.JsonMapper
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.utils.RandomInstance
 import com.vitorpamplona.quartz.utils.sha256.sha256
 import junit.framework.TestCase.assertNotNull
@@ -68,8 +68,8 @@ class Nip44v2Test {
         val privateKeyA = "f410f88bcec6cbfda04d6a273c7b1dd8bba144cd45b71e87109cfa11dd7ed561".hexToByteArray()
         val privateKeyB = "65f039136f8da8d3e87b4818746b53318d5481e24b2673f162815144223a0b5a".hexToByteArray()
 
-        val publicKeyA = Nip01.pubKeyCreate(privateKeyA)
-        val publicKeyB = Nip01.pubKeyCreate(privateKeyB)
+        val publicKeyA = Nip01Crypto.pubKeyCreate(privateKeyA)
+        val publicKeyB = Nip01Crypto.pubKeyCreate(privateKeyB)
 
         assertEquals(
             nip44v2.getConversationKey(privateKeyA, publicKeyB).toHexKey(),
@@ -82,8 +82,8 @@ class Nip44v2Test {
         val privateKeyA = "f410f88bcec6cbfda04d6a273c7b1dd8bba144cd45b71e87109cfa11dd7ed561".hexToByteArray()
         val privateKeyB = "e6159851715b4aa6190c22b899b0c792847de0a4435ac5b678f35738351c43b0".hexToByteArray()
 
-        val publicKeyA = Nip01.pubKeyCreate(privateKeyA)
-        val publicKeyB = Nip01.pubKeyCreate(privateKeyB)
+        val publicKeyA = Nip01Crypto.pubKeyCreate(privateKeyA)
+        val publicKeyB = Nip01Crypto.pubKeyCreate(privateKeyB)
 
         assertEquals(
             nip44v2.getConversationKey(privateKeyA, publicKeyB).toHexKey(),

quartz/src/androidDeviceTest/kotlin/com/vitorpamplona/quartz/nip55AndroidSigner/SignStringTest.kt

@@ -24,7 +24,7 @@ import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -37,7 +37,7 @@ class SignStringTest {
         val message = "8e58c8251bb406b6ded69e9eb14f55282a9a53bdab16fc49a3218c2ad3abc887".hexToByteArray()
         val keyPair = KeyPair("a5ab474552c8f9c46c2eda5a0b68f27430ad81f96cb405e0cb4e34bf0c6494a2".hexToByteArray())
 
-        val signedMessage = Nip01.sign(message, keyPair.privKey!!, random).toHexKey()
+        val signedMessage = Nip01Crypto.sign(message, keyPair.privKey!!, random).toHexKey()
         val expectedValue = "0f9be7e01ba53d5ee6874b9180c7956269fda7a5be424634c3d17b5cfcea6da001be89183876415ba08b7dafa6cff4555e393dc228fb8769b384344e9a27b77c"
         assertEquals(expectedValue, signedMessage)
 

quartz/src/androidHostTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.android.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz
+
+actual class TestResourceLoader actual constructor() {
+    actual fun loadString(file: String): String {
+        TODO("Not yet implemented")
+    }
+}

quartz/src/androidMain/kotlin/com/vitorpamplona/quartz/nip55AndroidSigner/SignString.kt

@@ -20,7 +20,7 @@
  */
 package com.vitorpamplona.quartz.nip55AndroidSigner
 
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.utils.RandomInstance
 import com.vitorpamplona.quartz.utils.sha256.sha256
 
@@ -28,4 +28,4 @@ fun signString(
     message: String,
     privKey: ByteArray,
     nonce: ByteArray = RandomInstance.bytes(32),
-): ByteArray = Nip01.sign(sha256(message.toByteArray()), privKey, nonce)
+): ByteArray = Nip01Crypto.sign(sha256(message.toByteArray()), privKey, nonce)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/interactiveStories/InteractiveStoryReadingStateEvent.kt

@@ -28,7 +28,7 @@ import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.core.builder
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
@@ -83,17 +83,16 @@ class InteractiveStoryReadingStateEvent(
 
         fun update(
             base: InteractiveStoryReadingStateEvent,
-            currentScene: InteractiveStoryBaseEvent,
-            currentSceneRelay: NormalizedRelayUrl?,
+            currentScene: EventHintBundle<InteractiveStoryBaseEvent>,
             createdAt: Long = TimeUtils.now(),
         ): EventTemplate<InteractiveStoryReadingStateEvent> {
             val rootTag = base.dTag()
-            val sceneTag = currentScene.aTag(currentSceneRelay)
+            val sceneTag = ATag(currentScene.event.address(), currentScene.relay)
 
             val status =
                 if (rootTag == sceneTag.toTag()) {
                     ReadStatusTag.STATUS.NEW
-                } else if (currentScene.options().isEmpty()) {
+                } else if (currentScene.event.options().isEmpty()) {
                     ReadStatusTag.STATUS.DONE
                 } else {
                     ReadStatusTag.STATUS.READING
@@ -109,34 +108,32 @@ class InteractiveStoryReadingStateEvent(
         }
 
         fun build(
-            root: InteractiveStoryBaseEvent,
-            rootRelay: NormalizedRelayUrl?,
-            currentScene: InteractiveStoryBaseEvent,
-            currentSceneRelay: NormalizedRelayUrl?,
+            root: EventHintBundle<InteractiveStoryBaseEvent>,
+            currentScene: EventHintBundle<InteractiveStoryBaseEvent>,
             createdAt: Long = TimeUtils.now(),
             initializer: TagArrayBuilder<InteractiveStoryReadingStateEvent>.() -> Unit = {},
         ) = eventTemplate(KIND, "", createdAt) {
-            val rootTag = root.aTag(rootRelay)
-            val sceneTag = currentScene.aTag(currentSceneRelay)
+            val rootTag = ATag(root.event.address(), root.relay)
+            val sceneTag = ATag(currentScene.event.address(), currentScene.relay)
             val status =
                 if (rootTag == sceneTag) {
                     ReadStatusTag.STATUS.NEW
-                } else if (currentScene.options().isEmpty()) {
+                } else if (currentScene.event.options().isEmpty()) {
                     ReadStatusTag.STATUS.DONE
                 } else {
                     ReadStatusTag.STATUS.READING
                 }
 
             dTag(rootTag.toTag())
-            alt(root.title()?.let { ALT2 + it } ?: ALT1)
+            alt(root.event.title()?.let { ALT2 + it } ?: ALT1)
 
             rootScene(rootTag)
             currentScene(sceneTag)
             status(status)
 
-            root.title()?.let { storyTitle(it) }
-            root.summary()?.let { storyImage(it) }
-            root.image()?.let { storySummary(it) }
+            root.event.title()?.let { storyTitle(it) }
+            root.event.summary()?.let { storyImage(it) }
+            root.event.image()?.let { storySummary(it) }
 
             initializer()
         }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/experimental/nipsOnNostr/NipTextEvent.kt

@@ -32,7 +32,6 @@ import com.vitorpamplona.quartz.nip01Core.hints.AddressHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
@@ -71,8 +70,6 @@ class NipTextEvent(
 
     override fun dTag() = tags.dTag()
 
-    override fun aTag(relayHint: NormalizedRelayUrl?) = ATag(kind, pubKey, dTag(), relayHint)
-
     override fun address() = Address(kind, pubKey, dTag())
 
     override fun addressTag() = Address.assemble(kind, pubKey, dTag())

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/core/AddressableEvent.kt

@@ -21,15 +21,11 @@
 package com.vitorpamplona.quartz.nip01Core.core
 
 import androidx.compose.runtime.Immutable
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
-import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 
 @Immutable
 interface AddressableEvent : IEvent {
     fun dTag(): String
 
-    fun aTag(relayHint: NormalizedRelayUrl? = null): ATag
-
     fun address(): Address
 
     fun addressTag(): String

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/core/BaseAddressableEvent.kt

@@ -21,8 +21,6 @@
 package com.vitorpamplona.quartz.nip01Core.core
 
 import androidx.compose.runtime.Immutable
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
-import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
 
 @Immutable
@@ -38,8 +36,6 @@ open class BaseAddressableEvent(
     AddressableEvent {
     override fun dTag() = tags.dTag()
 
-    override fun aTag(relayHint: NormalizedRelayUrl?) = ATag(kind, pubKey, dTag(), relayHint)
-
     override fun address() = Address(kind, pubKey, dTag())
 
     /**

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/core/BaseReplaceableEvent.kt

@@ -21,8 +21,6 @@
 package com.vitorpamplona.quartz.nip01Core.core
 
 import androidx.compose.runtime.Immutable
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
-import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 
 @Immutable
 open class BaseReplaceableEvent(
@@ -33,11 +31,10 @@ open class BaseReplaceableEvent(
     tags: TagArray,
     content: String,
     sig: HexKey,
-) : BaseAddressableEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+) : Event(id, pubKey, createdAt, kind, tags, content, sig),
+    AddressableEvent {
     override fun dTag() = FIXED_D_TAG
 
-    override fun aTag(relayHint: NormalizedRelayUrl?) = ATag(kind, pubKey, FIXED_D_TAG, relayHint)
-
     override fun address(): Address = Address(kind, pubKey, dTag())
 
     /**

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventAssembler.kt

@@ -26,29 +26,27 @@ import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.utils.EventFactory
 import com.vitorpamplona.quartz.utils.RandomInstance
 
-class EventAssembler {
-    companion object {
-        fun <T : Event> hashAndSign(
-            pubKey: HexKey,
-            createdAt: Long,
-            kind: Int,
-            tags: Array<Array<String>>,
-            content: String,
-            privKey: ByteArray,
-            nonce: ByteArray? = RandomInstance.bytes(32),
-        ): T {
-            val id = EventHasher.hashIdBytes(pubKey, createdAt, kind, tags, content)
-            val sig = Nip01.sign(id, privKey, nonce).toHexKey()
+object EventAssembler {
+    fun <T : Event> hashAndSign(
+        pubKey: HexKey,
+        createdAt: Long,
+        kind: Int,
+        tags: Array<Array<String>>,
+        content: String,
+        privKey: ByteArray,
+        nonce: ByteArray? = RandomInstance.bytes(32),
+    ): T {
+        val id = EventHasher.hashIdBytes(pubKey, createdAt, kind, tags, content)
+        val sig = Nip01Crypto.sign(id, privKey, nonce).toHexKey()
 
-            return EventFactory.create(
-                id.toHexKey(),
-                pubKey,
-                createdAt,
-                kind,
-                tags,
-                content,
-                sig,
-            )
-        }
+        return EventFactory.create(
+            id.toHexKey(),
+            pubKey,
+            createdAt,
+            kind,
+            tags,
+            content,
+            sig,
+        )
     }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventExt.kt

@@ -33,7 +33,7 @@ fun Event.verifyId(): Boolean {
 
 fun Event.verifySignature(): Boolean {
     if (id.isEmpty() || sig.isEmpty()) return false
-    return Nip01.verify(Hex.decode(sig), Hex.decode(id), Hex.decode(pubKey))
+    return Nip01Crypto.verify(Hex.decode(sig), Hex.decode(id), Hex.decode(pubKey))
 }
 
 /** Checks if the ID is correct and then if the pubKey's secret key signed the event. */

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventHasher.kt

@@ -24,33 +24,29 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.utils.sha256.sha256
 
-class EventHasher {
-    companion object {
-        fun hashIdBytes(
-            pubKey: HexKey,
-            createdAt: Long,
-            kind: Int,
-            tags: Array<Array<String>>,
-            content: String,
-        ): ByteArray = sha256(EventHasherSerializer.fastMakeJsonForId(pubKey, createdAt, kind, tags, content))
+object EventHasher {
+    fun hashIdBytes(
+        pubKey: HexKey,
+        createdAt: Long,
+        kind: Int,
+        tags: Array<Array<String>>,
+        content: String,
+    ): ByteArray = sha256(EventHasherSerializer.fastMakeJsonForId(pubKey, createdAt, kind, tags, content))
 
-        fun hashId(serializedJsonAsBytes: ByteArray): String = sha256(serializedJsonAsBytes).toHexKey()
+    fun hashId(
+        pubKey: HexKey,
+        createdAt: Long,
+        kind: Int,
+        tags: Array<Array<String>>,
+        content: String,
+    ): String = hashIdBytes(pubKey, createdAt, kind, tags, content).toHexKey()
 
-        fun hashId(
-            pubKey: HexKey,
-            createdAt: Long,
-            kind: Int,
-            tags: Array<Array<String>>,
-            content: String,
-        ): String = hashIdBytes(pubKey, createdAt, kind, tags, content).toHexKey()
-
-        fun hashIdCheck(
-            id: HexKey,
-            pubKey: HexKey,
-            createdAt: Long,
-            kind: Int,
-            tags: Array<Array<String>>,
-            content: String,
-        ): Boolean = EventHasherSerializer.makeJsonForIdHashAndCheck(id, pubKey, createdAt, kind, tags, content)
-    }
+    fun hashIdCheck(
+        id: HexKey,
+        pubKey: HexKey,
+        createdAt: Long,
+        kind: Int,
+        tags: Array<Array<String>>,
+        content: String,
+    ): Boolean = EventHasherSerializer.makeJsonForIdHashAndCheck(id, pubKey, createdAt, kind, tags, content)
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/KeyPair.kt

@@ -34,8 +34,8 @@ class KeyPair(
         if (privKey == null) {
             if (pubKey == null) {
                 // create new, random keys
-                this.privKey = Nip01.privKeyCreate()
-                this.pubKey = Nip01.pubKeyCreate(this.privKey)
+                this.privKey = Nip01Crypto.privKeyCreate()
+                this.pubKey = Nip01Crypto.pubKeyCreate(this.privKey)
             } else {
                 // this is a read-only account
                 check(pubKey.size == 32)
@@ -46,7 +46,7 @@ class KeyPair(
             // as private key is provided, ignore the public key and set keys according to private key
             this.privKey = privKey
             if (pubKey == null || forceReplacePubkey) {
-                this.pubKey = Nip01.pubKeyCreate(privKey)
+                this.pubKey = Nip01Crypto.pubKeyCreate(privKey)
             } else {
                 this.pubKey = pubKey
             }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/Nip01Crypto.kt

@@ -23,7 +23,7 @@ package com.vitorpamplona.quartz.nip01Core.crypto
 import com.vitorpamplona.quartz.utils.RandomInstance
 import com.vitorpamplona.quartz.utils.Secp256k1Instance
 
-object Nip01 {
+object Nip01Crypto {
     fun privKeyCreate() = RandomInstance.bytes(32)
 
     fun pubKeyCreate(privKey: ByteArray) = Secp256k1Instance.compressedPubKeyFor(privKey).copyOfRange(1, 33)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/tags/aTag/TagArrayBuilderExt.kt

@@ -20,11 +20,20 @@
  */
 package com.vitorpamplona.quartz.nip01Core.tags.aTag
 
+import com.vitorpamplona.quartz.nip01Core.core.Address
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 
 fun <T : Event> TagArrayBuilder<T>.aTag(tag: ATag) = add(tag.toATagArray())
 
+fun <T : Event> TagArrayBuilder<T>.aTag(
+    address: Address,
+    relayHint: NormalizedRelayUrl? = null,
+) = add(ATag.assemble(address, relayHint))
+
 fun <T : Event> TagArrayBuilder<T>.aTags(tag: List<ATag>) = addAll(tag.map { it.toATagArray() })
 
 fun <T : Event> TagArrayBuilder<T>.removeATag(tag: ATag) = this.removeIf(ATag::isSameAddress, tag.toATagArray())
+
+fun <T : Event> TagArrayBuilder<T>.removeAddress(address: Address) = this.removeIf(ATag::isSameAddress, ATag.assemble(address, null))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip09Deletions/DeletionEvent.kt

@@ -89,7 +89,7 @@ class DeletionEvent(
             deleteEvents.forEach {
                 eTag(ETag(it.id))
                 if (it is AddressableEvent) {
-                    aTag(it.aTag())
+                    aTag(it.address())
                 }
             }
 
@@ -108,7 +108,7 @@ class DeletionEvent(
 
             deleteEvents.forEach {
                 if (it is AddressableEvent) {
-                    aTag(it.aTag())
+                    aTag(it.address())
                 }
             }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip18Reposts/GenericRepostEvent.kt

@@ -26,9 +26,9 @@ import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.hints.AddressHintProvider
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
@@ -38,7 +38,6 @@ import com.vitorpamplona.quartz.nip01Core.tags.events.eTag
 import com.vitorpamplona.quartz.nip01Core.tags.kinds.kind
 import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
 import com.vitorpamplona.quartz.nip01Core.tags.people.pTag
-import com.vitorpamplona.quartz.nip31Alts.AltTag
 import com.vitorpamplona.quartz.nip31Alts.alt
 import com.vitorpamplona.quartz.utils.TimeUtils
 import com.vitorpamplona.quartz.utils.lastNotNullOfOrNull
@@ -93,45 +92,28 @@ class GenericRepostEvent(
         const val ALT = "Generic repost"
 
         fun build(
-            boostedPost: Event,
-            eventSourceRelay: NormalizedRelayUrl?,
-            authorHomeRelay: NormalizedRelayUrl?,
+            eventHint: EventHintBundle<Event>,
             createdAt: Long = TimeUtils.now(),
             initializer: TagArrayBuilder<GenericRepostEvent>.() -> Unit = {},
-        ) = eventTemplate(KIND, boostedPost.toJson(), createdAt) {
+        ) = eventTemplate(KIND, eventHint.event.toJson(), createdAt) {
+            val boostedPost = eventHint.event
+
             alt(ALT)
 
             kind(boostedPost.kind)
-            pTag(PTag(boostedPost.pubKey, authorHomeRelay))
-            eTag(ETag(boostedPost.id, eventSourceRelay, boostedPost.pubKey))
+            pTag(PTag(boostedPost.pubKey, eventHint.authorHomeRelay))
+            eTag(ETag(boostedPost.id, eventHint.relay, boostedPost.pubKey))
             if (boostedPost is AddressableEvent) {
-                aTag(boostedPost.aTag(eventSourceRelay))
+                aTag(boostedPost.address(), eventHint.relay)
             }
 
             initializer()
         }
 
         suspend fun create(
-            boostedPost: Event,
+            eventHint: EventHintBundle<Event>,
             signer: NostrSigner,
             createdAt: Long = TimeUtils.now(),
-        ): GenericRepostEvent {
-            val content = boostedPost.toJson()
-
-            val tags =
-                mutableListOf(
-                    arrayOf("e", boostedPost.id),
-                    arrayOf("p", boostedPost.pubKey),
-                )
-
-            if (boostedPost is AddressableEvent) {
-                tags.add(arrayOf("a", boostedPost.aTag().toTag()))
-            }
-
-            tags.add(arrayOf("k", "${boostedPost.kind}"))
-            tags.add(AltTag.assemble(ALT))
-
-            return signer.sign(createdAt, KIND, tags.toTypedArray(), content)
-        }
+        ): GenericRepostEvent = signer.sign(build(eventHint, createdAt))
     }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip18Reposts/RepostEvent.kt

@@ -26,9 +26,10 @@ import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.hints.AddressHintProvider
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.aTag
@@ -82,7 +83,7 @@ class RepostEvent(
     fun containedPost() =
         try {
             fromJson(content)
-        } catch (e: Exception) {
+        } catch (_: Exception) {
             null
         }
 
@@ -91,22 +92,28 @@ class RepostEvent(
         const val ALT = "Repost event"
 
         fun build(
-            boostedPost: Event,
-            eventSourceRelay: NormalizedRelayUrl?,
-            authorHomeRelay: NormalizedRelayUrl?,
+            eventHint: EventHintBundle<Event>,
             createdAt: Long = TimeUtils.now(),
             initializer: TagArrayBuilder<RepostEvent>.() -> Unit = {},
-        ) = eventTemplate(KIND, boostedPost.toJson(), createdAt) {
+        ) = eventTemplate(KIND, eventHint.event.toJson(), createdAt) {
+            val boostedPost = eventHint.event
+
             alt(ALT)
 
-            pTag(PTag(boostedPost.pubKey, authorHomeRelay))
-            eTag(ETag(boostedPost.id, eventSourceRelay, boostedPost.pubKey))
+            pTag(PTag(boostedPost.pubKey, eventHint.authorHomeRelay))
+            eTag(ETag(boostedPost.id, eventHint.relay, boostedPost.pubKey))
             if (boostedPost is AddressableEvent) {
-                aTag(boostedPost.aTag(eventSourceRelay))
+                aTag(boostedPost.address(), eventHint.relay)
             }
             kind(boostedPost.kind)
 
             initializer()
         }
+
+        suspend fun create(
+            eventHint: EventHintBundle<Event>,
+            signer: NostrSigner,
+            createdAt: Long = TimeUtils.now(),
+        ): RepostEvent = signer.sign(build(eventHint, createdAt))
     }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip19Bech32/Nip19Parser.kt

@@ -24,7 +24,6 @@ import androidx.compose.runtime.Immutable
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
 import com.vitorpamplona.quartz.nip19Bech32.bech32.bechToBytes
 import com.vitorpamplona.quartz.nip19Bech32.entities.Entity
 import com.vitorpamplona.quartz.nip19Bech32.entities.NAddress
@@ -175,7 +174,7 @@ object Nip19Parser {
 
 fun decodePublicKey(key: String): ByteArray =
     when (val parsed = Nip19Parser.uriToRoute(key)?.entity) {
-        is NSec -> Nip01.pubKeyCreate(parsed.hex.hexToByteArray())
+        is NSec -> parsed.toPubKey()
         is NPub -> parsed.hex.hexToByteArray()
         is NProfile -> parsed.hex.hexToByteArray()
         else -> Hex.decode(key) // crashes on purpose
@@ -202,7 +201,7 @@ fun decodePrivateKeyAsHexOrNull(key: String): HexKey? =
 fun decodePublicKeyAsHexOrNull(key: String): HexKey? =
     try {
         when (val parsed = Nip19Parser.uriToRoute(key)?.entity) {
-            is NSec -> Nip01.pubKeyCreate(parsed.hex.hexToByteArray()).toHexKey()
+            is NSec -> parsed.toPubKeyHex()
             is NPub -> parsed.hex
             is NProfile -> parsed.hex
             is NNote -> null

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip19Bech32/entities/NSec.kt

@@ -23,13 +23,15 @@ package com.vitorpamplona.quartz.nip19Bech32.entities
 import androidx.compose.runtime.Immutable
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 
 @Immutable
 data class NSec(
     val hex: String,
 ) : Entity {
-    fun toPubKeyHex() = Nip01.pubKeyCreate(hex.hexToByteArray()).toHexKey()
+    fun toPubKey() = Nip01Crypto.pubKeyCreate(hex.hexToByteArray())
+
+    fun toPubKeyHex() = toPubKey().toHexKey()
 
     companion object {
         fun parse(bytes: ByteArray): NSec? {

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip23LongContent/LongTextNoteEvent.kt

@@ -31,9 +31,7 @@ import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.PubKeyHint
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
-import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
 import com.vitorpamplona.quartz.nip01Core.tags.hashtags.hashtags
 import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
@@ -119,8 +117,6 @@ class LongTextNoteEvent(
 
     override fun dTag() = tags.dTag()
 
-    override fun aTag(relayHint: NormalizedRelayUrl?) = ATag(kind, pubKey, dTag(), relayHint)
-
     override fun address() = Address(kind, pubKey, dTag())
 
     override fun addressTag() = Address.assemble(kind, pubKey, dTag())

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip25Reactions/ReactionEvent.kt

@@ -91,7 +91,7 @@ class ReactionEvent(
         ) = eventTemplate<ReactionEvent>(KIND, reaction, createdAt) {
             eTag(reactedTo.toETag())
             if (reactedTo.event is AddressableEvent) {
-                aTag(reactedTo.event.aTag(reactedTo.relay))
+                aTag(reactedTo.event.address(), reactedTo.relay)
             }
             pTag(reactedTo.event.pubKey, reactedTo.relay)
             kind(reactedTo.event.kind)
@@ -104,7 +104,7 @@ class ReactionEvent(
         ) = eventTemplate<ReactionEvent>(KIND, reaction.toContentEncode(), createdAt) {
             eTag(reactedTo.toETag())
             if (reactedTo.event is AddressableEvent) {
-                aTag(reactedTo.event.aTag(reactedTo.relay))
+                aTag(reactedTo.event.address(), reactedTo.relay)
             }
             pTag(reactedTo.event.pubKey, reactedTo.relay)
             kind(reactedTo.event.kind)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip30CustomEmoji/selection/EmojiPackSelectionEvent.kt

@@ -78,7 +78,7 @@ class EmojiPackSelectionEvent(
             createdAt: Long = TimeUtils.now(),
             updater: TagArrayBuilder<EmojiPackSelectionEvent>.() -> Unit = {},
         ) = eventUpdate(currentSelection, createdAt) {
-            removePack(packToRemove.aTag(null))
+            removePack(packToRemove.address())
             updater()
         }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip30CustomEmoji/selection/TagArrayBuilderExt.kt

@@ -20,14 +20,15 @@
  */
 package com.vitorpamplona.quartz.nip30CustomEmoji.selection
 
+import com.vitorpamplona.quartz.nip01Core.core.Address
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.aTag
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.aTags
-import com.vitorpamplona.quartz.nip01Core.tags.aTag.removeATag
+import com.vitorpamplona.quartz.nip01Core.tags.aTag.removeAddress
 
 fun TagArrayBuilder<EmojiPackSelectionEvent>.pack(tag: ATag) = aTag(tag)
 
 fun TagArrayBuilder<EmojiPackSelectionEvent>.packs(tags: List<ATag>) = aTags(tags)
 
-fun TagArrayBuilder<EmojiPackSelectionEvent>.removePack(tag: ATag) = removeATag(tag)
+fun TagArrayBuilder<EmojiPackSelectionEvent>.removePack(address: Address) = removeAddress(address)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip54Wiki/WikiNoteEvent.kt

@@ -34,7 +34,6 @@ import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.PubKeyHint
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
 import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
@@ -129,8 +128,6 @@ class WikiNoteEvent(
 
     override fun dTag() = tags.dTag()
 
-    override fun aTag(relayHint: NormalizedRelayUrl?) = ATag(kind, pubKey, dTag(), relayHint)
-
     override fun address() = Address(kind, pubKey, dTag())
 
     override fun addressTag() = Address.assemble(kind, pubKey, dTag())

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip57Zaps/LnZapRequestEvent.kt

@@ -104,7 +104,7 @@ class LnZapRequestEvent(
                     AltTag.assemble(ALT),
                 )
             if (zappedEvent is AddressableEvent) {
-                tags = tags + listOf(arrayOf("a", zappedEvent.aTag().toTag()))
+                tags = tags + listOf(ATag.assemble(zappedEvent.address(), null))
             }
             if (pollOption != null && pollOption >= 0) {
                 tags = tags + listOf(arrayOf(PollOptionTag.TAG_NAME, pollOption.toString()))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip57Zaps/PrivateZapRequestBuilder.kt

@@ -25,7 +25,7 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
-import com.vitorpamplona.quartz.nip01Core.crypto.Nip01
+import com.vitorpamplona.quartz.nip01Core.crypto.Nip01Crypto
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSignerSync
 import com.vitorpamplona.quartz.nip01Core.signers.SignerExceptions
 
@@ -106,7 +106,7 @@ class PrivateZapRequestBuilder {
 
                 try {
                     if (altPubkeyToUse != null) {
-                        val altPubKeyFromPrivate = Nip01.pubKeyCreate(myPrivateKeyForThisEvent).toHexKey()
+                        val altPubKeyFromPrivate = Nip01Crypto.pubKeyCreate(myPrivateKeyForThisEvent).toHexKey()
 
                         if (altPubKeyFromPrivate == event.pubKey) {
                             // the sender is logged in.

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.kt

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+
+/**
+ * Platform-agnostic chess engine interface for move validation and generation
+ * Implemented using expect/actual for JVM/Android platforms
+ */
+expect class ChessEngine() {
+    /**
+     * Get the current position as FEN string
+     */
+    fun getFen(): String
+
+    /**
+     * Load a position from FEN notation
+     */
+    fun loadFen(fen: String)
+
+    /**
+     * Reset to starting position
+     */
+    fun reset()
+
+    /**
+     * Make a move using Standard Algebraic Notation (SAN)
+     * @param san Move in SAN format (e.g., "Nf3", "e4", "O-O")
+     * @return MoveResult with success status and resulting position
+     */
+    fun makeMove(san: String): MoveResult
+
+    /**
+     * Make a move from source to destination square
+     * @param from Source square in algebraic notation (e.g., "e2")
+     * @param to Destination square in algebraic notation (e.g., "e4")
+     * @param promotion Optional promotion piece type for pawn promotion
+     * @return MoveResult with success status and resulting position
+     */
+    fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType? = null,
+    ): MoveResult
+
+    /**
+     * Get all legal moves from the current position
+     * @return List of legal moves in SAN notation
+     */
+    fun getLegalMoves(): List<String>
+
+    /**
+     * Get all legal moves for a specific square
+     * @param square Square in algebraic notation (e.g., "e2")
+     * @return List of destination squares that are legal
+     */
+    fun getLegalMovesFrom(square: String): List<String>
+
+    /**
+     * Check if a move is legal in the current position
+     * @param san Move in SAN format
+     * @return true if the move is legal
+     */
+    fun isLegalMove(san: String): Boolean
+
+    /**
+     * Check if a move from-to is legal
+     */
+    fun isLegalMove(
+        from: String,
+        to: String,
+        promotion: PieceType? = null,
+    ): Boolean
+
+    /**
+     * Check if current position is checkmate
+     */
+    fun isCheckmate(): Boolean
+
+    /**
+     * Check if current position is stalemate
+     */
+    fun isStalemate(): Boolean
+
+    /**
+     * Check if current position is in check
+     */
+    fun isInCheck(): Boolean
+
+    /**
+     * Undo the last move
+     */
+    fun undoMove()
+
+    /**
+     * Get the current position as ChessPosition
+     */
+    fun getPosition(): ChessPosition
+
+    /**
+     * Get side to move
+     */
+    fun getSideToMove(): Color
+
+    /**
+     * Get move history in SAN notation
+     */
+    fun getMoveHistory(): List<String>
+}
+
+/**
+ * Result of attempting a chess move
+ */
+@Immutable
+data class MoveResult(
+    val success: Boolean,
+    val san: String? = null, // Move in SAN notation if successful
+    val position: ChessPosition? = null, // Resulting position if successful
+    val error: String? = null, // Error message if unsuccessful
+)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessGame.kt

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+
+/**
+ * Represents a complete chess game parsed from PGN
+ * Per NIP-64, content must be valid PGN format
+ */
+@Immutable
+data class ChessGame(
+    val metadata: Map<String, String>,
+    val moves: List<ChessMove>,
+    val positions: List<ChessPosition>,
+    val result: GameResult,
+) {
+    init {
+        require(positions.isNotEmpty()) { "Game must have at least starting position" }
+        require(positions.size == moves.size + 1) { "Position count must be moves + 1" }
+    }
+
+    /**
+     * Standard PGN tag accessors
+     */
+    val event: String? get() = metadata["Event"]
+    val site: String? get() = metadata["Site"]
+    val date: String? get() = metadata["Date"]
+    val round: String? get() = metadata["Round"]
+    val white: String? get() = metadata["White"]
+    val black: String? get() = metadata["Black"]
+
+    /**
+     * Get position after move N (0 = starting position)
+     */
+    fun positionAt(moveIndex: Int): ChessPosition = positions.getOrElse(moveIndex) { positions.last() }
+
+    /**
+     * Check if game has required metadata
+     */
+    fun hasRequiredMetadata(): Boolean =
+        metadata.containsKey("Event") &&
+            metadata.containsKey("Site") &&
+            metadata.containsKey("Date") &&
+            metadata.containsKey("Round") &&
+            metadata.containsKey("White") &&
+            metadata.containsKey("Black") &&
+            metadata.containsKey("Result")
+}
+
+/**
+ * Game result per PGN specification
+ */
+enum class GameResult(
+    val notation: String,
+) {
+    WHITE_WINS("1-0"),
+    BLACK_WINS("0-1"),
+    DRAW("1/2-1/2"),
+    IN_PROGRESS("*"),
+    ;
+
+    companion object {
+        fun parse(notation: String): GameResult = entries.find { it.notation == notation } ?: IN_PROGRESS
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessGameEvent.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * NIP-64: Chess Game Event
+ *
+ * Kind 64 events contain chess games in PGN (Portable Game Notation) format.
+ * Per NIP-64 specification:
+ * - Content must be valid PGN format (PGN-database)
+ * - Clients should accept "import format" (human-created, flexible)
+ * - Clients should publish in "export format" (machine-generated, strict)
+ * - Moves must comply with chess rules
+ * - Clients should display content as rendered chessboard
+ *
+ * @see <a href="https://github.com/nostr-protocol/nips/blob/master/64.md">NIP-64</a>
+ */
+@Immutable
+class ChessGameEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String, // PGN database format
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 64
+        const val ALT_DESCRIPTION = "Chess Game"
+
+        /**
+         * Create a chess game event from PGN content
+         * Per NIP-64, clients should publish in strict "export format"
+         *
+         * @param pgnContent Valid PGN format string
+         * @param altDescription Alt text for non-supporting clients (NIP-31)
+         * @param createdAt Event timestamp
+         * @param initializer Additional tag builder operations
+         */
+        fun build(
+            pgnContent: String,
+            altDescription: String = ALT_DESCRIPTION,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<ChessGameEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, pgnContent, createdAt) {
+            alt(altDescription)
+            initializer()
+        }
+    }
+
+    /**
+     * Get PGN content from event
+     */
+    fun pgn(): String = content
+
+    /**
+     * Get alt text for non-supporting clients (NIP-31)
+     */
+    fun altText(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "alt" }?.get(1)
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessGameNameGenerator.kt

@@ -0,0 +1,234 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import kotlin.random.Random
+
+/**
+ * Generates human-readable chess game names.
+ *
+ * Produces memorable names like "Bold Knight", "Swift Rook", etc.
+ */
+object ChessGameNameGenerator {
+    // Chess-themed adjectives
+    private val adjectives =
+        listOf(
+            "Bold",
+            "Swift",
+            "Cunning",
+            "Royal",
+            "Noble",
+            "Shadow",
+            "Silent",
+            "Golden",
+            "Silver",
+            "Iron",
+            "Fierce",
+            "Wise",
+            "Dark",
+            "Bright",
+            "Ancient",
+            "Brave",
+            "Mystic",
+            "Grand",
+            "Crimson",
+            "Azure",
+            "Ivory",
+            "Obsidian",
+            "Emerald",
+            "Sapphire",
+            "Ruby",
+            "Phantom",
+            "Eternal",
+            "Secret",
+            "Hidden",
+            "Blazing",
+        )
+
+    // Chess pieces and related nouns
+    private val chessNouns =
+        listOf(
+            "King",
+            "Queen",
+            "Rook",
+            "Bishop",
+            "Knight",
+            "Pawn",
+            "Castle",
+            "Crown",
+            "Throne",
+            "Gambit",
+            "Defense",
+            "Attack",
+            "Checkmate",
+            "Fortress",
+            "Tower",
+            "Endgame",
+            "Opening",
+            "Sacrifice",
+            "Pin",
+            "Fork",
+            "Strategy",
+            "Victory",
+            "Battle",
+            "Duel",
+            "Match",
+            "Challenge",
+        )
+
+    // Famous chess-related animals/themes
+    private val animals =
+        listOf(
+            "Dragon",
+            "Phoenix",
+            "Griffin",
+            "Eagle",
+            "Lion",
+            "Wolf",
+            "Tiger",
+            "Falcon",
+            "Hawk",
+            "Raven",
+            "Bear",
+            "Stallion",
+            "Serpent",
+            "Panther",
+            "Cobra",
+        )
+
+    /**
+     * Generate a random chess game name.
+     *
+     * @param includeNumber Whether to append a random number (1-99)
+     * @return A name like "Bold Knight" or "Swift Dragon 42"
+     */
+    fun generate(includeNumber: Boolean = false): String {
+        val adjective = adjectives.random()
+        val noun = if (Random.nextBoolean()) chessNouns.random() else animals.random()
+        val base = "$adjective $noun"
+
+        return if (includeNumber) {
+            val num = Random.nextInt(1, 100)
+            "$base $num"
+        } else {
+            base
+        }
+    }
+
+    /**
+     * Generate a name based on two player display names.
+     *
+     * Creates a name that incorporates elements from both players
+     * for a more personalized game name.
+     *
+     * @param playerName First player's display name (can be npub/pubkey)
+     * @param opponentName Second player's display name (can be npub/pubkey, or null for open challenge)
+     * @return A personalized game name
+     */
+    fun generateFromPlayers(
+        playerName: String?,
+        opponentName: String?,
+    ): String {
+        // Extract first letter or use adjective if name is a pubkey/npub
+        val p1Initial = extractInitial(playerName)
+        val p2Initial = opponentName?.let { extractInitial(it) }
+
+        // If we have good initials, use them in the name
+        val adjective =
+            if (p1Initial != null) {
+                // Try to find an adjective starting with that letter
+                adjectives.find { it.startsWith(p1Initial, ignoreCase = true) }
+                    ?: adjectives.random()
+            } else {
+                adjectives.random()
+            }
+
+        val noun =
+            if (p2Initial != null) {
+                // Try to find a noun starting with opponent's initial
+                (chessNouns + animals).find { it.startsWith(p2Initial, ignoreCase = true) }
+                    ?: if (Random.nextBoolean()) chessNouns.random() else animals.random()
+            } else {
+                // Open challenge - use "Challenge" or similar
+                listOf("Challenge", "Gambit", "Opening", "Battle", "Duel").random()
+            }
+
+        return "$adjective $noun"
+    }
+
+    /**
+     * Extract a usable initial from a name.
+     * Returns null if the name looks like a pubkey/npub.
+     */
+    private fun extractInitial(name: String?): Char? {
+        if (name.isNullOrBlank()) return null
+
+        // Skip if it looks like a hex pubkey or npub
+        if (name.length > 20 && name.all { it.isLetterOrDigit() }) return null
+        if (name.startsWith("npub") || name.startsWith("nprofile")) return null
+
+        // Get first letter of the display name
+        val firstChar = name.firstOrNull { it.isLetter() }
+        return firstChar?.uppercaseChar()
+    }
+
+    /**
+     * Generate a game ID that includes a readable component.
+     *
+     * @param timestamp Unix timestamp
+     * @return Game ID like "chess-1234567890-bold-knight"
+     */
+    fun generateGameId(timestamp: Long): String {
+        val name =
+            generate(includeNumber = false)
+                .lowercase()
+                .replace(" ", "-")
+        return "chess-$timestamp-$name"
+    }
+
+    /**
+     * Extract the human-readable name from a game ID.
+     *
+     * @param gameId Game ID like "chess-1234567890-bold-knight"
+     * @return Display name like "Bold Knight", or null if not a named game ID
+     */
+    fun extractDisplayName(gameId: String): String? {
+        // Pattern: chess-timestamp-name-parts
+        if (!gameId.startsWith("chess-")) return null
+
+        val parts = gameId.removePrefix("chess-").split("-")
+        if (parts.size < 2) return null
+
+        // First part is timestamp, rest is the name
+        val nameParts = parts.drop(1)
+        if (nameParts.isEmpty()) return null
+
+        // Check if it looks like a UUID (8 hex chars) - old format
+        if (nameParts.size == 1 && nameParts[0].length == 8 && nameParts[0].all { it.isLetterOrDigit() }) {
+            return null
+        }
+
+        // Convert to title case
+        return nameParts.joinToString(" ") { part ->
+            part.replaceFirstChar { it.uppercaseChar() }
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessMove.kt

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+
+/**
+ * Represents a single chess move in Standard Algebraic Notation (SAN)
+ * Per NIP-64, moves must comply with chess rules
+ */
+@Immutable
+data class ChessMove(
+    val san: String, // Standard Algebraic Notation, e.g., "Nf3", "e4", "O-O", "Qxe5+"
+    val moveNumber: Int, // Which move in the game (1-based)
+    val color: Color, // Who made the move
+    val piece: PieceType = PieceType.PAWN,
+    val fromSquare: String? = null, // Source square if known
+    val toSquare: String, // Destination square
+    val isCapture: Boolean = false,
+    val isCheck: Boolean = false,
+    val isCheckmate: Boolean = false,
+    val isCastling: Boolean = false,
+    val promotion: PieceType? = null,
+) {
+    override fun toString(): String = san
+}
+
+/**
+ * Chess piece types per standard notation
+ */
+enum class PieceType(
+    val symbol: Char,
+) {
+    KING('K'),
+    QUEEN('Q'),
+    ROOK('R'),
+    BISHOP('B'),
+    KNIGHT('N'),
+    PAWN('P'),
+    ;
+
+    companion object {
+        fun fromSymbol(c: Char): PieceType? = entries.find { it.symbol == c.uppercaseChar() }
+    }
+}
+
+/**
+ * Player color
+ */
+enum class Color {
+    WHITE,
+    BLACK,
+    ;
+
+    fun opposite(): Color =
+        when (this) {
+            WHITE -> BLACK
+            BLACK -> WHITE
+        }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessPosition.kt

@@ -0,0 +1,215 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+
+/**
+ * Represents a chess position using 8x8 board array
+ * Coordinates: file (a-h) = columns 0-7, rank (1-8) = rows 0-7
+ * a1 = [0,0], h1 = [7,0], a8 = [0,7], h8 = [7,7]
+ */
+@Immutable
+data class ChessPosition(
+    private val board: Array<Array<ChessPiece?>>,
+    val activeColor: Color,
+    val moveNumber: Int,
+    val castlingRights: CastlingRights = CastlingRights(),
+    val enPassantSquare: String? = null,
+    val halfMoveClock: Int = 0,
+) {
+    init {
+        require(board.size == 8) { "Board must be 8x8, got ${board.size} ranks" }
+        require(board.all { it.size == 8 }) { "Board must be 8x8, some ranks are not 8 files wide" }
+    }
+
+    /**
+     * Get piece at square using algebraic notation (e.g., "e4")
+     */
+    operator fun get(square: String): ChessPiece? {
+        val (file, rank) = parseSquare(square)
+        return board[rank][file]
+    }
+
+    /**
+     * Get piece at coordinates (file: 0-7, rank: 0-7)
+     */
+    fun pieceAt(
+        file: Int,
+        rank: Int,
+    ): ChessPiece? = board.getOrNull(rank)?.getOrNull(file)
+
+    /**
+     * Create new position with a piece moved
+     */
+    fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType? = null,
+    ): ChessPosition {
+        val (fromFile, fromRank) = parseSquare(from)
+        val (toFile, toRank) = parseSquare(to)
+
+        val newBoard = board.map { it.copyOf() }.toTypedArray()
+        val piece = newBoard[fromRank][fromFile] ?: throw IllegalArgumentException("No piece at $from")
+
+        // Handle promotion
+        val finalPiece =
+            if (promotion != null && piece.type == PieceType.PAWN) {
+                piece.copy(type = promotion)
+            } else {
+                piece
+            }
+
+        newBoard[toRank][toFile] = finalPiece
+        newBoard[fromRank][fromFile] = null
+
+        return copy(
+            board = newBoard,
+            activeColor = activeColor.opposite(),
+            moveNumber = if (activeColor == Color.BLACK) moveNumber + 1 else moveNumber,
+        )
+    }
+
+    /**
+     * Create new position with castling
+     */
+    fun makeCastlingMove(kingSide: Boolean): ChessPosition {
+        val rank = if (activeColor == Color.WHITE) 0 else 7
+        val newBoard = board.map { it.copyOf() }.toTypedArray()
+
+        if (kingSide) {
+            // King-side castling (O-O)
+            val king = newBoard[rank][4]
+            val rook = newBoard[rank][7]
+            newBoard[rank][6] = king
+            newBoard[rank][5] = rook
+            newBoard[rank][4] = null
+            newBoard[rank][7] = null
+        } else {
+            // Queen-side castling (O-O-O)
+            val king = newBoard[rank][4]
+            val rook = newBoard[rank][0]
+            newBoard[rank][2] = king
+            newBoard[rank][3] = rook
+            newBoard[rank][4] = null
+            newBoard[rank][0] = null
+        }
+
+        return copy(
+            board = newBoard,
+            activeColor = activeColor.opposite(),
+            moveNumber = if (activeColor == Color.BLACK) moveNumber + 1 else moveNumber,
+        )
+    }
+
+    private fun parseSquare(square: String): Pair<Int, Int> {
+        require(square.length == 2) { "Invalid square notation: $square" }
+        val file = square[0].lowercaseChar() - 'a' // 0-7
+        val rank = square[1] - '1' // 0-7
+        require(file in 0..7 && rank in 0..7) { "Square out of bounds: $square" }
+        return file to rank
+    }
+
+    companion object {
+        /**
+         * Standard starting position per FIDE rules
+         */
+        fun initial(): ChessPosition {
+            val board = Array(8) { Array<ChessPiece?>(8) { null } }
+
+            // White pieces (ranks 0-1)
+            board[0] =
+                arrayOf(
+                    ChessPiece(PieceType.ROOK, Color.WHITE),
+                    ChessPiece(PieceType.KNIGHT, Color.WHITE),
+                    ChessPiece(PieceType.BISHOP, Color.WHITE),
+                    ChessPiece(PieceType.QUEEN, Color.WHITE),
+                    ChessPiece(PieceType.KING, Color.WHITE),
+                    ChessPiece(PieceType.BISHOP, Color.WHITE),
+                    ChessPiece(PieceType.KNIGHT, Color.WHITE),
+                    ChessPiece(PieceType.ROOK, Color.WHITE),
+                )
+            board[1] = Array(8) { ChessPiece(PieceType.PAWN, Color.WHITE) }
+
+            // Black pieces (ranks 6-7)
+            board[6] = Array(8) { ChessPiece(PieceType.PAWN, Color.BLACK) }
+            board[7] =
+                arrayOf(
+                    ChessPiece(PieceType.ROOK, Color.BLACK),
+                    ChessPiece(PieceType.KNIGHT, Color.BLACK),
+                    ChessPiece(PieceType.BISHOP, Color.BLACK),
+                    ChessPiece(PieceType.QUEEN, Color.BLACK),
+                    ChessPiece(PieceType.KING, Color.BLACK),
+                    ChessPiece(PieceType.BISHOP, Color.BLACK),
+                    ChessPiece(PieceType.KNIGHT, Color.BLACK),
+                    ChessPiece(PieceType.ROOK, Color.BLACK),
+                )
+
+            return ChessPosition(
+                board = board,
+                activeColor = Color.WHITE,
+                moveNumber = 1,
+            )
+        }
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is ChessPosition) return false
+        return board.contentDeepEquals(other.board) &&
+            activeColor == other.activeColor &&
+            moveNumber == other.moveNumber &&
+            castlingRights == other.castlingRights &&
+            enPassantSquare == other.enPassantSquare &&
+            halfMoveClock == other.halfMoveClock
+    }
+
+    override fun hashCode(): Int {
+        var result = board.contentDeepHashCode()
+        result = 31 * result + activeColor.hashCode()
+        result = 31 * result + moveNumber
+        result = 31 * result + castlingRights.hashCode()
+        result = 31 * result + (enPassantSquare?.hashCode() ?: 0)
+        result = 31 * result + halfMoveClock
+        return result
+    }
+}
+
+/**
+ * Represents a chess piece
+ */
+@Immutable
+data class ChessPiece(
+    val type: PieceType,
+    val color: Color,
+)
+
+/**
+ * Castling availability
+ */
+@Immutable
+data class CastlingRights(
+    val whiteKingSide: Boolean = true,
+    val whiteQueenSide: Boolean = true,
+    val blackKingSide: Boolean = true,
+    val blackQueenSide: Boolean = true,
+)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessStateReconstructor.kt

@@ -0,0 +1,304 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+
+/**
+ * Deterministic chess state reconstruction from Jester protocol events.
+ *
+ * This is the single source of truth for converting a collection of Jester events
+ * into a consistent game state. Both Android and Desktop platforms must use this
+ * algorithm to ensure identical state from the same events.
+ *
+ * Jester Protocol Reconstruction:
+ * 1. Find start event (content.kind=0) → establishes startEventId, challenger color, players
+ * 2. Find move with longest history → this is the current state
+ * 3. Replay moves from history to build engine state
+ * 4. Check for result/termination in latest move → mark finished if present
+ *
+ * Key Jester differences:
+ * - No separate accept event (acceptance is implicit)
+ * - Full move history in every move event
+ * - Can reconstruct from any single move (has complete history)
+ * - startEventId is the game identifier (event ID of start event)
+ *
+ * Guarantees:
+ * - Same events always produce same state (deterministic)
+ * - Uses longest history for authoritative state
+ * - Invalid moves are skipped without error
+ */
+object ChessStateReconstructor {
+    /**
+     * Reconstruct game state from a collection of Jester events.
+     *
+     * @param events The collected Jester events for a single game
+     * @param viewerPubkey The pubkey of the user viewing the game (determines perspective)
+     * @return ReconstructionResult or error if reconstruction fails
+     */
+    fun reconstruct(
+        events: JesterGameEvents,
+        viewerPubkey: String,
+    ): ReconstructionResult {
+        // Step 1: Get start event (required for player info)
+        val startEvent =
+            events.startEvent
+                ?: return ReconstructionResult.Error("No start event found")
+
+        val startEventId = startEvent.id
+        val challengerPubkey = startEvent.pubKey
+        val challengerColor = startEvent.playerColor() ?: Color.WHITE
+        val challengedPubkey = startEvent.opponentPubkey()
+
+        // In Jester, we determine opponent from the p-tag or from move events
+        // For open challenges, we need to find who made the first move
+        val opponentFromMoves =
+            events.moves
+                .firstOrNull { it.pubKey != challengerPubkey }
+                ?.pubKey
+
+        val actualOpponent = challengedPubkey ?: opponentFromMoves
+
+        // Determine players based on challenger's color choice
+        val (whitePubkey, blackPubkey) =
+            if (challengerColor == Color.WHITE) {
+                challengerPubkey to actualOpponent
+            } else {
+                actualOpponent to challengerPubkey
+            }
+
+        // Determine viewer's role
+        val viewerRole =
+            when (viewerPubkey) {
+                whitePubkey -> ViewerRole.WHITE_PLAYER
+                blackPubkey -> ViewerRole.BLACK_PLAYER
+                else -> ViewerRole.SPECTATOR
+            }
+
+        val playerColor =
+            when (viewerRole) {
+                ViewerRole.WHITE_PLAYER -> Color.WHITE
+                ViewerRole.BLACK_PLAYER -> Color.BLACK
+                ViewerRole.SPECTATOR -> Color.WHITE // Spectators see from white's perspective
+            }
+
+        val opponentPubkey =
+            when (viewerRole) {
+                ViewerRole.WHITE_PLAYER -> blackPubkey ?: ""
+                ViewerRole.BLACK_PLAYER -> whitePubkey ?: ""
+                ViewerRole.SPECTATOR -> blackPubkey ?: "" // For spectators, "opponent" is black
+            }
+
+        // Check if game is pending (no moves yet AND viewer is the challenger)
+        // If viewer accepted someone else's challenge, the game is NOT pending
+        val isChallenger = viewerPubkey == startEvent.pubKey
+        val isPendingChallenge = events.moves.isEmpty() && isChallenger
+
+        // Step 2: Create engine and apply moves from the longest history
+        val engine = ChessEngine()
+        val latestMove = events.latestMove()
+        val history = latestMove?.history() ?: emptyList()
+
+        // Track applied moves
+        val appliedMoveNumbers = mutableSetOf<Int>()
+        var isDesynced = false
+
+        // Apply moves from history
+        for ((index, san) in history.withIndex()) {
+            val moveNumber = index + 1
+            val result = engine.makeMove(san)
+            if (result.success) {
+                appliedMoveNumbers.add(moveNumber)
+            } else {
+                // Move failed - game might be desynced
+                isDesynced = true
+                // Try to recover by loading the FEN from latest move if available
+                latestMove?.fen()?.let { fen ->
+                    engine.loadFen(fen)
+                }
+                break
+            }
+        }
+
+        // Verify final position matches if we have FEN
+        latestMove?.fen()?.let { expectedFen ->
+            val currentFen = engine.getFen()
+            if (!fenPositionsMatch(currentFen, expectedFen)) {
+                isDesynced = true
+                engine.loadFen(expectedFen)
+            }
+        }
+
+        // Step 3: Check game end status
+        val gameResult = latestMove?.result()
+        val gameStatus =
+            when {
+                gameResult != null -> {
+                    val result = parseGameResult(gameResult)
+                    GameStatus.Finished(result)
+                }
+
+                engine.isCheckmate() -> {
+                    val winner = engine.getSideToMove().opposite()
+                    GameStatus.Finished(
+                        if (winner == Color.WHITE) GameResult.WHITE_WINS else GameResult.BLACK_WINS,
+                    )
+                }
+
+                engine.isStalemate() -> {
+                    GameStatus.Finished(GameResult.DRAW)
+                }
+
+                else -> {
+                    GameStatus.InProgress
+                }
+            }
+
+        // Get the head event ID (for linking next move)
+        val headEventId = latestMove?.id ?: startEventId
+
+        // Build the reconstructed state
+        val state =
+            ReconstructedGameState(
+                startEventId = startEventId,
+                headEventId = headEventId,
+                whitePubkey = whitePubkey,
+                blackPubkey = blackPubkey,
+                viewerRole = viewerRole,
+                playerColor = playerColor,
+                opponentPubkey = opponentPubkey,
+                isPendingChallenge = isPendingChallenge,
+                currentPosition = engine.getPosition(),
+                moveHistory = engine.getMoveHistory(),
+                gameStatus = gameStatus,
+                isDesynced = isDesynced,
+                pendingDrawOffer = null, // Jester doesn't have explicit draw offers
+                appliedMoveNumbers = appliedMoveNumbers,
+                challengeCreatedAt = startEvent.createdAt,
+                timeControl = null, // Not supported in Jester
+            )
+
+        return ReconstructionResult.Success(state, engine)
+    }
+
+    /**
+     * Compare FEN positions, ignoring halfmove clock and fullmove number.
+     * This provides a more lenient comparison that focuses on the actual board state.
+     */
+    private fun fenPositionsMatch(
+        fen1: String,
+        fen2: String,
+    ): Boolean {
+        // FEN format: position activeColor castling enPassant halfmove fullmove
+        // Compare only first 4 parts (position, activeColor, castling, enPassant)
+        val parts1 = fen1.split(" ")
+        val parts2 = fen2.split(" ")
+
+        if (parts1.size < 4 || parts2.size < 4) {
+            return fen1 == fen2 // Fallback to exact match
+        }
+
+        return parts1[0] == parts2[0] && // Board position
+            parts1[1] == parts2[1] && // Active color
+            parts1[2] == parts2[2] && // Castling rights
+            parts1[3] == parts2[3] // En passant
+    }
+
+    private fun parseGameResult(result: String?): GameResult =
+        when (result) {
+            "1-0" -> GameResult.WHITE_WINS
+            "0-1" -> GameResult.BLACK_WINS
+            "1/2-1/2" -> GameResult.DRAW
+            else -> GameResult.IN_PROGRESS
+        }
+}
+
+/**
+ * The viewer's role in the game.
+ */
+enum class ViewerRole {
+    WHITE_PLAYER,
+    BLACK_PLAYER,
+    SPECTATOR,
+}
+
+/**
+ * Result of game state reconstruction.
+ */
+sealed class ReconstructionResult {
+    data class Success(
+        val state: ReconstructedGameState,
+        val engine: ChessEngine,
+    ) : ReconstructionResult()
+
+    data class Error(
+        val message: String,
+    ) : ReconstructionResult()
+
+    fun isSuccess(): Boolean = this is Success
+
+    fun getOrNull(): ReconstructedGameState? = (this as? Success)?.state
+
+    fun getEngineOrNull(): ChessEngine? = (this as? Success)?.engine
+}
+
+/**
+ * Reconstructed game state from Jester events.
+ * This is an immutable snapshot of the game at the time of reconstruction.
+ */
+@Immutable
+data class ReconstructedGameState(
+    /** The start event ID - this is the game identifier in Jester protocol */
+    val startEventId: String,
+    /** The current head event ID - used for linking the next move */
+    val headEventId: String,
+    val whitePubkey: String?,
+    val blackPubkey: String?,
+    val viewerRole: ViewerRole,
+    val playerColor: Color,
+    val opponentPubkey: String,
+    val isPendingChallenge: Boolean,
+    val currentPosition: ChessPosition,
+    val moveHistory: List<String>,
+    val gameStatus: GameStatus,
+    val isDesynced: Boolean,
+    val pendingDrawOffer: String?,
+    val appliedMoveNumbers: Set<Int>,
+    val challengeCreatedAt: Long,
+    val timeControl: String?,
+) {
+    /** Legacy alias for startEventId */
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+
+    fun isPlayerTurn(): Boolean =
+        when (viewerRole) {
+            ViewerRole.SPECTATOR -> false
+            ViewerRole.WHITE_PLAYER -> currentPosition.activeColor == Color.WHITE
+            ViewerRole.BLACK_PLAYER -> currentPosition.activeColor == Color.BLACK
+        }
+
+    fun isFinished(): Boolean = gameStatus is GameStatus.Finished
+
+    fun hasOpponentDrawOffer(playerPubkey: String): Boolean = pendingDrawOffer != null && pendingDrawOffer != playerPubkey
+
+    fun hasOurDrawOffer(playerPubkey: String): Boolean = pendingDrawOffer == playerPubkey
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/JesterEvents.kt

@@ -0,0 +1,382 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.utils.TimeUtils
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+
+/**
+ * Jester Protocol Implementation
+ *
+ * Compatible with jesterui (https://github.com/jesterui/jesterui)
+ *
+ * Key differences from previous implementation:
+ * - Single event kind (30) for all chess messages
+ * - Content is JSON with: version, kind, fen, move, history, nonce
+ * - Event linking via e-tags: [startId] or [startId, headId]
+ * - Full move history included in every move event
+ *
+ * Content kind values:
+ * - 0: Game start (challenge)
+ * - 1: Move
+ * - 2: Chat (not implemented)
+ *
+ * Reference: https://github.com/jesterui/jesterui/blob/devel/FLOW.md
+ */
+object JesterProtocol {
+    /** Jester uses kind 30 for all chess events */
+    const val KIND = 30
+
+    /** SHA256 of starting FEN position - used as reference for game discovery */
+    const val START_POSITION_HASH = "b1791d7fc9ae3d38966568c257ffb3a02cbf8394cdb4805bc70f64fc3c0b6879"
+
+    /** Standard starting FEN */
+    const val FEN_START = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+
+    /** Content kind for game start */
+    const val CONTENT_KIND_START = 0
+
+    /** Content kind for move */
+    const val CONTENT_KIND_MOVE = 1
+
+    /** Content kind for chat */
+    const val CONTENT_KIND_CHAT = 2
+}
+
+/**
+ * JSON content structure for Jester events
+ */
+@Serializable
+data class JesterContent(
+    val version: String = "0",
+    val kind: Int,
+    val fen: String = JesterProtocol.FEN_START,
+    val move: String? = null,
+    val history: List<String> = emptyList(),
+    val nonce: String? = null,
+    // Extended fields for Amethyst (backward compatible - jesterui ignores unknown fields)
+    val playerColor: String? = null, // "white" or "black" - challenger's color choice
+    val result: String? = null, // "1-0", "0-1", "1/2-1/2" for game end
+    val termination: String? = null, // "checkmate", "resignation", "draw_agreement", etc.
+)
+
+private val json =
+    Json {
+        ignoreUnknownKeys = true
+        encodeDefaults = false
+    }
+
+/**
+ * Jester Chess Event (Kind 30)
+ *
+ * Unified event class for all Jester chess messages.
+ * The content.kind field determines the event type:
+ * - 0: Game start/challenge
+ * - 1: Move
+ * - 2: Chat
+ */
+@Immutable
+class JesterEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, JesterProtocol.KIND, tags, content, sig) {
+    private val parsedContent: JesterContent? by lazy {
+        try {
+            json.decodeFromString<JesterContent>(content)
+        } catch (e: Exception) {
+            null
+        }
+    }
+
+    /** Get the content kind (0=start, 1=move, 2=chat) */
+    fun contentKind(): Int? = parsedContent?.kind
+
+    /** Check if this is a game start event */
+    fun isStartEvent(): Boolean = parsedContent?.kind == JesterProtocol.CONTENT_KIND_START
+
+    /** Check if this is a move event */
+    fun isMoveEvent(): Boolean = parsedContent?.kind == JesterProtocol.CONTENT_KIND_MOVE
+
+    /** Get the FEN position */
+    fun fen(): String? = parsedContent?.fen
+
+    /** Get the latest move (SAN notation) */
+    fun move(): String? = parsedContent?.move
+
+    /** Get the full move history */
+    fun history(): List<String> = parsedContent?.history ?: emptyList()
+
+    /** Get the nonce (for start events) */
+    fun nonce(): String? = parsedContent?.nonce
+
+    /** Get the player color choice (for start events) */
+    fun playerColor(): Color? =
+        parsedContent?.playerColor?.let {
+            if (it == "white") Color.WHITE else Color.BLACK
+        }
+
+    /** Get the game result (for end events) */
+    fun result(): String? = parsedContent?.result
+
+    /** Get the termination reason (for end events) */
+    fun termination(): String? = parsedContent?.termination
+
+    /** Get the start event ID (first e-tag) */
+    fun startEventId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "e" }?.get(1)
+
+    /** Get the head/parent move ID (second e-tag, for moves) */
+    fun headEventId(): String? = tags.filter { it.size >= 2 && it[0] == "e" }.getOrNull(1)?.get(1)
+
+    /** Get opponent pubkey (p-tag, for private games) */
+    fun opponentPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+
+    /** Get all e-tags */
+    fun eTags(): List<String> = tags.filter { it.size >= 2 && it[0] == "e" }.map { it[1] }
+
+    companion object {
+        const val KIND = JesterProtocol.KIND
+
+        /**
+         * Build a game start event (open challenge)
+         *
+         * @param playerColor Color the challenger wants to play
+         * @param nonce Unique nonce for this game
+         * @param createdAt Event timestamp
+         */
+        fun buildStart(
+            playerColor: Color,
+            nonce: String = generateNonce(),
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<JesterEvent>.() -> Unit = {},
+        ): EventTemplate<JesterEvent> {
+            val content =
+                JesterContent(
+                    kind = JesterProtocol.CONTENT_KIND_START,
+                    fen = JesterProtocol.FEN_START,
+                    history = emptyList(),
+                    nonce = nonce,
+                    playerColor = if (playerColor == Color.WHITE) "white" else "black",
+                )
+            return eventTemplate(KIND, json.encodeToString(content), createdAt) {
+                // Reference the standard start position for game discovery
+                add(arrayOf("e", JesterProtocol.START_POSITION_HASH))
+                initializer()
+            }
+        }
+
+        /**
+         * Build a private game start event (direct challenge)
+         *
+         * @param opponentPubkey Pubkey of the challenged player
+         * @param playerColor Color the challenger wants to play
+         * @param nonce Unique nonce for this game
+         * @param createdAt Event timestamp
+         */
+        fun buildPrivateStart(
+            opponentPubkey: String,
+            playerColor: Color,
+            nonce: String = generateNonce(),
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<JesterEvent>.() -> Unit = {},
+        ): EventTemplate<JesterEvent> {
+            val content =
+                JesterContent(
+                    kind = JesterProtocol.CONTENT_KIND_START,
+                    fen = JesterProtocol.FEN_START,
+                    history = emptyList(),
+                    nonce = nonce,
+                    playerColor = if (playerColor == Color.WHITE) "white" else "black",
+                )
+            return eventTemplate(KIND, json.encodeToString(content), createdAt) {
+                // Reference the standard start position
+                add(arrayOf("e", JesterProtocol.START_POSITION_HASH))
+                // Tag the opponent for notifications (only if valid pubkey)
+                if (opponentPubkey.isNotEmpty() && opponentPubkey.length == 64) {
+                    add(arrayOf("p", opponentPubkey))
+                }
+                initializer()
+            }
+        }
+
+        /**
+         * Build a move event
+         *
+         * @param startEventId ID of the game start event
+         * @param headEventId ID of the previous move (or start event for first move)
+         * @param move The move in SAN notation (e.g., "e4", "Nf3")
+         * @param fen Resulting board position in FEN
+         * @param history Complete move history including this move
+         * @param opponentPubkey Opponent's pubkey for notifications
+         * @param createdAt Event timestamp
+         */
+        fun buildMove(
+            startEventId: String,
+            headEventId: String,
+            move: String,
+            fen: String,
+            history: List<String>,
+            opponentPubkey: String,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<JesterEvent>.() -> Unit = {},
+        ): EventTemplate<JesterEvent> {
+            val content =
+                JesterContent(
+                    kind = JesterProtocol.CONTENT_KIND_MOVE,
+                    fen = fen,
+                    move = move,
+                    history = history,
+                )
+            return eventTemplate(KIND, json.encodeToString(content), createdAt) {
+                // e-tags: [startId, headId]
+                add(arrayOf("e", startEventId))
+                add(arrayOf("e", headEventId))
+                // Tag opponent for notifications (only if valid pubkey)
+                if (opponentPubkey.isNotEmpty() && opponentPubkey.length == 64) {
+                    add(arrayOf("p", opponentPubkey))
+                }
+                initializer()
+            }
+        }
+
+        /**
+         * Build a game end move (includes result in content)
+         *
+         * This is a move event with additional result/termination fields.
+         * Used when the game ends (checkmate, resignation, draw).
+         */
+        fun buildEndMove(
+            startEventId: String,
+            headEventId: String,
+            move: String?,
+            fen: String,
+            history: List<String>,
+            opponentPubkey: String,
+            result: GameResult,
+            termination: GameTermination,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<JesterEvent>.() -> Unit = {},
+        ): EventTemplate<JesterEvent> {
+            val content =
+                JesterContent(
+                    kind = JesterProtocol.CONTENT_KIND_MOVE,
+                    fen = fen,
+                    move = move,
+                    history = history,
+                    result = result.notation,
+                    termination = termination.name.lowercase(),
+                )
+            return eventTemplate(KIND, json.encodeToString(content), createdAt) {
+                add(arrayOf("e", startEventId))
+                add(arrayOf("e", headEventId))
+                // Tag opponent for notifications (only if valid pubkey)
+                if (opponentPubkey.isNotEmpty() && opponentPubkey.length == 64) {
+                    add(arrayOf("p", opponentPubkey))
+                }
+                initializer()
+            }
+        }
+
+        private fun generateNonce(): String {
+            val chars = "abcdefghijklmnopqrstuvwxyz0123456789"
+            return (1..8).map { chars.random() }.joinToString("")
+        }
+    }
+}
+
+/**
+ * Helper to check if an event is a Jester chess event
+ */
+fun Event.isJesterEvent(): Boolean = kind == JesterProtocol.KIND
+
+/**
+ * Helper to check if an event is a Jester start event
+ */
+fun Event.isJesterStartEvent(): Boolean {
+    if (kind != JesterProtocol.KIND) return false
+    return try {
+        val content = json.decodeFromString<JesterContent>(this.content)
+        content.kind == JesterProtocol.CONTENT_KIND_START && content.history.isEmpty()
+    } catch (e: Exception) {
+        false
+    }
+}
+
+/**
+ * Helper to check if an event is a Jester move event
+ */
+fun Event.isJesterMoveEvent(): Boolean {
+    if (kind != JesterProtocol.KIND) return false
+    return try {
+        val content = json.decodeFromString<JesterContent>(this.content)
+        content.kind == JesterProtocol.CONTENT_KIND_MOVE &&
+            content.history.isNotEmpty() &&
+            tags.count { it.size >= 2 && it[0] == "e" } == 2
+    } catch (e: Exception) {
+        false
+    }
+}
+
+/**
+ * Convert a raw Event to JesterEvent if valid
+ */
+fun Event.toJesterEvent(): JesterEvent? {
+    if (kind != JesterProtocol.KIND) return null
+    return JesterEvent(id, pubKey, createdAt, tags, content, sig)
+}
+
+/**
+ * Game events container for Jester protocol
+ */
+data class JesterGameEvents(
+    val startEvent: JesterEvent?,
+    val moves: List<JesterEvent>,
+) {
+    companion object {
+        fun empty() = JesterGameEvents(null, emptyList())
+    }
+
+    /** Get the latest move (with longest history) */
+    fun latestMove(): JesterEvent? = moves.maxByOrNull { it.history().size }
+
+    /** Get the current FEN position */
+    fun currentFen(): String = latestMove()?.fen() ?: startEvent?.fen() ?: JesterProtocol.FEN_START
+
+    /** Get the complete move history */
+    fun fullHistory(): List<String> = latestMove()?.history() ?: emptyList()
+
+    /** Check if game has ended */
+    fun isEnded(): Boolean = latestMove()?.result() != null
+
+    /** Get the game result if ended */
+    fun result(): String? = latestMove()?.result()
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/LiveChessEvents.kt

@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+/*
+ * Live chess game state and move events
+ *
+ * Uses Jester protocol (kind 30) for compatibility with jesterui.
+ * See: https://github.com/jesterui/jesterui/blob/devel/FLOW.md
+ *
+ * Key features of Jester protocol:
+ * - Single event kind (30) for all chess messages
+ * - Content is JSON with: version, kind (0=start, 1=move), fen, move, history
+ * - Full move history included in every move event
+ * - Event linking via e-tags: [startId] or [startId, headId]
+ *
+ * This enables:
+ * - Easy game reconstruction from any single move event
+ * - Tolerance for missing intermediate moves
+ * - Compatibility with jesterui and other Jester clients
+ */
+
+/**
+ * Game start/challenge data for publishing
+ *
+ * Jester protocol (kind 30) start event:
+ * - e-tag: reference to standard start position hash
+ * - p-tag: opponent pubkey (for private/direct challenges)
+ * - Content JSON with: version, kind=0, fen, history=[], nonce, playerColor
+ *
+ * @param opponentPubkey Opponent's pubkey for direct challenge (null = open challenge)
+ * @param playerColor Color the challenger wants to play
+ * @param nonce Unique identifier for this game
+ */
+data class ChessGameChallenge(
+    val opponentPubkey: String? = null, // null = open challenge
+    val playerColor: Color,
+    val nonce: String = generateNonce(),
+) {
+    companion object {
+        private fun generateNonce(): String {
+            val chars = "abcdefghijklmnopqrstuvwxyz0123456789"
+            return (1..8).map { chars.random() }.joinToString("")
+        }
+    }
+
+    // Legacy compatibility - gameId is now derived from start event ID after signing
+    @Deprecated("gameId is determined after event creation", ReplaceWith("startEventId"))
+    val gameId: String get() = nonce
+}
+
+/**
+ * Game acceptance data
+ *
+ * In Jester protocol, accepting a game is implicit - the opponent
+ * simply makes the first move (if challenger chose white) or waits
+ * for challenger's first move (if challenger chose black).
+ *
+ * This data class is kept for internal state tracking.
+ *
+ * @param startEventId ID of the game start event to accept
+ * @param challengerPubkey Pubkey of the challenger
+ */
+data class ChessGameAccept(
+    val startEventId: String,
+    val challengerPubkey: String,
+) {
+    // Legacy compatibility
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val challengeEventId: String get() = startEventId
+}
+
+/**
+ * Chess move data for publishing
+ *
+ * Jester protocol (kind 30) requires:
+ * - Full move history in every move event
+ * - e-tags linking: [startEventId, headEventId]
+ * - Content JSON with: version, kind=1, fen, move, history
+ *
+ * @param startEventId ID of the game start event
+ * @param headEventId ID of the previous move (or startEventId for first move)
+ * @param san Move in Standard Algebraic Notation (e.g., "e4", "Nf3")
+ * @param fen Resulting board position in FEN notation
+ * @param history Complete move history including this move
+ * @param opponentPubkey Opponent's pubkey for p-tag notification
+ */
+data class ChessMoveEvent(
+    val startEventId: String,
+    val headEventId: String,
+    val san: String,
+    val fen: String,
+    val history: List<String>,
+    val opponentPubkey: String,
+) {
+    /** Move number (1-based, derived from history length) */
+    val moveNumber: Int get() = history.size
+
+    // Legacy compatibility - some code still uses gameId
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+}
+
+/**
+ * Game end data for publishing
+ *
+ * In Jester protocol, game end is a move event with result/termination
+ * fields in the content JSON.
+ *
+ * @param startEventId ID of the game start event
+ * @param headEventId ID of the previous move
+ * @param lastMove The final move (null for resignation without move)
+ * @param fen Final board position
+ * @param history Complete move history
+ * @param result Game result (1-0, 0-1, 1/2-1/2)
+ * @param termination How the game ended
+ * @param opponentPubkey Opponent's pubkey for notification
+ */
+data class ChessGameEnd(
+    val startEventId: String,
+    val headEventId: String,
+    val lastMove: String?,
+    val fen: String,
+    val history: List<String>,
+    val result: GameResult,
+    val termination: GameTermination,
+    val opponentPubkey: String,
+) {
+    // Legacy compatibility
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+
+    val winnerPubkey: String? get() = null // Determined from result
+}
+
+/**
+ * Draw offer data
+ *
+ * In Jester protocol, draw offers can be communicated via:
+ * - Chat message (kind=2 in content)
+ * - Special field in move content
+ *
+ * Opponent can:
+ * - Accept by sending a game end with DRAW_AGREEMENT
+ * - Decline implicitly by making their next move
+ *
+ * @param startEventId ID of the game start event
+ * @param headEventId ID of the current head move
+ * @param opponentPubkey Opponent's pubkey for notification
+ * @param message Optional message with the draw offer
+ */
+data class ChessDrawOffer(
+    val startEventId: String,
+    val headEventId: String,
+    val opponentPubkey: String,
+    val message: String? = null,
+) {
+    // Legacy compatibility
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+}
+
+/**
+ * Game termination reason
+ */
+enum class GameTermination {
+    CHECKMATE,
+    RESIGNATION,
+    DRAW_AGREEMENT,
+    STALEMATE,
+    TIMEOUT,
+    ABANDONMENT,
+}
+
+/**
+ * Event kind constants for live chess (Jester protocol)
+ *
+ * Jester uses a single kind (30) for all chess events.
+ * The event type is determined by the content.kind field:
+ * - 0: Game start/challenge
+ * - 1: Move
+ * - 2: Chat
+ */
+object LiveChessEventKinds {
+    /** Jester protocol uses kind 30 for all chess events */
+    const val JESTER = 30
+
+    // Legacy constants - deprecated, use JESTER instead
+    @Deprecated("Jester uses single kind 30", ReplaceWith("JESTER"))
+    const val GAME_CHALLENGE = 30
+
+    @Deprecated("Jester uses single kind 30", ReplaceWith("JESTER"))
+    const val GAME_ACCEPT = 30
+
+    @Deprecated("Jester uses single kind 30", ReplaceWith("JESTER"))
+    const val CHESS_MOVE = 30
+
+    @Deprecated("Jester uses single kind 30", ReplaceWith("JESTER"))
+    const val GAME_END = 30
+
+    @Deprecated("Jester uses single kind 30", ReplaceWith("JESTER"))
+    const val DRAW_OFFER = 30
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/LiveChessGameEvents.kt

@@ -0,0 +1,295 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Live Chess Game Challenge Event (Kind 30064)
+ *
+ * Challenge another player to a chess game or create an open challenge.
+ * This is a parameterized replaceable event.
+ *
+ * Tags:
+ * - d: game_id (unique identifier for this game)
+ * - p: opponent pubkey (optional, for direct challenges)
+ * - player_color: "white" or "black"
+ * - time_control: optional time control (e.g., "10+0", "5+3")
+ */
+@Immutable
+class LiveChessGameChallengeEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 30064
+
+        fun build(
+            gameId: String,
+            playerColor: Color,
+            opponentPubkey: String? = null,
+            timeControl: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveChessGameChallengeEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            add(arrayOf("d", gameId))
+            add(arrayOf("player_color", if (playerColor == Color.WHITE) "white" else "black"))
+            opponentPubkey?.let { add(arrayOf("p", it)) }
+            timeControl?.let { add(arrayOf("time_control", it)) }
+            alt("Chess game challenge")
+            initializer()
+        }
+    }
+
+    fun gameId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "d" }?.get(1)
+
+    fun playerColor(): Color? =
+        tags
+            .firstOrNull { it.size >= 2 && it[0] == "player_color" }
+            ?.get(1)
+            ?.let { if (it == "white") Color.WHITE else Color.BLACK }
+
+    fun opponentPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+
+    fun timeControl(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "time_control" }?.get(1)
+}
+
+/**
+ * Live Chess Game Accept Event (Kind 30065)
+ *
+ * Accept a chess game challenge
+ *
+ * Tags:
+ * - d: game_id (same as challenge)
+ * - e: challenge event ID
+ * - p: challenger pubkey
+ */
+@Immutable
+class LiveChessGameAcceptEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 30065
+
+        fun build(
+            gameId: String,
+            challengeEventId: String,
+            challengerPubkey: String,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveChessGameAcceptEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            add(arrayOf("d", gameId))
+            add(arrayOf("e", challengeEventId))
+            add(arrayOf("p", challengerPubkey))
+            alt("Chess game acceptance")
+            initializer()
+        }
+    }
+
+    fun gameId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "d" }?.get(1)
+
+    fun challengeEventId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "e" }?.get(1)
+
+    fun challengerPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+}
+
+/**
+ * Live Chess Move Event (Kind 30066)
+ *
+ * Individual move in a live chess game
+ *
+ * Tags:
+ * - d: game_id
+ * - move_number: move number (1-based)
+ * - san: move in Standard Algebraic Notation
+ * - fen: resulting position in FEN notation
+ * - p: opponent pubkey
+ *
+ * Content: Optional move comment
+ */
+@Immutable
+class LiveChessMoveEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 30066
+
+        fun build(
+            gameId: String,
+            moveNumber: Int,
+            san: String,
+            fen: String,
+            opponentPubkey: String,
+            comment: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveChessMoveEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, comment, createdAt) {
+            add(arrayOf("d", "$gameId-$moveNumber"))
+            add(arrayOf("game_id", gameId))
+            add(arrayOf("move_number", moveNumber.toString()))
+            add(arrayOf("san", san))
+            add(arrayOf("fen", fen))
+            add(arrayOf("p", opponentPubkey))
+            alt("Chess move: $san")
+            initializer()
+        }
+    }
+
+    fun gameId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "game_id" }?.get(1)
+
+    fun moveNumber(): Int? =
+        tags
+            .firstOrNull { it.size >= 2 && it[0] == "move_number" }
+            ?.get(1)
+            ?.toIntOrNull()
+
+    fun san(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "san" }?.get(1)
+
+    fun fen(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "fen" }?.get(1)
+
+    fun opponentPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+
+    fun comment(): String = content
+}
+
+/**
+ * Live Chess Game End Event (Kind 30067)
+ *
+ * Game result and termination
+ *
+ * Tags:
+ * - d: game_id
+ * - result: "1-0"|"0-1"|"1/2-1/2"
+ * - termination: reason for game end
+ * - winner: pubkey of winner (if applicable)
+ * - p: opponent pubkey
+ *
+ * Content: Optional PGN of complete game
+ */
+@Immutable
+class LiveChessGameEndEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 30067
+
+        fun build(
+            gameId: String,
+            result: GameResult,
+            termination: GameTermination,
+            winnerPubkey: String? = null,
+            opponentPubkey: String,
+            pgn: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveChessGameEndEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, pgn, createdAt) {
+            add(arrayOf("d", gameId))
+            add(arrayOf("result", result.notation))
+            add(arrayOf("termination", termination.name.lowercase()))
+            winnerPubkey?.let { add(arrayOf("winner", it)) }
+            add(arrayOf("p", opponentPubkey))
+            alt("Chess game ended: ${result.notation}")
+            initializer()
+        }
+    }
+
+    fun gameId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "d" }?.get(1)
+
+    fun result(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "result" }?.get(1)
+
+    fun termination(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "termination" }?.get(1)
+
+    fun winnerPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "winner" }?.get(1)
+
+    fun opponentPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+
+    fun pgn(): String = content
+}
+
+/**
+ * Live Chess Draw Offer Event (Kind 30068)
+ *
+ * Offer a draw to opponent. Opponent can accept by sending a game end event
+ * with DRAW_AGREEMENT termination, or decline/ignore by making their next move.
+ *
+ * Tags:
+ * - d: game_id
+ * - p: opponent pubkey
+ *
+ * Content: Optional message
+ */
+@Immutable
+class LiveChessDrawOfferEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : BaseAddressableEvent(id, pubKey, createdAt, KIND, tags, content, sig) {
+    companion object {
+        const val KIND = 30068
+
+        fun build(
+            gameId: String,
+            opponentPubkey: String,
+            message: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveChessDrawOfferEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, message, createdAt) {
+            add(arrayOf("d", gameId))
+            add(arrayOf("p", opponentPubkey))
+            alt("Chess draw offer")
+            initializer()
+        }
+    }
+
+    fun gameId(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "d" }?.get(1)
+
+    fun opponentPubkey(): String? = tags.firstOrNull { it.size >= 2 && it[0] == "p" }?.get(1)
+
+    fun message(): String = content
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/LiveChessGameState.kt

@@ -0,0 +1,548 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import com.vitorpamplona.quartz.utils.TimeUtils
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * Manages state for a live chess game
+ *
+ * This class coordinates between:
+ * - ChessEngine (move validation, board state)
+ * - Nostr events (publishing moves, receiving opponent moves)
+ * - UI (game state, turn management)
+ *
+ * Jester Protocol Notes:
+ * - startEventId: ID of the game start event (used as game identifier)
+ * - headEventId: ID of the current head move (updated after each move)
+ * - Full move history is included in every published move event
+ */
+class LiveChessGameState(
+    /** Start event ID - the game identifier in Jester protocol */
+    val startEventId: String,
+    val playerPubkey: String,
+    val opponentPubkey: String,
+    val playerColor: Color,
+    val engine: ChessEngine,
+    val createdAt: Long = TimeUtils.now(),
+    val isSpectator: Boolean = false,
+    val isPendingChallenge: Boolean = false,
+    /** Initial head event ID - same as startEventId for new games */
+    initialHeadEventId: String? = null,
+) {
+    /** Legacy alias for startEventId */
+    @Deprecated("Use startEventId instead", ReplaceWith("startEventId"))
+    val gameId: String get() = startEventId
+
+    /** Current head event ID - tracks the most recent move for e-tag linking */
+    private val _headEventId = MutableStateFlow(initialHeadEventId ?: startEventId)
+    val headEventId: StateFlow<String> = _headEventId.asStateFlow()
+
+    companion object {
+        // Abandon timeout: 24 hours without a move
+        const val ABANDON_TIMEOUT_SECONDS = 24 * 60 * 60L
+
+        // Inactivity warning: 1 hour without a move
+        const val INACTIVITY_WARNING_SECONDS = 60 * 60L
+    }
+
+    private val _gameStatus = MutableStateFlow<GameStatus>(GameStatus.InProgress)
+    val gameStatus: StateFlow<GameStatus> = _gameStatus.asStateFlow()
+
+    private val _currentPosition = MutableStateFlow(engine.getPosition())
+    val currentPosition: StateFlow<ChessPosition> = _currentPosition.asStateFlow()
+
+    // Initialize from engine's history so freshly loaded games show all moves
+    private val _moveHistory = MutableStateFlow(engine.getMoveHistory())
+    val moveHistory: StateFlow<List<String>> = _moveHistory.asStateFlow()
+
+    private val _lastError = MutableStateFlow<String?>(null)
+    val lastError: StateFlow<String?> = _lastError.asStateFlow()
+
+    // Track when last activity occurred (move made or received)
+    private val _lastActivityAt = MutableStateFlow(createdAt)
+    val lastActivityAt: StateFlow<Long> = _lastActivityAt.asStateFlow()
+
+    // Track received move numbers to detect duplicates and out-of-order
+    private val receivedMoveNumbers = mutableSetOf<Int>()
+
+    // Pending moves waiting for earlier moves (move number -> move data)
+    private val pendingMoves = mutableMapOf<Int, Pair<String, String>>()
+
+    // Desync detection
+    private val _isDesynced = MutableStateFlow(false)
+    val isDesynced: StateFlow<Boolean> = _isDesynced.asStateFlow()
+
+    // Draw offer tracking - pubkey of who offered the draw (null = no pending offer)
+    private val _pendingDrawOffer = MutableStateFlow<String?>(null)
+    val pendingDrawOffer: StateFlow<String?> = _pendingDrawOffer.asStateFlow()
+
+    /**
+     * Check if there's a pending draw offer from opponent
+     */
+    fun hasOpponentDrawOffer(): Boolean = _pendingDrawOffer.value == opponentPubkey
+
+    /**
+     * Check if we have an outgoing draw offer
+     */
+    fun hasOurDrawOffer(): Boolean = _pendingDrawOffer.value == playerPubkey
+
+    /**
+     * Check if it's the player's turn
+     * Spectators never have a turn
+     */
+    fun isPlayerTurn(): Boolean = !isSpectator && engine.getSideToMove() == playerColor
+
+    /**
+     * Make a move (called when player makes a move on the board)
+     * Returns the move event data to be published to Nostr
+     *
+     * Jester Protocol: Move events include full history and link to previous event
+     */
+    fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType? = null,
+    ): ChessMoveEvent? {
+        if (!isPlayerTurn()) {
+            _lastError.value = "Not your turn"
+            return null
+        }
+
+        if (_gameStatus.value != GameStatus.InProgress) {
+            _lastError.value = "Game is not in progress"
+            return null
+        }
+
+        val result = engine.makeMove(from, to, promotion)
+
+        if (result.success && result.san != null && result.position != null) {
+            _currentPosition.value = result.position
+            _moveHistory.value = engine.getMoveHistory()
+            _lastActivityAt.value = TimeUtils.now()
+            _lastError.value = null
+
+            // Making a move implicitly declines any pending draw offer
+            _pendingDrawOffer.value = null
+
+            // Check for game end conditions
+            checkGameEnd()
+
+            // Return move event data with full history for Jester protocol
+            return ChessMoveEvent(
+                startEventId = startEventId,
+                headEventId = _headEventId.value,
+                san = result.san,
+                fen = engine.getFen(),
+                history = _moveHistory.value, // Full history for Jester
+                opponentPubkey = opponentPubkey,
+            )
+        } else {
+            _lastError.value = result.error ?: "Invalid move"
+            return null
+        }
+    }
+
+    /**
+     * Update the head event ID after a move is successfully published.
+     * Call this after the move event is signed and broadcast.
+     *
+     * @param newHeadEventId The ID of the newly published move event
+     */
+    fun updateHeadEventId(newHeadEventId: String) {
+        _headEventId.value = newHeadEventId
+    }
+
+    /**
+     * Undo the last move made.
+     * Used to revert a move when publishing fails.
+     *
+     * @return true if the move was successfully undone, false if there was nothing to undo
+     */
+    fun undoLastMove(): Boolean {
+        if (_moveHistory.value.isEmpty()) return false
+
+        engine.undoMove()
+        _currentPosition.value = engine.getPosition()
+        _moveHistory.value = engine.getMoveHistory()
+        _lastError.value = null
+
+        // Reset game status in case checkmate was detected
+        if (_gameStatus.value is GameStatus.Finished) {
+            _gameStatus.value = GameStatus.InProgress
+        }
+
+        return true
+    }
+
+    /**
+     * Apply opponent's move (called when receiving move event from Nostr)
+     */
+    fun applyOpponentMove(
+        san: String,
+        fen: String,
+        moveNumber: Int? = null,
+    ): Boolean {
+        // Check for duplicate move
+        if (moveNumber != null && receivedMoveNumbers.contains(moveNumber)) {
+            // Already processed this move, ignore
+            return true
+        }
+
+        // Check for out-of-order move
+        val expectedMoveNumber = _moveHistory.value.size + 1
+        if (moveNumber != null && moveNumber > expectedMoveNumber) {
+            // Store for later processing
+            pendingMoves[moveNumber] = san to fen
+            return true
+        }
+
+        if (isPlayerTurn()) {
+            _lastError.value = "Received move but it's not opponent's turn"
+            return false
+        }
+
+        // Verify the move is valid by trying to make it
+        val result = engine.makeMove(san)
+
+        if (result.success) {
+            // Mark as received
+            if (moveNumber != null) {
+                receivedMoveNumbers.add(moveNumber)
+            }
+
+            // Verify the resulting FEN matches what opponent sent
+            val currentFen = engine.getFen()
+            if (currentFen != fen) {
+                // Positions don't match - desync detected
+                _isDesynced.value = true
+                _lastError.value = "Position mismatch - syncing to opponent's position"
+                // Load the opponent's FEN to stay in sync
+                engine.loadFen(fen)
+            } else {
+                _isDesynced.value = false
+            }
+
+            _currentPosition.value = engine.getPosition()
+            _moveHistory.value = engine.getMoveHistory()
+            _lastActivityAt.value = TimeUtils.now()
+            _lastError.value = null
+
+            // Opponent making a move declines any pending draw offer
+            _pendingDrawOffer.value = null
+
+            // Check for game end conditions
+            checkGameEnd()
+
+            // Process any pending moves that are now valid
+            processPendingMoves()
+
+            return true
+        } else {
+            _lastError.value = "Invalid opponent move: $san"
+            return false
+        }
+    }
+
+    /**
+     * Process any pending out-of-order moves
+     */
+    private fun processPendingMoves() {
+        val nextMoveNumber = _moveHistory.value.size + 1
+        val pendingMove = pendingMoves.remove(nextMoveNumber)
+        if (pendingMove != null) {
+            val (san, fen) = pendingMove
+            applyOpponentMove(san, fen, nextMoveNumber)
+        }
+    }
+
+    /**
+     * Force resync to a specific FEN (manual recovery)
+     */
+    fun forceResync(fen: String) {
+        engine.loadFen(fen)
+        _currentPosition.value = engine.getPosition()
+        _moveHistory.value = engine.getMoveHistory()
+        _isDesynced.value = false
+        _lastError.value = null
+    }
+
+    /**
+     * Apply moves from another game state while preserving this state's participant info.
+     * This is used when relay reconstruction incorrectly marks us as spectator but has newer moves.
+     *
+     * @param other The other game state to take moves from
+     */
+    fun applyMovesFrom(other: LiveChessGameState) {
+        val currentMoves = _moveHistory.value
+        val otherMoves = other.moveHistory.value
+
+        if (otherMoves.size <= currentMoves.size) return // Nothing new to apply
+
+        // Apply only the new moves
+        for (i in currentMoves.size until otherMoves.size) {
+            val san = otherMoves[i]
+            val result = engine.makeMove(san)
+            if (!result.success) {
+                // Try to resync from the other engine's FEN
+                val otherFen = other.engine.getFen()
+                engine.loadFen(otherFen)
+                break
+            }
+        }
+
+        // Update state flows
+        _currentPosition.value = engine.getPosition()
+        _moveHistory.value = engine.getMoveHistory()
+        _lastActivityAt.value = other.lastActivityAt.value
+        _isDesynced.value = false
+        _lastError.value = null
+
+        // Update head event ID from other state
+        _headEventId.value = other.headEventId.value
+
+        // Mark new moves as received
+        val newMoveNumbers = (currentMoves.size + 1..otherMoves.size).toSet()
+        receivedMoveNumbers.addAll(newMoveNumbers)
+
+        // Check for game end conditions
+        checkGameEnd()
+    }
+
+    /**
+     * Mark move numbers as already received.
+     * Used when loading a game from cache to prevent duplicate move application during refresh.
+     *
+     * @param moveNumbers Set of move numbers that have been loaded
+     */
+    fun markMovesAsReceived(moveNumbers: Set<Int>) {
+        receivedMoveNumbers.addAll(moveNumbers)
+    }
+
+    /**
+     * Check if game appears abandoned (opponent hasn't moved in a long time)
+     */
+    fun isAbandoned(): Boolean {
+        if (_gameStatus.value != GameStatus.InProgress) return false
+        if (isPlayerTurn()) return false // Only check when waiting for opponent
+
+        val elapsed = TimeUtils.now() - _lastActivityAt.value
+        return elapsed > ABANDON_TIMEOUT_SECONDS
+    }
+
+    /**
+     * Check if opponent is inactive (warning threshold)
+     */
+    fun isOpponentInactive(): Boolean {
+        if (_gameStatus.value != GameStatus.InProgress) return false
+        if (isPlayerTurn()) return false
+
+        val elapsed = TimeUtils.now() - _lastActivityAt.value
+        return elapsed > INACTIVITY_WARNING_SECONDS
+    }
+
+    /**
+     * Claim victory due to abandonment
+     */
+    fun claimAbandonmentVictory(): ChessGameEnd? {
+        if (!isAbandoned()) return null
+
+        _gameStatus.value = GameStatus.Finished(GameResult.getResultForWinner(playerColor))
+
+        return ChessGameEnd(
+            startEventId = startEventId,
+            headEventId = _headEventId.value,
+            lastMove = null,
+            fen = engine.getFen(),
+            history = _moveHistory.value,
+            result = GameResult.getResultForWinner(playerColor),
+            termination = GameTermination.ABANDONMENT,
+            opponentPubkey = opponentPubkey,
+        )
+    }
+
+    /**
+     * Offer resignation (player resigns)
+     */
+    fun resign(): ChessGameEnd {
+        _gameStatus.value = GameStatus.Finished(GameResult.getResultForWinner(playerColor.opposite()))
+
+        return ChessGameEnd(
+            startEventId = startEventId,
+            headEventId = _headEventId.value,
+            lastMove = null,
+            fen = engine.getFen(),
+            history = _moveHistory.value,
+            result = GameResult.getResultForWinner(playerColor.opposite()),
+            termination = GameTermination.RESIGNATION,
+            opponentPubkey = opponentPubkey,
+        )
+    }
+
+    /**
+     * Offer a draw to opponent.
+     * Returns the draw offer data to be published to Nostr.
+     */
+    fun offerDraw(): ChessDrawOffer {
+        _pendingDrawOffer.value = playerPubkey
+        return ChessDrawOffer(
+            startEventId = startEventId,
+            headEventId = _headEventId.value,
+            opponentPubkey = opponentPubkey,
+        )
+    }
+
+    /**
+     * Handle receiving a draw offer from opponent (via Nostr event)
+     */
+    fun receiveDrawOffer(fromPubkey: String): Boolean {
+        if (fromPubkey != opponentPubkey) return false
+        _pendingDrawOffer.value = opponentPubkey
+        return true
+    }
+
+    /**
+     * Accept opponent's draw offer.
+     * Returns game end data to be published to Nostr.
+     */
+    fun acceptDraw(): ChessGameEnd? {
+        if (_pendingDrawOffer.value != opponentPubkey) {
+            _lastError.value = "No draw offer to accept"
+            return null
+        }
+
+        _pendingDrawOffer.value = null
+        _gameStatus.value = GameStatus.Finished(GameResult.DRAW)
+
+        return ChessGameEnd(
+            startEventId = startEventId,
+            headEventId = _headEventId.value,
+            lastMove = null,
+            fen = engine.getFen(),
+            history = _moveHistory.value,
+            result = GameResult.DRAW,
+            termination = GameTermination.DRAW_AGREEMENT,
+            opponentPubkey = opponentPubkey,
+        )
+    }
+
+    /**
+     * Decline a draw offer (explicit decline, also happens implicitly on move)
+     */
+    fun declineDraw() {
+        _pendingDrawOffer.value = null
+    }
+
+    /**
+     * Check if game has ended (checkmate, stalemate, etc.)
+     */
+    private fun checkGameEnd() {
+        when {
+            engine.isCheckmate() -> {
+                val winner = engine.getSideToMove().opposite()
+                _gameStatus.value = GameStatus.Finished(GameResult.getResultForWinner(winner))
+                // In a real implementation, you'd publish GameEnd event here
+            }
+
+            engine.isStalemate() -> {
+                _gameStatus.value = GameStatus.Finished(GameResult.DRAW)
+                // In a real implementation, you'd publish GameEnd event here
+            }
+        }
+    }
+
+    /**
+     * Generate PGN for the current game
+     */
+    private fun generatePGN(): String {
+        val moves = _moveHistory.value
+        val movePairs = moves.chunked(2)
+
+        val moveText =
+            movePairs
+                .mapIndexed { index, pair ->
+                    val moveNum = index + 1
+                    when (pair.size) {
+                        2 -> "$moveNum. ${pair[0]} ${pair[1]}"
+                        1 -> "$moveNum. ${pair[0]}"
+                        else -> ""
+                    }
+                }.joinToString(" ")
+
+        val result =
+            when (val status = _gameStatus.value) {
+                is GameStatus.Finished -> status.result.notation
+                else -> "*"
+            }
+
+        return """
+            [Event "Live Chess Game"]
+            [Site "Nostr"]
+            [White "${if (playerColor == Color.WHITE) playerPubkey else opponentPubkey}"]
+            [Black "${if (playerColor == Color.BLACK) playerPubkey else opponentPubkey}"]
+            [Result "$result"]
+
+            $moveText $result
+            """.trimIndent()
+    }
+
+    /**
+     * Mark game as finished with the given result.
+     * Used when loading a game from cache that already has an end event.
+     */
+    fun markAsFinished(result: GameResult) {
+        _gameStatus.value = GameStatus.Finished(result)
+    }
+
+    /**
+     * Reset game to initial position
+     */
+    fun reset() {
+        engine.reset()
+        _currentPosition.value = engine.getPosition()
+        _moveHistory.value = emptyList()
+        _gameStatus.value = GameStatus.InProgress
+        _lastError.value = null
+    }
+}
+
+/**
+ * Game status
+ */
+sealed class GameStatus {
+    data object InProgress : GameStatus()
+
+    data class Finished(
+        val result: GameResult,
+    ) : GameStatus()
+}
+
+/**
+ * Extension to get result for a winning color
+ */
+private fun GameResult.Companion.getResultForWinner(winner: Color): GameResult =
+    when (winner) {
+        Color.WHITE -> GameResult.WHITE_WINS
+        Color.BLACK -> GameResult.BLACK_WINS
+    }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip64Chess/PGNParser.kt

@@ -0,0 +1,325 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+/**
+ * Parse PGN (Portable Game Notation) format per NIP-64 specification
+ *
+ * Accepts "import format" (human-created, flexible) as per PGN spec
+ * Handles:
+ * - Tag pairs: [TagName "TagValue"]
+ * - Move text in Standard Algebraic Notation (SAN)
+ * - Comments: {...}
+ * - Variations: (...)
+ * - Result markers: 1-0, 0-1, 1/2-1/2, *
+ */
+object PGNParser {
+    /**
+     * Parse PGN content into ChessGame
+     *
+     * @param pgn PGN format string
+     * @return Result containing ChessGame or error
+     */
+    fun parse(pgn: String): Result<ChessGame> =
+        runCatching {
+            val lines = pgn.lines().map { it.trim() }
+
+            // Extract metadata tags [Key "Value"]
+            val metadata = parseMetadata(lines)
+
+            // Extract move text (everything after metadata)
+            val moveText =
+                lines
+                    .dropWhile { it.startsWith("[") || it.isEmpty() }
+                    .joinToString(" ")
+
+            val (moves, result) = parseMoves(moveText)
+
+            // Generate positions by replaying moves
+            val positions = generatePositions(moves)
+
+            ChessGame(
+                metadata = metadata,
+                moves = moves,
+                positions = positions,
+                result = result,
+            )
+        }
+
+    /**
+     * Extract PGN tag pairs from lines
+     * Format: [TagName "TagValue"]
+     */
+    private fun parseMetadata(lines: List<String>): Map<String, String> {
+        val tagRegex = """\[(\w+)\s+"([^"]*)"\]""".toRegex()
+        return lines
+            .mapNotNull { tagRegex.matchEntire(it) }
+            .associate { it.groupValues[1] to it.groupValues[2] }
+    }
+
+    /**
+     * Parse move text into list of moves and game result
+     */
+    private fun parseMoves(moveText: String): Pair<List<ChessMove>, GameResult> {
+        // Remove comments {...} and variations (...)
+        val cleaned =
+            moveText
+                .replace(Regex("""\{[^}]*\}"""), "") // Remove comments
+                .replace(Regex("""\([^)]*\)"""), "") // Remove variations
+                .replace(Regex("""\$\d+"""), "") // Remove NAG annotations
+                .trim()
+
+        // Extract result marker
+        val result =
+            when {
+                cleaned.contains("1-0") -> GameResult.WHITE_WINS
+                cleaned.contains("0-1") -> GameResult.BLACK_WINS
+                cleaned.contains("1/2-1/2") -> GameResult.DRAW
+                else -> GameResult.IN_PROGRESS
+            }
+
+        // Remove result marker from move text
+        val movesOnly =
+            cleaned
+                .replace("1-0", "")
+                .replace("0-1", "")
+                .replace("1/2-1/2", "")
+                .replace("*", "")
+                .replace(Regex("""\s+"""), " ") // Normalize whitespace
+                .trim()
+
+        // Parse move pairs: "1. e4 e5 2. Nf3 Nc6"
+        val moveRegex = """(\d+)\.\s*([^\s]+)(?:\s+([^\s]+))?""".toRegex()
+        val moves = mutableListOf<ChessMove>()
+
+        moveRegex.findAll(movesOnly).forEach { match ->
+            val moveNum = match.groupValues[1].toIntOrNull() ?: return@forEach
+            val whiteMove = match.groupValues[2]
+            val blackMove = match.groupValues.getOrNull(3)?.takeIf { it.isNotEmpty() }
+
+            // Skip if this is just a result marker
+            if (!isResultMarker(whiteMove)) {
+                moves.add(parseMove(whiteMove, moveNum, Color.WHITE))
+            }
+
+            blackMove?.let {
+                if (!isResultMarker(it)) {
+                    moves.add(parseMove(it, moveNum, Color.BLACK))
+                }
+            }
+        }
+
+        return moves to result
+    }
+
+    /**
+     * Check if text is a game result marker
+     * Valid results: 1-0, 0-1, 1/2-1/2, *
+     */
+    private fun isResultMarker(text: String): Boolean = text == "1-0" || text == "0-1" || text == "1/2-1/2" || text == "*"
+
+    /**
+     * Parse a single move in Standard Algebraic Notation (SAN)
+     *
+     * Examples:
+     * - e4 (pawn move)
+     * - Nf3 (knight to f3)
+     * - Bxe5 (bishop captures on e5)
+     * - O-O (kingside castling)
+     * - O-O-O (queenside castling)
+     * - e8=Q (pawn promotion to queen)
+     * - Nbd2 (knight from b-file to d2)
+     * - R1a3 (rook from rank 1 to a3)
+     * - Qh4+ (queen to h4 with check)
+     * - Qh4# (queen to h4 with checkmate)
+     */
+    private fun parseMove(
+        san: String,
+        moveNumber: Int,
+        color: Color,
+    ): ChessMove {
+        // Clean up annotations
+        var text = san.replace(Regex("[!?]+"), "").trim()
+
+        val isCheck = text.contains("+")
+        val isCheckmate = text.contains("#")
+        val isCapture = text.contains("x")
+
+        // Remove check/checkmate markers
+        text = text.replace("+", "").replace("#", "")
+
+        // Castling
+        if (text == "O-O" || text == "0-0") {
+            return ChessMove(
+                san = san,
+                moveNumber = moveNumber,
+                color = color,
+                piece = PieceType.KING,
+                toSquare = if (color == Color.WHITE) "g1" else "g8",
+                isCheck = isCheck,
+                isCheckmate = isCheckmate,
+                isCastling = true,
+            )
+        }
+
+        if (text == "O-O-O" || text == "0-0-0") {
+            return ChessMove(
+                san = san,
+                moveNumber = moveNumber,
+                color = color,
+                piece = PieceType.KING,
+                toSquare = if (color == Color.WHITE) "c1" else "c8",
+                isCheck = isCheck,
+                isCheckmate = isCheckmate,
+                isCastling = true,
+            )
+        }
+
+        // Remove capture marker
+        text = text.replace("x", "")
+
+        // Check for promotion (e.g., e8=Q)
+        val promotionRegex = """([a-h][18])=([QRBN])""".toRegex()
+        val promotionMatch = promotionRegex.find(text)
+        val promotion = promotionMatch?.groupValues?.get(2)?.let { PieceType.fromSymbol(it[0]) }
+        if (promotionMatch != null) {
+            text = text.replace(promotionRegex, promotionMatch.groupValues[1])
+        }
+
+        // Determine piece type (first char if uppercase, otherwise pawn)
+        val piece =
+            if (text.isNotEmpty() && text[0].isUpperCase()) {
+                PieceType.fromSymbol(text[0]) ?: PieceType.PAWN
+            } else {
+                PieceType.PAWN
+            }
+
+        // Remove piece symbol if present
+        if (piece != PieceType.PAWN && text.isNotEmpty()) {
+            text = text.substring(1)
+        }
+
+        // Extract destination square (last 2 chars should be file+rank)
+        val squareRegex = """([a-h][1-8])$""".toRegex()
+        val squareMatch = squareRegex.find(text)
+        val toSquare = squareMatch?.value ?: ""
+
+        // Extract disambiguation (file or rank between piece and destination)
+        val fromSquare = text.replace(toSquare, "").takeIf { it.isNotEmpty() }
+
+        return ChessMove(
+            san = san,
+            moveNumber = moveNumber,
+            color = color,
+            piece = piece,
+            fromSquare = fromSquare,
+            toSquare = toSquare,
+            isCapture = isCapture,
+            isCheck = isCheck,
+            isCheckmate = isCheckmate,
+            promotion = promotion,
+        )
+    }
+
+    /**
+     * Generate list of positions by replaying moves from starting position
+     *
+     * Note: This implementation uses simplified move application.
+     * Full legal move validation would require complete chess engine logic.
+     */
+    private fun generatePositions(moves: List<ChessMove>): List<ChessPosition> {
+        val positions = mutableListOf(ChessPosition.initial())
+        var current = ChessPosition.initial()
+
+        moves.forEach { move ->
+            try {
+                current =
+                    when {
+                        move.isCastling -> {
+                            // Castling
+                            val kingSide = move.toSquare.contains("g")
+                            current.makeCastlingMove(kingSide)
+                        }
+
+                        move.fromSquare != null -> {
+                            // Move with disambiguation (we can infer full source)
+                            // For now, just use simplified move
+                            makeSimplifiedMove(current, move)
+                        }
+
+                        else -> {
+                            // Regular move
+                            makeSimplifiedMove(current, move)
+                        }
+                    }
+                positions.add(current)
+            } catch (e: Exception) {
+                // If move application fails, keep previous position
+                positions.add(current)
+            }
+        }
+
+        return positions
+    }
+
+    /**
+     * Simplified move application without full legal move validation
+     * Finds piece that can move to destination and creates new position
+     */
+    private fun makeSimplifiedMove(
+        position: ChessPosition,
+        move: ChessMove,
+    ): ChessPosition {
+        // For MVP: Try to find a piece of the right type that could move to destination
+        // This is simplified and doesn't validate full chess rules
+        val targetSquare = move.toSquare
+
+        // Find all pieces of the moving color and type
+        val candidates = mutableListOf<String>()
+        for (rank in 0..7) {
+            for (file in 0..7) {
+                val piece = position.pieceAt(file, rank)
+                if (piece != null &&
+                    piece.color == move.color &&
+                    piece.type == move.piece
+                ) {
+                    val square = "${'a' + file}${rank + 1}"
+                    candidates.add(square)
+                }
+            }
+        }
+
+        // Use disambiguation if provided
+        val fromSquare =
+            if (move.fromSquare != null) {
+                candidates.firstOrNull { it.contains(move.fromSquare) }
+            } else {
+                candidates.firstOrNull()
+            } ?: ""
+
+        return if (fromSquare.isNotEmpty()) {
+            position.makeMove(fromSquare, targetSquare, move.promotion)
+        } else {
+            // If we can't find source, return current position unchanged
+            position
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/PollEvent.kt

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip22Comments.RootScope
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollType
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class PollEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    RootScope {
+    fun options() = tags.options()
+
+    fun relays() = tags.relays()
+
+    fun pollType() = tags.pollType()
+
+    fun endsAt() = tags.endsAt()
+
+    fun hasEnded() = tags.hasEnded()
+
+    companion object {
+        const val KIND = 1068
+        const val ALT_DESCRIPTION = "Poll"
+
+        fun build(
+            description: String,
+            options: List<OptionTag>,
+            endsAt: Long?,
+            relays: List<NormalizedRelayUrl>,
+            pollType: PollType = PollType.SINGLE_CHOICE,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<PollEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, description, createdAt) {
+            alt(ALT_DESCRIPTION)
+            poolType(pollType)
+            options(options)
+            relays(relays)
+            endsAt?.let {
+                endsAt(it)
+            }
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/TagArrayBuilderExt.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.EndsAtTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollType
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollTypeTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.RelayTag
+
+fun TagArrayBuilder<PollEvent>.poolType(type: PollType) = addUnique(PollTypeTag.assemble(type))
+
+fun TagArrayBuilder<PollEvent>.endsAt(timestamp: Long) = addUnique(EndsAtTag.assemble(timestamp))
+
+fun TagArrayBuilder<PollEvent>.relays(relays: List<NormalizedRelayUrl>) = addAll(RelayTag.assemble(relays))
+
+fun TagArrayBuilder<PollEvent>.options(options: List<OptionTag>) = addAll(OptionTag.assemble(options))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/TagArrayExt.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.EndsAtTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.EndsAtTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollType
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollTypeTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollTypeTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.RelayTag
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.RelayTag.Companion.parse
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+fun TagArray.options() = mapNotNull(OptionTag::parse)
+
+fun TagArray.relays() = mapNotNull(RelayTag::parse)
+
+fun TagArray.pollType() = firstNotNullOfOrNull(PollTypeTag::parse) ?: PollType.SINGLE_CHOICE
+
+fun TagArray.endsAt() = firstNotNullOfOrNull(EndsAtTag::parse)
+
+fun TagArray.hasEnded() = endsAt()?.let { it < TimeUtils.now() } ?: false

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/tags/EndsAtTag.kt

@@ -18,23 +18,24 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.quartz.nip01Core.crypto
+package com.vitorpamplona.quartz.nip88Polls.poll.tags
 
-import com.vitorpamplona.quartz.nip01Core.core.Event
-import com.vitorpamplona.quartz.nip01Core.core.HexKey
-import com.vitorpamplona.quartz.nip01Core.core.toHexKey
-import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.arrayOfNotNull
+import com.vitorpamplona.quartz.utils.ensure
 
-class DeterministicSigner(
-    val key: KeyPair,
-    val pubKey: HexKey = key.pubKey.toHexKey(),
-) {
-    fun <T : Event> sign(
-        createdAt: Long,
-        kind: Int,
-        tags: Array<Array<String>>,
-        content: String,
-    ): T = EventAssembler.hashAndSign(pubKey, createdAt, kind, tags, content, key.privKey!!, nonce = null)
+class EndsAtTag {
+    companion object {
+        const val TAG_NAME = "endsAt"
 
-    fun <T : Event> sign(ev: EventTemplate<T>): T = sign(ev.createdAt, ev.kind, ev.tags, ev.content)
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): Long? {
+            ensure(tag.has(1) && tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1].toLongOrNull()
+        }
+
+        fun assemble(time: Long) = arrayOfNotNull(TAG_NAME, time.toString())
+    }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/tags/OptionTag.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll.tags
+
+import androidx.compose.runtime.Stable
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+@Stable
+class OptionTag(
+    val code: String,
+    val label: String,
+) {
+    companion object {
+        const val TAG_NAME = "option"
+
+        fun isTag(tag: Array<String>) = tag.has(2) && tag[0] == TAG_NAME && tag[1].isNotEmpty() && tag[2].isNotEmpty()
+
+        fun parse(tag: Array<String>): OptionTag? {
+            ensure(tag.has(2)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            ensure(tag[2].isNotEmpty()) { return null }
+            return OptionTag(tag[1], tag[2])
+        }
+
+        fun assemble(
+            code: String,
+            label: String,
+        ) = arrayOf(TAG_NAME, code, label)
+
+        fun assemble(option: OptionTag) = assemble(option.code, option.label)
+
+        fun assemble(labels: List<OptionTag>) = labels.map { opt -> assemble(opt) }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/tags/PollTypeTag.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+enum class PollType(
+    val code: String,
+) {
+    SINGLE_CHOICE("singlechoice"),
+    MULTI_CHOICE("multiplechoice"),
+}
+
+class PollTypeTag {
+    companion object {
+        const val TAG_NAME = "polltype"
+
+        fun isTag(tag: Array<String>) = tag.has(2) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): PollType? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+
+            return when (tag[1]) {
+                PollType.SINGLE_CHOICE.code -> PollType.SINGLE_CHOICE
+                PollType.MULTI_CHOICE.code -> PollType.MULTI_CHOICE
+                else -> null
+            }
+        }
+
+        fun assemble(type: PollType) = arrayOf(TAG_NAME, type.code)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/poll/tags/RelayTag.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.poll.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
+import com.vitorpamplona.quartz.utils.ensure
+
+class RelayTag {
+    companion object {
+        const val TAG_NAME = "relay"
+
+        fun match(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun notMatch(tag: Array<String>) = !(tag.has(0) && tag[0] == TAG_NAME)
+
+        fun parse(tag: Array<String>): NormalizedRelayUrl? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+
+            return RelayUrlNormalizer.normalizeOrNull(tag[1])
+        }
+
+        fun assemble(relay: NormalizedRelayUrl) = arrayOf(TAG_NAME, relay.url)
+
+        fun assemble(relays: List<NormalizedRelayUrl>) = relays.map { assemble(it) }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/response/PollResponseEvent.kt

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.response
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
+import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.events.ETag.Companion.parseAsHint
+import com.vitorpamplona.quartz.nip01Core.tags.events.ETag.Companion.parseId
+import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
+import com.vitorpamplona.quartz.nip01Core.tags.people.PTag.Companion.parseAsHint
+import com.vitorpamplona.quartz.nip01Core.tags.people.PTag.Companion.parseKey
+import com.vitorpamplona.quartz.nip22Comments.RootScope
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip88Polls.response.responses
+import com.vitorpamplona.quartz.nip88Polls.response.tags.PollTag
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class PollResponseEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    EventHintProvider,
+    PubKeyHintProvider,
+    RootScope {
+    override fun eventHints() = tags.mapNotNull(PollTag::parseAsHint)
+
+    override fun linkedEventIds() = tags.mapNotNull(PollTag::parseId)
+
+    override fun pubKeyHints() = tags.mapNotNull(PTag::parseAsHint)
+
+    override fun linkedPubKeys() = tags.mapNotNull(PTag::parseKey)
+
+    fun responses() = tags.responses()
+
+    fun poll() = tags.poll()
+
+    companion object {
+        const val KIND = 1018
+        const val ALT_DESCRIPTION = "Poll Response"
+
+        fun build(
+            poll: EventHintBundle<PollEvent>,
+            responses: Set<String>,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<PollResponseEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, "", createdAt) {
+            alt(ALT_DESCRIPTION)
+            poll(poll)
+            notifyAuthor(poll)
+            responses(responses)
+            initializer()
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/response/TagArrayBuilderExt.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.response
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.tags.people.toPTag
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip88Polls.response.tags.PollTag
+import com.vitorpamplona.quartz.nip88Polls.response.tags.ResponseTag
+
+fun TagArrayBuilder<PollResponseEvent>.poll(pollHint: EventHintBundle<PollEvent>) = addUnique(PollTag.assemble(pollHint))
+
+fun TagArrayBuilder<PollResponseEvent>.responses(responses: Set<String>) = addAll(ResponseTag.assemble(responses))
+
+fun TagArrayBuilder<PollResponseEvent>.notifyAuthor(pollHint: EventHintBundle<PollEvent>) = add(pollHint.toPTag().toTagArray())

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/response/TagArrayExt.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.response
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip01Core.tags.events.ETag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.EndsAtTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollTypeTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.poll.tags.RelayTag.Companion.parse
+import com.vitorpamplona.quartz.nip88Polls.response.tags.PollTag
+import com.vitorpamplona.quartz.nip88Polls.response.tags.ResponseTag
+import com.vitorpamplona.quartz.nip88Polls.response.tags.ResponseTag.Companion.parse
+
+fun TagArray.responses() = mapNotNull(ResponseTag::parse)
+
+fun TagArray.poll() = firstNotNullOfOrNull(PollTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/response/tags/PollTag.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.response.tags
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
+import com.vitorpamplona.quartz.nip01Core.tags.events.GenericETag
+import com.vitorpamplona.quartz.nip19Bech32.entities.NEvent
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.utils.arrayOfNotNull
+import com.vitorpamplona.quartz.utils.ensure
+
+@Immutable
+data class PollTag(
+    override val eventId: HexKey,
+) : GenericETag {
+    override var relay: NormalizedRelayUrl? = null
+    override var author: HexKey? = null
+
+    constructor(eventId: HexKey, relayHint: NormalizedRelayUrl? = null, authorPubKeyHex: HexKey? = null) : this(eventId) {
+        this.relay = relayHint
+        this.author = authorPubKeyHex
+    }
+
+    fun toNEvent(): String = NEvent.create(eventId, author, null, relay)
+
+    override fun toTagArray() = assemble(eventId, relay, author)
+
+    companion object {
+        const val TAG_NAME = "e"
+
+        fun isTagged(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].length == 64
+
+        fun isTagged(
+            tag: Array<String>,
+            eventId: HexKey,
+        ) = tag.has(1) && tag[0] == TAG_NAME && tag[1] == eventId
+
+        fun isTagged(
+            tag: Array<String>,
+            eventIds: Set<HexKey>,
+        ) = tag.has(1) && tag[0] == TAG_NAME && tag[1] in eventIds
+
+        fun parse(tag: Array<String>): PollTag? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+
+            val hint = tag.getOrNull(2)?.let { RelayUrlNormalizer.normalizeOrNull(it) }
+
+            return PollTag(tag[1], hint, tag.getOrNull(3))
+        }
+
+        fun parseId(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+            return tag[1]
+        }
+
+        fun parseAsHint(tag: Array<String>): EventIdHint? {
+            ensure(tag.has(2)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].length == 64) { return null }
+            ensure(tag[2].isNotEmpty()) { return null }
+
+            val hint = RelayUrlNormalizer.normalizeOrNull(tag[2])
+
+            ensure(hint != null) { return null }
+
+            return EventIdHint(tag[1], hint)
+        }
+
+        fun assemble(
+            eventId: HexKey,
+            relay: NormalizedRelayUrl?,
+            author: HexKey?,
+        ) = arrayOfNotNull(TAG_NAME, eventId, relay?.url, author)
+
+        fun assemble(eventHint: EventHintBundle<PollEvent>) = assemble(eventHint.event.id, eventHint.relay, eventHint.event.pubKey)
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip88Polls/response/tags/ResponseTag.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip88Polls.response.tags
+
+import com.vitorpamplona.quartz.nip01Core.core.has
+import com.vitorpamplona.quartz.utils.ensure
+
+class ResponseTag {
+    companion object {
+        const val TAG_NAME = "response"
+
+        fun isTag(tag: Array<String>) = tag.has(1) && tag[0] == TAG_NAME && tag[1].isNotEmpty()
+
+        fun parse(tag: Array<String>): String? {
+            ensure(tag.has(1)) { return null }
+            ensure(tag[0] == TAG_NAME) { return null }
+            ensure(tag[1].isNotEmpty()) { return null }
+            return tag[1]
+        }
+
+        fun assemble(code: String) = arrayOf(TAG_NAME, code)
+
+        fun assemble(responses: Set<String>) = responses.map { code -> assemble(code) }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt

@@ -112,6 +112,13 @@ import com.vitorpamplona.quartz.nip58Badges.BadgeProfilesEvent
 import com.vitorpamplona.quartz.nip59Giftwrap.seals.SealedRumorEvent
 import com.vitorpamplona.quartz.nip59Giftwrap.wraps.GiftWrapEvent
 import com.vitorpamplona.quartz.nip62RequestToVanish.RequestToVanishEvent
+import com.vitorpamplona.quartz.nip64Chess.ChessGameEvent
+import com.vitorpamplona.quartz.nip64Chess.JesterEvent
+import com.vitorpamplona.quartz.nip64Chess.LiveChessDrawOfferEvent
+import com.vitorpamplona.quartz.nip64Chess.LiveChessGameAcceptEvent
+import com.vitorpamplona.quartz.nip64Chess.LiveChessGameChallengeEvent
+import com.vitorpamplona.quartz.nip64Chess.LiveChessGameEndEvent
+import com.vitorpamplona.quartz.nip64Chess.LiveChessMoveEvent
 import com.vitorpamplona.quartz.nip65RelayList.AdvertisedRelayListEvent
 import com.vitorpamplona.quartz.nip68Picture.PictureEvent
 import com.vitorpamplona.quartz.nip71Video.VideoHorizontalEvent
@@ -124,6 +131,8 @@ import com.vitorpamplona.quartz.nip72ModCommunities.follow.CommunityListEvent
 import com.vitorpamplona.quartz.nip75ZapGoals.GoalEvent
 import com.vitorpamplona.quartz.nip78AppData.AppSpecificDataEvent
 import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip88Polls.response.PollResponseEvent
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
 import com.vitorpamplona.quartz.nip89AppHandlers.recommendation.AppRecommendationEvent
 import com.vitorpamplona.quartz.nip90Dvms.NIP90ContentDiscoveryRequestEvent
@@ -183,6 +192,13 @@ class EventFactory {
                 CalendarEvent.KIND -> CalendarEvent(id, pubKey, createdAt, tags, content, sig)
                 CalendarTimeSlotEvent.KIND -> CalendarTimeSlotEvent(id, pubKey, createdAt, tags, content, sig)
                 CalendarRSVPEvent.KIND -> CalendarRSVPEvent(id, pubKey, createdAt, tags, content, sig)
+                ChessGameEvent.KIND -> ChessGameEvent(id, pubKey, createdAt, tags, content, sig)
+                JesterEvent.KIND -> JesterEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveChessGameChallengeEvent.KIND -> LiveChessGameChallengeEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveChessGameAcceptEvent.KIND -> LiveChessGameAcceptEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveChessMoveEvent.KIND -> LiveChessMoveEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveChessGameEndEvent.KIND -> LiveChessGameEndEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveChessDrawOfferEvent.KIND -> LiveChessDrawOfferEvent(id, pubKey, createdAt, tags, content, sig)
                 ChannelCreateEvent.KIND -> ChannelCreateEvent(id, pubKey, createdAt, tags, content, sig)
                 ChannelHideMessageEvent.KIND -> ChannelHideMessageEvent(id, pubKey, createdAt, tags, content, sig)
                 ChannelListEvent.KIND -> ChannelListEvent(id, pubKey, createdAt, tags, content, sig)
@@ -254,6 +270,8 @@ class EventFactory {
                 PictureEvent.KIND -> PictureEvent(id, pubKey, createdAt, tags, content, sig)
                 PinListEvent.KIND -> PinListEvent(id, pubKey, createdAt, tags, content, sig)
                 PollNoteEvent.KIND -> PollNoteEvent(id, pubKey, createdAt, tags, content, sig)
+                PollEvent.KIND -> PollEvent(id, pubKey, createdAt, tags, content, sig)
+                PollResponseEvent.KIND -> PollResponseEvent(id, pubKey, createdAt, tags, content, sig)
                 PrivateDmEvent.KIND -> PrivateDmEvent(id, pubKey, createdAt, tags, content, sig)
                 PrivateOutboxRelayListEvent.KIND -> PrivateOutboxRelayListEvent(id, pubKey, createdAt, tags, content, sig)
                 ProxyRelayListEvent.KIND -> ProxyRelayListEvent(id, pubKey, createdAt, tags, content, sig)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/TimeUtils.kt

@@ -55,6 +55,8 @@ object TimeUtils {
 
     fun oneDayAgo() = now() - ONE_DAY
 
+    fun oneDayAhead() = now() + ONE_DAY
+
     fun eightHoursAgo() = now() - EIGHT_HOURS
 
     fun twoDays() = ONE_DAY * 2

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt

@@ -20,26 +20,6 @@
  */
 package com.vitorpamplona.quartz
 
-/**
- * Copyright (c) 2025 Vitor Pamplona
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
- * Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
 expect class TestResourceLoader() {
     fun loadString(file: String): String
 }

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip01Core/hints/HintIndexerTest.kt

@@ -56,18 +56,20 @@ class HintIndexerTest {
                 )
             }
 
-        val relays =
-            TestResourceLoader()
-                .loadString("relayDB.txt")
-                .split('\n')
-                .mapNotNull {
-                    val relay = RelayUrlNormalizer.normalizeOrNull(it)
-                    if (relay == null || relay.isLocalHost()) {
-                        null
-                    } else {
-                        relay
+        val relays by
+            lazy {
+                TestResourceLoader()
+                    .loadString("relayDB.txt")
+                    .split('\n')
+                    .mapNotNull {
+                        val relay = RelayUrlNormalizer.normalizeOrNull(it)
+                        if (relay == null || relay.isLocalHost()) {
+                            null
+                        } else {
+                            relay
+                        }
                     }
-                }
+            }
 
         val indexer by lazy {
             val result = HintIndexer()

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessGameEventTest.kt

@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+/**
+ * Tests for ChessGameEvent (NIP-64 Kind 64 event)
+ *
+ * Verifies:
+ * - Event kind is 64
+ * - PGN content storage
+ * - Alt text support (NIP-31)
+ * - Event structure compliance
+ */
+class ChessGameEventTest {
+    private val samplePGN =
+        """
+        [Event "Test Game"]
+        [Site "Internet"]
+        [Date "2024.12.28"]
+        [Round "1"]
+        [White "Alice"]
+        [Black "Bob"]
+        [Result "1-0"]
+
+        1. e4 e5 2. Qh5 Nc6 3. Bc4 Nf6 4. Qxf7# 1-0
+        """.trimIndent()
+
+    @Test
+    fun `verify event kind is 64`() {
+        assertEquals(64, ChessGameEvent.KIND, "Chess game event should be kind 64")
+    }
+
+    @Test
+    fun `pgn content is accessible`() {
+        // Create a mock event manually for testing
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Chess Game")),
+                content = samplePGN,
+                sig = "test_sig",
+            )
+
+        assertEquals(samplePGN, testEvent.pgn(), "PGN content should be accessible via pgn()")
+        assertEquals(samplePGN, testEvent.content, "PGN should be in content field")
+    }
+
+    @Test
+    fun `alt text is accessible when present`() {
+        val customAltText = "Scholar's Mate Example"
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", customAltText)),
+                content = samplePGN,
+                sig = "test_sig",
+            )
+
+        assertEquals(customAltText, testEvent.altText(), "Alt text should be extractable from tags")
+    }
+
+    @Test
+    fun `alt text returns null when not present`() {
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = samplePGN,
+                sig = "test_sig",
+            )
+
+        assertEquals(null, testEvent.altText(), "Should return null when no alt tag present")
+    }
+
+    @Test
+    fun `event can store complete game with metadata`() {
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Chess Game")),
+                content = samplePGN,
+                sig = "test_sig",
+            )
+
+        // Parse the PGN to verify it's valid
+        val gameResult = PGNParser.parse(testEvent.pgn())
+        assertTrue(gameResult.isSuccess, "Event should contain valid PGN")
+
+        val game = gameResult.getOrThrow()
+        assertEquals("Test Game", game.event)
+        assertEquals("Alice", game.white)
+        assertEquals("Bob", game.black)
+        assertEquals(GameResult.WHITE_WINS, game.result)
+    }
+
+    @Test
+    fun `event can store minimal PGN`() {
+        val minimalPGN = "1. e4 *"
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Chess Game")),
+                content = minimalPGN,
+                sig = "test_sig",
+            )
+
+        val gameResult = PGNParser.parse(testEvent.pgn())
+        assertTrue(gameResult.isSuccess, "Should handle minimal PGN")
+
+        val game = gameResult.getOrThrow()
+        assertEquals(1, game.moves.size)
+        assertEquals(GameResult.IN_PROGRESS, game.result)
+    }
+
+    @Test
+    fun `event can store game in progress`() {
+        val inProgressPGN =
+            """
+            [Event "Live Game"]
+            [Result "*"]
+
+            1. e4 e5 2. Nf3 Nc6 3. Bb5 *
+            """.trimIndent()
+
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Live Chess Game")),
+                content = inProgressPGN,
+                sig = "test_sig",
+            )
+
+        val gameResult = PGNParser.parse(testEvent.pgn())
+        assertTrue(gameResult.isSuccess)
+
+        val game = gameResult.getOrThrow()
+        assertEquals(GameResult.IN_PROGRESS, game.result)
+        assertEquals("*", game.metadata["Result"])
+    }
+
+    @Test
+    fun `event preserves PGN formatting`() {
+        val formattedPGN =
+            """
+            [Event "Formatted Game"]
+            [White "Player 1"]
+            [Black "Player 2"]
+
+            1. e4 e5
+            2. Nf3 Nc6
+            3. Bb5 a6
+            *
+            """.trimIndent()
+
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Chess Game")),
+                content = formattedPGN,
+                sig = "test_sig",
+            )
+
+        // Content should be preserved exactly as provided
+        assertEquals(formattedPGN, testEvent.pgn())
+    }
+
+    @Test
+    fun `default alt text is Chess Game`() {
+        assertEquals("Chess Game", ChessGameEvent.ALT_DESCRIPTION)
+    }
+
+    @Test
+    fun `event inherits from Event base class`() {
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = "1. e4 *",
+                sig = "test_sig",
+            )
+
+        // Verify base Event properties
+        assertEquals("test_id", testEvent.id)
+        assertEquals("test_pubkey", testEvent.pubKey)
+        assertEquals(1000L, testEvent.createdAt)
+        assertEquals(64, testEvent.kind)
+        assertEquals("test_sig", testEvent.sig)
+    }
+
+    @Test
+    fun `event can contain long tournament game`() {
+        val longPGN =
+            """
+            [Event "Tournament Game"]
+            [Site "Online"]
+            [Date "2024.12.28"]
+            [Round "5"]
+            [White "GM Player"]
+            [Black "IM Player"]
+            [Result "1/2-1/2"]
+
+            1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5
+            7. O-O Nc6 8. d5 Ne7 9. Ne1 Nd7 10. Nd3 f5 11. Bd2 Nf6 12. f3 f4
+            13. Rc1 g5 14. Nb5 Ng6 15. c5 Rf7 16. Qa4 h5 17. Rfe1 Bf8
+            18. cxd6 cxd6 19. Rc6 Bd7 20. Rec1 Bxc6 21. Rxc6 Qd7 22. Rc1 Rc8
+            23. Rxc8 Qxc8 24. Qa6 Qc2 25. Qxb7 Qxb2 26. Qxa7 Qxa2 27. Qb7 Qa1+
+            28. Kf2 Qb2 29. Qa7 Ra7 30. Qa4 Qa2 31. Qa8 Qb2 32. Qa4 Qa2 1/2-1/2
+            """.trimIndent()
+
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags = arrayOf(arrayOf("alt", "Long Tournament Game")),
+                content = longPGN,
+                sig = "test_sig",
+            )
+
+        val gameResult = PGNParser.parse(testEvent.pgn())
+        assertTrue(gameResult.isSuccess)
+
+        val game = gameResult.getOrThrow()
+        assertTrue(game.moves.size > 50, "Should handle long games")
+        assertEquals(GameResult.DRAW, game.result)
+    }
+
+    @Test
+    fun `verify tags array structure`() {
+        val testEvent =
+            ChessGameEvent(
+                id = "test_id",
+                pubKey = "test_pubkey",
+                createdAt = 1000L,
+                tags =
+                    arrayOf(
+                        arrayOf("alt", "Test Alt Text"),
+                        arrayOf("t", "chess"),
+                        arrayOf("t", "game"),
+                    ),
+                content = "1. e4 *",
+                sig = "test_sig",
+            )
+
+        // Verify tags structure
+        assertTrue(testEvent.tags.size >= 1)
+        assertEquals("alt", testEvent.tags[0][0])
+        assertEquals("Test Alt Text", testEvent.tags[0][1])
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip64Chess/JesterEventTest.kt

@@ -0,0 +1,573 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+/**
+ * Tests for JesterEvent (Jester Protocol kind 30 events)
+ *
+ * Verifies:
+ * - Event kind is 30
+ * - JSON content parsing (version, kind, fen, move, history)
+ * - e-tag structure for event linking
+ * - p-tag for opponent tagging
+ * - Start vs Move event detection
+ * - Compatibility with jesterui protocol
+ *
+ * Reference: https://github.com/jesterui/jesterui/blob/devel/FLOW.md
+ */
+class JesterEventTest {
+    private val testPubkey = "abc123def456"
+    private val opponentPubkey = "opponent789xyz"
+    private val startEventId = "start-event-id-001"
+
+    // ==========================================================================
+    // PROTOCOL CONSTANTS
+    // ==========================================================================
+
+    @Test
+    fun `verify event kind is 30`() {
+        assertEquals(30, JesterProtocol.KIND, "Jester protocol uses kind 30")
+        assertEquals(30, JesterEvent.KIND, "JesterEvent.KIND should be 30")
+    }
+
+    @Test
+    fun `verify start position hash constant`() {
+        assertEquals(
+            "b1791d7fc9ae3d38966568c257ffb3a02cbf8394cdb4805bc70f64fc3c0b6879",
+            JesterProtocol.START_POSITION_HASH,
+            "Should match jesterui's START_POSITION_HASH",
+        )
+    }
+
+    @Test
+    fun `verify starting FEN constant`() {
+        assertEquals(
+            "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
+            JesterProtocol.FEN_START,
+            "Standard chess starting position",
+        )
+    }
+
+    @Test
+    fun `verify content kind constants`() {
+        assertEquals(0, JesterProtocol.CONTENT_KIND_START, "Start event kind should be 0")
+        assertEquals(1, JesterProtocol.CONTENT_KIND_MOVE, "Move event kind should be 1")
+        assertEquals(2, JesterProtocol.CONTENT_KIND_CHAT, "Chat event kind should be 2")
+    }
+
+    // ==========================================================================
+    // START EVENT TESTS
+    // ==========================================================================
+
+    @Test
+    fun `parse start event - open challenge`() {
+        val content = """{"version":"0","kind":0,"fen":"${JesterProtocol.FEN_START}","history":[],"nonce":"abc12345","playerColor":"white"}"""
+        val event =
+            JesterEvent(
+                id = startEventId,
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", JesterProtocol.START_POSITION_HASH),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals(30, event.kind)
+        assertTrue(event.isStartEvent(), "Should be detected as start event")
+        assertFalse(event.isMoveEvent(), "Should not be a move event")
+        assertEquals(0, event.contentKind())
+        assertEquals(JesterProtocol.FEN_START, event.fen())
+        assertEquals(Color.WHITE, event.playerColor())
+        assertEquals("abc12345", event.nonce())
+        assertTrue(event.history().isEmpty(), "Start event has no history")
+        assertNull(event.opponentPubkey(), "Open challenge has no opponent")
+    }
+
+    @Test
+    fun `parse start event - private challenge`() {
+        val content = """{"version":"0","kind":0,"fen":"${JesterProtocol.FEN_START}","history":[],"nonce":"xyz98765","playerColor":"black"}"""
+        val event =
+            JesterEvent(
+                id = startEventId,
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", JesterProtocol.START_POSITION_HASH),
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertTrue(event.isStartEvent())
+        assertEquals(Color.BLACK, event.playerColor())
+        assertEquals(opponentPubkey, event.opponentPubkey(), "Private challenge should have opponent")
+    }
+
+    @Test
+    fun `start event e-tag references START_POSITION_HASH`() {
+        val content = """{"version":"0","kind":0,"fen":"${JesterProtocol.FEN_START}","history":[]}"""
+        val event =
+            JesterEvent(
+                id = startEventId,
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", JesterProtocol.START_POSITION_HASH),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        val eTags = event.eTags()
+        assertEquals(1, eTags.size)
+        assertEquals(JesterProtocol.START_POSITION_HASH, eTags[0], "Start event should reference START_POSITION_HASH")
+    }
+
+    // ==========================================================================
+    // MOVE EVENT TESTS
+    // ==========================================================================
+
+    @Test
+    fun `parse move event - first move e4`() {
+        val content = """{"version":"0","kind":1,"fen":"rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1","move":"e4","history":["e4"]}"""
+        val event =
+            JesterEvent(
+                id = "move-001",
+                pubKey = testPubkey,
+                createdAt = 2000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", startEventId), // For first move, head is also start
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertFalse(event.isStartEvent(), "Should not be a start event")
+        assertTrue(event.isMoveEvent(), "Should be detected as move event")
+        assertEquals(1, event.contentKind())
+        assertEquals("e4", event.move())
+        assertEquals(listOf("e4"), event.history())
+        assertEquals("rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1", event.fen())
+        assertEquals(opponentPubkey, event.opponentPubkey())
+    }
+
+    @Test
+    fun `parse move event - multiple moves in history`() {
+        val content = """{"version":"0","kind":1,"fen":"rnbqkbnr/pppp1ppp/8/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2","move":"Nf3","history":["e4","e5","Nf3"]}"""
+        val event =
+            JesterEvent(
+                id = "move-003",
+                pubKey = testPubkey,
+                createdAt = 4000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", "move-002"), // Previous move
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertTrue(event.isMoveEvent())
+        assertEquals("Nf3", event.move())
+        assertEquals(listOf("e4", "e5", "Nf3"), event.history())
+        assertEquals(3, event.history().size)
+    }
+
+    @Test
+    fun `move event e-tags structure - startEventId and headEventId`() {
+        val content = """{"version":"0","kind":1,"fen":"test","move":"e4","history":["e4"]}"""
+        val headEventId = "move-002"
+        val event =
+            JesterEvent(
+                id = "move-003",
+                pubKey = testPubkey,
+                createdAt = 3000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", headEventId),
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals(startEventId, event.startEventId(), "First e-tag should be startEventId")
+        assertEquals(headEventId, event.headEventId(), "Second e-tag should be headEventId")
+
+        val eTags = event.eTags()
+        assertEquals(2, eTags.size)
+        assertEquals(startEventId, eTags[0])
+        assertEquals(headEventId, eTags[1])
+    }
+
+    // ==========================================================================
+    // GAME END EVENT TESTS
+    // ==========================================================================
+
+    @Test
+    fun `parse game end event - checkmate`() {
+        val content = """{"version":"0","kind":1,"fen":"r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4","move":"Qxf7#","history":["e4","e5","Qh5","Nc6","Bc4","Nf6","Qxf7#"],"result":"1-0","termination":"checkmate"}"""
+        val event =
+            JesterEvent(
+                id = "move-007",
+                pubKey = testPubkey,
+                createdAt = 8000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", "move-006"),
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertTrue(event.isMoveEvent(), "End event is still a move event")
+        assertEquals("1-0", event.result(), "Should have result")
+        assertEquals("checkmate", event.termination(), "Should have termination reason")
+        assertEquals(7, event.history().size)
+    }
+
+    @Test
+    fun `parse game end event - resignation`() {
+        val content = """{"version":"0","kind":1,"fen":"test","move":"e5","history":["e4","e5"],"result":"0-1","termination":"resignation"}"""
+        val event =
+            JesterEvent(
+                id = "move-002",
+                pubKey = opponentPubkey,
+                createdAt = 3000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", "move-001"),
+                        arrayOf("p", testPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals("0-1", event.result(), "Black wins")
+        assertEquals("resignation", event.termination())
+    }
+
+    @Test
+    fun `parse game end event - draw`() {
+        val content = """{"version":"0","kind":1,"fen":"test","move":"Kf1","history":["e4","e5","Kf1"],"result":"1/2-1/2","termination":"draw_agreement"}"""
+        val event =
+            JesterEvent(
+                id = "move-003",
+                pubKey = testPubkey,
+                createdAt = 4000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                        arrayOf("e", "move-002"),
+                        arrayOf("p", opponentPubkey),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals("1/2-1/2", event.result(), "Draw")
+        assertEquals("draw_agreement", event.termination())
+    }
+
+    // ==========================================================================
+    // EDGE CASES AND ERROR HANDLING
+    // ==========================================================================
+
+    @Test
+    fun `handle malformed JSON content gracefully`() {
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = "invalid json {{{}",
+                sig = "test_sig",
+            )
+
+        assertNull(event.contentKind(), "Should return null for invalid JSON")
+        assertFalse(event.isStartEvent(), "Should not crash on invalid content")
+        assertFalse(event.isMoveEvent(), "Should not crash on invalid content")
+        assertNull(event.fen())
+        assertNull(event.move())
+        assertTrue(event.history().isEmpty())
+    }
+
+    @Test
+    fun `handle empty content`() {
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = "",
+                sig = "test_sig",
+            )
+
+        assertNull(event.contentKind())
+        assertFalse(event.isStartEvent())
+        assertFalse(event.isMoveEvent())
+    }
+
+    @Test
+    fun `handle missing optional fields`() {
+        // Minimal valid content with only required fields
+        val content = """{"kind":1}"""
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals(1, event.contentKind())
+        assertNull(event.move())
+        assertTrue(event.history().isEmpty())
+        assertNull(event.result())
+        assertNull(event.termination())
+        assertNull(event.playerColor())
+    }
+
+    @Test
+    fun `handle event with no e-tags`() {
+        val content = """{"version":"0","kind":0}"""
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertNull(event.startEventId(), "No e-tags means no startEventId")
+        assertNull(event.headEventId(), "No e-tags means no headEventId")
+        assertTrue(event.eTags().isEmpty())
+    }
+
+    @Test
+    fun `handle event with only one e-tag`() {
+        val content = """{"version":"0","kind":1}"""
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags =
+                    arrayOf(
+                        arrayOf("e", startEventId),
+                    ),
+                content = content,
+                sig = "test_sig",
+            )
+
+        assertEquals(startEventId, event.startEventId())
+        assertNull(event.headEventId(), "Only one e-tag means no headEventId")
+    }
+
+    // ==========================================================================
+    // JESTER GAME EVENTS CONTAINER TESTS
+    // ==========================================================================
+
+    @Test
+    fun `JesterGameEvents - empty returns correct values`() {
+        val events = JesterGameEvents.empty()
+
+        assertNull(events.startEvent)
+        assertTrue(events.moves.isEmpty())
+        assertNull(events.latestMove())
+        assertEquals(JesterProtocol.FEN_START, events.currentFen())
+        assertTrue(events.fullHistory().isEmpty())
+        assertFalse(events.isEnded())
+        assertNull(events.result())
+    }
+
+    @Test
+    fun `JesterGameEvents - latestMove returns move with longest history`() {
+        val move1 = createTestMoveEvent("move-001", listOf("e4"))
+        val move2 = createTestMoveEvent("move-002", listOf("e4", "e5"))
+        val move3 = createTestMoveEvent("move-003", listOf("e4", "e5", "Nf3"))
+
+        // Provide moves in random order
+        val events =
+            JesterGameEvents(
+                startEvent = null,
+                moves = listOf(move2, move3, move1),
+            )
+
+        val latest = events.latestMove()
+        assertNotNull(latest)
+        assertEquals("move-003", latest.id, "Should return move with longest history")
+        assertEquals(3, latest.history().size)
+    }
+
+    @Test
+    fun `JesterGameEvents - currentFen returns FEN from latest move`() {
+        val move1 = createTestMoveEvent("move-001", listOf("e4"), fen = "fen-after-e4")
+        val move2 = createTestMoveEvent("move-002", listOf("e4", "e5"), fen = "fen-after-e5")
+
+        val events =
+            JesterGameEvents(
+                startEvent = null,
+                moves = listOf(move1, move2),
+            )
+
+        assertEquals("fen-after-e5", events.currentFen())
+    }
+
+    @Test
+    fun `JesterGameEvents - fullHistory returns history from latest move`() {
+        val move1 = createTestMoveEvent("move-001", listOf("e4"))
+        val move2 = createTestMoveEvent("move-002", listOf("e4", "e5"))
+
+        val events =
+            JesterGameEvents(
+                startEvent = null,
+                moves = listOf(move1, move2),
+            )
+
+        assertEquals(listOf("e4", "e5"), events.fullHistory())
+    }
+
+    @Test
+    fun `JesterGameEvents - isEnded detects result in latest move`() {
+        val normalMove = createTestMoveEvent("move-001", listOf("e4"))
+        val endMove = createTestMoveEventWithResult("move-002", listOf("e4", "Qxf7#"), result = "1-0")
+
+        val ongoingGame = JesterGameEvents(startEvent = null, moves = listOf(normalMove))
+        val finishedGame = JesterGameEvents(startEvent = null, moves = listOf(normalMove, endMove))
+
+        assertFalse(ongoingGame.isEnded())
+        assertTrue(finishedGame.isEnded())
+        assertEquals("1-0", finishedGame.result())
+    }
+
+    // ==========================================================================
+    // EXTENSION FUNCTION TESTS
+    // ==========================================================================
+
+    @Test
+    fun `isJesterEvent extension detects kind 30`() {
+        val jesterEvent =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = "{}",
+                sig = "sig",
+            )
+
+        assertTrue(jesterEvent.isJesterEvent())
+    }
+
+    @Test
+    fun `toJesterEvent converts valid Event`() {
+        val event =
+            JesterEvent(
+                id = "test",
+                pubKey = testPubkey,
+                createdAt = 1000L,
+                tags = emptyArray(),
+                content = """{"kind":0}""",
+                sig = "sig",
+            )
+
+        val jesterEvent = event.toJesterEvent()
+        assertNotNull(jesterEvent)
+        assertEquals("test", jesterEvent.id)
+    }
+
+    // ==========================================================================
+    // HELPER FUNCTIONS
+    // ==========================================================================
+
+    private fun createTestMoveEvent(
+        id: String,
+        history: List<String>,
+        fen: String = "test-fen",
+    ): JesterEvent {
+        val historyJson = history.joinToString(",") { "\"$it\"" }
+        val content = """{"version":"0","kind":1,"fen":"$fen","move":"${history.last()}","history":[$historyJson]}"""
+        return JesterEvent(
+            id = id,
+            pubKey = testPubkey,
+            createdAt = 1000L + history.size * 1000,
+            tags =
+                arrayOf(
+                    arrayOf("e", startEventId),
+                    arrayOf("e", "prev-move"),
+                    arrayOf("p", opponentPubkey),
+                ),
+            content = content,
+            sig = "sig",
+        )
+    }
+
+    private fun createTestMoveEventWithResult(
+        id: String,
+        history: List<String>,
+        result: String,
+    ): JesterEvent {
+        val historyJson = history.joinToString(",") { "\"$it\"" }
+        val content = """{"version":"0","kind":1,"fen":"test-fen","move":"${history.last()}","history":[$historyJson],"result":"$result","termination":"checkmate"}"""
+        return JesterEvent(
+            id = id,
+            pubKey = testPubkey,
+            createdAt = 1000L + history.size * 1000,
+            tags =
+                arrayOf(
+                    arrayOf("e", startEventId),
+                    arrayOf("e", "prev-move"),
+                    arrayOf("p", opponentPubkey),
+                ),
+            content = content,
+            sig = "sig",
+        )
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip64Chess/PGNParserTest.kt

@@ -0,0 +1,454 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+
+/**
+ * Comprehensive tests for PGN parsing per NIP-64 specification
+ *
+ * Tests cover:
+ * - PGN metadata extraction
+ * - Move parsing in Standard Algebraic Notation
+ * - Game result parsing
+ * - Comments and variations handling
+ * - Edge cases and error handling
+ */
+class PGNParserTest {
+    // Test 1: Parse minimal PGN (NIP-64 requirement: accept import format)
+    @Test
+    fun `parse minimal PGN with single move`() {
+        val pgn = "1. e4 *"
+        val result = PGNParser.parse(pgn)
+
+        assertTrue(result.isSuccess, "Should successfully parse minimal PGN")
+        val game = result.getOrThrow()
+        assertEquals(1, game.moves.size, "Should have 1 move")
+        assertEquals("e4", game.moves[0].san)
+        assertEquals(GameResult.IN_PROGRESS, game.result)
+    }
+
+    // Test 2: Parse complete game with metadata (NIP-64 requirement)
+    @Test
+    fun `parse PGN with full metadata tags`() {
+        val pgn =
+            """
+            [Event "F/S Return Match"]
+            [Site "Belgrade, Serbia JUG"]
+            [Date "1992.11.04"]
+            [Round "29"]
+            [White "Fischer, Robert J."]
+            [Black "Spassky, Boris V."]
+            [Result "1/2-1/2"]
+
+            1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 1/2-1/2
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Verify metadata extraction
+        assertEquals("F/S Return Match", game.event)
+        assertEquals("Belgrade, Serbia JUG", game.site)
+        assertEquals("1992.11.04", game.date)
+        assertEquals("29", game.round)
+        assertEquals("Fischer, Robert J.", game.white)
+        assertEquals("Spassky, Boris V.", game.black)
+        assertEquals(GameResult.DRAW, game.result)
+
+        // Verify moves
+        assertEquals(6, game.moves.size)
+        assertEquals("e4", game.moves[0].san)
+        assertEquals("Nf3", game.moves[2].san)
+    }
+
+    // Test 3: Scholar's Mate (4 move checkmate)
+    @Test
+    fun `parse scholars mate with checkmate notation`() {
+        val pgn =
+            """
+            [Event "Scholar's Mate"]
+            [White "Alice"]
+            [Black "Bob"]
+            [Result "1-0"]
+
+            1. e4 e5 2. Bc4 Nc6 3. Qh5 Nf6 4. Qxf7# 1-0
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals(7, game.moves.size)
+        assertEquals(GameResult.WHITE_WINS, game.result)
+
+        // Verify last move has checkmate marker
+        val lastMove = game.moves.last()
+        assertEquals("Qxf7#", lastMove.san)
+        assertTrue(lastMove.isCheckmate, "Last move should be checkmate")
+        assertTrue(lastMove.isCapture, "Last move should be capture")
+    }
+
+    // Test 4: Fool's Mate (2 move checkmate)
+    @Test
+    fun `parse fools mate shortest checkmate`() {
+        val pgn =
+            """
+            1. f3 e5 2. g4 Qh4# 0-1
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals(4, game.moves.size)
+        assertEquals(GameResult.BLACK_WINS, game.result)
+
+        val lastMove = game.moves.last()
+        assertEquals("Qh4#", lastMove.san)
+        assertTrue(lastMove.isCheckmate)
+    }
+
+    // Test 5: Castling notation
+    @Test
+    fun `parse castling moves kingside and queenside`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O O-O 5. d3 d6 6. c3 a6 7. a4 a5 8. O-O-O *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Find castling moves
+        val kingsideCastling = game.moves.filter { it.san == "O-O" }
+        val queensideCastling = game.moves.filter { it.san == "O-O-O" }
+
+        assertEquals(2, kingsideCastling.size, "Should have 2 kingside castling moves")
+        assertEquals(1, queensideCastling.size, "Should have 1 queenside castling move")
+
+        kingsideCastling.forEach { move ->
+            assertTrue(move.isCastling, "O-O should be marked as castling")
+            assertEquals(PieceType.KING, move.piece)
+        }
+
+        queensideCastling.forEach { move ->
+            assertTrue(move.isCastling, "O-O-O should be marked as castling")
+            assertEquals(PieceType.KING, move.piece)
+        }
+    }
+
+    // Test 6: Pawn promotion
+    @Test
+    fun `parse pawn promotion to queen`() {
+        val pgn =
+            """
+            [Event "Promotion Example"]
+
+            1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 c6 5. Nf3 Bg4 6. Bf4 e6
+            7. h3 Bxf3 8. Qxf3 Bb4 9. Be2 Nd7 10. a3 O-O-O 11. axb4 Qxa1+
+            12. Kd2 Qxh1 13. Qxh1 a6 14. c4 f6 15. b5 axb5 16. cxb5 c5
+            17. b6 Ne7 18. Qh2 h6 19. dxc5 Nxc5 20. b3 Kc8 21. Qg3 Ncd7
+            22. Bd6 Nf5 23. Qf4 Nxd6 24. Qxd6 Nb8 25. Kc3 Rh7 26. Kb4 Rd7
+            27. Qc5+ Kd8 28. Bf3 Ke8 29. Bd5 exd5 30. Nxd5 Kf7 31. b7 Kg6
+            32. b8=Q *
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Find promotion move
+        val promotionMove = game.moves.firstOrNull { it.promotion != null }
+        assertNotNull(promotionMove, "Should have promotion move")
+        assertEquals(PieceType.QUEEN, promotionMove.promotion)
+        assertTrue(promotionMove.san.contains("=Q"), "Promotion move should contain =Q")
+    }
+
+    // Test 7: Captures
+    @Test
+    fun `parse capture notation`() {
+        val pgn = "1. e4 d5 2. exd5 Qxd5 3. Nc3 Qxd4 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        val captures = game.moves.filter { it.isCapture }
+        assertEquals(3, captures.size, "Should have 3 capture moves")
+
+        captures.forEach { move ->
+            assertTrue(move.san.contains("x"), "Capture moves should contain 'x'")
+        }
+    }
+
+    // Test 8: Check notation
+    @Test
+    fun `parse check and checkmate markers`() {
+        val pgn = "1. e4 e5 2. Qh5 Nc6 3. Bc4 Nf6 4. Qxf7# 1-0"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        val checkMoves = game.moves.filter { it.isCheck }
+        val checkmateMoves = game.moves.filter { it.isCheckmate }
+
+        assertTrue(checkmateMoves.isNotEmpty(), "Should have checkmate moves")
+        checkmateMoves.forEach { move ->
+            assertTrue(move.san.contains("#"), "Checkmate moves should contain #")
+        }
+    }
+
+    // Test 9: Comments and variations (NIP-64: should handle PGN comments)
+    @Test
+    fun `parse PGN with comments and variations stripped`() {
+        val pgn =
+            """
+            1. e4 {Best by test} e5 (1...c5 2. Nf3) 2. Nf3 Nc6 {Developing} 3. Bb5 *
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Comments and variations should be stripped
+        assertEquals(5, game.moves.size)
+        assertEquals("e4", game.moves[0].san)
+        assertEquals("e5", game.moves[1].san)
+        assertEquals("Nf3", game.moves[2].san)
+    }
+
+    // Test 10: NAG annotations (Numeric Annotation Glyphs)
+    @Test
+    fun `parse PGN with NAG annotations`() {
+        val pgn = "1. e4$1 e5$6 2. Nf3$10 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals(3, game.moves.size)
+    }
+
+    // Test 11: Disambiguating moves
+    @Test
+    fun `parse moves with disambiguation`() {
+        val pgn =
+            """
+            1. Nf3 Nf6 2. Nc3 Nc6 3. d4 d5 4. Bf4 Bf5 5. e3 e6
+            6. Nbd2 Nbd7 7. Bd3 Bd6 *
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Check for disambiguated moves (Nbd2, Nbd7)
+        val disambiguatedMoves = game.moves.filter { it.fromSquare != null }
+        assertTrue(disambiguatedMoves.isNotEmpty(), "Should have disambiguated moves")
+    }
+
+    // Test 12: All possible game results
+    @Test
+    fun `parse all game result notations`() {
+        val whiteWins = "1. e4 e5 2. Qh5 Nc6 3. Bc4 Nf6 4. Qxf7# 1-0"
+        val blackWins = "1. f3 e5 2. g4 Qh4# 0-1"
+        val draw = "1. e4 e5 2. Nf3 Nc6 1/2-1/2"
+        val inProgress = "1. e4 e5 *"
+
+        assertEquals(GameResult.WHITE_WINS, PGNParser.parse(whiteWins).getOrThrow().result)
+        assertEquals(GameResult.BLACK_WINS, PGNParser.parse(blackWins).getOrThrow().result)
+        assertEquals(GameResult.DRAW, PGNParser.parse(draw).getOrThrow().result)
+        assertEquals(GameResult.IN_PROGRESS, PGNParser.parse(inProgress).getOrThrow().result)
+    }
+
+    // Test 13: Empty/invalid PGN handling
+    @Test
+    fun `handle empty PGN gracefully`() {
+        val emptyPgn = ""
+        val result = PGNParser.parse(emptyPgn)
+
+        // Should not crash, might return empty game
+        assertTrue(result.isSuccess || result.isFailure)
+    }
+
+    // Test 14: Position generation
+    @Test
+    fun `generate positions for each move`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bb5 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // Should have starting position + one per move
+        assertEquals(game.moves.size + 1, game.positions.size)
+
+        // First position should be starting position
+        val startPos = game.positions[0]
+        assertEquals(Color.WHITE, startPos.activeColor)
+        assertEquals(1, startPos.moveNumber)
+    }
+
+    // Test 15: Verify required metadata (NIP-64: PGN should have standard tags)
+    @Test
+    fun `detect presence of required PGN metadata tags`() {
+        val fullPgn =
+            """
+            [Event "FIDE World Championship"]
+            [Site "London"]
+            [Date "2018.11.28"]
+            [Round "12"]
+            [White "Carlsen, Magnus"]
+            [Black "Caruana, Fabiano"]
+            [Result "1-0"]
+
+            1. e4 *
+            """.trimIndent()
+
+        val minimalPgn = "1. e4 *"
+
+        val fullGame = PGNParser.parse(fullPgn).getOrThrow()
+        val minimalGame = PGNParser.parse(minimalPgn).getOrThrow()
+
+        assertTrue(fullGame.hasRequiredMetadata(), "Full PGN should have required metadata")
+        assertFalse(minimalGame.hasRequiredMetadata(), "Minimal PGN should not have required metadata")
+    }
+
+    // Test 16: Long tournament game
+    @Test
+    fun `parse realistic tournament game`() {
+        val pgn =
+            """
+            [Event "Wch"]
+            [Site "New York"]
+            [Date "1886.??.??"]
+            [Round "1"]
+            [White "Zukertort, Johannes"]
+            [Black "Steinitz, William"]
+            [Result "0-1"]
+
+            1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. e3 c5 5. Nf3 Nc6 6. a3 dxc4
+            7. Bxc4 cxd4 8. exd4 Be7 9. O-O O-O 10. Qd3 Bd7 11. Qe2 Qb8
+            12. Rd1 Rd8 13. Be3 Be8 14. Ne5 Nxe5 15. dxe5 Rxd1+ 16. Rxd1 Nd7
+            17. f4 Nc5 18. Qf2 Rc8 19. b4 Na6 20. Bd3 Nb8 21. Ne4 Nc6
+            22. Nd6 Bxd6 23. exd6 Qxd6 24. Bxh7+ Kh8 25. Bf5 Qc7 26. Bxc8 Qxc8
+            27. Qd2 Bg6 28. Qd7 Qxd7 29. Rxd7 b6 30. Bc1 Nd8 31. Rxd8+ 0-1
+            """.trimIndent()
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals("Zukertort, Johannes", game.white)
+        assertEquals("Steinitz, William", game.black)
+        assertEquals(GameResult.BLACK_WINS, game.result)
+        assertTrue(game.moves.size > 50, "Tournament game should have many moves")
+    }
+
+    // Test 17: Alternative castling notation (0-0 instead of O-O)
+    @Test
+    fun `parse alternative castling notation with zeros`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. 0-0 0-0 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        val castlingMoves = game.moves.filter { it.isCastling }
+        assertEquals(2, castlingMoves.size)
+    }
+
+    // Test 18: Move count verification
+    @Test
+    fun `verify move numbers are correct`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals(6, game.moves.size)
+
+        // Verify move numbers
+        assertEquals(1, game.moves[0].moveNumber) // e4
+        assertEquals(1, game.moves[1].moveNumber) // e5
+        assertEquals(2, game.moves[2].moveNumber) // Nf3
+        assertEquals(2, game.moves[3].moveNumber) // Nc6
+        assertEquals(3, game.moves[4].moveNumber) // Bb5
+        assertEquals(3, game.moves[5].moveNumber) // a6
+    }
+
+    // Test 19: Move colors are correct
+    @Test
+    fun `verify move colors alternate correctly`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        assertEquals(Color.WHITE, game.moves[0].color)
+        assertEquals(Color.BLACK, game.moves[1].color)
+        assertEquals(Color.WHITE, game.moves[2].color)
+        assertEquals(Color.BLACK, game.moves[3].color)
+        assertEquals(Color.WHITE, game.moves[4].color)
+        assertEquals(Color.BLACK, game.moves[5].color)
+    }
+
+    // Test 20: Piece type detection
+    @Test
+    fun `detect piece types from SAN notation`() {
+        val pgn = "1. e4 e5 2. Nf3 Nc6 3. Bb5 Bc5 4. Qa4 Qf6 5. Ke2 Ke7 6. Ra3 Ra6 *"
+
+        val result = PGNParser.parse(pgn)
+        assertTrue(result.isSuccess)
+        val game = result.getOrThrow()
+
+        // e4, e5 - pawns
+        assertEquals(PieceType.PAWN, game.moves[0].piece)
+        assertEquals(PieceType.PAWN, game.moves[1].piece)
+
+        // Nf3, Nc6 - knights
+        assertEquals(PieceType.KNIGHT, game.moves[2].piece)
+        assertEquals(PieceType.KNIGHT, game.moves[3].piece)
+
+        // Bb5, Bc5 - bishops
+        assertEquals(PieceType.BISHOP, game.moves[4].piece)
+        assertEquals(PieceType.BISHOP, game.moves[5].piece)
+
+        // Qa4, Qf6 - queens
+        assertEquals(PieceType.QUEEN, game.moves[6].piece)
+        assertEquals(PieceType.QUEEN, game.moves[7].piece)
+
+        // Ke2, Ke7 - kings
+        assertEquals(PieceType.KING, game.moves[8].piece)
+        assertEquals(PieceType.KING, game.moves[9].piece)
+
+        // Ra3, Ra6 - rooks
+        assertEquals(PieceType.ROOK, game.moves[10].piece)
+        assertEquals(PieceType.ROOK, game.moves[11].piece)
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/utils/SignerUtils.kt

@@ -20,10 +20,28 @@
  */
 package com.vitorpamplona.quartz.utils
 
-import com.vitorpamplona.quartz.nip01Core.crypto.DeterministicSigner
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.toHexKey
+import com.vitorpamplona.quartz.nip01Core.crypto.EventAssembler
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
+import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
 import com.vitorpamplona.quartz.nip19Bech32.bech32.bechToBytes
 
 fun String.nsecToKeyPair() = KeyPair(this.bechToBytes())
 
 fun String.nsecToSigner() = this.nsecToKeyPair().let { DeterministicSigner(it) }
+
+class DeterministicSigner(
+    val key: KeyPair,
+    val pubKey: HexKey = key.pubKey.toHexKey(),
+) {
+    fun <T : Event> sign(
+        createdAt: Long,
+        kind: Int,
+        tags: Array<Array<String>>,
+        content: String,
+    ): T = EventAssembler.hashAndSign(pubKey, createdAt, kind, tags, content, key.privKey!!, nonce = null)
+
+    fun <T : Event> sign(ev: EventTemplate<T>): T = sign(ev.createdAt, ev.kind, ev.tags, ev.content)
+}

quartz/src/iosMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.ios.kt

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+actual class ChessEngine actual constructor() {
+    actual fun getFen(): String {
+        TODO("Not yet implemented")
+    }
+
+    actual fun loadFen(fen: String) {
+    }
+
+    actual fun reset() {
+    }
+
+    actual fun makeMove(san: String): MoveResult {
+        TODO("Not yet implemented")
+    }
+
+    actual fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): MoveResult {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getLegalMoves(): List<String> {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getLegalMovesFrom(square: String): List<String> {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isLegalMove(san: String): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isLegalMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isCheckmate(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isStalemate(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isInCheck(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun undoMove() {
+    }
+
+    actual fun getPosition(): ChessPosition {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getSideToMove(): Color {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getMoveHistory(): List<String> {
+        TODO("Not yet implemented")
+    }
+}

quartz/src/iosTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt

@@ -32,11 +32,22 @@ import platform.darwin.NSObjectMeta
 actual class TestResourceLoader {
     @OptIn(ExperimentalForeignApi::class, BetaInteropApi::class)
     actual fun loadString(file: String): String {
-        val bundle = NSBundle.Companion.bundleForClass(BundleMarker)
+        // Split the filename and extension (e.g., "data.json" -> "data", "json")
+        val basename = file.substringBeforeLast(".")
+        val extension = file.substringAfterLast(".", "")
+
+        // Locate the file in the main application bundle
         val path =
-            bundle.pathForResource(file, ofType = null)
+            NSBundle.mainBundle.pathForResource(basename, ofType = extension)
                 ?: throw IllegalArgumentException("Resource not found: $file")
-        return NSString.Companion.stringWithContentsOfFile(path, encoding = NSUTF8StringEncoding, error = null)!!
+
+        // Read the file content as a UTF-8 string
+        return NSString
+            .stringWithContentsOfFile(
+                path = path,
+                encoding = NSUTF8StringEncoding,
+                error = null,
+            ).toString()
     }
 
     private class BundleMarker : NSObject() {

quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.jvmAndroid.kt

@@ -0,0 +1,349 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import com.github.bhlangonijr.chesslib.Board
+import com.github.bhlangonijr.chesslib.Piece
+import com.github.bhlangonijr.chesslib.Side
+import com.github.bhlangonijr.chesslib.Square
+import com.github.bhlangonijr.chesslib.move.Move
+
+/**
+ * JVM/Android implementation of ChessEngine using kchesslib.
+ *
+ * Maintains its own SAN history because chesslib's Move.toString() returns
+ * UCI/coordinate notation (e.g. "e2e4") rather than proper SAN (e.g. "e4").
+ */
+actual class ChessEngine {
+    private val board = Board()
+    private val sanHistory = mutableListOf<String>()
+
+    actual fun getFen(): String = board.fen
+
+    actual fun loadFen(fen: String) {
+        board.loadFromFen(fen)
+        sanHistory.clear()
+    }
+
+    actual fun reset() {
+        board.loadFromFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
+        sanHistory.clear()
+    }
+
+    actual fun makeMove(san: String): MoveResult =
+        try {
+            if (board.doMove(san)) {
+                // Input is already SAN from Nostr events, store directly
+                sanHistory.add(san)
+                MoveResult(
+                    success = true,
+                    san = san,
+                    position = boardToPosition(),
+                )
+            } else {
+                MoveResult(
+                    success = false,
+                    error = "Invalid move: $san",
+                )
+            }
+        } catch (e: Exception) {
+            MoveResult(
+                success = false,
+                error = e.message ?: "Unknown error making move $san",
+            )
+        }
+
+    actual fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): MoveResult =
+        try {
+            val fromSquare = Square.fromValue(from.uppercase())
+            val toSquare = Square.fromValue(to.uppercase())
+
+            val promotionPiece =
+                when (promotion) {
+                    PieceType.QUEEN -> if (board.sideToMove == Side.WHITE) Piece.WHITE_QUEEN else Piece.BLACK_QUEEN
+                    PieceType.ROOK -> if (board.sideToMove == Side.WHITE) Piece.WHITE_ROOK else Piece.BLACK_ROOK
+                    PieceType.BISHOP -> if (board.sideToMove == Side.WHITE) Piece.WHITE_BISHOP else Piece.BLACK_BISHOP
+                    PieceType.KNIGHT -> if (board.sideToMove == Side.WHITE) Piece.WHITE_KNIGHT else Piece.BLACK_KNIGHT
+                    else -> Piece.NONE
+                }
+
+            val move = Move(fromSquare, toSquare, promotionPiece)
+
+            if (board.legalMoves().contains(move)) {
+                val san = computeSan(move)
+                board.doMove(move)
+                sanHistory.add(san)
+                MoveResult(
+                    success = true,
+                    san = san,
+                    position = boardToPosition(),
+                )
+            } else {
+                MoveResult(
+                    success = false,
+                    error = "Illegal move: $from to $to",
+                )
+            }
+        } catch (e: Exception) {
+            MoveResult(
+                success = false,
+                error = e.message ?: "Unknown error making move $from to $to",
+            )
+        }
+
+    actual fun getLegalMoves(): List<String> = board.legalMoves().map { it.toString() }
+
+    actual fun getLegalMovesFrom(square: String): List<String> {
+        val sq = Square.fromValue(square.uppercase())
+        return board
+            .legalMoves()
+            .filterNotNull()
+            .filter { it.from == sq }
+            .map { it.to.toString().lowercase() }
+    }
+
+    actual fun isLegalMove(san: String): Boolean =
+        try {
+            if (board.doMove(san)) {
+                board.undoMove()
+                true
+            } else {
+                false
+            }
+        } catch (e: Exception) {
+            false
+        }
+
+    actual fun isLegalMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): Boolean =
+        try {
+            val fromSquare = Square.fromValue(from.uppercase())
+            val toSquare = Square.fromValue(to.uppercase())
+
+            val promotionPiece =
+                when (promotion) {
+                    PieceType.QUEEN -> if (board.sideToMove == Side.WHITE) Piece.WHITE_QUEEN else Piece.BLACK_QUEEN
+                    PieceType.ROOK -> if (board.sideToMove == Side.WHITE) Piece.WHITE_ROOK else Piece.BLACK_ROOK
+                    PieceType.BISHOP -> if (board.sideToMove == Side.WHITE) Piece.WHITE_BISHOP else Piece.BLACK_BISHOP
+                    PieceType.KNIGHT -> if (board.sideToMove == Side.WHITE) Piece.WHITE_KNIGHT else Piece.BLACK_KNIGHT
+                    else -> Piece.NONE
+                }
+
+            val move = Move(fromSquare, toSquare, promotionPiece)
+            board.legalMoves().contains(move)
+        } catch (e: Exception) {
+            false
+        }
+
+    actual fun isCheckmate(): Boolean = board.isMated
+
+    actual fun isStalemate(): Boolean = board.isStaleMate
+
+    actual fun isInCheck(): Boolean = board.isKingAttacked
+
+    actual fun undoMove() {
+        board.undoMove()
+        if (sanHistory.isNotEmpty()) {
+            sanHistory.removeAt(sanHistory.lastIndex)
+        }
+    }
+
+    actual fun getPosition(): ChessPosition = boardToPosition()
+
+    actual fun getSideToMove(): Color =
+        when (board.sideToMove) {
+            Side.WHITE -> Color.WHITE
+            Side.BLACK -> Color.BLACK
+        }
+
+    actual fun getMoveHistory(): List<String> = sanHistory.toList()
+
+    /**
+     * Compute proper SAN notation for a move BEFORE it is applied to the board.
+     * Handles pieces, pawns, castling, captures, promotion, disambiguation, check/checkmate.
+     */
+    private fun computeSan(move: Move): String {
+        val fromSquare = move.from
+        val toSquare = move.to
+        val piece = board.getPiece(fromSquare)
+        val pt = piece.pieceType ?: return move.toString()
+        val promotionPiece = move.promotion ?: Piece.NONE
+
+        // Castling
+        if (pt == com.github.bhlangonijr.chesslib.PieceType.KING) {
+            val fileDiff = toSquare.file.ordinal - fromSquare.file.ordinal
+            if (fileDiff == 2) {
+                val suffix = checkSuffixAfterMove(move)
+                return "O-O$suffix"
+            }
+            if (fileDiff == -2) {
+                val suffix = checkSuffixAfterMove(move)
+                return "O-O-O$suffix"
+            }
+        }
+
+        val sb = StringBuilder()
+        val epTarget = board.enPassantTarget
+        val isCapture =
+            board.getPiece(toSquare) != Piece.NONE ||
+                (
+                    pt == com.github.bhlangonijr.chesslib.PieceType.PAWN &&
+                        epTarget != null && epTarget != Square.NONE && toSquare == epTarget
+                )
+
+        if (pt != com.github.bhlangonijr.chesslib.PieceType.PAWN) {
+            sb.append(sanSymbol(pt))
+
+            // Disambiguation: check if other pieces of same type can reach the same square
+            val ambiguous =
+                board.legalMoves().filterNotNull().filter {
+                    it.to == toSquare &&
+                        board.getPiece(it.from).pieceType == pt &&
+                        it.from != fromSquare
+                }
+
+            if (ambiguous.isNotEmpty()) {
+                val sameFile = ambiguous.any { it.from.file == fromSquare.file }
+                val sameRank = ambiguous.any { it.from.rank == fromSquare.rank }
+                when {
+                    !sameFile -> {
+                        sb.append(fileChar(fromSquare))
+                    }
+
+                    !sameRank -> {
+                        sb.append(rankChar(fromSquare))
+                    }
+
+                    else -> {
+                        sb.append(fileChar(fromSquare))
+                        sb.append(rankChar(fromSquare))
+                    }
+                }
+            }
+        } else if (isCapture) {
+            // Pawn captures include the source file
+            sb.append(fileChar(fromSquare))
+        }
+
+        if (isCapture) sb.append('x')
+
+        sb.append(toSquare.toString().lowercase())
+
+        // Promotion
+        if (promotionPiece != Piece.NONE) {
+            sb.append('=')
+            val promType = promotionPiece.pieceType
+            if (promType != null) sb.append(sanSymbol(promType))
+        }
+
+        // Check/checkmate suffix
+        sb.append(checkSuffixAfterMove(move))
+
+        return sb.toString()
+    }
+
+    /**
+     * Temporarily apply a move to check for check/checkmate, then undo.
+     */
+    private fun checkSuffixAfterMove(move: Move): String {
+        board.doMove(move)
+        val suffix =
+            when {
+                board.isMated -> "#"
+                board.isKingAttacked -> "+"
+                else -> ""
+            }
+        board.undoMove()
+        return suffix
+    }
+
+    private fun sanSymbol(pt: com.github.bhlangonijr.chesslib.PieceType): String =
+        when (pt) {
+            com.github.bhlangonijr.chesslib.PieceType.KING -> "K"
+            com.github.bhlangonijr.chesslib.PieceType.QUEEN -> "Q"
+            com.github.bhlangonijr.chesslib.PieceType.ROOK -> "R"
+            com.github.bhlangonijr.chesslib.PieceType.BISHOP -> "B"
+            com.github.bhlangonijr.chesslib.PieceType.KNIGHT -> "N"
+            else -> ""
+        }
+
+    private fun fileChar(square: Square): Char = 'a' + square.file.ordinal
+
+    private fun rankChar(square: Square): Char = '1' + square.rank.ordinal
+
+    /**
+     * Convert kchesslib Board to our ChessPosition model
+     */
+    private fun boardToPosition(): ChessPosition {
+        val positionArray = Array(8) { Array<ChessPiece?>(8) { null } }
+
+        for (rank in 0..7) {
+            for (file in 0..7) {
+                val square = Square.squareAt(rank * 8 + file)
+                val piece = board.getPiece(square)
+
+                if (piece != Piece.NONE) {
+                    val pieceType =
+                        when (piece.pieceType) {
+                            com.github.bhlangonijr.chesslib.PieceType.KING -> PieceType.KING
+                            com.github.bhlangonijr.chesslib.PieceType.QUEEN -> PieceType.QUEEN
+                            com.github.bhlangonijr.chesslib.PieceType.ROOK -> PieceType.ROOK
+                            com.github.bhlangonijr.chesslib.PieceType.BISHOP -> PieceType.BISHOP
+                            com.github.bhlangonijr.chesslib.PieceType.KNIGHT -> PieceType.KNIGHT
+                            com.github.bhlangonijr.chesslib.PieceType.PAWN -> PieceType.PAWN
+                            else -> PieceType.PAWN
+                        }
+
+                    val color =
+                        when (piece.pieceSide) {
+                            Side.WHITE -> Color.WHITE
+                            Side.BLACK -> Color.BLACK
+                            else -> Color.WHITE
+                        }
+
+                    positionArray[rank][file] = ChessPiece(pieceType, color)
+                }
+            }
+        }
+
+        return ChessPosition(
+            board = positionArray,
+            activeColor = getSideToMove(),
+            moveNumber = board.moveCounter,
+            castlingRights =
+                CastlingRights(
+                    whiteKingSide = board.castleRight.toString().contains("K"),
+                    whiteQueenSide = board.castleRight.toString().contains("Q"),
+                    blackKingSide = board.castleRight.toString().contains("k"),
+                    blackQueenSide = board.castleRight.toString().contains("q"),
+                ),
+            enPassantSquare = board.enPassantTarget?.let { it.toString().lowercase() },
+            halfMoveClock = board.halfMoveCounter,
+        )
+    }
+}

quartz/src/jvmAndroidTest/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessStateReconstructorTest.kt

@@ -0,0 +1,808 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+/**
+ * Integration tests for ChessStateReconstructor with Jester protocol.
+ *
+ * These tests verify that the reconstruction algorithm produces correct,
+ * deterministic game states from Jester events (kind 30).
+ *
+ * Jester Protocol:
+ * - Single event kind (30) for all chess messages
+ * - Content is JSON with: version, kind, fen, move, history
+ * - Start events have content.kind=0 and reference START_POSITION_HASH via e-tag
+ * - Move events have content.kind=1 and reference [startEventId, headEventId] via e-tags
+ * - Full move history is included in every move event
+ * - No separate accept event - acceptance is implicit when opponent makes first move
+ *
+ * Test Categories:
+ * 1. Basic game lifecycle (challenge, moves, end)
+ * 2. Move ordering and reconstruction from history
+ * 3. Game end conditions (checkmate, resignation)
+ * 4. Viewer perspective (white player, black player, spectator)
+ * 5. Determinism tests
+ */
+class ChessStateReconstructorTest {
+    // Test pubkeys
+    private val whitePubkey = "white_pubkey_abc123"
+    private val blackPubkey = "black_pubkey_def456"
+    private val spectatorPubkey = "spectator_pubkey_xyz789"
+    private val startEventId = "start-event-001"
+
+    // ==========================================================================
+    // 1. BASIC GAME LIFECYCLE TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct pending challenge - no moves yet`() {
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = emptyList(),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess(), "Should reconstruct pending challenge")
+
+        val state = result.getOrNull()!!
+        assertTrue(state.isPendingChallenge, "Game should be pending")
+        assertEquals(startEventId, state.startEventId)
+        assertEquals(whitePubkey, state.whitePubkey)
+        assertEquals(ViewerRole.WHITE_PLAYER, state.viewerRole)
+        assertEquals(Color.WHITE, state.playerColor)
+        assertTrue(state.moveHistory.isEmpty(), "No moves yet")
+        assertEquals(GameStatus.InProgress, state.gameStatus)
+    }
+
+    @Test
+    fun `reconstruct game with initial moves - e4 e5`() {
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(move1, move2),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(2, state.moveHistory.size)
+        assertEquals("e4", state.moveHistory[0])
+        assertEquals("e5", state.moveHistory[1])
+        assertTrue(state.isPlayerTurn(), "White's turn after e4 e5")
+        assertEquals(Color.WHITE, state.currentPosition.activeColor)
+    }
+
+    @Test
+    fun `reconstruct game - acceptance is implicit via first opponent move`() {
+        // In Jester, there's no separate accept event
+        // Game is considered accepted when opponent makes their first move
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(move1),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertFalse(state.isPendingChallenge, "Game is active with moves")
+        assertEquals(blackPubkey, state.blackPubkey)
+        assertEquals(Color.BLACK, state.currentPosition.activeColor, "Black's turn after e4")
+    }
+
+    // ==========================================================================
+    // 2. MOVE RECONSTRUCTION FROM HISTORY
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct from latest move with full history`() {
+        // In Jester, each move contains the full history
+        // Reconstruction uses the move with the longest history
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+                createdAt = 1000,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+                createdAt = 2000,
+            )
+        val move3 =
+            createMoveEvent(
+                id = "move-003",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = "move-002",
+                move = "Nf3",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2",
+                history = listOf("e4", "e5", "Nf3"),
+                opponentPubkey = blackPubkey,
+                createdAt = 3000,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(move1, move2, move3),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(3, state.moveHistory.size)
+        assertEquals(listOf("e4", "e5", "Nf3"), state.moveHistory)
+        assertEquals("move-003", state.headEventId, "Head should be latest move")
+    }
+
+    @Test
+    fun `reconstruct with out-of-order moves - uses longest history`() {
+        // Events might arrive out of order, but we use the longest history
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+            )
+
+        // Events arrive in reverse order
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(move2, move1), // Reverse order
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(2, state.moveHistory.size)
+        assertEquals("e4", state.moveHistory[0], "First move should be e4")
+        assertEquals("e5", state.moveHistory[1], "Second move should be e5")
+    }
+
+    @Test
+    fun `reconstruct with duplicate moves - uses longest history`() {
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move1Duplicate =
+            createMoveEvent(
+                id = "move-001-dup",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(move1, move1Duplicate, move2),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        // Move2 has the longest history (2 moves), so that's what we reconstruct
+        assertEquals(2, state.moveHistory.size, "Should have 2 moves from longest history")
+    }
+
+    // ==========================================================================
+    // 3. GAME END CONDITIONS TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct scholar's mate - checkmate by engine detection`() {
+        // Scholar's mate: 1. e4 e5 2. Qh5 Nc6 3. Bc4 Nf6 4. Qxf7#
+        val finalMove =
+            createMoveEvent(
+                id = "move-007",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = "move-006",
+                move = "Qxf7#",
+                fen = "r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4",
+                history = listOf("e4", "e5", "Qh5", "Nc6", "Bc4", "Nf6", "Qxf7#"),
+                opponentPubkey = blackPubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(finalMove), // Only need latest move with full history
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(7, state.moveHistory.size)
+
+        val engine = result.getEngineOrNull()!!
+        assertTrue(engine.isCheckmate(), "Engine should detect checkmate")
+
+        assertTrue(state.gameStatus is GameStatus.Finished)
+        assertEquals(
+            GameResult.WHITE_WINS,
+            state.gameStatus.result,
+            "White wins by checkmate",
+        )
+    }
+
+    @Test
+    fun `reconstruct game with resignation - result in move content`() {
+        // In Jester, resignation is indicated by result field in move content
+        val resignationMove =
+            createMoveEventWithResult(
+                id = "move-002",
+                pubKey = blackPubkey, // Black resigns
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+                result = "1-0", // White wins by resignation
+                termination = "resignation",
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(resignationMove),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertTrue(state.gameStatus is GameStatus.Finished)
+        assertEquals(
+            GameResult.WHITE_WINS,
+            state.gameStatus.result,
+            "White wins by resignation",
+        )
+    }
+
+    @Test
+    fun `reconstruct fool's mate - 4 move checkmate for black`() {
+        // 1. f3 e5 2. g4 Qh4#
+        val finalMove =
+            createMoveEvent(
+                id = "move-004",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-003",
+                move = "Qh4#",
+                fen = "rnb1kbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 1 3",
+                history = listOf("f3", "e5", "g4", "Qh4#"),
+                opponentPubkey = whitePubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(finalMove),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertTrue(state.gameStatus is GameStatus.Finished)
+        assertEquals(
+            GameResult.BLACK_WINS,
+            state.gameStatus.result,
+            "Black wins by fool's mate",
+        )
+    }
+
+    // ==========================================================================
+    // 4. VIEWER PERSPECTIVE TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct as white player - correct perspective`() {
+        val events = createBasicGameEvents()
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(ViewerRole.WHITE_PLAYER, state.viewerRole)
+        assertEquals(Color.WHITE, state.playerColor)
+        assertEquals(blackPubkey, state.opponentPubkey)
+    }
+
+    @Test
+    fun `reconstruct as black player - correct perspective`() {
+        val events = createBasicGameEvents()
+
+        val result = ChessStateReconstructor.reconstruct(events, blackPubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(ViewerRole.BLACK_PLAYER, state.viewerRole)
+        assertEquals(Color.BLACK, state.playerColor)
+        assertEquals(whitePubkey, state.opponentPubkey)
+    }
+
+    @Test
+    fun `reconstruct as spectator - white perspective, no turn`() {
+        val events = createBasicGameEvents()
+
+        val result = ChessStateReconstructor.reconstruct(events, spectatorPubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(ViewerRole.SPECTATOR, state.viewerRole)
+        assertEquals(Color.WHITE, state.playerColor, "Spectators see from white's perspective")
+        assertFalse(state.isPlayerTurn(), "Spectators never have a turn")
+    }
+
+    @Test
+    fun `challenger is black - roles reversed correctly`() {
+        // Challenger chooses black
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey, // Opponent (white) makes first move
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, blackPubkey, Color.BLACK, whitePubkey),
+                moves = listOf(move1),
+            )
+
+        val whiteResult = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        val blackResult = ChessStateReconstructor.reconstruct(events, blackPubkey)
+
+        assertTrue(whiteResult.isSuccess())
+        assertTrue(blackResult.isSuccess())
+
+        val whiteState = whiteResult.getOrNull()!!
+        val blackState = blackResult.getOrNull()!!
+
+        assertEquals(whitePubkey, whiteState.whitePubkey)
+        assertEquals(blackPubkey, whiteState.blackPubkey)
+        assertEquals(ViewerRole.WHITE_PLAYER, whiteState.viewerRole)
+        assertEquals(ViewerRole.BLACK_PLAYER, blackState.viewerRole)
+    }
+
+    // ==========================================================================
+    // 5. ERROR HANDLING TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct without start event - should fail`() {
+        val events = JesterGameEvents(startEvent = null, moves = emptyList())
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result is ReconstructionResult.Error)
+        assertEquals("No start event found", result.message)
+    }
+
+    @Test
+    fun `reconstruct with empty events - should fail`() {
+        val events = JesterGameEvents.empty()
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result is ReconstructionResult.Error)
+    }
+
+    // ==========================================================================
+    // 6. CASTLING AND SPECIAL MOVES TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct game with kingside castling`() {
+        // 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O
+        val finalMove =
+            createMoveEvent(
+                id = "move-007",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = "move-006",
+                move = "O-O",
+                fen = "r1bqk1nr/pppp1ppp/2n5/2b1p3/2B1P3/5N2/PPPP1PPP/RNBQ1RK1 b kq - 5 4",
+                history = listOf("e4", "e5", "Nf3", "Nc6", "Bc4", "Bc5", "O-O"),
+                opponentPubkey = blackPubkey,
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+                moves = listOf(finalMove),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertEquals(7, state.moveHistory.size)
+        assertEquals("O-O", state.moveHistory[6])
+        assertEquals(Color.BLACK, state.currentPosition.activeColor, "Black's turn after white castled")
+    }
+
+    // ==========================================================================
+    // 7. DETERMINISM TESTS
+    // ==========================================================================
+
+    @Test
+    fun `same events always produce same state`() {
+        val events = createBasicGameEvents()
+
+        // Reconstruct multiple times
+        val results =
+            (1..5).map {
+                ChessStateReconstructor.reconstruct(events, whitePubkey)
+            }
+
+        // All should succeed
+        assertTrue(results.all { it.isSuccess() })
+
+        // All states should be identical
+        val states = results.map { it.getOrNull()!! }
+        val first = states.first()
+
+        states.forEach { state ->
+            assertEquals(first.startEventId, state.startEventId)
+            assertEquals(first.moveHistory, state.moveHistory)
+            assertEquals(first.gameStatus, state.gameStatus)
+            assertEquals(first.currentPosition.activeColor, state.currentPosition.activeColor)
+            assertEquals(first.currentPosition.moveNumber, state.currentPosition.moveNumber)
+            assertEquals(first.appliedMoveNumbers, state.appliedMoveNumbers)
+        }
+    }
+
+    @Test
+    fun `different move list order produces same state`() {
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+            )
+        val move3 =
+            createMoveEvent(
+                id = "move-003",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = "move-002",
+                move = "Nf3",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2",
+                history = listOf("e4", "e5", "Nf3"),
+                opponentPubkey = blackPubkey,
+            )
+
+        val startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey)
+
+        // Order 1: moves in order
+        val events1 = JesterGameEvents(startEvent, listOf(move1, move2, move3))
+
+        // Order 2: moves reversed (but move3 has longest history, so result is same)
+        val events2 = JesterGameEvents(startEvent, listOf(move3, move1, move2))
+
+        val result1 = ChessStateReconstructor.reconstruct(events1, whitePubkey)
+        val result2 = ChessStateReconstructor.reconstruct(events2, whitePubkey)
+
+        assertTrue(result1.isSuccess())
+        assertTrue(result2.isSuccess())
+
+        val state1 = result1.getOrNull()!!
+        val state2 = result2.getOrNull()!!
+
+        assertEquals(state1.moveHistory, state2.moveHistory, "Move history should be identical")
+        assertEquals(state1.appliedMoveNumbers, state2.appliedMoveNumbers)
+    }
+
+    // ==========================================================================
+    // 8. OPEN CHALLENGE TESTS
+    // ==========================================================================
+
+    @Test
+    fun `reconstruct open challenge - no specific opponent`() {
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, null), // Open challenge
+                moves = emptyList(),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertTrue(state.isPendingChallenge)
+        assertEquals(whitePubkey, state.whitePubkey)
+        assertEquals(null, state.blackPubkey, "No opponent assigned yet for open challenge")
+    }
+
+    @Test
+    fun `reconstruct open challenge with first opponent move`() {
+        // When an unknown player makes the first move, they become the opponent
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey, // Now we know the opponent
+            )
+
+        val events =
+            JesterGameEvents(
+                startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, null), // Open challenge
+                moves = listOf(move1),
+            )
+
+        val result = ChessStateReconstructor.reconstruct(events, whitePubkey)
+        assertTrue(result.isSuccess())
+
+        val state = result.getOrNull()!!
+        assertFalse(state.isPendingChallenge)
+        assertEquals(whitePubkey, state.whitePubkey)
+        // Opponent is determined from move events when not specified in start
+    }
+
+    // ==========================================================================
+    // HELPER FUNCTIONS
+    // ==========================================================================
+
+    private fun createBasicGameEvents(): JesterGameEvents {
+        val move1 =
+            createMoveEvent(
+                id = "move-001",
+                pubKey = whitePubkey,
+                startEventId = startEventId,
+                headEventId = startEventId,
+                move = "e4",
+                fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
+                history = listOf("e4"),
+                opponentPubkey = blackPubkey,
+            )
+        val move2 =
+            createMoveEvent(
+                id = "move-002",
+                pubKey = blackPubkey,
+                startEventId = startEventId,
+                headEventId = "move-001",
+                move = "e5",
+                fen = "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2",
+                history = listOf("e4", "e5"),
+                opponentPubkey = whitePubkey,
+            )
+
+        return JesterGameEvents(
+            startEvent = createStartEvent(startEventId, whitePubkey, Color.WHITE, blackPubkey),
+            moves = listOf(move1, move2),
+        )
+    }
+
+    private fun createStartEvent(
+        id: String,
+        challengerPubkey: String,
+        challengerColor: Color,
+        opponentPubkey: String?,
+        createdAt: Long = 1000,
+    ): JesterEvent {
+        val tags =
+            mutableListOf(
+                arrayOf("e", JesterProtocol.START_POSITION_HASH),
+            )
+        opponentPubkey?.let { tags.add(arrayOf("p", it)) }
+
+        val colorString = if (challengerColor == Color.WHITE) "white" else "black"
+        val content = """{"version":"0","kind":0,"fen":"${JesterProtocol.FEN_START}","history":[],"nonce":"test123","playerColor":"$colorString"}"""
+
+        return JesterEvent(
+            id = id,
+            pubKey = challengerPubkey,
+            createdAt = createdAt,
+            tags = tags.toTypedArray(),
+            content = content,
+            sig = "sig-start",
+        )
+    }
+
+    private fun createMoveEvent(
+        id: String,
+        pubKey: String,
+        startEventId: String,
+        headEventId: String,
+        move: String,
+        fen: String,
+        history: List<String>,
+        opponentPubkey: String,
+        createdAt: Long = 2000,
+    ): JesterEvent {
+        val historyJson = history.joinToString(",") { "\"$it\"" }
+        val content = """{"version":"0","kind":1,"fen":"$fen","move":"$move","history":[$historyJson]}"""
+
+        return JesterEvent(
+            id = id,
+            pubKey = pubKey,
+            createdAt = createdAt,
+            tags =
+                arrayOf(
+                    arrayOf("e", startEventId),
+                    arrayOf("e", headEventId),
+                    arrayOf("p", opponentPubkey),
+                ),
+            content = content,
+            sig = "sig-move",
+        )
+    }
+
+    private fun createMoveEventWithResult(
+        id: String,
+        pubKey: String,
+        startEventId: String,
+        headEventId: String,
+        move: String,
+        fen: String,
+        history: List<String>,
+        opponentPubkey: String,
+        result: String,
+        termination: String,
+        createdAt: Long = 2000,
+    ): JesterEvent {
+        val historyJson = history.joinToString(",") { "\"$it\"" }
+        val content = """{"version":"0","kind":1,"fen":"$fen","move":"$move","history":[$historyJson],"result":"$result","termination":"$termination"}"""
+
+        return JesterEvent(
+            id = id,
+            pubKey = pubKey,
+            createdAt = createdAt,
+            tags =
+                arrayOf(
+                    arrayOf("e", startEventId),
+                    arrayOf("e", headEventId),
+                    arrayOf("p", opponentPubkey),
+                ),
+            content = content,
+            sig = "sig-move",
+        )
+    }
+}