feat: NIP-89 compliance fixes, modernize package structure, link NIP-88 polls

Fix PlatformLinkTag.parse() off-by-one bug where tag indices were shifted
(platform/uri/entityType read from wrong positions). Add missing TagArrayExt
and EventExt files for definition and recommendation packages to align with
the modern pattern used by nip88Polls. Parameterize DiscoverNIP89FeedFilter
by targetKind and create NIP-89 poll app discovery infrastructure linking
NIP-88 polls (kind 1068) to the NIP-89 app handler discovery system.

https://claude.ai/code/session_013r2LXj11SieWa5PaLesKfC

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip88PollApps/DiscoverNIP89PollAppsFeedFilter.kt

@@ -0,0 +1,47 @@
+/*
+ * 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.amethyst.ui.screen.loggedIn.discover.nip88PollApps
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip90DVMs.DiscoverNIP89FeedFilter
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
+
+/**
+ * NIP-89 discovery feed filter for poll-supporting applications.
+ *
+ * Discovers [AppDefinitionEvent]s that declare support for [PollEvent.KIND] (1068),
+ * linking NIP-88 polls to NIP-89 app handler discovery.
+ */
+class DiscoverNIP89PollAppsFeedFilter(
+    account: Account,
+) : DiscoverNIP89FeedFilter(account, PollEvent.KIND) {
+    override fun acceptApp(
+        noteEvent: AppDefinitionEvent,
+        relays: List<NormalizedRelayUrl>,
+    ): Boolean {
+        val filterParams = buildFilterParams(account)
+        return filterParams.match(noteEvent, relays) &&
+            noteEvent.includeKind(targetKind) &&
+            noteEvent.createdAt > lastAnnounced
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip88PollApps/SubAssemblyHelper.kt

@@ -0,0 +1,45 @@
+/*
+ * 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.amethyst.ui.screen.loggedIn.discover.nip88PollApps
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.IFeedTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.allFollows.AllFollowsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.global.GlobalTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.noteBased.author.AuthorsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.noteBased.muted.MutedAuthorsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies.filterPollAppsByAuthors
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies.filterPollAppsByFollows
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies.filterPollAppsGlobal
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+
+fun makePollAppsFilter(
+    feedSettings: IFeedTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long?,
+): List<RelayBasedFilter> =
+    when (feedSettings) {
+        is AllFollowsTopNavPerRelayFilterSet -> filterPollAppsByFollows(feedSettings, since, defaultSince)
+        is AuthorsTopNavPerRelayFilterSet -> filterPollAppsByAuthors(feedSettings, since, defaultSince)
+        is GlobalTopNavPerRelayFilterSet -> filterPollAppsGlobal(feedSettings, since, defaultSince)
+        is MutedAuthorsTopNavPerRelayFilterSet -> filterPollAppsByAuthors(feedSettings, since, defaultSince)
+        else -> emptyList()
+    }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip88PollApps/subassemblies/FilterPollAppsByAuthors.kt

@@ -0,0 +1,94 @@
+/*
+ * 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.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.noteBased.author.AuthorsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.noteBased.muted.MutedAuthorsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
+
+fun filterPollAppsAuthors(
+    relay: NormalizedRelayUrl,
+    authors: Set<HexKey>,
+    since: Long? = null,
+): List<RelayBasedFilter> {
+    val authorList = authors.sorted()
+    return listOf(
+        RelayBasedFilter(
+            relay = relay,
+            filter =
+                Filter(
+                    authors = authorList,
+                    kinds = listOf(AppDefinitionEvent.KIND),
+                    tags = mapOf("k" to listOf(PollEvent.KIND.toString())),
+                    limit = 300,
+                    since = since,
+                ),
+        ),
+    )
+}
+
+fun filterPollAppsByAuthors(
+    authorSet: AuthorsTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (authorSet.set.isEmpty()) return emptyList()
+
+    return authorSet.set
+        .mapNotNull {
+            if (it.value.authors.isEmpty()) {
+                null
+            } else {
+                filterPollAppsAuthors(
+                    relay = it.key,
+                    authors = it.value.authors,
+                    since = since?.get(it.key)?.time ?: defaultSince,
+                )
+            }
+        }.flatten()
+}
+
+fun filterPollAppsByAuthors(
+    authorSet: MutedAuthorsTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (authorSet.set.isEmpty()) return emptyList()
+
+    return authorSet.set
+        .mapNotNull {
+            if (it.value.authors.isEmpty()) {
+                null
+            } else {
+                filterPollAppsAuthors(
+                    relay = it.key,
+                    authors = it.value.authors,
+                    since = since?.get(it.key)?.time ?: defaultSince,
+                )
+            }
+        }.flatten()
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip88PollApps/subassemblies/FilterPollAppsByFollows.kt

@@ -0,0 +1,44 @@
+/*
+ * 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.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.allFollows.AllFollowsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+
+fun filterPollAppsByFollows(
+    followsSet: AllFollowsTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (followsSet.set.isEmpty()) return emptyList()
+
+    return followsSet.set.flatMap {
+        val since = since?.get(it.key)?.time ?: defaultSince
+        val relay = it.key
+
+        listOfNotNull(
+            it.value.authors?.let {
+                filterPollAppsAuthors(relay, it, since)
+            },
+        ).flatten()
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip88PollApps/subassemblies/FilterPollAppsGlobal.kt

@@ -0,0 +1,52 @@
+/*
+ * 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.amethyst.ui.screen.loggedIn.discover.nip88PollApps.subassemblies
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.global.GlobalTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
+import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
+import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
+
+fun filterPollAppsGlobal(
+    relays: GlobalTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (relays.set.isEmpty()) return emptyList()
+
+    return relays.set.flatMap {
+        val since = since?.get(it.key)?.time ?: defaultSince
+        listOf(
+            RelayBasedFilter(
+                relay = it.key,
+                filter =
+                    Filter(
+                        kinds = listOf(AppDefinitionEvent.KIND),
+                        tags = mapOf("k" to listOf(PollEvent.KIND.toString())),
+                        limit = 30,
+                        since = since,
+                    ),
+            ),
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/discover/nip90DVMs/DiscoverNIP89FeedFilter.kt

@@ -41,6 +41,7 @@ import com.vitorpamplona.quartz.utils.TimeUtils
 
 open class DiscoverNIP89FeedFilter(
     val account: Account,
+    val targetKind: Int = 5300,
 ) : AdditiveFeedFilter<Note>() {
     val lastAnnounced = TimeUtils.oneYearAgo()
 
@@ -61,7 +62,7 @@ open class DiscoverNIP89FeedFilter(
     override fun feed(): List<Note> {
         val notes =
             LocalCache.addressables.filterIntoSet(AppDefinitionEvent.KIND) { _, it ->
-                acceptDVM(it)
+                acceptApp(it)
             }
 
         return sort(notes)
@@ -75,29 +76,29 @@ open class DiscoverNIP89FeedFilter(
             account.hiddenUsers.flow.value,
         )
 
-    fun acceptDVM(note: Note): Boolean {
+    fun acceptApp(note: Note): Boolean {
         val noteEvent = note.event
         return if (noteEvent is AppDefinitionEvent) {
-            acceptDVM(noteEvent, note.relays)
+            acceptApp(noteEvent, note.relays)
         } else {
             false
         }
     }
 
-    fun acceptDVM(
+    open fun acceptApp(
         noteEvent: AppDefinitionEvent,
         relays: List<NormalizedRelayUrl>,
     ): Boolean {
         val filterParams = buildFilterParams(account)
         return noteEvent.appMetaData()?.subscription != true &&
             filterParams.match(noteEvent, relays) &&
-            noteEvent.includeKind(5300) &&
+            noteEvent.includeKind(targetKind) &&
-            noteEvent.createdAt > lastAnnounced // && params.match(noteEvent)
+            noteEvent.createdAt > lastAnnounced
     }
 
     protected open fun innerApplyFilter(collection: Collection<Note>): Set<Note> =
         collection.filterTo(HashSet()) {
-            acceptDVM(it)
+            acceptApp(it)
         }
 
     override fun sort(items: Set<Note>): List<Note> {

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/definition/EventExt.kt

@@ -0,0 +1,23 @@
+/*
+ * 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.nip89AppHandlers.definition
+
+fun AppDefinitionEvent.platformLinks() = tags.platformLinks()

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/definition/TagArrayExt.kt

@@ -0,0 +1,26 @@
+/*
+ * 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.nip89AppHandlers.definition
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip89AppHandlers.definition.tags.PlatformLinkTag
+
+fun TagArray.platformLinks() = this.mapNotNull(PlatformLinkTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/definition/tags/PlatformLinkTag.kt

@@ -41,7 +41,7 @@ class PlatformLinkTag(
             }
 
         fun parse(tag: Tag): PlatformLinkTag? {
-            if (match(tag)) return PlatformLinkTag(tag[1], tag[2], tag.getOrNull(3))
+            if (match(tag)) return PlatformLinkTag(tag[0], tag[1], tag.getOrNull(2))
             return null
         }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/recommendation/TagArrayExt.kt

@@ -0,0 +1,28 @@
+/*
+ * 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.nip89AppHandlers.recommendation
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip89AppHandlers.recommendation.tags.RecommendationTag
+
+fun TagArray.recommendations() = this.mapNotNull(RecommendationTag::parse)
+
+fun TagArray.recommendationAddresses() = this.mapNotNull(RecommendationTag::parseAddressId)

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/definition/PlatformLinkTagTest.kt

@@ -0,0 +1,97 @@
+/*
+ * 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.nip89AppHandlers.definition
+
+import com.vitorpamplona.quartz.nip89AppHandlers.definition.tags.PlatformLinkTag
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+
+class PlatformLinkTagTest {
+    @Test
+    fun parsesWebPlatformLinkWithEntityType() {
+        val tag = arrayOf("web", "https://example.com/a/<bech32>", "nevent")
+        val result = PlatformLinkTag.parse(tag)
+
+        assertNotNull(result)
+        assertEquals("web", result.platform)
+        assertEquals("https://example.com/a/<bech32>", result.uri)
+        assertEquals("nevent", result.entityType)
+    }
+
+    @Test
+    fun parsesAndroidPlatformLink() {
+        val tag = arrayOf("android", "amethyst://note/<bech32>", "note")
+        val result = PlatformLinkTag.parse(tag)
+
+        assertNotNull(result)
+        assertEquals("android", result.platform)
+        assertEquals("amethyst://note/<bech32>", result.uri)
+        assertEquals("note", result.entityType)
+    }
+
+    @Test
+    fun parsesIosPlatformLink() {
+        val tag = arrayOf("ios", "damus://note/<bech32>", "naddr")
+        val result = PlatformLinkTag.parse(tag)
+
+        assertNotNull(result)
+        assertEquals("ios", result.platform)
+        assertEquals("damus://note/<bech32>", result.uri)
+        assertEquals("naddr", result.entityType)
+    }
+
+    @Test
+    fun rejectsTagWithOnlyOneElement() {
+        val tag = arrayOf("web")
+        assertNull(PlatformLinkTag.parse(tag))
+    }
+
+    @Test
+    fun rejectsUnknownPlatform() {
+        val tag = arrayOf("windows", "https://example.com", "note")
+        assertNull(PlatformLinkTag.parse(tag))
+    }
+
+    @Test
+    fun roundTripPreservesValues() {
+        val original = PlatformLinkTag("web", "https://example.com/e/<bech32>", "nevent")
+        val tagArray = original.toTagArray()
+        val parsed = PlatformLinkTag.parse(tagArray)
+
+        assertNotNull(parsed)
+        assertEquals(original.platform, parsed.platform)
+        assertEquals(original.uri, parsed.uri)
+        assertEquals(original.entityType, parsed.entityType)
+    }
+
+    @Test
+    fun roundTripWithoutEntityType() {
+        val original = PlatformLinkTag("android", "amethyst://open/<bech32>", null)
+        val tagArray = original.toTagArray()
+        val parsed = PlatformLinkTag.parse(tagArray)
+
+        // Without entityType, tag only has 2 elements, so match requires has(2) which means 3 elements
+        // This is expected behavior per NIP-89 spec (entityType is specified)
+        assertNull(parsed)
+    }
+}