feat: surface pasted user/event references in the post notify section

When an npub/nprofile (a user) or a note/nevent/naddr (an event, whose
author is notified) is pasted or typed into the post body, add the resolved
user to the notify list live, mirroring the @ autocomplete path. These
authors were already added to the p tags at send time by NewMessageTagger;
this keeps the notify chips in sync so the user can review who will be
tagged.

Extracts the mention-collection loop from NewMessageTagger.run() into a
reusable collectMentions() and adds a cheap mightContainNostrReference()
guard so plain text isn't reparsed on every keystroke. Applied to both
screens that render the Notifying() section (short note + comment).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016HSBvxobGdB6VrqwAtkFwi

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewMessageTagger.kt

@@ -33,6 +33,7 @@ import com.vitorpamplona.quartz.nip19Bech32.bech32.bechToBytes
 import com.vitorpamplona.quartz.nip19Bech32.entities.NAddress
 import com.vitorpamplona.quartz.nip19Bech32.entities.NEmbed
 import com.vitorpamplona.quartz.nip19Bech32.entities.NEvent
+import com.vitorpamplona.quartz.nip19Bech32.entities.NNote
 import com.vitorpamplona.quartz.nip19Bech32.entities.NProfile
 import com.vitorpamplona.quartz.nip19Bech32.entities.NPub
 import com.vitorpamplona.quartz.nip19Bech32.entities.NRelay
@@ -50,6 +51,13 @@ class NewMessageTagger(
     val directMentionsNotes = mutableSetOf<Note>()
     val directMentionsUsers = mutableSetOf<User>()
 
+    companion object {
+        private val bechPrefixes = listOf("npub1", "nprofile1", "nevent1", "note1", "naddr1", "nsec1")
+
+        /** Cheap pre-check so callers can skip parsing plain text that cannot hold a reference. */
+        fun mightContainNostrReference(text: String): Boolean = bechPrefixes.any { text.contains(it, ignoreCase = true) }
+    }
+
     fun addUserToMentions(user: User) {
         directMentionsUsers.add(user)
         directMentions.add(user.pubkeyHex)
@@ -64,8 +72,15 @@ class NewMessageTagger(
         eTags = if (eTags?.contains(note) == true) eTags else eTags?.plus(note) ?: listOf(note)
     }
 
-    suspend fun run() {
-        // adds all references to mentions and reply tos
+    /**
+     * Scans the message for user (npub/nprofile) and event (note/nevent/naddr)
+     * references, resolving each into the users that should be notified — the
+     * referenced user itself, or the referenced event's author. Populates the
+     * mention/reply-to sets (and [pTags]/[eTags]) as a side effect and returns
+     * the resolved users. Does not rewrite the message, so it is cheap enough
+     * to call live as the user types or pastes.
+     */
+    suspend fun collectMentions(): Set<User> {
         message.split('\n').forEach { paragraph: String ->
             paragraph.split(' ').forEach { word: String ->
                 val results = parseDirtyWordForKey(word)
@@ -79,7 +94,7 @@ class NewMessageTagger(
                         addUserToMentions(dao.getOrCreateUser(entity.hex))
                     }
 
-                    is com.vitorpamplona.quartz.nip19Bech32.entities.NNote -> {
+                    is NNote -> {
                         addNoteToReplyTos(dao.getOrCreateNote(entity.hex))
                     }
 
@@ -105,6 +120,13 @@ class NewMessageTagger(
             }
         }
 
+        return directMentionsUsers
+    }
+
+    suspend fun run() {
+        // adds all references to mentions and reply tos
+        collectMentions()
+
         // Tags the text in the correct order.
         message =
             message
@@ -123,7 +145,7 @@ class NewMessageTagger(
                                     getNostrAddress(dao.getOrCreateUser(entity.hex).toNProfile(), results.restOfWord)
                                 }
 
-                                is com.vitorpamplona.quartz.nip19Bech32.entities.NNote -> {
+                                is NNote -> {
                                     getNostrAddress(dao.getOrCreateNote(entity.hex).toNEvent(), results.restOfWord)
                                 }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/nip22Comments/CommentPostViewModel.kt

@@ -786,6 +786,12 @@ open class CommentPostViewModel :
         notifying = notifying?.filter { it != userToRemove }
     }
 
+    fun addToReplyList(user: User) {
+        if (notifying?.contains(user) != true) {
+            notifying = (notifying ?: emptyList()).plus(user)
+        }
+    }
+
     override fun onMessageChanged() {
         urlPreviews.update(message.text.toString())
         revalidateDraft()
@@ -803,9 +809,28 @@ open class CommentPostViewModel :
             emojiSuggestions?.processCurrentWord(lastWord)
         }
 
+        addNotifiedUsersFromMessage()
+
         draftTag.newVersion()
     }
 
+    /**
+     * Surfaces users referenced in the message body (pasted or typed npub/nprofile,
+     * or the author of a pasted note/nevent/naddr) in the notify section, mirroring
+     * what [autocompleteWithUser] does for the @ dropdown. The comment already
+     * notifies these authors at send time via [NewMessageTagger]; this keeps the
+     * notify chips in sync so the user can see (and review) who will be tagged.
+     */
+    private fun addNotifiedUsersFromMessage() {
+        val text = message.text.toString()
+        if (!NewMessageTagger.mightContainNostrReference(text)) return
+
+        viewModelScope.launch(Dispatchers.IO) {
+            val mentioned = NewMessageTagger(message = text, dao = accountViewModel).collectMentions()
+            mentioned.forEach { addToReplyList(it) }
+        }
+    }
+
     override fun onForwardZapTextChanged() {
         if (forwardZapToEditting.selection.collapsed) {
             val lastWord = forwardZapToEditting.text.toString()
@@ -820,6 +845,7 @@ open class CommentPostViewModel :
                 val lastWord = message.currentWord()
                 userSuggestions.replaceCurrentWord(message, lastWord, item)
                 urlPreviews.update(message.text.toString())
+                addToReplyList(item)
             } else if (userSuggestionsMainMessage == UserSuggestionAnchor.FORWARD_ZAPS) {
                 forwardZapTo.value.addItem(item)
                 forwardZapToEditting.clearText()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/ShortNotePostViewModel.kt

@@ -1352,10 +1352,29 @@ open class ShortNotePostViewModel :
             emojiSuggestions?.processCurrentWord(lastWord)
         }
 
+        addNotifiedUsersFromMessage()
+
         precomputeAiResults()
         draftTag.newVersion()
     }
 
+    /**
+     * Surfaces users referenced in the message body (pasted or typed npub/nprofile,
+     * or the author of a pasted note/nevent/naddr) in the notify section, mirroring
+     * what [autocompleteWithUser] does for the @ dropdown. The post already notifies
+     * these authors at send time via [NewMessageTagger]; this keeps the notify chips
+     * in sync so the user can see (and review) who will be tagged.
+     */
+    private fun addNotifiedUsersFromMessage() {
+        val text = message.text.toString()
+        if (!NewMessageTagger.mightContainNostrReference(text)) return
+
+        viewModelScope.launch(Dispatchers.IO) {
+            val mentioned = NewMessageTagger(message = text, dao = accountViewModel).collectMentions()
+            mentioned.forEach { addToReplyList(it) }
+        }
+    }
+
     override fun onForwardZapTextChanged() {
         if (forwardZapToEditting.selection.collapsed) {
             val lastWord = forwardZapToEditting.text.toString()
@@ -1370,6 +1389,7 @@ open class ShortNotePostViewModel :
                 val lastWord = message.currentWord()
                 userSuggestions.replaceCurrentWord(message, lastWord, item)
                 urlPreviews.update(message.text.toString())
+                addToReplyList(item)
             } else if (userSuggestionsMainMessage == UserSuggestionAnchor.FORWARD_ZAPS) {
                 forwardZapTo.value.addItem(item)
                 forwardZapToEditting.clearText()