Merge pull request #3793 from vitorpamplona/claude/highlight-events-browser-ywz5wr

Add NIP-84 highlights support: composer, feed, and share intent

amethyst/src/main/AndroidManifest.xml

@@ -295,6 +295,24 @@
             </intent-filter>
         </activity-alias>
 
+        <!-- "New Highlight" share target: a browser (or reader) shares a selected passage of
+             text and it opens the NIP-84 highlight composer. Text-only — a highlight is a text
+             passage, so no image/video filters here. The android:name simple class
+             ("ShareAsHighlightAlias") is matched at runtime by
+             ShareIntentRouting.SHARE_AS_HIGHLIGHT_ALIAS_SIMPLE_NAME; keep the two in sync. -->
+        <activity-alias
+            android:name=".ui.ShareAsHighlightAlias"
+            android:exported="true"
+            android:label="@string/share_target_as_highlight"
+            android:targetActivity=".ui.MainActivity">
+
+            <intent-filter android:label="@string/share_target_as_highlight">
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
+        </activity-alias>
+
         <!-- Health Connect privacy-policy rationale on Android 14+. Without this activity-alias
              the permission request fails silently (no dialog appears). The system launches it,
              guarded by START_VIEW_PERMISSION_USAGE, to show our privacy policy; it routes into

amethyst/src/main/java/com/vitorpamplona/amethyst/LocalPreferences.kt

@@ -132,6 +132,7 @@ private object PrefKeys {
     const val DEFAULT_NSITES_FOLLOW_LIST = "defaultNsitesFollowList"
     const val DEFAULT_WORKOUTS_FOLLOW_LIST = "defaultWorkoutsFollowList"
     const val DEFAULT_GIT_REPOSITORIES_FOLLOW_LIST = "defaultGitRepositoriesFollowList"
+    const val DEFAULT_HIGHLIGHTS_FOLLOW_LIST = "defaultHighlightsFollowList"
     const val DEFAULT_CALENDARS_FOLLOW_LIST = "defaultCalendarsFollowList"
     const val DEFAULT_PRODUCTS_FOLLOW_LIST = "defaultProductsFollowList"
     const val DEFAULT_SHORTS_FOLLOW_LIST = "defaultShortsFollowList"
@@ -522,6 +523,7 @@ object LocalPreferences {
                     putString(PrefKeys.DEFAULT_NSITES_FOLLOW_LIST, JsonMapper.toJson(settings.defaultNsitesFollowList.value))
                     putString(PrefKeys.DEFAULT_WORKOUTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultWorkoutsFollowList.value))
                     putString(PrefKeys.DEFAULT_GIT_REPOSITORIES_FOLLOW_LIST, JsonMapper.toJson(settings.defaultGitRepositoriesFollowList.value))
+                    putString(PrefKeys.DEFAULT_HIGHLIGHTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultHighlightsFollowList.value))
                     putString(PrefKeys.DEFAULT_CALENDARS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultCalendarsFollowList.value))
                     putString(PrefKeys.DEFAULT_PRODUCTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultProductsFollowList.value))
                     putString(PrefKeys.DEFAULT_SHORTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultShortsFollowList.value))
@@ -935,6 +937,7 @@ object LocalPreferences {
                         defaultNsitesFollowList = MutableStateFlow(followListPrefs.nsites),
                         defaultWorkoutsFollowList = MutableStateFlow(followListPrefs.workouts),
                         defaultGitRepositoriesFollowList = MutableStateFlow(followListPrefs.gitRepositories),
+                        defaultHighlightsFollowList = MutableStateFlow(followListPrefs.highlights),
                         defaultCalendarsFollowList = MutableStateFlow(followListPrefs.calendars),
                         defaultProductsFollowList = MutableStateFlow(followListPrefs.products),
                         defaultShortsFollowList = MutableStateFlow(followListPrefs.shorts),
@@ -1044,6 +1047,7 @@ object LocalPreferences {
         val nsites: TopFilter,
         val workouts: TopFilter,
         val gitRepositories: TopFilter,
+        val highlights: TopFilter,
         val calendars: TopFilter,
         val products: TopFilter,
         val shorts: TopFilter,
@@ -1101,6 +1105,7 @@ object LocalPreferences {
             nsites = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_NSITES_FOLLOW_LIST, null), TopFilter.Global),
             workouts = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_WORKOUTS_FOLLOW_LIST, null), TopFilter.Global),
             gitRepositories = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_GIT_REPOSITORIES_FOLLOW_LIST, null), TopFilter.Global),
+            highlights = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_HIGHLIGHTS_FOLLOW_LIST, null), TopFilter.Global),
             calendars = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_CALENDARS_FOLLOW_LIST, null), TopFilter.Global),
             products = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_PRODUCTS_FOLLOW_LIST, null), TopFilter.AroundMe),
             shorts = parseTopFilterOrDefault(getString(PrefKeys.DEFAULT_SHORTS_FOLLOW_LIST, null), TopFilter.Global),

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -873,6 +873,9 @@ class Account(
     val liveGitRepositoriesFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultGitRepositoriesFollowList)
     val liveGitRepositoriesFollowListsPerRelay = OutboxLoaderState(liveGitRepositoriesFollowLists, cache, scope).flow
 
+    val liveHighlightsFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultHighlightsFollowList)
+    val liveHighlightsFollowListsPerRelay = OutboxLoaderState(liveHighlightsFollowLists, cache, scope).flow
+
     val liveCalendarsFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultCalendarsFollowList)
     val liveCalendarsFollowListsPerRelay = OutboxLoaderState(liveCalendarsFollowLists, cache, scope).flow
 

amethyst/src/main/java/com/vitorpamplona/amethyst/model/AccountSettings.kt

@@ -251,6 +251,7 @@ class AccountSettings(
     val defaultNsitesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultWorkoutsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultGitRepositoriesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
+    val defaultHighlightsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultCalendarsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultProductsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.AroundMe),
     val defaultShortsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
@@ -895,6 +896,17 @@ class AccountSettings(
         }
     }
 
+    fun changeDefaultHighlightsFollowList(name: FeedDefinition) {
+        changeDefaultHighlightsFollowList(name.code)
+    }
+
+    fun changeDefaultHighlightsFollowList(name: TopFilter) {
+        if (defaultHighlightsFollowList.value != name) {
+            defaultHighlightsFollowList.tryEmit(name)
+            saveAccountSettings()
+        }
+    }
+
     fun changeDefaultCalendarsFollowList(name: FeedDefinition) {
         changeDefaultCalendarsFollowList(name.code)
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/reqCommand/RelaySubscriptionsCoordinator.kt

@@ -61,6 +61,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.geohash.datasource.GeoHashF
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepo.datasource.RepositoryFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepositories.datasource.GitRepositoriesFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.hashtag.datasource.HashtagFilterAssembler
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.HighlightsFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.datasource.HomeFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.livestreams.datasource.LiveStreamsFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.longs.datasource.LongsFilterAssembler
@@ -170,6 +171,7 @@ class RelaySubscriptionsCoordinator(
     val pictures = PicturesFilterAssembler(client)
     val workouts = WorkoutsFilterAssembler(client)
     val gitRepositories = GitRepositoriesFilterAssembler(client)
+    val highlights = HighlightsFilterAssembler(client)
     val calendars = CalendarsFilterAssembler(client)
     val products = ProductsFilterAssembler(client)
     val shorts = ShortsFilterAssembler(client)
@@ -235,6 +237,7 @@ class RelaySubscriptionsCoordinator(
             pictures,
             workouts,
             gitRepositories,
+            highlights,
             calendars,
             products,
             shorts,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/feeds/RememberForeverStates.kt

@@ -69,6 +69,7 @@ object ScrollStateKeys {
     const val PICTURES_SCREEN = "PicturesFeed"
     const val WORKOUTS_SCREEN = "WorkoutsFeed"
     const val GIT_REPOSITORIES_SCREEN = "GitRepositoriesFeed"
+    const val HIGHLIGHTS_SCREEN = "HighlightsFeed"
     const val RELAY_GROUPS_DISCOVERY_SCREEN = "RelayGroupsDiscoveryFeed"
     const val CALENDARS_SCREEN = "CalendarsFeed"
     const val CALENDAR_COLLECTIONS_SCREEN = "CalendarCollectionsFeed"

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/AppNavigation.kt

@@ -193,6 +193,8 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepo.GitRepositoryScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepositories.GitRepositoriesScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.hashtag.HashtagPostScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.hashtag.HashtagScreen
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.HighlightsScreen
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.NewHighlightScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.HomeScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.ShortNotePostScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.VoiceReplyScreen
@@ -310,6 +312,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedOff.AddAccountDialog
 import com.vitorpamplona.amethyst.ui.uriToRoute
 import com.vitorpamplona.quartz.nip01Core.core.Address
 import com.vitorpamplona.quartz.nip19Bech32.Nip19Parser
+import com.vitorpamplona.quartz.nip84Highlights.parse.SharedHighlightParser
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import java.net.URI
@@ -439,6 +442,8 @@ fun BuildNavigation(
         composableFromEnd<Route.Pictures> { PicturesScreen(accountViewModel, nav) }
         composableFromEnd<Route.Workouts> { WorkoutsScreen(accountViewModel, nav) }
         composableFromEnd<Route.GitRepositories> { GitRepositoriesScreen(accountViewModel, nav) }
+
+        composableFromEnd<Route.Highlights> { HighlightsScreen(accountViewModel, nav) }
         composableFromEnd<Route.SoftwareApps> { SoftwareAppsScreen(accountViewModel, nav) }
         composableFromEnd<Route.Napplets> { NappletsScreen(accountViewModel, nav) }
         composableFromEnd<Route.Nsites> { NsitesScreen(accountViewModel, nav) }
@@ -935,6 +940,22 @@ fun BuildNavigation(
             )
         }
 
+        composableFromBottomArgs<Route.NewHighlight> {
+            NewHighlightScreen(
+                quote = it.quote,
+                url = it.url,
+                prefix = it.prefix,
+                suffix = it.suffix,
+                comment = it.comment,
+                context = it.context,
+                sourceAddress = it.sourceAddress,
+                sourceEventId = it.sourceEventId,
+                author = it.author,
+                accountViewModel = accountViewModel,
+                nav = nav,
+            )
+        }
+
         composableFromBottomArgs<Route.VoiceReply> {
             VoiceReplyScreen(
                 replyToNoteId = it.replyToNoteId,
@@ -967,10 +988,13 @@ private fun NavigateIfIntentRequested(
 
     if (activity.intent.action == Intent.ACTION_SEND) {
         val isShareAsDm = ShareIntentRouting.isShareAsDm(activity.intent.component?.className)
+        val isShareAsHighlight = ShareIntentRouting.isShareAsHighlight(activity.intent.component?.className)
 
         // avoids restarting the destination screen when the intent is for the screen.
         // Microsoft's swift key sends Gifs as new actions
-        if (isShareAsDm) {
+        if (isShareAsHighlight) {
+            if (isBaseRoute<Route.NewHighlight>(nav.controller)) return
+        } else if (isShareAsDm) {
             if (isBaseRoute<Route.ShareToDM>(nav.controller)) return
         } else {
             if (isBaseRoute<Route.NewShortNote>(nav.controller)) return
@@ -991,7 +1015,17 @@ private fun NavigateIfIntentRequested(
             )
         }
 
-        if (isShareAsDm) {
+        if (isShareAsHighlight) {
+            val parsed = message?.let { SharedHighlightParser.parse(it) }
+            nav.newStack(
+                Route.NewHighlight(
+                    quote = parsed?.quote,
+                    url = parsed?.url,
+                    prefix = parsed?.prefix,
+                    suffix = parsed?.suffix,
+                ),
+            )
+        } else if (isShareAsDm) {
             nav.newStack(Route.ShareToDM(message = message, attachment = media?.toString()))
         } else {
             nav.newStack(Route.NewShortNote(message = message, attachment = media.toString()))
@@ -1063,9 +1097,22 @@ private fun NavigateIfIntentRequested(
                 Consumer<Intent> { intent ->
                     if (intent.action == Intent.ACTION_SEND) {
                         val isShareAsDm = ShareIntentRouting.isShareAsDm(intent.component?.className)
+                        val isShareAsHighlight = ShareIntentRouting.isShareAsHighlight(intent.component?.className)
                         // avoids restarting the destination screen when the intent is for the screen.
                         // Microsoft's swift key sends Gifs as new actions
-                        if (isShareAsDm) {
+                        if (isShareAsHighlight) {
+                            if (!isBaseRoute<Route.NewHighlight>(nav.controller)) {
+                                val parsed = intent.getStringExtra(Intent.EXTRA_TEXT)?.ifBlank { null }?.let { SharedHighlightParser.parse(it) }
+                                nav.newStack(
+                                    Route.NewHighlight(
+                                        quote = parsed?.quote,
+                                        url = parsed?.url,
+                                        prefix = parsed?.prefix,
+                                        suffix = parsed?.suffix,
+                                    ),
+                                )
+                            }
+                        } else if (isShareAsDm) {
                             if (!isBaseRoute<Route.ShareToDM>(nav.controller)) {
                                 val message = intent.getStringExtra(Intent.EXTRA_TEXT)?.ifBlank { null }
                                 val attachment =

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/ShareIntentRouting.kt

@@ -21,9 +21,9 @@
 package com.vitorpamplona.amethyst.ui.navigation
 
 /**
- * Distinguishes the "Send as DM" share target from the default "New Post" share
- * target. Both intent-filters resolve to MainActivity; they are told apart by the
- * component class name of the launching intent (the activity-alias name).
+ * Distinguishes the extra share targets ("Send as DM", "New Highlight") from the default
+ * "New Post" share target. Every SEND intent-filter resolves to MainActivity; they are told
+ * apart by the component class name of the launching intent (the activity-alias name).
  */
 object ShareIntentRouting {
     /**
@@ -34,5 +34,14 @@ object ShareIntentRouting {
      */
     const val SHARE_AS_DM_ALIAS_SIMPLE_NAME = "ShareAsDMAlias"
 
+    /**
+     * Simple class name of the `<activity-alias>` declared in AndroidManifest.xml
+     * (android:name=".ui.ShareAsHighlightAlias"). MUST stay in sync with the manifest —
+     * see the caveat on [SHARE_AS_DM_ALIAS_SIMPLE_NAME].
+     */
+    const val SHARE_AS_HIGHLIGHT_ALIAS_SIMPLE_NAME = "ShareAsHighlightAlias"
+
     fun isShareAsDm(componentClassName: String?): Boolean = componentClassName?.endsWith(".$SHARE_AS_DM_ALIAS_SIMPLE_NAME") == true
+
+    fun isShareAsHighlight(componentClassName: String?): Boolean = componentClassName?.endsWith(".$SHARE_AS_HIGHLIGHT_ALIAS_SIMPLE_NAME") == true
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/bottombars/NavBarItem.kt

@@ -55,6 +55,7 @@ enum class NavBarItem {
     PICTURES,
     WORKOUTS,
     GIT_REPOSITORIES,
+    HIGHLIGHTS,
     SOFTWARE_APPS,
     NAPPLETS,
     NSITES,
@@ -246,6 +247,13 @@ val NavBarCatalog: Map<NavBarItem, NavBarItemDef> =
                 icon = MaterialSymbols.Code,
                 resolveRoute = { Route.GitRepositories },
             ),
+        NavBarItem.HIGHLIGHTS to
+            NavBarItemDef(
+                id = NavBarItem.HIGHLIGHTS,
+                labelRes = R.string.highlights,
+                icon = MaterialSymbols.FormatQuote,
+                resolveRoute = { Route.Highlights },
+            ),
         NavBarItem.SOFTWARE_APPS to
             NavBarItemDef(
                 id = NavBarItem.SOFTWARE_APPS,
@@ -534,6 +542,7 @@ val BottomBarCategories: List<NavBarCategory> =
                 NavBarItem.PRODUCTS,
                 NavBarItem.WORKOUTS,
                 NavBarItem.GIT_REPOSITORIES,
+                NavBarItem.HIGHLIGHTS,
                 NavBarItem.COMMUNITIES,
                 NavBarItem.FOLLOW_PACKS,
                 NavBarItem.CALENDARS,
@@ -574,6 +583,7 @@ val DrawerFeedsItems: List<NavBarItem> =
         NavBarItem.PRODUCTS,
         NavBarItem.WORKOUTS,
         NavBarItem.GIT_REPOSITORIES,
+        NavBarItem.HIGHLIGHTS,
         NavBarItem.LIVE_STREAMS,
         NavBarItem.NESTS,
         NavBarItem.COMMUNITIES,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/routes/Routes.kt

@@ -87,6 +87,8 @@ sealed class Route {
 
     @Serializable object GitRepositories : Route()
 
+    @Serializable object Highlights : Route()
+
     @Serializable object SoftwareApps : Route()
 
     @Serializable object Napplets : Route()
@@ -987,6 +989,26 @@ sealed class Route {
         val draft: String? = null,
     ) : Route()
 
+    /**
+     * The NIP-84 highlight composer. Opened by the "Add highlight" action (all fields null) or
+     * when a browser shares a text selection to Amethyst — in which case the shared string has
+     * already been run through SharedHighlightParser and the pieces arrive pre-split here.
+     */
+    @Serializable
+    data class NewHighlight(
+        val quote: String? = null,
+        val url: String? = null,
+        val prefix: String? = null,
+        val suffix: String? = null,
+        val comment: String? = null,
+        val context: String? = null,
+        // A nostr source (set when highlighting a nostr article/note rather than a web page):
+        // an addressable coordinate (`a`), a specific event id (`e`) and the author (`p`).
+        val sourceAddress: String? = null,
+        val sourceEventId: String? = null,
+        val author: String? = null,
+    ) : Route()
+
     @Serializable data object NewHlsVideo : Route()
 
     @Serializable

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/elements/NoteActionSections.kt

@@ -171,6 +171,25 @@ fun noteActionSections(
                     }
                 },
             )
+            // Highlight this note/article as its source: opens the NIP-84 composer with the
+            // nostr source pre-tagged (`a` for an addressable article, else `e`) plus the author,
+            // and the passage left for the user to type or paste. Prose kinds only, and never a
+            // private rumor (a public highlight would e-tag the unsigned rumor onto relays).
+            if (!isPrivateRumor && (note.event is TextNoteEvent || note.event is LongTextNoteEvent)) {
+                add(
+                    NoteAction(MaterialSymbols.FormatQuote, stringRes(R.string.highlight_action)) {
+                        val author = note.author?.pubkeyHex
+                        val route =
+                            if (note is AddressableNote) {
+                                Route.NewHighlight(sourceAddress = note.address.toValue(), author = author)
+                            } else {
+                                Route.NewHighlight(sourceEventId = note.idHex, author = author)
+                            }
+                        nav.nav(route)
+                        handlers.onDismiss()
+                    },
+                )
+            }
             if (!isPrivateRumor) {
                 add(NoteAction(MaterialSymbols.Share, stringRes(R.string.quick_action_share), onClick = handlers.onShare))
             }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/TopNavFilterState.kt

@@ -337,6 +337,24 @@ class TopNavFilterState(
             )
         }
 
+    private val _highlightsRoutes =
+        combineTransform(
+            livePeopleListsFlow,
+            liveInterestFlows,
+        ) { peopleLists, interests ->
+            checkNotInMainThread()
+            emit(
+                listOf(
+                    // Highlights can be narrowed by author, hashtag and geohash, so this mirrors
+                    // the kind3 catalog plus "Mine" — the user's own highlights.
+                    listOf(allFollows, userFollows, kind3Follows, aroundMe, teleport, globalFollow, mineFollow),
+                    peopleLists,
+                    interests,
+                    listOf(muteListFollow),
+                ).flatten().toImmutableList(),
+            )
+        }
+
     private val _relayGroupsDiscoveryRoutes =
         combineTransform(
             livePeopleListsFlow,
@@ -470,6 +488,11 @@ class TopNavFilterState(
             .flowOn(Dispatchers.IO)
             .stateIn(scope, SharingStarted.Eagerly, persistentListOf(allFollows, userFollows, kind3Follows, aroundMe, teleport, globalFollow, mineFollow, muteListFollow))
 
+    val highlightsRoutes =
+        _highlightsRoutes
+            .flowOn(Dispatchers.IO)
+            .stateIn(scope, SharingStarted.Eagerly, persistentListOf(allFollows, userFollows, kind3Follows, aroundMe, teleport, globalFollow, mineFollow, muteListFollow))
+
     val relayGroupsDiscoveryRoutes =
         _relayGroupsDiscoveryRoutes
             .flowOn(Dispatchers.IO)

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

@@ -49,6 +49,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.drafts.dal.DraftEventsFeedF
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.emojipacks.browse.dal.BrowseEmojiSetsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.followPacks.list.dal.FollowPacksFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepositories.dal.GitRepositoriesFeedFilter
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.dal.HighlightsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.dal.HomeConversationsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.dal.HomeEverythingFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.dal.HomeLiveFilter
@@ -117,6 +118,7 @@ class AccountFeedContentStates(
     val picturesFeed = FeedContentState(PictureFeedFilter(account), scope, LocalCache)
     val workoutsFeed = FeedContentState(WorkoutFeedFilter(account), scope, LocalCache)
     val gitRepositoriesFeed = FeedContentState(GitRepositoriesFeedFilter(account), scope, LocalCache)
+    val highlightsFeed = FeedContentState(HighlightsFeedFilter(account), scope, LocalCache)
     val relayGroupsDiscoveryFeed = FeedContentState(RelayGroupDiscoveryFeedFilter(account), scope, LocalCache)
     val calendarAppointmentsFeed = FeedContentState(CalendarAppointmentsFeedFilter(account), scope, LocalCache)
     val calendarCollectionsFeed = FeedContentState(CalendarCollectionsFeedFilter(account), scope, LocalCache)
@@ -327,6 +329,7 @@ class AccountFeedContentStates(
         picturesFeed.updateFeedWith(newNotes)
         workoutsFeed.updateFeedWith(newNotes)
         gitRepositoriesFeed.updateFeedWith(newNotes)
+        highlightsFeed.updateFeedWith(newNotes)
         relayGroupsDiscoveryFeed.updateFeedWith(newNotes)
         productsFeed.updateFeedWith(newNotes)
         shortsFeed.updateFeedWith(newNotes)
@@ -390,6 +393,7 @@ class AccountFeedContentStates(
         picturesFeed.deleteFromFeed(newNotes)
         workoutsFeed.deleteFromFeed(newNotes)
         gitRepositoriesFeed.deleteFromFeed(newNotes)
+        highlightsFeed.deleteFromFeed(newNotes)
         relayGroupsDiscoveryFeed.deleteFromFeed(newNotes)
         productsFeed.deleteFromFeed(newNotes)
         shortsFeed.deleteFromFeed(newNotes)
@@ -449,6 +453,7 @@ class AccountFeedContentStates(
         picturesFeed.trimToSize(maxItems)
         workoutsFeed.trimToSize(maxItems)
         gitRepositoriesFeed.trimToSize(maxItems)
+        highlightsFeed.trimToSize(maxItems)
         relayGroupsDiscoveryFeed.trimToSize(maxItems)
         calendarAppointmentsFeed.trimToSize(maxItems)
         calendarCollectionsFeed.trimToSize(maxItems)

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

@@ -36,6 +36,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.datasource.Discove
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.emojipacks.browse.datasource.BrowseEmojiSetsFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.followPacks.list.datasource.FollowPacksFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.gitRepositories.datasource.GitRepositoriesFilterAssemblerSubscription
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.HighlightsFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.datasource.HomeFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.livestreams.datasource.LiveStreamsFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.longs.datasource.LongsFilterAssemblerSubscription
@@ -100,6 +101,8 @@ private fun PreloadFor(
 
         NavBarItem.GIT_REPOSITORIES -> GitRepositoriesFilterAssemblerSubscription(accountViewModel)
 
+        NavBarItem.HIGHLIGHTS -> HighlightsFilterAssemblerSubscription(accountViewModel)
+
         NavBarItem.SOFTWARE_APPS -> SoftwareAppsFilterAssemblerSubscription(accountViewModel)
 
         // Napplets & nSites read directly from the local cache; their screens open the discovery

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/HighlightsScreen.kt

@@ -0,0 +1,108 @@
+/*
+ * 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.highlights
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.commons.ui.feeds.FeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.RefresheableBox
+import com.vitorpamplona.amethyst.ui.feeds.RenderFeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.SaveableFeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.ScrollStateKeys
+import com.vitorpamplona.amethyst.ui.feeds.WatchLifecycleAndUpdateModel
+import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.AppBottomBar
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.HighlightsFilterAssemblerSubscription
+
+@Composable
+fun HighlightsScreen(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    HighlightsScreen(
+        highlightsFeedContentState = accountViewModel.feedStates.highlightsFeed,
+        accountViewModel = accountViewModel,
+        nav = nav,
+    )
+}
+
+@Composable
+fun HighlightsScreen(
+    highlightsFeedContentState: FeedContentState,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    WatchLifecycleAndUpdateModel(highlightsFeedContentState)
+    WatchAccountForHighlightsScreen(highlightsFeedContentState = highlightsFeedContentState, accountViewModel = accountViewModel)
+    HighlightsFilterAssemblerSubscription(accountViewModel)
+
+    DisappearingScaffold(
+        isInvertedLayout = false,
+        topBar = {
+            HighlightsTopBar(accountViewModel, nav)
+        },
+        bottomBar = {
+            AppBottomBar(Route.Highlights, nav, accountViewModel) { route ->
+                if (route == Route.Highlights) {
+                    highlightsFeedContentState.sendToTop()
+                } else {
+                    nav.navBottomBar(route)
+                }
+            }
+        },
+        floatingButton = {
+            NewHighlightButton(nav)
+        },
+        accountViewModel = accountViewModel,
+    ) {
+        RefresheableBox(highlightsFeedContentState, true) {
+            SaveableFeedContentState(highlightsFeedContentState, scrollStateKey = ScrollStateKeys.HIGHLIGHTS_SCREEN) { listState ->
+                RenderFeedContentState(
+                    feedContentState = highlightsFeedContentState,
+                    accountViewModel = accountViewModel,
+                    listState = listState,
+                    nav = nav,
+                    routeForLastRead = "HighlightsFeed",
+                )
+            }
+        }
+    }
+}
+
+@Composable
+fun WatchAccountForHighlightsScreen(
+    highlightsFeedContentState: FeedContentState,
+    accountViewModel: AccountViewModel,
+) {
+    val listState by accountViewModel.account.liveHighlightsFollowLists.collectAsStateWithLifecycle()
+    val hiddenUsers =
+        accountViewModel.account.hiddenUsers.flow
+            .collectAsStateWithLifecycle()
+
+    LaunchedEffect(accountViewModel, listState, hiddenUsers) {
+        highlightsFeedContentState.checkKeysInvalidateDataAndSendToTop()
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/HighlightsTopBar.kt

@@ -0,0 +1,70 @@
+/*
+ * 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.highlights
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.topbars.FeedFilterSpinner
+import com.vitorpamplona.amethyst.ui.navigation.topbars.UserDrawerSearchTopBar
+import com.vitorpamplona.amethyst.ui.screen.FeedDefinition
+import com.vitorpamplona.amethyst.ui.screen.TopNavFilterState
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+
+@Composable
+fun HighlightsTopBar(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    UserDrawerSearchTopBar(accountViewModel, nav) {
+        val list by accountViewModel.account.settings.defaultHighlightsFollowList
+            .collectAsStateWithLifecycle()
+
+        HighlightsTopNavFilterBar(
+            followListsModel = accountViewModel.feedStates.feedListOptions,
+            listName = list,
+            accountViewModel = accountViewModel,
+            onChange = accountViewModel.account.settings::changeDefaultHighlightsFollowList,
+        )
+    }
+}
+
+@Composable
+private fun HighlightsTopNavFilterBar(
+    followListsModel: TopNavFilterState,
+    listName: TopFilter,
+    accountViewModel: AccountViewModel,
+    onChange: (FeedDefinition) -> Unit,
+) {
+    val allLists by followListsModel.highlightsRoutes.collectAsStateWithLifecycle()
+
+    FeedFilterSpinner(
+        placeholderCode = listName,
+        explainer = stringRes(R.string.select_list_to_filter),
+        options = allLists,
+        onSelect = onChange,
+        accountViewModel = accountViewModel,
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/NewHighlightButton.kt

@@ -0,0 +1,53 @@
+/*
+ * 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.highlights
+
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.amethyst.ui.painterRes
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.amethyst.ui.theme.Size26Modifier
+import com.vitorpamplona.amethyst.ui.theme.Size55Modifier
+
+@Composable
+fun NewHighlightButton(nav: INav) {
+    FloatingActionButton(
+        onClick = {
+            nav.nav(Route.NewHighlight())
+        },
+        modifier = Size55Modifier,
+        shape = CircleShape,
+        containerColor = MaterialTheme.colorScheme.primary,
+    ) {
+        Icon(
+            painter = painterRes(R.drawable.ic_compose, 4),
+            contentDescription = stringRes(R.string.new_highlight_title),
+            modifier = Size26Modifier,
+            tint = MaterialTheme.colorScheme.onPrimary,
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/NewHighlightPostViewModel.kt

@@ -0,0 +1,212 @@
+/*
+ * 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.highlights
+
+import androidx.compose.foundation.text.input.TextFieldState
+import androidx.compose.foundation.text.input.setTextAndPlaceCursorAtEnd
+import androidx.compose.runtime.Stable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.lifecycle.ViewModel
+import com.vitorpamplona.amethyst.commons.model.nip30CustomEmojis.EmojiPackState.EmojiMedia
+import com.vitorpamplona.amethyst.commons.model.nip30CustomEmojis.EmojiSuggestionState
+import com.vitorpamplona.amethyst.commons.ui.text.currentWord
+import com.vitorpamplona.amethyst.commons.ui.text.replaceCurrentWord
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.ui.actions.NewMessageTagger
+import com.vitorpamplona.amethyst.ui.note.creators.messagefield.IMessageField
+import com.vitorpamplona.amethyst.ui.note.creators.userSuggestions.UserSuggestionState
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.quartz.nip01Core.core.Address
+import com.vitorpamplona.quartz.nip01Core.tags.hashtags.hashtags
+import com.vitorpamplona.quartz.nip01Core.tags.people.pTags
+import com.vitorpamplona.quartz.nip01Core.tags.people.toPTag
+import com.vitorpamplona.quartz.nip01Core.tags.references.references
+import com.vitorpamplona.quartz.nip10Notes.content.findHashtags
+import com.vitorpamplona.quartz.nip10Notes.content.findNostrUris
+import com.vitorpamplona.quartz.nip10Notes.content.findURLs
+import com.vitorpamplona.quartz.nip18Reposts.quotes.quotes
+import com.vitorpamplona.quartz.nip30CustomEmoji.emojis
+import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
+
+/**
+ * Backs the "New Highlight" composer. A NIP-84 highlight is a quoted passage (the event
+ * `content`), its source, and an optional annotation. The annotation reuses the short-note
+ * composer's rich [message] field via [IMessageField], so it gets @-mention and custom-emoji
+ * autocomplete and inline previews; on publish it becomes the highlight's `comment` tag with
+ * the mentions, emoji, URLs, hashtags and quotes it references emitted as their own tags.
+ *
+ * The passage, the `textquoteselector` prefix/suffix, the surrounding `context`, and the
+ * nostr source (`a`/`e`/`p`) are carried through from the share or the "Highlight this note"
+ * action. When a nostr event is the source, [originalNote] is resolved so the screen can
+ * render it as a reply-style preview instead of showing a URL field.
+ */
+@Stable
+class NewHighlightPostViewModel :
+    ViewModel(),
+    IMessageField {
+    private var accountViewModel: AccountViewModel? = null
+    private var account: Account? = null
+
+    /** The highlighted passage — becomes the event `content`. */
+    var quote by mutableStateOf("")
+
+    /** The source URL — becomes an `r` tag. Hidden when a nostr event is the source. */
+    var url by mutableStateOf("")
+
+    /** The user's annotation — the rich comment field; becomes a `comment` tag. */
+    override val message = TextFieldState()
+
+    /** The source note, when highlighting a nostr article/note, for the reply-style preview. */
+    var originalNote by mutableStateOf<Note?>(null)
+        private set
+
+    var userSuggestions: UserSuggestionState? = null
+    var emojiSuggestions: EmojiSuggestionState? = null
+
+    private var prefix: String? = null
+    private var suffix: String? = null
+    private var context: String? = null
+    private var sourceAddress: String? = null
+    private var sourceEventId: String? = null
+    private var author: String? = null
+
+    private var loaded = false
+
+    fun init(accountViewModel: AccountViewModel) {
+        if (this.accountViewModel == accountViewModel) return
+        this.accountViewModel = accountViewModel
+        this.account = accountViewModel.account
+        userSuggestions = UserSuggestionState(accountViewModel.account, accountViewModel.nip05ClientBuilder())
+        emojiSuggestions = EmojiSuggestionState(accountViewModel.account.emoji)
+    }
+
+    /**
+     * Applies the incoming source once, and resolves [originalNote] for a nostr source. Guarded
+     * so a recomposition can't clobber edits the user already made.
+     */
+    fun load(
+        quote: String?,
+        url: String?,
+        prefix: String?,
+        suffix: String?,
+        comment: String?,
+        context: String?,
+        sourceAddress: String?,
+        sourceEventId: String?,
+        author: String?,
+    ) {
+        if (loaded) return
+        loaded = true
+
+        this.quote = quote.orEmpty()
+        this.url = url.orEmpty()
+        comment?.ifBlank { null }?.let { message.setTextAndPlaceCursorAtEnd(it) }
+        this.prefix = prefix
+        this.suffix = suffix
+        this.context = context
+        this.sourceAddress = sourceAddress
+        this.sourceEventId = sourceEventId
+        this.author = author
+
+        val accountViewModel = accountViewModel
+        if (accountViewModel != null) {
+            originalNote =
+                when {
+                    !sourceAddress.isNullOrBlank() -> Address.parse(sourceAddress)?.let { accountViewModel.getOrCreateAddressableNote(it) }
+                    !sourceEventId.isNullOrBlank() -> accountViewModel.getOrCreateNote(sourceEventId)
+                    else -> null
+                }
+        }
+    }
+
+    override fun onMessageChanged() {
+        if (message.selection.collapsed) {
+            val lastWord = message.currentWord()
+            if (lastWord.startsWith("@")) {
+                userSuggestions?.processCurrentWord(lastWord)
+            } else {
+                userSuggestions?.reset()
+            }
+            emojiSuggestions?.processCurrentWord(lastWord)
+        }
+    }
+
+    fun autocompleteWithUser(item: User) {
+        userSuggestions?.let {
+            val lastWord = message.currentWord()
+            it.replaceCurrentWord(message, lastWord, item)
+            it.reset()
+        }
+    }
+
+    fun autocompleteWithEmoji(item: EmojiMedia) {
+        emojiSuggestions?.autocompleteInto(message, item)
+    }
+
+    fun autocompleteWithEmojiUrl(item: EmojiMedia) {
+        message.replaceCurrentWord(item.link + " ")
+        emojiSuggestions?.reset()
+    }
+
+    fun canPost(): Boolean = quote.isNotBlank()
+
+    suspend fun sendHighlight() {
+        val account = account ?: return
+        val dao = accountViewModel ?: return
+        if (!canPost()) return
+
+        // Resolve @mentions, nostr: refs, emoji, URLs and hashtags out of the annotation the same
+        // way the short-note composer does, so a highlight comment behaves like any other note.
+        val tagger = NewMessageTagger(message.text.toString().trim(), null, null, dao)
+        tagger.run()
+
+        val commentText = tagger.message.ifBlank { null }
+        val mentions = tagger.directMentionsUsers.map { it.toPTag() }
+        val emojiTags = account.emoji.findEmojiTags(tagger.message)
+        val urls = findURLs(tagger.message)
+        val tags = findHashtags(tagger.message)
+        val quotes = findNostrUris(tagger.message)
+
+        account.signAndComputeBroadcast(
+            HighlightEvent.build(
+                quote = quote.trim(),
+                url = url.trim().ifBlank { null },
+                prefix = prefix,
+                suffix = suffix,
+                comment = commentText,
+                context = context,
+                address = sourceAddress,
+                event = sourceEventId,
+                author = author,
+            ) {
+                if (mentions.isNotEmpty()) pTags(mentions)
+                references(urls)
+                hashtags(tags)
+                quotes(quotes)
+                emojis(emojiTags)
+            },
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/NewHighlightScreen.kt

@@ -0,0 +1,329 @@
+/*
+ * 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.highlights
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.IntrinsicSize
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.consumeWindowInsets
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.BasicTextField
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.LocalTextStyle
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.em
+import androidx.compose.ui.unit.sp
+import androidx.lifecycle.viewmodel.compose.viewModel
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
+import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbol
+import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
+import com.vitorpamplona.amethyst.commons.nip30CustomEmojis.ui.ShowEmojiSuggestionList
+import com.vitorpamplona.amethyst.ui.navigation.navs.Nav
+import com.vitorpamplona.amethyst.ui.navigation.topbars.PostingTopBar
+import com.vitorpamplona.amethyst.ui.note.NoteCompose
+import com.vitorpamplona.amethyst.ui.note.creators.emojiSuggestions.WatchAndLoadMyEmojiList
+import com.vitorpamplona.amethyst.ui.note.creators.messagefield.MessageField
+import com.vitorpamplona.amethyst.ui.note.creators.userSuggestions.ShowUserSuggestionList
+import com.vitorpamplona.amethyst.ui.note.types.ReplyRenderType
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.amethyst.ui.theme.SuggestionListDefaultHeightPage
+import com.vitorpamplona.amethyst.ui.theme.replyModifier
+
+/** A warm highlighter amber — the highlight metaphor reads as yellow regardless of theme. */
+private val MarkerAccent = Color(0xFFF5C518)
+
+/**
+ * The "New Highlight" composer. Reached either from the "Add highlight" action, a browser
+ * share, or the "Highlight" note-action, routed in as
+ * [com.vitorpamplona.amethyst.ui.navigation.routes.Route.NewHighlight].
+ *
+ * A NIP-84 highlight is a quoted passage, its source, and an optional annotation:
+ * - the passage is a pull-quote you craft (accent bar + quotation-mark watermark),
+ * - the source is either a nostr event — rendered as a reply-style preview — or a web URL,
+ * - the annotation is the same rich composer field the short-note screen uses, so it gets
+ *   @-mention and custom-emoji autocomplete and inline previews.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun NewHighlightScreen(
+    quote: String? = null,
+    url: String? = null,
+    prefix: String? = null,
+    suffix: String? = null,
+    comment: String? = null,
+    context: String? = null,
+    sourceAddress: String? = null,
+    sourceEventId: String? = null,
+    author: String? = null,
+    accountViewModel: AccountViewModel,
+    nav: Nav,
+) {
+    val postViewModel: NewHighlightPostViewModel = viewModel()
+    postViewModel.init(accountViewModel)
+
+    WatchAndLoadMyEmojiList(accountViewModel)
+
+    LaunchedEffect(Unit) {
+        postViewModel.load(quote, url, prefix, suffix, comment, context, sourceAddress, sourceEventId, author)
+    }
+
+    Scaffold(
+        topBar = {
+            PostingTopBar(
+                titleRes = R.string.new_highlight_title,
+                isActive = postViewModel::canPost,
+                onCancel = { nav.popBack() },
+                onPost = {
+                    // Uses the accountViewModel scope so releasing the post ViewModel on
+                    // popBack can't cancel the in-flight publish.
+                    accountViewModel.launchSigner {
+                        postViewModel.sendHighlight()
+                        nav.popBack()
+                    }
+                },
+            )
+        },
+    ) { pad ->
+        Column(
+            modifier =
+                Modifier
+                    .padding(pad)
+                    .consumeWindowInsets(pad)
+                    .imePadding()
+                    .fillMaxSize(),
+        ) {
+            Column(
+                modifier =
+                    Modifier
+                        .weight(1f)
+                        .fillMaxWidth()
+                        .verticalScroll(rememberScrollState())
+                        .padding(horizontal = 20.dp, vertical = 16.dp),
+                verticalArrangement = Arrangement.spacedBy(16.dp),
+            ) {
+                HighlightEditorCard(
+                    passage = postViewModel.quote,
+                    onPassageChange = { postViewModel.quote = it },
+                )
+
+                val source = postViewModel.originalNote
+                if (source != null) {
+                    NoteCompose(
+                        baseNote = source,
+                        modifier = MaterialTheme.colorScheme.replyModifier,
+                        isQuotedNote = true,
+                        unPackReply = ReplyRenderType.NONE,
+                        makeItShort = true,
+                        quotesLeft = 1,
+                        accountViewModel = accountViewModel,
+                        nav = nav,
+                    )
+                } else {
+                    IconField(
+                        symbol = MaterialSymbols.Link,
+                        value = postViewModel.url,
+                        onValueChange = { postViewModel.url = it },
+                        label = stringRes(R.string.new_highlight_source_label),
+                        placeholder = "https://example.com/article",
+                        singleLine = true,
+                    )
+                }
+
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    Icon(
+                        symbol = MaterialSymbols.EditNote,
+                        contentDescription = null,
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.size(20.dp),
+                    )
+                    Spacer(Modifier.width(8.dp))
+                    Text(
+                        text = stringRes(R.string.new_highlight_note_label),
+                        style = MaterialTheme.typography.labelLarge,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+                MessageField(
+                    placeholder = R.string.new_highlight_note_placeholder,
+                    viewModel = postViewModel,
+                    requestFocus = false,
+                )
+            }
+
+            postViewModel.userSuggestions?.let {
+                ShowUserSuggestionList(
+                    it,
+                    postViewModel::autocompleteWithUser,
+                    accountViewModel,
+                    modifier = SuggestionListDefaultHeightPage,
+                )
+            }
+
+            postViewModel.emojiSuggestions?.let {
+                ShowEmojiSuggestionList(
+                    it,
+                    postViewModel::autocompleteWithEmoji,
+                    postViewModel::autocompleteWithEmojiUrl,
+                    modifier = SuggestionListDefaultHeightPage,
+                )
+            }
+        }
+    }
+}
+
+/**
+ * The hero: a rounded, tonal card carrying a quotation-mark watermark, a highlighter-yellow
+ * accent bar, and the editable passage set in a large, comfortable type.
+ */
+@Composable
+private fun HighlightEditorCard(
+    passage: String,
+    onPassageChange: (String) -> Unit,
+) {
+    Surface(
+        shape = RoundedCornerShape(24.dp),
+        color = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f),
+        tonalElevation = 2.dp,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Box(modifier = Modifier.fillMaxWidth()) {
+            Icon(
+                symbol = MaterialSymbols.FormatQuote,
+                contentDescription = null,
+                tint = MarkerAccent.copy(alpha = 0.20f),
+                modifier =
+                    Modifier
+                        .align(Alignment.TopStart)
+                        .offset(x = 8.dp, y = (-6).dp)
+                        .size(80.dp),
+            )
+
+            Row(
+                modifier =
+                    Modifier
+                        .fillMaxWidth()
+                        .height(IntrinsicSize.Min)
+                        .padding(20.dp),
+            ) {
+                Spacer(
+                    Modifier
+                        .width(4.dp)
+                        .fillMaxHeight()
+                        .clip(RoundedCornerShape(2.dp))
+                        .background(MarkerAccent),
+                )
+                Spacer(Modifier.width(16.dp))
+                Column(modifier = Modifier.weight(1f)) {
+                    BasicTextField(
+                        value = passage,
+                        onValueChange = onPassageChange,
+                        textStyle =
+                            LocalTextStyle.current.copy(
+                                color = MaterialTheme.colorScheme.onSurface,
+                                fontSize = 20.sp,
+                                lineHeight = 1.4.em,
+                                fontWeight = FontWeight.Medium,
+                            ),
+                        cursorBrush = SolidColor(MarkerAccent),
+                        modifier = Modifier.fillMaxWidth().heightIn(min = 88.dp),
+                        decorationBox = { inner ->
+                            if (passage.isEmpty()) {
+                                Text(
+                                    text = stringRes(R.string.new_highlight_passage_placeholder),
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.6f),
+                                    fontSize = 20.sp,
+                                    lineHeight = 1.4.em,
+                                )
+                            }
+                            inner()
+                        },
+                    )
+                    Spacer(Modifier.height(10.dp))
+                    Text(
+                        text = "${passage.length}",
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        textAlign = TextAlign.End,
+                        modifier = Modifier.fillMaxWidth(),
+                    )
+                }
+            }
+        }
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun IconField(
+    symbol: MaterialSymbol,
+    value: String,
+    onValueChange: (String) -> Unit,
+    label: String,
+    placeholder: String,
+    singleLine: Boolean,
+    minLines: Int = 1,
+) {
+    OutlinedTextField(
+        value = value,
+        onValueChange = onValueChange,
+        modifier = Modifier.fillMaxWidth(),
+        label = { Text(label) },
+        placeholder = { Text(placeholder) },
+        leadingIcon = {
+            Icon(symbol = symbol, contentDescription = null, modifier = Modifier.size(20.dp))
+        },
+        singleLine = singleLine,
+        minLines = minLines,
+        shape = RoundedCornerShape(16.dp),
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/dal/HighlightsFeedFilter.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.screen.loggedIn.highlights.dal
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.ui.dal.AdditiveFeedFilter
+import com.vitorpamplona.amethyst.ui.dal.FilterByListParams
+import com.vitorpamplona.amethyst.ui.dal.sortedByDefaultFeedOrder
+import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
+
+/**
+ * The client-side data-access layer for the Highlights feed. Mirrors
+ * `GitRepositoriesFeedFilter`, but highlights (kind 9802) are *regular* events rather than
+ * addressable ones, so it scans `LocalCache.notes` instead of `LocalCache.addressables`.
+ * The `FilterByListParams` handles the selected top-nav follow-list, hidden users and
+ * future-dated / spam checks.
+ */
+class HighlightsFeedFilter(
+    val account: Account,
+) : AdditiveFeedFilter<Note>() {
+    override fun feedKey(): String = account.userProfile().pubkeyHex + "-" + followList().code
+
+    override fun limit() = 200
+
+    fun followList(): TopFilter = account.settings.defaultHighlightsFollowList.value
+
+    fun TopFilter.isMuteList() = this is TopFilter.MuteList
+
+    fun TopFilter.isBlockList() = this is TopFilter.PeopleList && this.address == account.blockPeopleList.getBlockListAddress()
+
+    fun TopFilter.wantsToSeeNegativeStuff() = isMuteList() || isBlockList()
+
+    override fun showHiddenKey(): Boolean = followList().wantsToSeeNegativeStuff()
+
+    override fun feed(): List<Note> {
+        val params = buildFilterParams(account)
+        val notes =
+            LocalCache.notes.filterIntoSet { _, it ->
+                val noteEvent = it.event
+                noteEvent is HighlightEvent && params.match(noteEvent, it.relays)
+            }
+
+        return sort(notes)
+    }
+
+    override fun applyFilter(newItems: Set<Note>): Set<Note> = innerApplyFilter(newItems)
+
+    fun buildFilterParams(account: Account): FilterByListParams =
+        FilterByListParams.create(
+            account.liveHighlightsFollowLists.value,
+            account.hiddenUsers.flow.value,
+        )
+
+    private fun innerApplyFilter(collection: Collection<Note>): Set<Note> {
+        val params = buildFilterParams(account)
+
+        return collection.filterTo(HashSet()) {
+            val noteEvent = it.event
+            noteEvent is HighlightEvent && params.match(noteEvent, it.relays)
+        }
+    }
+
+    override fun sort(items: Set<Note>): List<Note> = items.sortedByDefaultFeedOrder()
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/HighlightsFilter.kt

@@ -0,0 +1,60 @@
+/*
+ * 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.highlights.datasource
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.IFeedTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.allFollows.AllFollowsTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.aroundMe.LocationTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.global.GlobalTopNavPerRelayFilterSet
+import com.vitorpamplona.amethyst.model.topNavFeeds.hashtag.HashtagTopNavPerRelayFilterSet
+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.highlights.datasource.subassemblies.filterHighlightsByAuthors
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.subassemblies.filterHighlightsByFollows
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.subassemblies.filterHighlightsByGeohashes
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.subassemblies.filterHighlightsByHashtag
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.subassemblies.filterHighlightsByMutedAuthors
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.highlights.datasource.subassemblies.filterHighlightsGlobal
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+
+/**
+ * Routes the resolved top-nav filter set (author/hashtag/geohash/global/follows, per relay,
+ * via the outbox model) to the matching subassembly that pins kind 9802 to specific relays.
+ *
+ * Highlights are not community-scoped, so — unlike git repositories — the community filter
+ * sets fall through to [emptyList]; those options aren't offered in the top-nav catalog
+ * anyway (see TopNavFilterState._highlightsRoutes).
+ */
+fun makeHighlightsFilter(
+    feedSettings: IFeedTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> =
+    when (feedSettings) {
+        is AllFollowsTopNavPerRelayFilterSet -> filterHighlightsByFollows(feedSettings, since, defaultSince)
+        is AuthorsTopNavPerRelayFilterSet -> filterHighlightsByAuthors(feedSettings, since, defaultSince)
+        is GlobalTopNavPerRelayFilterSet -> filterHighlightsGlobal(feedSettings, since, defaultSince)
+        is HashtagTopNavPerRelayFilterSet -> filterHighlightsByHashtag(feedSettings, since, defaultSince)
+        is LocationTopNavPerRelayFilterSet -> filterHighlightsByGeohashes(feedSettings, since, defaultSince)
+        is MutedAuthorsTopNavPerRelayFilterSet -> filterHighlightsByMutedAuthors(feedSettings, since, defaultSince)
+        else -> emptyList()
+    }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/HighlightsFilterAssembler.kt

@@ -0,0 +1,50 @@
+/*
+ * 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.highlights.datasource
+
+import androidx.compose.runtime.Stable
+import com.vitorpamplona.amethyst.commons.relayClient.composeSubscriptionManagers.ComposeSubscriptionManager
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountFeedContentStates
+import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
+import kotlinx.coroutines.CoroutineScope
+
+class HighlightsQueryState(
+    val account: Account,
+    val feedStates: AccountFeedContentStates,
+    val scope: CoroutineScope,
+)
+
+@Stable
+class HighlightsFilterAssembler(
+    client: INostrClient,
+) : ComposeSubscriptionManager<HighlightsQueryState>() {
+    val group =
+        listOf(
+            HighlightsSubAssembler(client, ::allKeys),
+        )
+
+    override fun invalidateKeys() = invalidateFilters()
+
+    override fun invalidateFilters() = group.forEach { it.invalidateFilters() }
+
+    override fun destroy() = group.forEach { it.destroy() }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/HighlightsFilterAssemblerSubscription.kt

@@ -0,0 +1,48 @@
+/*
+ * 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.highlights.datasource
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.lifecycle.viewModelScope
+import com.vitorpamplona.amethyst.commons.relayClient.subscriptions.LifecycleAwareKeyDataSourceSubscription
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+
+@Composable
+fun HighlightsFilterAssemblerSubscription(accountViewModel: AccountViewModel) {
+    HighlightsFilterAssemblerSubscription(
+        accountViewModel.dataSources().highlights,
+        accountViewModel,
+    )
+}
+
+@Composable
+fun HighlightsFilterAssemblerSubscription(
+    dataSource: HighlightsFilterAssembler,
+    accountViewModel: AccountViewModel,
+) {
+    val state =
+        remember(accountViewModel.account) {
+            HighlightsQueryState(accountViewModel.account, accountViewModel.feedStates, accountViewModel.viewModelScope)
+        }
+
+    LifecycleAwareKeyDataSourceSubscription(state, dataSource)
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/HighlightsSubAssembler.kt

@@ -0,0 +1,100 @@
+/*
+ * 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.highlights.datasource
+
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.service.relayClient.eoseManagers.PerUserAndFollowListEoseManager
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+import com.vitorpamplona.quartz.nip01Core.relay.client.subscriptions.Subscription
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.sample
+import kotlinx.coroutines.launch
+
+class HighlightsSubAssembler(
+    client: INostrClient,
+    allKeys: () -> Set<HighlightsQueryState>,
+) : PerUserAndFollowListEoseManager<HighlightsQueryState, TopFilter>(client, allKeys) {
+    override fun updateFilter(
+        key: HighlightsQueryState,
+        since: SincePerRelayMap?,
+    ): List<RelayBasedFilter> {
+        // "Mine" needs no special-case: the shared TopFilter.Mine flow resolves to an author
+        // filter scoped to the user, so followsPerRelay() already carries authors=[me] against the
+        // user's own outbox.
+        val feedSettings = key.followsPerRelay()
+
+        return makeHighlightsFilter(feedSettings, since, key.feedStates.highlightsFeed.lastNoteCreatedAtIfFilled())
+    }
+
+    override fun user(key: HighlightsQueryState) = key.account.userProfile()
+
+    override fun list(key: HighlightsQueryState) = key.listName()
+
+    fun HighlightsQueryState.listNameFlow() = account.settings.defaultHighlightsFollowList
+
+    fun HighlightsQueryState.listName() = listNameFlow().value
+
+    fun HighlightsQueryState.followsPerRelayFlow() = account.liveHighlightsFollowListsPerRelay
+
+    fun HighlightsQueryState.followsPerRelay() = followsPerRelayFlow().value
+
+    val userJobMap = mutableMapOf<User, List<Job>>()
+
+    @OptIn(FlowPreview::class)
+    override fun newSub(key: HighlightsQueryState): Subscription {
+        val user = user(key)
+        userJobMap[user]?.forEach { it.cancel() }
+        userJobMap[user] =
+            listOf(
+                key.scope.launch(Dispatchers.IO) {
+                    key.listNameFlow().collectLatest {
+                        invalidateFilters()
+                    }
+                },
+                key.scope.launch(Dispatchers.IO) {
+                    key.followsPerRelayFlow().sample(500).collectLatest {
+                        invalidateFilters()
+                    }
+                },
+                key.account.scope.launch(Dispatchers.IO) {
+                    key.feedStates.highlightsFeed.lastNoteCreatedAtWhenFullyLoaded.sample(5000).collectLatest {
+                        invalidateFilters()
+                    }
+                },
+            )
+
+        return super.newSub(key)
+    }
+
+    override fun endSub(
+        key: User,
+        subId: String,
+    ) {
+        super.endSub(key, subId)
+        userJobMap[key]?.forEach { it.cancel() }
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/subassemblies/FilterHighlightsByAuthors.kt

@@ -0,0 +1,92 @@
+/*
+ * 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.highlights.datasource.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.nip84Highlights.HighlightEvent
+
+fun filterHighlightsByAuthors(
+    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(HighlightEvent.KIND),
+                    limit = 200,
+                    since = since,
+                ),
+        ),
+    )
+}
+
+fun filterHighlightsByAuthors(
+    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 {
+                filterHighlightsByAuthors(
+                    relay = it.key,
+                    authors = it.value.authors,
+                    since = since?.get(it.key)?.time ?: defaultSince,
+                )
+            }
+        }.flatten()
+}
+
+fun filterHighlightsByMutedAuthors(
+    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 {
+                filterHighlightsByAuthors(
+                    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/highlights/datasource/subassemblies/FilterHighlightsByFollows.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.highlights.datasource.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 filterHighlightsByFollows(
+    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 {
+                filterHighlightsByAuthors(relay, it, since)
+            },
+        ).flatten()
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/subassemblies/FilterHighlightsByGeohashes.kt

@@ -0,0 +1,70 @@
+/*
+ * 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.highlights.datasource.subassemblies
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.aroundMe.LocationTopNavPerRelayFilterSet
+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.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
+
+fun filterHighlightsByGeohashes(
+    relay: NormalizedRelayUrl,
+    geotags: Set<String>,
+    since: Long?,
+): List<RelayBasedFilter> {
+    if (geotags.isEmpty()) return emptyList()
+
+    return listOf(
+        RelayBasedFilter(
+            relay = relay,
+            filter =
+                Filter(
+                    kinds = listOf(HighlightEvent.KIND),
+                    tags = mapOf("g" to geotags.sorted()),
+                    limit = 100,
+                    since = since,
+                ),
+        ),
+    )
+}
+
+fun filterHighlightsByGeohashes(
+    geoSet: LocationTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long?,
+): List<RelayBasedFilter> {
+    if (geoSet.set.isEmpty()) return emptyList()
+
+    return geoSet.set
+        .mapNotNull {
+            if (it.value.geotags.isEmpty()) {
+                null
+            } else {
+                filterHighlightsByGeohashes(
+                    relay = it.key,
+                    geotags = it.value.geotags,
+                    since = since?.get(it.key)?.time ?: defaultSince,
+                )
+            }
+        }.flatten()
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/subassemblies/FilterHighlightsByHashtag.kt

@@ -0,0 +1,67 @@
+/*
+ * 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.highlights.datasource.subassemblies
+
+import com.vitorpamplona.amethyst.model.topNavFeeds.hashtag.HashtagTopNavPerRelayFilterSet
+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.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.nip84Highlights.HighlightEvent
+
+fun filterHighlightsByHashtag(
+    relay: NormalizedRelayUrl,
+    hashtags: Set<String>,
+    since: Long? = null,
+): List<RelayBasedFilter> =
+    listOf(
+        RelayBasedFilter(
+            relay = relay,
+            filter =
+                Filter(
+                    kinds = listOf(HighlightEvent.KIND),
+                    tags = mapOf("t" to hashtags.toList()),
+                    limit = 200,
+                    since = since,
+                ),
+        ),
+    )
+
+fun filterHighlightsByHashtag(
+    hashtagSet: HashtagTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (hashtagSet.set.isEmpty()) return emptyList()
+
+    return hashtagSet.set
+        .mapNotNull { relayHashSet ->
+            if (relayHashSet.value.hashtags.isEmpty()) {
+                null
+            } else {
+                filterHighlightsByHashtag(
+                    relay = relayHashSet.key,
+                    hashtags = relayHashSet.value.hashtags,
+                    since = since?.get(relayHashSet.key)?.time ?: defaultSince,
+                )
+            }
+        }.flatten()
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/highlights/datasource/subassemblies/FilterHighlightsGlobal.kt

@@ -0,0 +1,49 @@
+/*
+ * 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.highlights.datasource.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.nip84Highlights.HighlightEvent
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+fun filterHighlightsGlobal(
+    relays: GlobalTopNavPerRelayFilterSet,
+    since: SincePerRelayMap?,
+    defaultSince: Long? = null,
+): List<RelayBasedFilter> {
+    if (relays.set.isEmpty()) return emptyList()
+
+    return relays.set.map {
+        val since = since?.get(it.key)?.time ?: defaultSince ?: TimeUtils.oneWeekAgo()
+        RelayBasedFilter(
+            relay = it.key,
+            filter =
+                Filter(
+                    kinds = listOf(HighlightEvent.KIND),
+                    limit = 200,
+                    since = since,
+                ),
+        )
+    }
+}

amethyst/src/main/res/values/strings.xml

@@ -2764,6 +2764,14 @@
     <string name="share_target_as_dm">Send as DM</string>
     <string name="share_to_dm_title">Send to…</string>
     <string name="share_to_dm_start_new">New message</string>
+    <string name="share_target_as_highlight">New Highlight</string>
+    <string name="new_highlight_title">New Highlight</string>
+    <string name="new_highlight_passage_label">Highlighted text</string>
+    <string name="new_highlight_passage_placeholder">What stood out to you?</string>
+    <string name="new_highlight_source_label">Source URL</string>
+    <string name="new_highlight_note_label">Your note (optional)</string>
+    <string name="new_highlight_note_placeholder">Add your thoughts…</string>
+    <string name="highlight_action">Highlight</string>
     <string name="copy_url_to_clipboard">Copy URL to clipboard</string>
     <string name="copy_the_note_id_to_the_clipboard">Copy Note ID to clipboard</string>
     <string name="add_media_to_gallery">Add Media to Gallery</string>
@@ -3807,6 +3815,7 @@
     <string name="git_repo_settings_topics">Topics (comma separated)</string>
     <string name="git_repo_settings_save">Save</string>
     <string name="git_repositories">Git Repositories</string>
+    <string name="highlights">Highlights</string>
     <string name="nsite_title">nSite: %1$s</string>
     <string name="napplet_card_title">nApplet: %1$s</string>
     <string name="napplet_card_permissions">Permissions:</string>

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip84Highlights/HighlightEvent.kt

@@ -22,13 +22,16 @@ package com.vitorpamplona.quartz.nip84Highlights
 
 import androidx.compose.runtime.Immutable
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
 import com.vitorpamplona.quartz.nip01Core.hints.AddressHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.PubKeyHintProvider
 import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.EventIdHint
 import com.vitorpamplona.quartz.nip01Core.hints.types.PubKeyHint
+import com.vitorpamplona.quartz.nip01Core.signers.EventTemplate
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.firstTaggedATag
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.firstTaggedAddress
@@ -190,5 +193,99 @@ class HighlightEvent(
             signer: NostrSigner,
             createdAt: Long = TimeUtils.now(),
         ): HighlightEvent = signer.sign(createdAt, KIND, emptyArray(), msg)
+
+        /**
+         * Builds a fully-tagged NIP-84 highlight from the pieces a browser share (or the
+         * highlight composer) produces. The highlighted passage becomes the event `content`;
+         * the remaining inputs are emitted as their NIP-84 tags when present:
+         *
+         * - [address] → an `a` reference to a nostr addressable source (e.g. a NIP-23 article),
+         * - [event] → an `e` reference to a specific nostr event version highlighted,
+         * - [author] → a `p` attribution to the highlighted content's author,
+         * - [url] → an `r` source reference (normalized by [ReferenceTag]; clean it of
+         *   trackers with [com.vitorpamplona.quartz.nip84Highlights.parse.UrlTrackerCleaner] first),
+         * - [prefix]/[suffix] → a `textquoteselector` anchor (the `exact` field stays a
+         *   placeholder since the passage already lives in `content`),
+         * - [context] → the surrounding paragraph as a `context` tag,
+         * - [comment] → the user's own note as a `comment` tag (turns it into a quote highlight).
+         *
+         * This covers every NIP-84 source: a web page ([url]), a nostr article ([address]),
+         * a nostr note ([event]), each with optional author attribution and the user's note.
+         */
+        suspend fun create(
+            quote: String,
+            url: String? = null,
+            prefix: String? = null,
+            suffix: String? = null,
+            comment: String? = null,
+            context: String? = null,
+            address: String? = null,
+            event: String? = null,
+            author: String? = null,
+            signer: NostrSigner,
+            createdAt: Long = TimeUtils.now(),
+        ): HighlightEvent = signer.sign(createdAt, KIND, assembleTags(url, prefix, suffix, comment, context, address, event, author), quote)
+
+        /**
+         * The unsigned [EventTemplate] counterpart of [create], for the app's
+         * sign-and-broadcast pipeline (`account.signAndComputeBroadcast(...)`). Same tag
+         * assembly; the caller supplies the signer.
+         */
+        fun build(
+            quote: String,
+            url: String? = null,
+            prefix: String? = null,
+            suffix: String? = null,
+            comment: String? = null,
+            context: String? = null,
+            address: String? = null,
+            event: String? = null,
+            author: String? = null,
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<HighlightEvent>.() -> Unit = {},
+        ): EventTemplate<HighlightEvent> =
+            eventTemplate(KIND, quote, createdAt) {
+                addAll(assembleTags(url, prefix, suffix, comment, context, address, event, author))
+                initializer()
+            }
+
+        private fun assembleTags(
+            url: String?,
+            prefix: String?,
+            suffix: String?,
+            comment: String?,
+            context: String?,
+            address: String? = null,
+            event: String? = null,
+            author: String? = null,
+        ): Array<Array<String>> {
+            val tags = mutableListOf<Array<String>>()
+
+            if (!address.isNullOrBlank()) {
+                tags.add(ATag.assemble(address, null))
+            }
+            if (!event.isNullOrBlank()) {
+                tags.add(ETag.assemble(event, null, null))
+            }
+            if (!author.isNullOrBlank()) {
+                // Mark the role so [author] attributes to this p tag even when the highlight also
+                // carries `mention` p tags — the producer-side counterpart of that reader logic.
+                tags.add(arrayOf(PTag.TAG_NAME, author, "", AUTHOR_MARKER))
+            }
+            if (!url.isNullOrBlank()) {
+                tags.add(ReferenceTag.assemble(url))
+            }
+            if (!prefix.isNullOrEmpty() || !suffix.isNullOrEmpty()) {
+                tags.add(TextQuoteSelectorTag.assemble(null, prefix, suffix))
+            }
+            if (!context.isNullOrBlank()) {
+                tags.add(ContextTag.assemble(context))
+            }
+            if (!comment.isNullOrBlank()) {
+                tags.add(CommentTag.assemble(comment))
+            }
+
+            return tags.toTypedArray()
+        }
     }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/SharedHighlight.kt

@@ -0,0 +1,48 @@
+/*
+ * 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.nip84Highlights.parse
+
+/**
+ * The structured result of parsing a browser share into the pieces a NIP-84 kind:9802
+ * highlight needs. Produced by [SharedHighlightParser]; consumed by
+ * [com.vitorpamplona.quartz.nip84Highlights.HighlightEvent.Companion.create] and by the
+ * highlight composer UI (which pre-fills its fields and lets the user confirm/edit before
+ * signing).
+ *
+ * @property quote the highlighted passage → the event `content`
+ * @property url the cleaned source URL (trackers and text-fragment stripped) → an `r` tag
+ * @property prefix text just before the highlight, for a `textquoteselector` anchor
+ * @property suffix text just after the highlight, for a `textquoteselector` anchor
+ */
+class SharedHighlight(
+    val quote: String?,
+    val url: String?,
+    val prefix: String?,
+    val suffix: String?,
+) {
+    /** True when nothing usable was found (neither a passage nor a source URL). */
+    fun isEmpty(): Boolean = quote.isNullOrBlank() && url.isNullOrBlank()
+
+    /** True when there is at least a highlighted passage or a source URL. */
+    fun isNotEmpty(): Boolean = !isEmpty()
+
+    fun hasSelector(): Boolean = !prefix.isNullOrEmpty() || !suffix.isNullOrEmpty()
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/SharedHighlightParser.kt

@@ -0,0 +1,144 @@
+/*
+ * 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.nip84Highlights.parse
+
+/**
+ * Turns the free-form text a browser hands Amethyst on "Share selection" into the pieces of
+ * a NIP-84 highlight. The share intent's plain text can arrive in several shapes and this
+ * parser normalises all of them:
+ *
+ * - **Selection only** — `"Some highlighted sentence."` → quote, no URL.
+ * - **Selection + page URL** — `"Some highlighted sentence."\n\nhttps://example.com/post`
+ *   (what many browsers and read-it-later apps emit) → quote + source URL.
+ * - **URL only** — `https://example.com/post` → source URL, no quote yet.
+ * - **Link to highlight** — `https://example.com/post#:~:text=prefix-,Some%20sentence,-after`
+ *   (Chrome/Edge/Safari "Copy link to highlight") → the passage decoded from the text
+ *   fragment plus its prefix/suffix anchors, with the fragment stripped off the stored URL.
+ *
+ * The URL is always cleaned of tracking parameters ([UrlTrackerCleaner]) and of its
+ * text-fragment directive ([TextFragmentParser]) before being returned. Surrounding quote
+ * marks the browser wraps around the selection are trimmed off the passage.
+ *
+ * The result is a best-effort pre-fill: the composer screen lets the user confirm and edit
+ * every field before the event is signed.
+ */
+object SharedHighlightParser {
+    private val URL_REGEX = Regex("""https?://\S+""", RegexOption.IGNORE_CASE)
+
+    // Trailing punctuation that is part of the surrounding sentence, not the URL token.
+    // Closing brackets are handled separately (balance-aware) so a Wikipedia URL such as
+    // `.../wiki/Mercury_(planet)` keeps its trailing `)`.
+    private const val URL_TRAILING_TRIM = ".,;:!?>\"'»”’"
+
+    private val OPEN_TO_CLOSE = mapOf('(' to ')', '[' to ']', '{' to '}')
+
+    // Quote marks a browser may wrap around a shared selection (straight, curly, guillemets).
+    private const val QUOTE_CHARS = "\"'“”‘’«»"
+
+    fun parse(shared: String): SharedHighlight {
+        val input = shared.trim()
+        if (input.isEmpty()) return SharedHighlight(null, null, null, null)
+
+        // The source URL is normally appended after the selection, so prefer the last URL in
+        // the string (a URL inside the highlighted text itself stays part of the quote).
+        val match = URL_REGEX.findAll(input).lastOrNull()
+
+        var url: String? = null
+        var prefix: String? = null
+        var suffix: String? = null
+        var fragmentQuote: String? = null
+        var remainder = input
+
+        if (match != null) {
+            val rawToken = match.value
+            val rawUrl = trimUrlEnd(rawToken)
+
+            val fragment = TextFragmentParser.parse(rawUrl)
+            prefix = fragment?.prefix
+            suffix = fragment?.suffix
+            fragmentQuote = fragment?.start
+
+            val stripped = TextFragmentParser.stripTextFragment(rawUrl)
+            url = UrlTrackerCleaner.clean(stripped).takeIf { it.isNotBlank() }
+
+            // Remove the whole matched token (incl. any trailing punctuation) from the passage.
+            remainder = dropDanglingOpenBracket(input.removeRange(match.range).trim())
+        }
+
+        val quote = cleanQuote(remainder) ?: fragmentQuote?.let { cleanQuote(it) }
+
+        return SharedHighlight(
+            quote = quote,
+            url = url,
+            prefix = prefix,
+            suffix = suffix,
+        )
+    }
+
+    /**
+     * Strips trailing sentence punctuation the URL token accidentally swallowed. A closing
+     * bracket is only stripped when it is unbalanced within the token — so a wrapping
+     * `(https://example.com)` loses its `)`, but `.../Mercury_(planet)` keeps it.
+     */
+    private fun trimUrlEnd(token: String): String {
+        var end = token.length
+        while (end > 0) {
+            val c = token[end - 1]
+            when {
+                c in URL_TRAILING_TRIM -> end--
+                c == ')' || c == ']' || c == '}' -> {
+                    val open = OPEN_TO_CLOSE.entries.first { it.value == c }.key
+                    val opens = token.count { it == open }
+                    val closes = token.take(end).count { it == c }
+                    if (closes > opens) end-- else return token.substring(0, end)
+                }
+                else -> return token.substring(0, end)
+            }
+        }
+        return token.substring(0, end)
+    }
+
+    /**
+     * Drops a bracket left dangling at the end of the passage once the URL token carried its
+     * closing partner away. `See this quote (https://example.com/article)` loses the wrapping `)`
+     * in [trimUrlEnd], which would otherwise publish the passage as `See this quote (`.
+     *
+     * Only an *unbalanced* trailing bracket goes, so `He said (see below) https://…` keeps its
+     * matched pair, and a bracket anywhere but the very end is left alone — the URL removal can
+     * only ever orphan one at the tail.
+     */
+    private fun dropDanglingOpenBracket(text: String): String {
+        var out = text.trimEnd()
+        while (out.isNotEmpty()) {
+            val open = out.last()
+            val close = OPEN_TO_CLOSE[open] ?: return out
+            if (out.count { it == open } <= out.count { it == close }) return out
+            out = out.dropLast(1).trimEnd()
+        }
+        return out
+    }
+
+    /** Trims surrounding whitespace and matching quote marks; returns null when nothing is left. */
+    private fun cleanQuote(text: String): String? {
+        val trimmed = text.trim { it.isWhitespace() || it in QUOTE_CHARS }
+        return trimmed.ifBlank { null }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/TextFragmentParser.kt

@@ -0,0 +1,156 @@
+/*
+ * 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.nip84Highlights.parse
+
+/**
+ * The decoded pieces of a WICG Text Fragment directive
+ * (`#:~:text=[prefix-,]textStart[,textEnd][,-suffix]`), the anchor browsers append when a
+ * user shares a "link to highlight" of selected text.
+ *
+ * All fields are percent-decoded and never blank (empty pieces become null).
+ *
+ * @property prefix the text immediately before the match, used for disambiguation
+ * @property start the beginning of the matched (highlighted) text — the whole match when [end] is null
+ * @property end the end of the matched text when the browser split a long selection into start/end bounds
+ * @property suffix the text immediately after the match, used for disambiguation
+ */
+class TextFragment(
+    val prefix: String?,
+    val start: String?,
+    val end: String?,
+    val suffix: String?,
+)
+
+/**
+ * Parses (and strips) WICG Text Fragment directives from a URL.
+ *
+ * Text fragments live in the URL fragment after a `:~:` delimiter, e.g.
+ * `https://example.com/page#:~:text=prefix-,highlighted%20text,-suffix`. This is what
+ * Chrome/Edge/Safari emit when a user shares a link to selected text; the same encoding
+ * is used by the "Copy link to highlight" and text-selection share actions.
+ */
+object TextFragmentParser {
+    private const val DIRECTIVE_DELIMITER = ":~:"
+    private const val TEXT_PARAM = "text="
+
+    /**
+     * Extracts the first `text=` directive from [url]'s fragment, or null when there is
+     * no text fragment. Only the first `text=` directive is read — a URL may carry several
+     * (`&text=`), but a single highlight maps to one passage.
+     */
+    fun parse(url: String): TextFragment? {
+        val hashIndex = url.indexOf('#')
+        if (hashIndex < 0) return null
+
+        val fragment = url.substring(hashIndex + 1)
+        val directiveIndex = fragment.indexOf(DIRECTIVE_DELIMITER)
+        if (directiveIndex < 0) return null
+
+        val directives = fragment.substring(directiveIndex + DIRECTIVE_DELIMITER.length)
+        val textParam = directives.split("&").firstOrNull { it.startsWith(TEXT_PARAM) } ?: return null
+        val value = textParam.substring(TEXT_PARAM.length)
+        if (value.isEmpty()) return null
+
+        // Commas that belong to the highlighted text itself are percent-encoded (%2C), so the
+        // raw commas here are always the directive's own start/end/prefix/suffix separators.
+        val tokens = value.split(",").toMutableList()
+
+        var prefix: String? = null
+        var suffix: String? = null
+
+        if (tokens.isNotEmpty() && tokens.first().endsWith("-")) {
+            prefix = tokens.removeAt(0).dropLast(1)
+        }
+        if (tokens.isNotEmpty() && tokens.last().startsWith("-")) {
+            suffix = tokens.removeAt(tokens.size - 1).drop(1)
+        }
+
+        val start = tokens.getOrNull(0)
+        val end = tokens.getOrNull(1)
+
+        return TextFragment(
+            prefix = decode(prefix),
+            start = decode(start),
+            end = decode(end),
+            suffix = decode(suffix),
+        )
+    }
+
+    /**
+     * Returns [url] with any `:~:` text-fragment directive removed, so it can be stored as a
+     * clean `r` source reference. A surrounding `#` that only introduced the directive is
+     * dropped too; a real element-id fragment before the `:~:` is kept.
+     */
+    fun stripTextFragment(url: String): String {
+        val hashIndex = url.indexOf('#')
+        if (hashIndex < 0) return url
+
+        val fragment = url.substring(hashIndex + 1)
+        val directiveIndex = fragment.indexOf(DIRECTIVE_DELIMITER)
+        if (directiveIndex < 0) return url
+
+        val beforeDirective = fragment.substring(0, directiveIndex)
+        val base = url.substring(0, hashIndex)
+
+        return if (beforeDirective.isEmpty()) base else "$base#$beforeDirective"
+    }
+
+    private fun decode(value: String?): String? {
+        if (value.isNullOrEmpty()) return null
+        return percentDecode(value).takeIf { it.isNotEmpty() }
+    }
+
+    /**
+     * Percent-decodes a text-fragment component. Unlike form decoding it leaves `+`
+     * verbatim (a literal plus in the text is `+`, not a space — spaces arrive as `%20`),
+     * and decodes multi-byte UTF-8 sequences byte-by-byte.
+     */
+    private fun percentDecode(input: String): String {
+        if (!input.contains('%')) return input
+
+        val bytes = ArrayList<Byte>(input.length)
+        var i = 0
+        while (i < input.length) {
+            val c = input[i]
+            if (c == '%' && i + 2 < input.length) {
+                val hi = hexValue(input[i + 1])
+                val lo = hexValue(input[i + 2])
+                if (hi >= 0 && lo >= 0) {
+                    bytes.add(((hi shl 4) or lo).toByte())
+                    i += 3
+                    continue
+                }
+            }
+            // Non-escape character: re-encode as UTF-8 so it round-trips with decoded bytes.
+            c.toString().encodeToByteArray().forEach { bytes.add(it) }
+            i++
+        }
+        return bytes.toByteArray().decodeToString()
+    }
+
+    private fun hexValue(c: Char): Int =
+        when (c) {
+            in '0'..'9' -> c - '0'
+            in 'a'..'f' -> c - 'a' + 10
+            in 'A'..'F' -> c - 'A' + 10
+            else -> -1
+        }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/UrlTrackerCleaner.kt

@@ -0,0 +1,100 @@
+/*
+ * 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.nip84Highlights.parse
+
+/**
+ * Strips known tracking parameters from a URL's query string.
+ *
+ * NIP-84 asks clients to "do a best effort of cleaning the URL from trackers" before
+ * tagging the source of a highlight, so the same passage highlighted from two different
+ * campaign links collapses to one canonical `r` tag instead of leaking the sharer's
+ * `utm_*`/`fbclid`/etc. attribution into the published event.
+ *
+ * Only the query component is touched — the path and any fragment (including a
+ * `#:~:text=` directive) are preserved verbatim.
+ */
+object UrlTrackerCleaner {
+    /**
+     * Exact parameter names known to be pure tracking/attribution noise. Names are matched
+     * case-insensitively. Any parameter whose name starts with `utm_` is also dropped
+     * regardless of this set.
+     */
+    private val TRACKER_PARAMS =
+        setOf(
+            "fbclid",
+            "gclid",
+            "gclsrc",
+            "gbraid",
+            "wbraid",
+            "dclid",
+            "msclkid",
+            "yclid",
+            "twclid",
+            "ttclid",
+            "igshid",
+            "igsh",
+            "mc_eid",
+            "mc_cid",
+            "mkt_tok",
+            "_hsenc",
+            "_hsmi",
+            "vero_id",
+            "vero_conv",
+            "oly_anon_id",
+            "oly_enc_id",
+            "wickedid",
+            "ncid",
+            "s_cid",
+            "cmpid",
+            "spm",
+            "scm",
+            "ref_src",
+            "ref_url",
+            "_ga",
+        )
+
+    private fun isTracker(name: String): Boolean {
+        val lower = name.lowercase()
+        return lower.startsWith("utm_") || lower in TRACKER_PARAMS
+    }
+
+    fun clean(url: String): String {
+        val queryStart = url.indexOf('?')
+        if (queryStart < 0) return url
+
+        // Keep any fragment (element id and/or `:~:text=` directive) untouched.
+        val fragmentStart = url.indexOf('#', queryStart)
+        val query = if (fragmentStart >= 0) url.substring(queryStart + 1, fragmentStart) else url.substring(queryStart + 1)
+        val fragment = if (fragmentStart >= 0) url.substring(fragmentStart) else ""
+        val base = url.substring(0, queryStart)
+
+        val kept =
+            query
+                .split("&")
+                .filter { it.isNotEmpty() && !isTracker(it.substringBefore("=")) }
+
+        return if (kept.isEmpty()) {
+            base + fragment
+        } else {
+            base + "?" + kept.joinToString("&") + fragment
+        }
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip84Highlights/HighlightEventBuilderTest.kt

@@ -0,0 +1,182 @@
+/*
+ * 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.nip84Highlights
+
+import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSignerInternal
+import com.vitorpamplona.quartz.nip84Highlights.parse.SharedHighlightParser
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class HighlightEventBuilderTest {
+    private val signer = NostrSignerInternal(KeyPair())
+
+    @Test
+    fun buildsBarePassageWithNoTags() =
+        runTest {
+            val event = HighlightEvent.create(quote = "just a passage", signer = signer)
+
+            assertEquals(HighlightEvent.KIND, event.kind)
+            assertEquals("just a passage", event.quote())
+            assertTrue(event.tags.isEmpty())
+        }
+
+    @Test
+    fun buildsSourceReferenceTag() =
+        runTest {
+            val event =
+                HighlightEvent.create(
+                    quote = "a passage",
+                    url = "https://example.com/post",
+                    signer = signer,
+                )
+
+            assertEquals("https://example.com/post", event.inUrl())
+        }
+
+    @Test
+    fun buildsSelectorFromPrefixSuffix() =
+        runTest {
+            val event =
+                HighlightEvent.create(
+                    quote = "the passage",
+                    url = "https://example.com/post",
+                    prefix = "before ",
+                    suffix = " after",
+                    signer = signer,
+                )
+
+            val selector = event.textQuoteSelector()
+            assertNull(selector?.exact) // placeholder — the passage is in .content
+            assertEquals("before ", selector?.prefix)
+            assertEquals(" after", selector?.suffix)
+        }
+
+    @Test
+    fun omitsSelectorWhenNoPrefixOrSuffix() =
+        runTest {
+            val event =
+                HighlightEvent.create(
+                    quote = "the passage",
+                    url = "https://example.com/post",
+                    signer = signer,
+                )
+
+            assertNull(event.textQuoteSelector())
+        }
+
+    @Test
+    fun buildsCommentAndContextTags() =
+        runTest {
+            val event =
+                HighlightEvent.create(
+                    quote = "the passage",
+                    url = "https://example.com/post",
+                    comment = "my note about it",
+                    context = "The surrounding paragraph with the passage in it.",
+                    signer = signer,
+                )
+
+            assertEquals("my note about it", event.comment())
+            assertEquals("The surrounding paragraph with the passage in it.", event.context())
+        }
+
+    @Test
+    fun blankOptionalsAreSkipped() =
+        runTest {
+            val event =
+                HighlightEvent.create(
+                    quote = "the passage",
+                    url = "   ",
+                    comment = "",
+                    context = "  ",
+                    signer = signer,
+                )
+
+            assertTrue(event.tags.isEmpty())
+        }
+
+    @Test
+    fun buildsNostrSourceTags() =
+        runTest {
+            val article = "30023:6e468422dfb74a5738702a8823b9b28168abab8655faacb6853cd0ee15deee93:my-article"
+            val author = "6e468422dfb74a5738702a8823b9b28168abab8655faacb6853cd0ee15deee93"
+            val version = "8d7ae10a57ef178a17563a6ecbf9a399bb1796a2e032ca72703b00913b4cfd42"
+
+            val event =
+                HighlightEvent.create(
+                    quote = "a passage from an article",
+                    address = article,
+                    event = version,
+                    author = author,
+                    signer = signer,
+                )
+
+            assertEquals(article, event.inPostAddress()?.toValue())
+            assertEquals(version, event.inPostVersion()?.eventId)
+            assertEquals(author, event.author())
+            // The p tag carries the NIP-84 "author" role so attribution survives mention p tags.
+            assertTrue(event.tags.any { it[0] == "p" && it[1] == author && it.getOrNull(3) == "author" })
+        }
+
+    @Test
+    fun buildProducesUnsignedTemplateWithSameTags() {
+        val template =
+            HighlightEvent.build(
+                quote = "the passage",
+                url = "https://example.com/post",
+                prefix = "before ",
+                comment = "note",
+            )
+
+        assertEquals(HighlightEvent.KIND, template.kind)
+        assertEquals("the passage", template.content)
+        assertTrue(template.tags.any { it[0] == "r" && it[1] == "https://example.com/post" })
+        assertTrue(template.tags.any { it[0] == "textquoteselector" })
+        assertTrue(template.tags.any { it[0] == "comment" && it[1] == "note" })
+    }
+
+    @Test
+    fun roundTripsFromSharedHighlightParser() =
+        runTest {
+            val parsed =
+                SharedHighlightParser.parse(
+                    "https://example.com/post?utm_source=x#:~:text=the%20-,highlighted%20passage,-follows",
+                )
+
+            val event =
+                HighlightEvent.create(
+                    quote = parsed.quote!!,
+                    url = parsed.url,
+                    prefix = parsed.prefix,
+                    suffix = parsed.suffix,
+                    signer = signer,
+                )
+
+            assertEquals("highlighted passage", event.quote())
+            assertEquals("https://example.com/post", event.inUrl())
+            assertEquals("the ", event.textQuoteSelector()?.prefix)
+            assertEquals("follows", event.textQuoteSelector()?.suffix)
+        }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/SharedHighlightParserTest.kt

@@ -0,0 +1,210 @@
+/*
+ * 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.nip84Highlights.parse
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class SharedHighlightParserTest {
+    @Test
+    fun emptyInputYieldsEmptyResult() {
+        val result = SharedHighlightParser.parse("   ")
+        assertTrue(result.isEmpty())
+        assertNull(result.quote)
+        assertNull(result.url)
+    }
+
+    @Test
+    fun selectionOnly() {
+        val result = SharedHighlightParser.parse("Nostr is a simple, open protocol.")
+        assertEquals("Nostr is a simple, open protocol.", result.quote)
+        assertNull(result.url)
+        assertTrue(result.isNotEmpty())
+    }
+
+    @Test
+    fun urlOnly() {
+        val result = SharedHighlightParser.parse("https://example.com/post")
+        assertNull(result.quote)
+        assertEquals("https://example.com/post", result.url)
+    }
+
+    @Test
+    fun selectionThenUrlOnSeparateLines() {
+        val result =
+            SharedHighlightParser.parse("Nostr is a simple, open protocol.\n\nhttps://example.com/post")
+        assertEquals("Nostr is a simple, open protocol.", result.quote)
+        assertEquals("https://example.com/post", result.url)
+    }
+
+    @Test
+    fun stripsWrappingQuotesFromSelection() {
+        val result = SharedHighlightParser.parse("\"Nostr is great\" https://example.com/post")
+        assertEquals("Nostr is great", result.quote)
+        assertEquals("https://example.com/post", result.url)
+    }
+
+    @Test
+    fun stripsCurlyQuotesAndGuillemets() {
+        assertEquals("inside", SharedHighlightParser.parse("“inside”").quote)
+        assertEquals("inside", SharedHighlightParser.parse("«inside»").quote)
+    }
+
+    @Test
+    fun cleansTrackersFromSharedUrl() {
+        val result =
+            SharedHighlightParser.parse("Some quote\n\nhttps://example.com/post?utm_source=twitter&id=9")
+        assertEquals("Some quote", result.quote)
+        assertEquals("https://example.com/post?id=9", result.url)
+    }
+
+    @Test
+    fun linkToHighlightWithoutSeparateSelectionUsesFragmentText() {
+        val result =
+            SharedHighlightParser.parse(
+                "https://example.com/post#:~:text=the%20-,highlighted%20passage,-and%20on",
+            )
+        assertEquals("highlighted passage", result.quote)
+        assertEquals("https://example.com/post", result.url)
+        assertEquals("the ", result.prefix)
+        assertEquals("and on", result.suffix)
+        assertTrue(result.hasSelector())
+    }
+
+    @Test
+    fun explicitSelectionWinsOverFragmentTextButKeepsAnchors() {
+        // The browser shared the exact selection AND a link-to-highlight; keep the readable
+        // selection as the passage but retain the prefix/suffix anchors from the fragment.
+        val result =
+            SharedHighlightParser.parse(
+                "The full readable passage.\n\nhttps://example.com/post#:~:text=before-,The%20full,-after",
+            )
+        assertEquals("The full readable passage.", result.quote)
+        assertEquals("https://example.com/post", result.url)
+        assertEquals("before", result.prefix)
+        assertEquals("after", result.suffix)
+    }
+
+    @Test
+    fun trailingSentencePunctuationNotSwallowedIntoUrl() {
+        val result = SharedHighlightParser.parse("See (https://example.com/post).")
+        assertEquals("https://example.com/post", result.url)
+    }
+
+    @Test
+    fun keepsBalancedTrailingParenInUrl() {
+        // A Wikipedia article whose slug ends in "(planet)" — the closing paren is part of
+        // the URL, not sentence punctuation.
+        val result =
+            SharedHighlightParser.parse("Mercury is small.\n\nhttps://en.wikipedia.org/wiki/Mercury_(planet)")
+        assertEquals("https://en.wikipedia.org/wiki/Mercury_(planet)", result.url)
+    }
+
+    @Test
+    fun stripsOnlyTheWrappingParenNotTheSlugParen() {
+        val result =
+            SharedHighlightParser.parse("(https://en.wikipedia.org/wiki/Mercury_(planet))")
+        assertEquals("https://en.wikipedia.org/wiki/Mercury_(planet)", result.url)
+    }
+
+    @Test
+    fun dropsTheOpenParenOrphanedByTheUrlTrim() {
+        // The wrapping ")" leaves with the URL in trimUrlEnd; the "(" it opened must not be
+        // left dangling as the tail of the published passage.
+        val result = SharedHighlightParser.parse("See this quote (https://example.com/article)")
+        assertEquals("https://example.com/article", result.url)
+        assertEquals("See this quote", result.quote)
+    }
+
+    @Test
+    fun keepsAMatchedBracketPairInThePassage() {
+        // Nothing was orphaned here, so the passage keeps its own parenthetical intact.
+        val result = SharedHighlightParser.parse("He said (see below) https://example.com/a")
+        assertEquals("https://example.com/a", result.url)
+        assertEquals("He said (see below)", result.quote)
+    }
+
+    @Test
+    fun keepsTheSlugParenCaseQuoteIntact() {
+        // Regression guard for the opposite direction: nothing was trimmed off this URL, so
+        // the passage must be untouched too.
+        val result =
+            SharedHighlightParser.parse("Mercury is small.\n\nhttps://en.wikipedia.org/wiki/Mercury_(planet)")
+        assertEquals("https://en.wikipedia.org/wiki/Mercury_(planet)", result.url)
+        assertEquals("Mercury is small.", result.quote)
+    }
+
+    @Test
+    fun urlInsideSelectionStaysWithQuoteWhenSourceAppended() {
+        // The last URL is treated as the source; an earlier URL inside the passage is kept.
+        val result =
+            SharedHighlightParser.parse("Visit https://inside.example first.\n\nhttps://source.example/a")
+        assertEquals("Visit https://inside.example first.", result.quote)
+        assertEquals("https://source.example/a", result.url)
+    }
+
+    @Test
+    fun noSelectorWhenPlainUrl() {
+        val result = SharedHighlightParser.parse("quote\n\nhttps://example.com")
+        assertFalse(result.hasSelector())
+        assertNull(result.prefix)
+        assertNull(result.suffix)
+    }
+
+    @Test
+    fun realWorldChromeCopyLinkWithPrefixSuffixAndEncodedHyphen() {
+        // Chrome "copy link to highlight": a short selection with prefix/suffix anchors, and an
+        // encoded hyphen (%2D "pró-Irã") inside the prefix that must not be read as a delimiter.
+        val result =
+            SharedHighlightParser.parse(
+                "\"baseados\"\n https://g1.globo.com/mundo/noticia/2026/07/28/ira-rompe-tregua-e-lanca-misseis-balisticos-contra-bases-dos-eua-no-oriente-medio.ghtml" +
+                    "#:~:text=Saudita%20lan%C3%A7aram%20ataques%20em%20conjunto%20contra%20militantes%20pr%C3%B3%2DIr%C3%A3-,baseados,-no%20Iraque.",
+            )
+        assertEquals("baseados", result.quote)
+        assertEquals(
+            "https://g1.globo.com/mundo/noticia/2026/07/28/ira-rompe-tregua-e-lanca-misseis-balisticos-contra-bases-dos-eua-no-oriente-medio.ghtml",
+            result.url,
+        )
+        assertEquals("Saudita lançaram ataques em conjunto contra militantes pró-Irã", result.prefix)
+        assertEquals("no Iraque", result.suffix)
+    }
+
+    @Test
+    fun realWorldChromeCopyLinkStartOnlyWithEncodedCommas() {
+        // A long start-only fragment whose commas are encoded (%2C) so they don't split the
+        // directive, and whose apostrophe (’) inside the passage must survive quote-trimming.
+        val passage =
+            "cherish those corners. Geohot’s blog is one such corner that I rediscovered recently. " +
+                "Oh, what a joy to read something human from an actual human. His stuff makes me cry, laugh, and everything in"
+        val result =
+            SharedHighlightParser.parse(
+                "\"$passage\"\n https://dergigi.com/2026/07/28/typing/" +
+                    "#:~:text=cherish%20those%20corners.%20Geohot%E2%80%99s%20blog%20is%20one%20such%20corner%20that%20I%20rediscovered%20recently.%20Oh%2C%20what%20a%20joy%20to%20read%20something%20human%20from%20an%20actual%20human.%20His%20stuff%20makes%20me%20cry%2C%20laugh%2C%20and%20everything%20in",
+            )
+        assertEquals(passage, result.quote)
+        assertEquals("https://dergigi.com/2026/07/28/typing/", result.url)
+        assertNull(result.prefix)
+        assertNull(result.suffix)
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/TextFragmentParserTest.kt

@@ -0,0 +1,118 @@
+/*
+ * 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.nip84Highlights.parse
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+class TextFragmentParserTest {
+    @Test
+    fun returnsNullWhenNoFragment() {
+        assertNull(TextFragmentParser.parse("https://example.com/post"))
+    }
+
+    @Test
+    fun returnsNullForPlainElementFragment() {
+        assertNull(TextFragmentParser.parse("https://example.com/post#section-2"))
+    }
+
+    @Test
+    fun parsesStartOnly() {
+        val fragment = TextFragmentParser.parse("https://example.com/post#:~:text=hello%20world")
+        assertEquals("hello world", fragment?.start)
+        assertNull(fragment?.prefix)
+        assertNull(fragment?.suffix)
+        assertNull(fragment?.end)
+    }
+
+    @Test
+    fun parsesPrefixStartSuffix() {
+        val fragment =
+            TextFragmentParser.parse(
+                "https://example.com/post#:~:text=the%20-,highlighted%20passage,-follows%20on",
+            )
+        assertEquals("the ", fragment?.prefix)
+        assertEquals("highlighted passage", fragment?.start)
+        assertEquals("follows on", fragment?.suffix)
+    }
+
+    @Test
+    fun parsesStartAndEndRange() {
+        val fragment =
+            TextFragmentParser.parse("https://example.com/post#:~:text=start%20of,end%20of")
+        assertEquals("start of", fragment?.start)
+        assertEquals("end of", fragment?.end)
+    }
+
+    @Test
+    fun decodesEncodedCommaWithinText() {
+        // A comma that belongs to the passage arrives percent-encoded (%2C) so it is not
+        // mistaken for the directive's own start/end separator.
+        val fragment = TextFragmentParser.parse("https://example.com/post#:~:text=one%2C%20two%2C%20three")
+        assertEquals("one, two, three", fragment?.start)
+        assertNull(fragment?.end)
+    }
+
+    @Test
+    fun leavesLiteralPlusVerbatim() {
+        // Form decoding would turn `+` into a space; a text fragment must not.
+        val fragment = TextFragmentParser.parse("https://example.com/post#:~:text=c%2B%2B%20rocks")
+        assertEquals("c++ rocks", fragment?.start)
+    }
+
+    @Test
+    fun readsFirstTextDirectiveWhenSeveral() {
+        val fragment =
+            TextFragmentParser.parse("https://example.com/post#:~:text=first&text=second")
+        assertEquals("first", fragment?.start)
+    }
+
+    @Test
+    fun parsesDirectiveAfterElementId() {
+        val fragment = TextFragmentParser.parse("https://example.com/post#heading:~:text=quoted")
+        assertEquals("quoted", fragment?.start)
+    }
+
+    @Test
+    fun stripsDirectiveAndBareHash() {
+        assertEquals(
+            "https://example.com/post",
+            TextFragmentParser.stripTextFragment("https://example.com/post#:~:text=hello"),
+        )
+    }
+
+    @Test
+    fun stripsDirectiveButKeepsElementId() {
+        assertEquals(
+            "https://example.com/post#heading",
+            TextFragmentParser.stripTextFragment("https://example.com/post#heading:~:text=hello"),
+        )
+    }
+
+    @Test
+    fun stripLeavesPlainFragmentUntouched() {
+        assertEquals(
+            "https://example.com/post#section",
+            TextFragmentParser.stripTextFragment("https://example.com/post#section"),
+        )
+    }
+}

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip84Highlights/parse/UrlTrackerCleanerTest.kt

@@ -0,0 +1,87 @@
+/*
+ * 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.nip84Highlights.parse
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class UrlTrackerCleanerTest {
+    @Test
+    fun keepsUrlsWithoutQuery() {
+        assertEquals("https://example.com/post", UrlTrackerCleaner.clean("https://example.com/post"))
+    }
+
+    @Test
+    fun keepsMeaningfulQueryParams() {
+        assertEquals(
+            "https://example.com/search?q=nostr&page=2",
+            UrlTrackerCleaner.clean("https://example.com/search?q=nostr&page=2"),
+        )
+    }
+
+    @Test
+    fun stripsUtmParams() {
+        assertEquals(
+            "https://example.com/post?id=42",
+            UrlTrackerCleaner.clean("https://example.com/post?utm_source=twitter&id=42&utm_medium=social"),
+        )
+    }
+
+    @Test
+    fun stripsKnownClickIds() {
+        assertEquals(
+            "https://example.com/post",
+            UrlTrackerCleaner.clean("https://example.com/post?fbclid=abc123&gclid=xyz"),
+        )
+    }
+
+    @Test
+    fun dropsQuestionMarkWhenOnlyTrackersRemain() {
+        assertEquals(
+            "https://example.com/post",
+            UrlTrackerCleaner.clean("https://example.com/post?utm_campaign=spring"),
+        )
+    }
+
+    @Test
+    fun matchesTrackerNamesCaseInsensitively() {
+        assertEquals(
+            "https://example.com/post",
+            UrlTrackerCleaner.clean("https://example.com/post?UTM_Source=x&FBCLID=y"),
+        )
+    }
+
+    @Test
+    fun preservesFragmentAfterCleaning() {
+        assertEquals(
+            "https://example.com/post?id=42#section",
+            UrlTrackerCleaner.clean("https://example.com/post?utm_source=x&id=42#section"),
+        )
+    }
+
+    @Test
+    fun preservesTextFragmentDirective() {
+        assertEquals(
+            "https://example.com/post#:~:text=hello",
+            UrlTrackerCleaner.clean("https://example.com/post?fbclid=abc#:~:text=hello"),
+        )
+    }
+}