Code review:

- consolidate thread-root resolution
- consolidate mute-state writes

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/Note.kt

@@ -39,6 +39,7 @@ import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.tags.hashtags.anyHashTag
 import com.vitorpamplona.quartz.nip01Core.tags.publishedAt.PublishedAtProvider
 import com.vitorpamplona.quartz.nip10Notes.BaseThreadedEvent
+import com.vitorpamplona.quartz.nip10Notes.threadRootIdOrSelf
 import com.vitorpamplona.quartz.nip18Reposts.GenericRepostEvent
 import com.vitorpamplona.quartz.nip18Reposts.RepostEvent
 import com.vitorpamplona.quartz.nip19Bech32.entities.NAddress
@@ -860,10 +861,10 @@ open class Note(
             return true
         }
 
-        // if this note belongs to a muted thread (by NIP-10 root id)
-        if (accountChoices.mutedThreads.isNotEmpty()) {
-            val rootId = (thisEvent as? BaseThreadedEvent)?.root()?.eventId ?: idHex
-            if (accountChoices.mutedThreads.contains(rootId)) return true
+        if (accountChoices.mutedThreads.isNotEmpty() &&
+            accountChoices.mutedThreads.contains(thisEvent.threadRootIdOrSelf())
+        ) {
+            return true
         }
 
         // if the post is sensitive and the user doesn't want to see sensitive content

commons/src/commonTest/kotlin/com/vitorpamplona/amethyst/commons/model/NoteIsHiddenForTest.kt

@@ -25,22 +25,11 @@ import kotlin.test.Test
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
-/**
- * Unit tests for Note.isHiddenFor() focusing on the mutedThreads check.
- *
- * Fixture approach:
- * - TextNoteEvent is constructed directly via its primary constructor (no signing needed —
- *   the sig field is not validated in isHiddenFor).
- * - A Note is created with the event's id, then note.event is set.
- * - LiveHiddenUsers is a plain data class — no Android plumbing required.
- */
 class NoteIsHiddenForTest {
-    // 64-char hex constants
     private val rootId = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
     private val replyId = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
     private val authorPubKey = "cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
 
-    // Minimal LiveHiddenUsers with all filters off (used as a baseline)
     private val noHidden =
         LiveHiddenUsers(
             showSensitiveContent = null,
@@ -50,12 +39,6 @@ class NoteIsHiddenForTest {
             mutedThreads = emptySet(),
         )
 
-    /**
-     * Build a TextNoteEvent.
-     *
-     * @param id The event id (64 hex chars).
-     * @param eTags Raw `e` tag arrays included in the event's tags.
-     */
     private fun textNoteEvent(
         id: String,
         pubKey: String = authorPubKey,
@@ -69,21 +52,12 @@ class NoteIsHiddenForTest {
         sig = "sig",
     )
 
-    /** A marked `e` tag array with marker="root" at index 3. */
     private fun rootETag(eventId: String) = arrayOf("e", eventId, "", "root")
 
-    // -------------------------------------------------------------------------
-
     @Test
     fun reply_inMutedThread_isHidden() {
-        // A reply whose NIP-10 root points to `rootId`, which is muted.
-        val event =
-            textNoteEvent(
-                id = replyId,
-                eTags = arrayOf(rootETag(rootId)),
-            )
+        val event = textNoteEvent(id = replyId, eTags = arrayOf(rootETag(rootId)))
         val note = Note(replyId).also { it.event = event }
-
         val choices = noHidden.copy(mutedThreads = setOf(rootId))
 
         assertTrue(note.isHiddenFor(choices), "Reply inside a muted thread must be hidden")
@@ -91,14 +65,8 @@ class NoteIsHiddenForTest {
 
     @Test
     fun topLevelNote_ownIdMuted_isHidden() {
-        // A top-level note (no e-tags) whose own id is in mutedThreads.
-        val event =
-            textNoteEvent(
-                id = rootId,
-                eTags = emptyArray(),
-            )
+        val event = textNoteEvent(id = rootId, eTags = emptyArray())
         val note = Note(rootId).also { it.event = event }
-
         val choices = noHidden.copy(mutedThreads = setOf(rootId))
 
         assertTrue(note.isHiddenFor(choices), "Top-level note whose id is muted must be hidden")
@@ -106,16 +74,9 @@ class NoteIsHiddenForTest {
 
     @Test
     fun note_inUnmutedThread_isNotHidden() {
-        // A reply note whose root is NOT in mutedThreads, author not hidden.
         val otherRoot = "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
-        val event =
-            textNoteEvent(
-                id = replyId,
-                eTags = arrayOf(rootETag(otherRoot)),
-            )
+        val event = textNoteEvent(id = replyId, eTags = arrayOf(rootETag(otherRoot)))
         val note = Note(replyId).also { it.event = event }
-
-        // rootId is muted, but this note's root is otherRoot
         val choices = noHidden.copy(mutedThreads = setOf(rootId))
 
         assertFalse(note.isHiddenFor(choices), "Reply in an un-muted thread must not be hidden")
@@ -123,15 +84,9 @@ class NoteIsHiddenForTest {
 
     @Test
     fun authorHidden_isHidden_regression() {
-        // Regression guard: author-hidden notes must still return true.
         val event = textNoteEvent(id = replyId)
         val note = Note(replyId).also { it.event = event }
-
-        // Put the author's pubKey hashCode into hiddenUsersHashCodes
-        val choices =
-            noHidden.copy(
-                hiddenUsersHashCodes = setOf(authorPubKey.hashCode()),
-            )
+        val choices = noHidden.copy(hiddenUsersHashCodes = setOf(authorPubKey.hashCode()))
 
         assertTrue(note.isHiddenFor(choices), "Note whose author is hidden must still be hidden")
     }