feat(core,app,android,ios): My List, synced, and New badges with new-episode rows

My List is a list of titles to watch later, kept in my-list.json by
title key (pstr-core::mylist) and synced as one list/<key> register per
title, so an add or a removal on one device reaches every other. A list
file that will not parse is never written over: changing the list is
refused instead. It is a filter, a row on the library, a button on the
banner and the title page, and an entry in each tile's menu.

pstr-core::news reads node_first_seen against each share's first crawl,
so a newly added share does not badge its whole library. A title that
arrived in the last two weeks and was never played is New; a series
being watched counts the unwatched episodes that arrived after it was
last played ("3 new"). They fill the tile badge and the "New episodes"
and "Recently added" rows. shelves::home puts every row in one order
for all three apps, and a shelf tile of an airing show shows a
countdown ("Ep 8 · in 2 d").

The bridge gains TitleRecord.on_list and .badge, set_on_list, the
MyList filter, airing_countdown and SyncRecord.list_changed.

android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt

@@ -591,7 +591,9 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
             }
         }
         if (report.settingsChanged) AppearanceState.reload()
-        if (report.applied > 0u || report.titles > 0u || report.settingsChanged || report.sharesRemoved.isNotEmpty()) {
+        if (report.applied > 0u || report.titles > 0u || report.settingsChanged || report.listChanged ||
+            report.sharesRemoved.isNotEmpty()
+        ) {
             reloadNow()
         }
         if (report.sharesAdded.isNotEmpty()) {
@@ -625,7 +627,17 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
      * title's positions are what this throws away, and a mis-tap on a tile's
      * menu should not cost them.
      */
-    fun setTitleWatched(title: TitleRecord, watched: Boolean) =
+    /** Put a title on My List, or take it off. */
+    fun setOnList(title: TitleRecord, on: Boolean) {
+        viewModelScope.launch {
+            runCatching {
+                withContext(Dispatchers.IO) { NativeRuntime.engine().setOnList(title.key, on) }
+            }.onFailure(::reportError)
+            reload()
+        }
+    }
+
+        fun setTitleWatched(title: TitleRecord, watched: Boolean) =
         markEpisodes(title.seasons.flatMap { it.episodes }, watched, title.displayName)
 
     /**

android/app/src/main/java/io/narl/protonstream/ui/Common.kt

@@ -18,6 +18,13 @@ import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.RowScope
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.FilledTonalIconButton
+import androidx.compose.material3.Icon
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.MaterialTheme
@@ -323,3 +330,25 @@ internal fun SpecBadge(text: String) {
             .padding(horizontal = 5.dp, vertical = 1.dp),
     )
 }
+
+/**
+ * My List's button: a plus to put the title on it, a tick once it is, which
+ * takes it off again. [compact] is the icon alone, for the banner's row, where
+ * a third labelled button does not fit a phone.
+ */
+@Composable
+internal fun ListButton(onList: Boolean, onSet: (Boolean) -> Unit, compact: Boolean = false) {
+    val icon = if (onList) Icons.Default.Check else Icons.Default.Add
+    val label = if (onList) "Remove from My List" else "Add to My List"
+    if (compact) {
+        FilledTonalIconButton(onClick = { onSet(!onList) }, shape = MaterialTheme.shapes.small) {
+            Icon(icon, contentDescription = label)
+        }
+    } else {
+        TonalButton(onClick = { onSet(!onList) }, modifier = Modifier.semantics { contentDescription = label }) {
+            Icon(icon, contentDescription = null)
+            Spacer(Modifier.width(6.dp))
+            Text("My List")
+        }
+    }
+}

android/app/src/main/java/io/narl/protonstream/ui/LibraryScreen.kt

@@ -47,6 +47,7 @@ import io.narl.protonstream.settings.SettingsStore
 import io.narl.protonstream.ui.theme.QuietButton
 import java.time.LocalDate
 import androidx.compose.foundation.combinedClickable
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.CheckCircle
 import androidx.compose.material.icons.filled.Download
 import androidx.compose.material.icons.filled.Edit
@@ -116,6 +117,7 @@ import uniffi.pstr_android.LibrarySort
 import uniffi.pstr_android.SeasonRecord
 import uniffi.pstr_android.TitleRecord
 import uniffi.pstr_android.TitleType
+import uniffi.pstr_android.airingCountdown
 
 /**
  * How many shows the continue-watching shelf holds.
@@ -145,6 +147,7 @@ internal fun LibraryFilter.label(): String = when (this) {
     LibraryFilter.WATCHING -> "Watching"
     LibraryFilter.UNWATCHED -> "Not started"
     LibraryFilter.DOWNLOADED -> "Downloaded"
+    LibraryFilter.MY_LIST -> "My List"
 }
 
 /** The offer of posters and synopses, and its two answers. */
@@ -190,6 +193,7 @@ internal fun LibraryScreen(
     onAddShare: () -> Unit = {},
     onOpenSettings: () -> Unit = {},
     onFilter: (LibraryFilter) -> Unit = {},
+    onSetOnList: (TitleRecord, Boolean) -> Unit = { _, _ -> },
 ) {
     val download = rememberDownload()
     val context = LocalContext.current
@@ -293,6 +297,7 @@ internal fun LibraryScreen(
                         },
                         featured = if (overBanner) featured else emptyList(),
                         grid = grid,
+                        onSetOnList = onSetOnList,
                     )
                 }
             }
@@ -307,6 +312,10 @@ internal fun LibraryScreen(
                 onResume(title, nextUpIndex(playlist, title.continueIndex))
             }
             MenuRow(Icons.Default.Info, "Open") { onTitle(title) }
+            MenuRow(
+                if (title.onList) Icons.Default.Check else Icons.Default.Add,
+                if (title.onList) "Remove from My List" else "Add to My List",
+            ) { onSetOnList(title, !title.onList) }
             MenuRow(Icons.Default.Download, "Download all") { download(playlist, title.displayName) }
             MenuRow(
                 if (allWatched) Icons.Outlined.CheckCircle else Icons.Default.CheckCircle,
@@ -493,6 +502,7 @@ private fun LibraryGrid(
     metadataOffer: MetadataOffer? = null,
     featured: List<TitleRecord> = emptyList(),
     grid: LazyGridState = rememberLazyGridState(),
+    onSetOnList: (TitleRecord, Boolean) -> Unit = { _, _ -> },
 ) {
     // The arrangement names titles by key; before it has arrived, the titles
     // as they came are the grid.
@@ -525,6 +535,7 @@ private fun LibraryGrid(
                     resumable,
                     onPlay = onResume,
                     onOpen = onTitle,
+                    onSetOnList = onSetOnList,
                     modifier = Modifier.bleed(16.dp),
                 )
             }
@@ -574,6 +585,9 @@ private fun LibraryGrid(
                                     onLongClick = { onTitleMenu(title) },
                                     modifier = Modifier.width(SHELF_TILE_WIDTH),
                                     shared = false,
+                                    // On a shelf, an airing show says when its
+                                    // next episode is out.
+                                    badge = title.badge ?: title.countdown(),
                                 )
                             }
                         }
@@ -729,6 +743,7 @@ private fun FeaturedBanner(
     resumable: List<Resumable>,
     onPlay: (TitleRecord, Int) -> Unit,
     onOpen: (TitleRecord) -> Unit,
+    onSetOnList: (TitleRecord, Boolean) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val pager = rememberPagerState { titles.size }
@@ -750,6 +765,7 @@ private fun FeaturedBanner(
                 resumable.firstOrNull { it.title.key == title.key },
                 onPlay = { onPlay(title, it) },
                 onOpen = { onOpen(title) },
+                onSetOnList = { onSetOnList(title, it) },
             )
         }
         if (titles.size > 1) {
@@ -780,7 +796,13 @@ private fun FeaturedBanner(
 
 /** One title on the banner: its art, its veil, and what it is, from the bottom up. */
 @Composable
-private fun FeaturedPage(title: TitleRecord, resume: Resumable?, onPlay: (Int) -> Unit, onOpen: () -> Unit) {
+private fun FeaturedPage(
+    title: TitleRecord,
+    resume: Resumable?,
+    onPlay: (Int) -> Unit,
+    onOpen: () -> Unit,
+    onSetOnList: (Boolean) -> Unit,
+) {
     val playlist = remember(title) { title.seasons.flatMap(SeasonRecord::episodes) }
     var mood by remember(title.key) { mutableStateOf<Color?>(null) }
     val background = MaterialTheme.colorScheme.background
@@ -846,6 +868,7 @@ private fun FeaturedPage(title: TitleRecord, resume: Resumable?, onPlay: (Int) -
                     Spacer(Modifier.width(6.dp))
                     Text("More info")
                 }
+                ListButton(title.onList, onSetOnList, compact = true)
             }
             val episode = resume?.episode
             val progress = episode?.progress?.takeIf { episode.resumeAt != null }
@@ -943,6 +966,7 @@ private fun PosterTile(
     modifier: Modifier = Modifier,
     folded: Int = 0,
     shared: Boolean = true,
+    badge: String? = title.badge,
 ) {
     Column(
         modifier
@@ -976,6 +1000,20 @@ private fun PosterTile(
                         .semantics { contentDescription = "and $folded more" },
                 )
             }
+            if (badge != null) {
+                Text(
+                    badge,
+                    style = MaterialTheme.typography.labelSmall,
+                    fontWeight = FontWeight.SemiBold,
+                    color = MaterialTheme.colorScheme.onPrimary,
+                    modifier = Modifier
+                        .align(Alignment.TopStart)
+                        .padding(6.dp)
+                        .clip(MaterialTheme.shapes.small)
+                        .background(MaterialTheme.colorScheme.primary)
+                        .padding(horizontal = 6.dp, vertical = 2.dp),
+                )
+            }
         }
         Spacer(Modifier.height(6.dp))
         Text(
@@ -1017,3 +1055,10 @@ private fun EpisodeRecord.timeLeft(): String? {
     val minutes = ((at / fraction - at) / 60).toInt()
     return if (minutes < 1) "under a minute left" else "$minutes min left"
 }
+
+/** `Ep 8 · in 2 d` for a show whose next episode is still to air. */
+internal fun TitleRecord.countdown(now: Long = System.currentTimeMillis() / 1000): String? {
+    val at = nextAiringAt?.takeIf { it > now } ?: return null
+    val episode = nextEpisode ?: return null
+    return airingCountdown(episode, at, now)
+}

android/app/src/main/java/io/narl/protonstream/ui/ProtonStreamApp.kt

@@ -234,6 +234,7 @@ fun ProtonStreamApp(
                                 },
                                 onOpenSettings = { destination = Destination.Settings },
                                 onFilter = model::filter,
+                                onSetOnList = model::setOnList,
                                 )
                         }
                         val titlePane = @Composable { selected: TitleRecord ->
@@ -255,6 +256,7 @@ fun ProtonStreamApp(
                                     state.titles.firstOrNull { it.key == key }
                                 },
                                 onOpenTitle = { selectedTitleKey = it.key },
+                                onSetOnList = model::setOnList,
                                 )
                         }
                         if (maxWidth >= TWO_PANE_WIDTH) {

android/app/src/main/java/io/narl/protonstream/ui/TitleScreen.kt

@@ -50,6 +50,9 @@ import androidx.compose.material.icons.filled.CheckCircle
 import androidx.compose.material.icons.outlined.CheckCircle
 import androidx.compose.material.icons.filled.DoneAll
 import androidx.compose.material.icons.filled.Download
+import androidx.compose.ui.semantics.stateDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.RemoveDone
 import androidx.compose.material.icons.filled.Pause
@@ -119,6 +122,7 @@ internal fun TitleScreen(
     /** Every title of its franchise, in release order, this one included. */
     franchise: List<TitleRecord> = emptyList(),
     onOpenTitle: (TitleRecord) -> Unit = {},
+    onSetOnList: (TitleRecord, Boolean) -> Unit = { _, _ -> },
 ) {
     val context = LocalContext.current
     val download = rememberDownload()
@@ -311,6 +315,13 @@ internal fun TitleScreen(
                     // three button styles used to wrap over three lines and bury
                     // the episodes under them.
                     Row(Modifier.fillMaxWidth().padding(top = 12.dp)) {
+                        TitleAction(
+                            if (title.onList) Icons.Default.Check else Icons.Default.Add,
+                            "My List",
+                            Modifier.weight(1f).semantics {
+                                stateDescription = if (title.onList) "On My List" else "Not on My List"
+                            },
+                        ) { onSetOnList(title, !title.onList) }
                         // Only where it would do something different: an unstarted
                         // show already starts at the beginning.
                         if (upNext?.resumeAt != null || title.watchedCount > 0uL) {