feat(podcasts): dedicated Podcast Bookmarks screen + detail-screen toggle

Adds a Podcasts row to the Bookmark lists screen (mirroring Git
Repositories), opening a feed of just the bookmarked podcasts:

- quartz: isPodcastEvent() — a reusable predicate matching shows,
  episodes (NIP-F4 + Podcasting-2.0) and trailers, used to pull the
  podcast subset out of the mixed NIP-51 kind:10003 bookmark list.
- BookmarkPodcastsFeedFilter / ...FeedViewModel / BookmarkedPodcastsScreen
  filter the bookmark list (public + private) down to podcast notes,
  newest first, and render them with the standard podcast cards.
- Route.BookmarkedPodcasts + AppNavigation wiring; a "Podcasts" row with a
  live count in ListOfBookmarkGroupsFeedView.
- The single-podcast detail screen (PodcastScreen) gains a bookmark action
  in its top bar that reflects and toggles bookmarked state (reusing the
  stateful PodcastBookmarkButton). TopBarExtensibleWithBackButton now
  accepts an actions slot to host it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JGa1EM5KWyDo1o5Yr6sS18

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

@@ -82,6 +82,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.list.metadat
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.membershipManagement.ArticleBookmarkListManagementScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.membershipManagement.PostBookmarkListManagementScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.old.OldBookmarkListScreen
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.podcasts.BookmarkedPodcastsScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.repositories.BookmarkedRepositoriesScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.browser.BrowserScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.browser.WebAppScreen
@@ -454,6 +455,7 @@ fun BuildNavigation(
         composableFromEnd<Route.OldBookmarks> { OldBookmarkListScreen(accountViewModel, nav) }
         composableFromEnd<Route.PinnedNotes> { PinnedNotesScreen(accountViewModel, nav) }
         composableFromEnd<Route.BookmarkedRepositories> { BookmarkedRepositoriesScreen(accountViewModel, nav) }
+        composableFromEnd<Route.BookmarkedPodcasts> { BookmarkedPodcastsScreen(accountViewModel, nav) }
         composableFromEnd<Route.WebBookmarks> { WebBookmarksScreen(accountViewModel, nav) }
         composableFromEnd<Route.Drafts> { DraftListScreen(accountViewModel, nav) }
         composableFromEnd<Route.ScheduledPosts> { ScheduledPostsScreen(accountViewModel, nav) }

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

@@ -315,6 +315,8 @@ sealed class Route {
 
     @Serializable object BookmarkedRepositories : Route()
 
+    @Serializable object BookmarkedPodcasts : Route()
+
     @Serializable object BookmarkGroups : Route()
 
     @Serializable object InterestSets : Route()

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/topbars/TopBarExtensibleWithBackButton.kt

@@ -44,13 +44,14 @@ import com.vitorpamplona.amethyst.ui.theme.isLight
 fun TopBarExtensibleWithBackButton(
     title: @Composable RowScope.() -> Unit,
     extendableRow: (@Composable () -> Unit)? = null,
+    actions: @Composable RowScope.() -> Unit = {},
     popBack: () -> Unit,
 ) {
     MyExtensibleTopAppBar(
         title = title,
         extendableRow = extendableRow,
         navigationIcon = { IconButton(onClick = popBack) { ArrowBackIcon() } },
-        actions = {},
+        actions = actions,
     )
 }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/bookmarkgroups/list/ListOfBookmarkGroupsFeedView.kt

@@ -53,6 +53,7 @@ import com.vitorpamplona.amethyst.ui.theme.DividerThickness
 import com.vitorpamplona.amethyst.ui.theme.FeedPadding
 import com.vitorpamplona.amethyst.ui.theme.Size40Modifier
 import com.vitorpamplona.amethyst.ui.theme.StdVertSpacer
+import com.vitorpamplona.quartz.nipXXPodcasting20.metadata.isPodcastEvent
 import kotlinx.coroutines.flow.StateFlow
 
 @Composable
@@ -66,6 +67,7 @@ fun ListOfBookmarkGroupsFeedView(
     openOldBookmarks: () -> Unit,
     openPinnedNotes: () -> Unit,
     openRepositories: () -> Unit,
+    openPodcasts: () -> Unit,
     onOpenItem: (String, BookmarkType) -> Unit,
     onRenameItem: (targetBookmarkGroup: LabeledBookmarkList) -> Unit,
     onItemDescriptionChange: (bookmarkGroup: LabeledBookmarkList) -> Unit,
@@ -99,6 +101,11 @@ fun ListOfBookmarkGroupsFeedView(
             HorizontalDivider(thickness = DividerThickness)
         }
 
+        item {
+            PodcastsBookmarkList(defaultBookmarks, openPodcasts)
+            HorizontalDivider(thickness = DividerThickness)
+        }
+
         itemsIndexed(
             bookmarkGroupFeedState,
             key = { _: Int, item: LabeledBookmarkList -> item.identifier },
@@ -249,6 +256,54 @@ fun RepositoriesBookmarkList(
     )
 }
 
+@Composable
+fun PodcastsBookmarkList(
+    defaultBookmarks: BookmarkListState,
+    openPodcasts: () -> Unit,
+) {
+    val bookmarkState by defaultBookmarks.bookmarks.collectAsStateWithLifecycle()
+
+    // Podcasts live in the same kind:10003 list as everything else, so count the podcast subset.
+    val podcastCount =
+        (bookmarkState.public + bookmarkState.private).count { isPodcastEvent(it.event) }
+
+    ListItem(
+        modifier = Modifier.clickable(onClick = openPodcasts),
+        headlineContent = {
+            Text(stringRes(R.string.podcast_bookmarks), maxLines = 1, overflow = TextOverflow.Ellipsis)
+        },
+        supportingContent = {
+            Column(
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Text(
+                    stringRes(R.string.podcast_bookmarks_explainer),
+                    overflow = TextOverflow.Ellipsis,
+                    maxLines = 2,
+                )
+            }
+        },
+        leadingContent = {
+            Column(
+                verticalArrangement = Arrangement.Center,
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                Icon(
+                    symbol = MaterialSymbols.Podcasts,
+                    contentDescription = stringRes(R.string.bookmark_list_icon_label),
+                    modifier = Size40Modifier,
+                )
+                Spacer(StdVertSpacer)
+                BookmarkMembershipStatusAndNumberDisplay(
+                    modifier = Modifier.align(Alignment.CenterHorizontally),
+                    postBookmarksSize = podcastCount,
+                    articleBookmarksSize = 0,
+                )
+            }
+        },
+    )
+}
+
 @Composable
 fun OldBookmarkList(
     oldBookmarks: OldBookmarkListState,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/bookmarkgroups/list/ListOfBookmarkGroupsScreen.kt

@@ -66,6 +66,7 @@ fun ListOfBookmarkGroupsScreen(
         openOldBookmarks = { nav.nav(Route.OldBookmarks) },
         openPinnedNotes = { nav.nav(Route.PinnedNotes) },
         openRepositories = { nav.nav(Route.BookmarkedRepositories) },
+        openPodcasts = { nav.nav(Route.BookmarkedPodcasts) },
         addBookmarkGroup = { nav.nav(Route.BookmarkGroupMetadataEdit()) },
         openBookmarkGroup = { identifier, bookmarkType ->
             nav.nav(Route.BookmarkGroupView(identifier, bookmarkType))
@@ -110,6 +111,7 @@ fun ListOfBookmarkGroupsFeed(
     openOldBookmarks: () -> Unit,
     openPinnedNotes: () -> Unit,
     openRepositories: () -> Unit,
+    openPodcasts: () -> Unit,
     addBookmarkGroup: () -> Unit,
     openBookmarkGroup: (identifier: String, bookmarkType: BookmarkType) -> Unit,
     renameBookmarkGroup: (bookmarkGroup: LabeledBookmarkList) -> Unit,
@@ -159,6 +161,7 @@ fun ListOfBookmarkGroupsFeed(
                 openOldBookmarks = openOldBookmarks,
                 openPinnedNotes = openPinnedNotes,
                 openRepositories = openRepositories,
+                openPodcasts = openPodcasts,
                 onOpenItem = openBookmarkGroup,
                 onRenameItem = renameBookmarkGroup,
                 onItemDescriptionChange = changeBookmarkGroupDescription,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/bookmarkgroups/podcasts/BookmarkedPodcastsScreen.kt

@@ -0,0 +1,69 @@
+/*
+ * 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.bookmarkgroups.podcasts
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.viewmodel.compose.viewModel
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.topbars.TopBarWithBackButton
+import com.vitorpamplona.amethyst.ui.screen.RefresheableFeedView
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.bookmarkgroups.podcasts.dal.BookmarkPodcastsFeedViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+
+@Composable
+fun BookmarkedPodcastsScreen(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val podcastsFeedViewModel: BookmarkPodcastsFeedViewModel =
+        viewModel(
+            key = "NostrBookmarkPodcastsFeedViewModel",
+            factory = BookmarkPodcastsFeedViewModel.Factory(accountViewModel.account),
+        )
+
+    val bookmarks by accountViewModel.account.bookmarkState.bookmarks
+        .collectAsStateWithLifecycle()
+
+    LaunchedEffect(bookmarks) {
+        podcastsFeedViewModel.invalidateData()
+    }
+
+    DisappearingScaffold(
+        isInvertedLayout = false,
+        topBar = {
+            TopBarWithBackButton(stringRes(id = R.string.podcast_bookmarks), nav)
+        },
+        accountViewModel = accountViewModel,
+    ) {
+        RefresheableFeedView(
+            podcastsFeedViewModel,
+            null,
+            accountViewModel = accountViewModel,
+            nav = nav,
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/bookmarkgroups/podcasts/dal/BookmarkPodcastsFeedFilter.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.bookmarkgroups.podcasts.dal
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.ui.dal.FeedFilter
+import com.vitorpamplona.quartz.nipXXPodcasting20.metadata.isPodcastEvent
+
+/**
+ * The podcast subset of the user's NIP-51 bookmark list (kind 10003): podcasts (shows and episodes)
+ * are bookmarked into the same general list as everything else, so this filter pulls just the
+ * podcast-typed notes ([isPodcastEvent]) back out — both public and private — newest first.
+ */
+class BookmarkPodcastsFeedFilter(
+    val account: Account,
+) : FeedFilter<Note>() {
+    override fun feedKey(): String =
+        account.bookmarkState.bookmarks.value
+            .hashCode()
+            .toString()
+
+    override fun feed(): List<Note> {
+        val bookmarks = account.bookmarkState.bookmarks.value
+        return (bookmarks.public + bookmarks.private)
+            .filter { isPodcastEvent(it.event) }
+            .distinct()
+            .sortedByDescending { it.createdAt() ?: 0L }
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/bookmarkgroups/podcasts/dal/BookmarkPodcastsFeedViewModel.kt

@@ -0,0 +1,39 @@
+/*
+ * 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.bookmarkgroups.podcasts.dal
+
+import androidx.compose.runtime.Stable
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.ui.screen.AndroidFeedViewModel
+
+@Stable
+class BookmarkPodcastsFeedViewModel(
+    val account: Account,
+) : AndroidFeedViewModel(BookmarkPodcastsFeedFilter(account)) {
+    class Factory(
+        val account: Account,
+    ) : ViewModelProvider.Factory {
+        @Suppress("UNCHECKED_CAST")
+        override fun <T : ViewModel> create(modelClass: Class<T>): T = BookmarkPodcastsFeedViewModel(account) as T
+    }
+}

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

@@ -53,6 +53,7 @@ import com.vitorpamplona.amethyst.ui.feeds.WatchLifecycleAndUpdateModel
 import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.TopBarExtensibleWithBackButton
+import com.vitorpamplona.amethyst.ui.note.types.PodcastBookmarkButton
 import com.vitorpamplona.amethyst.ui.screen.SaveableFeedState
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.podcasts.dal.OnePodcastFeedViewModel
@@ -129,6 +130,13 @@ fun PodcastScreen(
                         modifier = Modifier.weight(1f),
                     )
                 },
+                actions = {
+                    // Only offer bookmarking once the show metadata has loaded — there must be a
+                    // resolved event to add to the NIP-51 list. The button reflects bookmarked state.
+                    if (show != null) {
+                        PodcastBookmarkButton(metadataNote, accountViewModel)
+                    }
+                },
                 popBack = nav::popBack,
             )
         },

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

@@ -1130,6 +1130,8 @@
     <string name="public_bookmarks">Public Bookmarks</string>
     <string name="repository_bookmarks">Repositories</string>
     <string name="repository_bookmarks_explainer">Your bookmarked git repositories</string>
+    <string name="podcast_bookmarks">Podcasts</string>
+    <string name="podcast_bookmarks_explainer">Your bookmarked podcasts and episodes</string>
     <string name="add_to_private_bookmarks">Add to Private Bookmarks</string>
     <string name="add_to_public_bookmarks">Add to Public Bookmarks</string>
     <string name="remove_from_private_bookmarks">Remove from Private Bookmarks</string>

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nipXXPodcasting20/metadata/PodcastShowResolver.kt

@@ -23,6 +23,8 @@ package com.vitorpamplona.quartz.nipXXPodcasting20.metadata
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip78AppData.AppSpecificDataEvent
 import com.vitorpamplona.quartz.nipF4Podcasts.metadata.PodcastMetadataEvent
+import com.vitorpamplona.quartz.nipXXPodcasting20.trailer.Podcasting20TrailerEvent
+import com.vitorpamplona.quartz.podcasts.PodcastEpisode
 import com.vitorpamplona.quartz.podcasts.PodcastShow
 
 /**
@@ -34,6 +36,16 @@ fun isPodcastShowEvent(event: Event?): Boolean =
     event is PodcastMetadataEvent ||
         (event is AppSpecificDataEvent && event.dTag() == Podcasting20PodcastMetadata.PODCAST_METADATA_D_TAG)
 
+/**
+ * Whether [event] is any podcast event — a show ([isPodcastShowEvent]), an episode (NIP-F4 `kind:54`
+ * or Podcasting-2.0 `kind:30054`, both [PodcastEpisode]), or a Podcasting-2.0 trailer (`kind:30055`).
+ * Used to pull podcast items out of mixed lists (e.g. the NIP-51 bookmark list) for podcast-only views.
+ */
+fun isPodcastEvent(event: Event?): Boolean =
+    isPodcastShowEvent(event) ||
+        event is PodcastEpisode ||
+        event is Podcasting20TrailerEvent
+
 /**
  * Adapts [event] to the spec-neutral [PodcastShow], or returns null if it is not a podcast show
  * (or its Podcasting-2.0 JSON content fails to parse). NIP-F4 metadata events implement