feat: implement NIP-7D thread events (kind 11)

Add support for NIP-7D thread events with title rendering in both
NoteCompose (feed view) and ThreadFeedView (detail view). Replies
use existing NIP-22 kind 1111 comments.

https://claude.ai/code/session_01MR2hLpmq3pkzzT11t86dAt

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt

@@ -153,6 +153,7 @@ import com.vitorpamplona.amethyst.ui.note.types.RenderRelayRemoveMember
 import com.vitorpamplona.amethyst.ui.note.types.RenderReport
 import com.vitorpamplona.amethyst.ui.note.types.RenderTextEvent
 import com.vitorpamplona.amethyst.ui.note.types.RenderTextModificationEvent
+import com.vitorpamplona.amethyst.ui.note.types.RenderThread
 import com.vitorpamplona.amethyst.ui.note.types.RenderTorrent
 import com.vitorpamplona.amethyst.ui.note.types.RenderTorrentComment
 import com.vitorpamplona.amethyst.ui.note.types.RenderVoiceTrack
@@ -266,6 +267,7 @@ import com.vitorpamplona.quartz.nip72ModCommunities.communityAddress
 import com.vitorpamplona.quartz.nip72ModCommunities.definition.CommunityDefinitionEvent
 import com.vitorpamplona.quartz.nip72ModCommunities.isACommunityPost
 import com.vitorpamplona.quartz.nip75ZapGoals.GoalEvent
+import com.vitorpamplona.quartz.nip7DThreads.ThreadEvent
 import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
 import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
@@ -851,6 +853,20 @@ private fun RenderNoteRow(
             RenderLongFormContent(baseNote, accountViewModel, nav)
         }
 
+        is ThreadEvent -> {
+            RenderThread(
+                baseNote,
+                makeItShort,
+                canPreview,
+                quotesLeft,
+                unPackReply,
+                backgroundColor,
+                editState,
+                accountViewModel,
+                nav,
+            )
+        }
+
         is CodeSnippetEvent -> {
             RenderCodeSnippetEvent(baseNote)
         }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/Thread.kt

@@ -0,0 +1,85 @@
+/*
+ * 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.note.types
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.State
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.ui.components.GenericLoadable
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.theme.StdVertSpacer
+import com.vitorpamplona.amethyst.ui.theme.replyModifier
+import com.vitorpamplona.quartz.nip7DThreads.ThreadEvent
+
+@Composable
+fun RenderThread(
+    note: Note,
+    makeItShort: Boolean,
+    canPreview: Boolean,
+    quotesLeft: Int,
+    unPackReply: ReplyRenderType,
+    backgroundColor: MutableState<Color>,
+    editState: State<GenericLoadable<EditState>>,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val noteEvent = note.event as? ThreadEvent ?: return
+    val title = noteEvent.title()
+
+    if (title != null) {
+        Column(MaterialTheme.colorScheme.replyModifier) {
+            Text(
+                text = title,
+                style = MaterialTheme.typography.bodyLarge,
+                fontWeight = FontWeight.Bold,
+                modifier =
+                    Modifier
+                        .fillMaxWidth()
+                        .padding(start = 10.dp, end = 10.dp, top = 10.dp, bottom = 10.dp),
+            )
+        }
+        Spacer(modifier = StdVertSpacer)
+    }
+
+    RenderTextEvent(
+        note,
+        makeItShort,
+        canPreview,
+        quotesLeft,
+        unPackReply,
+        backgroundColor,
+        editState,
+        accountViewModel,
+        nav,
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/threadview/ThreadFeedView.kt

@@ -267,6 +267,7 @@ import com.vitorpamplona.quartz.nip72ModCommunities.approval.CommunityPostApprov
 import com.vitorpamplona.quartz.nip72ModCommunities.communityAddress
 import com.vitorpamplona.quartz.nip72ModCommunities.isACommunityPost
 import com.vitorpamplona.quartz.nip75ZapGoals.GoalEvent
+import com.vitorpamplona.quartz.nip7DThreads.ThreadEvent
 import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
 import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
@@ -563,6 +564,7 @@ private fun FullBleedNoteCompose(
         when (noteEvent) {
             is BadgeDefinitionEvent -> BadgeDisplay(baseNote = baseNote, accountViewModel)
             is LongTextNoteEvent -> RenderLongFormHeaderForThread(noteEvent, baseNote, accountViewModel)
+            is ThreadEvent -> RenderThreadHeaderForThread(noteEvent)
             is WikiNoteEvent -> RenderWikiHeaderForThread(noteEvent, accountViewModel, nav)
             is ClassifiedsEvent -> RenderClassifiedsReaderForThread(noteEvent, baseNote, accountViewModel, nav)
             is CodeSnippetEvent -> RenderCodeSnippetHeaderForThread(noteEvent)
@@ -1124,6 +1126,20 @@ private fun RenderLongFormHeaderForThread(
     }
 }
 
+@Composable
+private fun RenderThreadHeaderForThread(noteEvent: ThreadEvent) {
+    noteEvent.title()?.let {
+        Column(modifier = Modifier.padding(start = 12.dp, end = 12.dp, bottom = 12.dp)) {
+            Text(
+                text = it,
+                fontSize = 28.sp,
+                fontWeight = FontWeight.Bold,
+                modifier = Modifier.fillMaxWidth(),
+            )
+        }
+    }
+}
+
 @Preview
 @Composable
 private fun RenderWikiHeaderForThreadPreview() {

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip7DThreads/TagArrayBuilderExt.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.nip7DThreads
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+
+fun TagArrayBuilder<ThreadEvent>.title(title: String) = addUnique(TitleTag.assemble(title))

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip7DThreads/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.nip7DThreads
+
+import com.vitorpamplona.quartz.nip01Core.core.TagArray
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+
+fun TagArray.title() = firstNotNullOfOrNull(TitleTag::parse)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip7DThreads/ThreadEvent.kt

@@ -0,0 +1,63 @@
+/*
+ * 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.nip7DThreads
+
+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.nip22Comments.RootScope
+import com.vitorpamplona.quartz.nip31Alts.alt
+import com.vitorpamplona.quartz.nip50Search.SearchableEvent
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+@Immutable
+class ThreadEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    RootScope,
+    SearchableEvent {
+    override fun indexableContent() = "title: " + title() + "\n" + content
+
+    fun title() = tags.title()
+
+    companion object {
+        const val KIND = 11
+        const val ALT_DESCRIPTION = "Thread"
+
+        fun build(
+            content: String,
+            title: String,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<ThreadEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, content, createdAt) {
+            alt(ALT_DESCRIPTION)
+            title(title)
+            initializer()
+        }
+    }
+}

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

@@ -154,6 +154,7 @@ import com.vitorpamplona.quartz.nip72ModCommunities.definition.CommunityDefiniti
 import com.vitorpamplona.quartz.nip72ModCommunities.follow.CommunityListEvent
 import com.vitorpamplona.quartz.nip75ZapGoals.GoalEvent
 import com.vitorpamplona.quartz.nip78AppData.AppSpecificDataEvent
+import com.vitorpamplona.quartz.nip7DThreads.ThreadEvent
 import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
 import com.vitorpamplona.quartz.nip85TrustedAssertions.addressables.AddressableAssertionEvent
 import com.vitorpamplona.quartz.nip85TrustedAssertions.events.EventAssertionEvent
@@ -348,6 +349,7 @@ class EventFactory {
                 SearchRelayListEvent.KIND -> SearchRelayListEvent(id, pubKey, createdAt, tags, content, sig)
                 StatusEvent.KIND -> StatusEvent(id, pubKey, createdAt, tags, content, sig)
                 TextNoteEvent.KIND -> TextNoteEvent(id, pubKey, createdAt, tags, content, sig)
+                ThreadEvent.KIND -> ThreadEvent(id, pubKey, createdAt, tags, content, sig)
                 TextNoteModificationEvent.KIND -> TextNoteModificationEvent(id, pubKey, createdAt, tags, content, sig)
                 TokenEvent.KIND -> TokenEvent(id, pubKey, createdAt, tags, content, sig)
                 TorrentEvent.KIND -> TorrentEvent(id, pubKey, createdAt, tags, content, sig)