Adds support for Stemstr

quartz/src/main/java/com/vitorpamplona/quartz/events/AudioHeaderEvent.kt

@@ -0,0 +1,59 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.HexKey
+
+@Immutable
+class AudioHeaderEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: List<List<String>>,
+    content: String,
+    sig: HexKey
+) : Event(id, pubKey, createdAt, kind, tags, content, sig) {
+
+    fun download() = tags.firstOrNull { it.size > 1 && it[0] == DOWNLOAD_URL }?.get(1)
+    fun stream() = tags.firstOrNull { it.size > 1 && it[0] == STREAM_URL }?.get(1)
+    fun wavefrom() = tags.firstOrNull { it.size > 1 && it[0] == WAVEFORM }?.get(1)
+
+    companion object {
+        const val kind = 1808
+
+        private const val DOWNLOAD_URL = "download_url"
+        private const val STREAM_URL = "stream_url"
+        private const val WAVEFORM = "waveform"
+
+        fun create(
+            description: String,
+            downloadUrl: String,
+            streamUrl: String? = null,
+            wavefront: String? = null,
+            sensitiveContent: Boolean? = null,
+            privateKey: ByteArray,
+            createdAt: Long = TimeUtils.now()
+        ): AudioHeaderEvent {
+            val tags = listOfNotNull(
+                downloadUrl.let { listOf(DOWNLOAD_URL, it) },
+                streamUrl?.let { listOf(STREAM_URL, it) },
+                wavefront?.let { listOf(WAVEFORM, it) },
+                sensitiveContent?.let {
+                    if (it) {
+                        listOf("content-warning", "")
+                    } else {
+                        null
+                    }
+                }
+            )
+
+            val content = description
+            val pubKey = CryptoUtils.pubkeyCreate(privateKey).toHexKey()
+            val id = generateId(pubKey, createdAt, kind, tags, content)
+            val sig = CryptoUtils.sign(id, privateKey)
+            return AudioHeaderEvent(id.toHexKey(), pubKey, createdAt, tags, content, sig.toHexKey())
+        }
+    }
+}

quartz/src/main/java/com/vitorpamplona/quartz/events/EventFactory.kt

@@ -16,6 +16,7 @@ class EventFactory {
             AdvertisedRelayListEvent.kind -> AdvertisedRelayListEvent(id, pubKey, createdAt, tags, content, sig)
             AppDefinitionEvent.kind -> AppDefinitionEvent(id, pubKey, createdAt, tags, content, sig)
             AppRecommendationEvent.kind -> AppRecommendationEvent(id, pubKey, createdAt, tags, content, sig)
+            AudioHeaderEvent.kind -> AudioHeaderEvent(id, pubKey, createdAt, tags, content, sig)
             AudioTrackEvent.kind -> AudioTrackEvent(id, pubKey, createdAt, tags, content, sig)
             BadgeAwardEvent.kind -> BadgeAwardEvent(id, pubKey, createdAt, tags, content, sig)
             BadgeDefinitionEvent.kind -> BadgeDefinitionEvent(id, pubKey, createdAt, tags, content, sig)