feat(itch): collections filter in the Library (#1597)

* Add itch.io collections to the Library

A Collections button on the Library's itch tab filters the library to one collection of the signed-in account. Its games that are not installed show in the Not installed section.

* Keep itch collections complete across failures, sign-out and empty libraries

A failed later page no longer publishes a partial collection, selecting a collection refreshes it, pagination runs until an empty page, signing out clears collection state, and the itch chip shows for a signed-in account with no owned games.

* Tie itch collection requests to the account that started them

Requests capture the account generation before reading the key and dedupe per generation, sign-out clears collections after the token is removed, and the collections load follows the itch sign-in state.

* Keep paging itch collections past a page of already seen games

* Run the itch collections tests under Robolectric like the other itch tests

* Let the Installed filter apply inside a collection and keep the grid for an empty itch account

* fix(itch): stop paging a collection when a page adds no new games

* Keep the collections icon on the itch collections tab when it opens

---------

Co-authored-by: maxjivi05 <maxjividen@gmail.com>

app/src/main/java/com/droiddeck/launcher/stores/StoresState.kt

@@ -130,7 +130,7 @@ object StoresState {
 
     fun detailItem(store: Store, id: String): CatalogItem? = detailCatalogItem(
         store, id, library[store].orEmpty(),
-        found[store].orEmpty() + if (store == Store.ITCH) com.droiddeck.launcher.stores.itch.ItchBrowseState.items else emptyList(),
+        found[store].orEmpty() + if (store == Store.ITCH) com.droiddeck.launcher.stores.itch.ItchBrowseState.items + com.droiddeck.launcher.stores.itch.ItchCollections.items() else emptyList(),
         shelves[store],
     )
 
@@ -191,6 +191,7 @@ object StoresState {
             backend?.signOut(app)
             if (store == Store.GOG) com.droiddeck.launcher.stores.gog.GogComet.replaceAccount { StoreAccounts.clear(app, store) }
             else if (store != Store.XBOX || backend == null) StoreAccounts.clear(app, store)
+            if (store == Store.ITCH) com.droiddeck.launcher.stores.itch.ItchCollections.clear()
             main.post {
                 if (store == Store.XBOX && StoreAccounts.signedInAs(app, store) != null) return@post
                 accounts.remove(store); library.remove(store); status.remove(store); problems.remove(store); libraryAsked.remove(store)

app/src/main/java/com/droiddeck/launcher/stores/itch/ItchApi.kt

@@ -19,6 +19,11 @@ internal object ItchApi {
 
     fun ownedKeys(key: String, page: Int): JSONObject? = get("/profile/owned-keys?page=$page&per_page=500", key)
 
+    fun collections(key: String): JSONArray? = get("/profile/collections", key)?.optJSONArray("collections")
+
+    fun collectionGames(key: String, collectionId: String, page: Int): JSONObject? =
+        get("/collections/$collectionId/collection-games?page=$page", key)
+
     fun uploads(key: String, gameId: String, downloadKeyId: String): JSONArray? =
         get("/games/$gameId/uploads" + keyQuery(downloadKeyId), key)?.optJSONArray("uploads")
 

app/src/main/java/com/droiddeck/launcher/stores/itch/ItchCollections.kt

@@ -0,0 +1,116 @@
+package com.droiddeck.launcher.stores.itch
+
+import android.content.Context
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateMapOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import com.droiddeck.launcher.stores.CatalogItem
+import com.droiddeck.launcher.stores.StoresState
+import org.json.JSONArray
+import org.json.JSONObject
+import java.util.concurrent.ConcurrentHashMap
+
+internal class ItchCollection(val id: String, val title: String, val count: Int)
+
+internal object ItchCollections {
+    var list by mutableStateOf<List<ItchCollection>>(emptyList())
+        private set
+    var selected by mutableStateOf<String?>(null)
+        private set
+    private val games = mutableStateMapOf<String, List<CatalogItem>>()
+    private val loading = ConcurrentHashMap.newKeySet<String>()
+    @Volatile private var generation = 0
+
+    fun items(): List<CatalogItem> = games.values.flatten()
+
+    fun gamesOf(id: String): List<CatalogItem>? = games[id]
+
+    fun chosen(): ItchCollection? = list.firstOrNull { it.id == selected }
+
+    fun clear() {
+        generation++
+        StoresState.post {
+            list = emptyList()
+            selected = null
+            games.clear()
+        }
+    }
+
+    fun load(context: Context) {
+        val app = context.applicationContext
+        val started = generation
+        val guard = "$started:"
+        if (!loading.add(guard)) return
+        Thread({
+            try {
+                val key = ItchAuth.key(app)
+                if (key.isBlank()) return@Thread
+                val parsed = parseCollections(ItchApi.collections(key) ?: return@Thread)
+                if (started != generation) return@Thread
+                StoresState.post {
+                    if (started != generation) return@post
+                    list = parsed
+                    if (selected != null && parsed.none { it.id == selected }) selected = null
+                }
+                StoresState.logLine("itch.io: ${parsed.size} collections")
+                selected?.let { fetchGames(key, it, started) }
+            } finally {
+                loading.remove(guard)
+            }
+        }, "itch-collections").start()
+    }
+
+    fun select(context: Context, id: String?) {
+        selected = id
+        if (id == null) return
+        val app = context.applicationContext
+        val started = generation
+        Thread({
+            val key = ItchAuth.key(app)
+            if (key.isNotBlank()) fetchGames(key, id, started)
+        }, "itch-collection-games").start()
+    }
+
+    private fun fetchGames(key: String, id: String, started: Int) {
+        val guard = "$started:$id"
+        if (!loading.add(guard)) return
+        try {
+            val out = ArrayList<CatalogItem>()
+            val seen = HashSet<String>()
+            var page = 1
+            while (true) {
+                val body = ItchApi.collectionGames(key, id, page)
+                if (body == null) {
+                    StoresState.logLine("itch.io: collection $id page $page failed")
+                    return
+                }
+                val batch = parseGames(body)
+                if (batch.isEmpty()) break
+                val before = out.size
+                out.addAll(batch.filter { seen.add(it.id) })
+                if (out.size == before) break
+                page++
+            }
+            val distinct = out.toList()
+            StoresState.post { if (started == generation) games[id] = distinct }
+            StoresState.logLine("itch.io: collection $id has ${distinct.size} games")
+        } finally {
+            loading.remove(guard)
+        }
+    }
+
+    internal fun parseCollections(array: JSONArray): List<ItchCollection> = (0 until array.length()).mapNotNull { i ->
+        val c = array.optJSONObject(i) ?: return@mapNotNull null
+        val id = c.opt("id")?.toString().orEmpty().takeIf { it.isNotBlank() && it != "null" } ?: return@mapNotNull null
+        val title = c.optString("title").ifBlank { return@mapNotNull null }
+        ItchCollection(id, title, c.optInt("games_count", c.optInt("gamesCount")))
+    }
+
+    internal fun parseGames(body: JSONObject): List<CatalogItem> {
+        val rows = body.optJSONArray("collection_games") ?: body.optJSONArray("collectionGames") ?: return emptyList()
+        return (0 until rows.length()).mapNotNull { i ->
+            rows.optJSONObject(i)?.optJSONObject("game")?.let { ItchLibrary.item(it, "") }
+        }
+    }
+}

app/src/main/java/com/droiddeck/launcher/ui/CollectionsIcon.kt

@@ -0,0 +1,15 @@
+package com.droiddeck.launcher.ui
+
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.graphics.vector.addPathNodes
+import androidx.compose.ui.unit.dp
+
+internal val CollectionsIcon: ImageVector = ImageVector.Builder("Collections", 24.dp, 24.dp, 24f, 24f).apply {
+    for (d in listOf(
+        "M2.65,4.6H7.33V22H2.65Z",
+        "M8.32,2H13V22H8.32Z",
+        "M13.9,5.4H18.5L21.4,22H16.8Z",
+    )) addPath(addPathNodes(d), fill = SolidColor(Color.Black))
+}.build()

app/src/main/java/com/droiddeck/launcher/ui/LibraryPage.kt

@@ -89,6 +89,8 @@ import com.droiddeck.launcher.stores.StoresState
 import com.droiddeck.launcher.stores.arrangeStoreTabs
 import com.droiddeck.launcher.stores.download.DownloadEntry
 import com.droiddeck.launcher.stores.formatBytes
+import com.droiddeck.launcher.stores.itch.ItchCollection
+import com.droiddeck.launcher.stores.itch.ItchCollections
 import com.droiddeck.launcher.stores.retainOrder
 import com.droiddeck.launcher.stores.xbox.XboxLibraryFilter
 import com.droiddeck.launcher.stores.sortGames
@@ -127,6 +129,14 @@ internal fun libraryEntries(
     return out.distinctBy { it.key }
 }
 
+internal fun collectionEntries(all: List<LibraryEntry>, items: List<CatalogItem>): List<LibraryEntry> {
+    val keys = items.map { it.key }.toSet()
+    val itch = all.filter { it.source == Store.ITCH.id }
+    val have = itch.mapNotNull { it.storeKey }.toSet()
+    return itch.filter { it.storeKey in keys } +
+        items.filter { it.key !in have }.map { LibraryEntry(GameRef.key(it), Store.ITCH.id, it.title, null, it, false) }
+}
+
 internal fun installedFirst(entries: List<LibraryEntry>): List<LibraryEntry> = entries.partition { it.installed }.let { (on, off) -> on + off }
 
 internal const val LIBRARY_ALL = "all"
@@ -169,19 +179,30 @@ internal fun LibraryPage(s: FrontEndState, a: FrontEndActions, selected: String,
     val all = remember(s.steamGames, cloudRows, owned, installedStore) { libraryEntries(s.steamGames + cloudRows, owned, installedStore) }
     LaunchedEffect(Unit) { XboxLibraryFilter.load(ctx) }
     var showUninstalled by remember(LibraryView.ownedRequest) { mutableStateOf(SessionPrefs.libraryShowUninstalled(ctx)) }
+    var collectionShows by remember { mutableStateOf<Pair<String, Boolean>?>(null) }
     val setShowUninstalled = { show: Boolean ->
-        showUninstalled = show
-        SessionPrefs.setLibraryShowUninstalled(ctx, show)
+        val picked = ItchCollections.selected.takeIf { LibraryView.source == Store.ITCH.id }
+        if (picked != null) collectionShows = picked to show
+        else {
+            showUninstalled = show
+            SessionPrefs.setLibraryShowUninstalled(ctx, show)
+        }
     }
-    val sources = librarySources(all, SessionPrefs.storesTabOrder(ctx))
+    val itchSignedIn = owned.containsKey(Store.ITCH)
+    val listed = librarySources(all, SessionPrefs.storesTabOrder(ctx))
+    val sources = if (itchSignedIn && Store.ITCH.id !in listed) listed + Store.ITCH.id else listed
     val source = LibraryView.source.takeIf { it == LIBRARY_ALL || it in sources } ?: LIBRARY_ALL
     val q = LibraryView.query.trim().lowercase()
     val xboxFilter = if (source == Store.XBOX.id) XboxLibraryFilter.current else XboxLibraryFilter.ALL
-    val matching = all.filter {
+    LaunchedEffect(source, itchSignedIn) { if (source == Store.ITCH.id && itchSignedIn) ItchCollections.load(ctx) }
+    val collection = if (source == Store.ITCH.id) ItchCollections.chosen() else null
+    val pool = if (collection == null) all else collectionEntries(all, ItchCollections.gamesOf(collection.id).orEmpty())
+    val matching = pool.filter {
         (source == LIBRARY_ALL || it.source == source) && (q.isEmpty() || it.title.lowercase().contains(q)) && keepsXbox(xboxFilter, it)
     }
-    val candidates = if (showUninstalled) matching else matching.filter { it.installed }
-    val hiddenUninstalled = if (showUninstalled) 0 else matching.count { !it.installed }
+    val listUninstalled = if (collection == null) showUninstalled else collectionShows?.takeIf { it.first == collection.id }?.second ?: true
+    val candidates = if (listUninstalled) matching else matching.filter { it.installed }
+    val hiddenUninstalled = if (listUninstalled) 0 else matching.count { !it.installed }
     val sort = s.storesSort
     val sizeSort = sort == "sizeAsc" || sort == "sizeDesc"
     val installedAt = StoresState.installed.associate { it.key to it.sidecar.installedAt }
@@ -264,7 +285,7 @@ internal fun LibraryPage(s: FrontEndState, a: FrontEndActions, selected: String,
         kotlinx.coroutines.delay(Motion.ms(240).toLong())
         focusWithinFrames({ ff.last?.startsWith("card:") == true }) { if (ff.firstTileAttached > 0) ff.firstTile else FocusRequester.Default }
     }
-    if (all.isEmpty() && open == null) {
+    if (all.isEmpty() && open == null && !itchSignedIn) {
         LibraryEmpty(s, a, modifier)
         return
     }
@@ -272,7 +293,7 @@ internal fun LibraryPage(s: FrontEndState, a: FrontEndActions, selected: String,
     val detailScroll = rememberScrollState()
     var cycled by remember { mutableIntStateOf(0) }
     var gridFocused by remember { mutableStateOf(false) }
-    LaunchedEffect(source, sort, showUninstalled) { grid.scrollToItem(0) }
+    LaunchedEffect(source, sort, listUninstalled) { grid.scrollToItem(0) }
     LaunchedEffect(cycled) {
         if (cycled == 0 || ff == null || inputMode.inputMode != androidx.compose.ui.input.InputMode.Keyboard) return@LaunchedEffect
         focusWithinFrames({ gridFocused }) {
@@ -288,7 +309,7 @@ internal fun LibraryPage(s: FrontEndState, a: FrontEndActions, selected: String,
         grid = {
             LibraryGrid(
                 s, a, grid, visible, split, visible.size, sources, source, sizesPending, syncing,
-                showUninstalled = showUninstalled.takeIf { stores }, onShowUninstalled = setShowUninstalled,
+                showUninstalled = listUninstalled.takeIf { stores }, onShowUninstalled = setShowUninstalled,
                 hiddenUninstalled = hiddenUninstalled,
                 onSource = { LibraryView.source = it },
                 onCycle = { step ->
@@ -383,7 +404,7 @@ private fun LibraryGrid(
         contentPadding = PaddingValues(top = 4.dp, bottom = 16.dp),
     ) {
         item(key = "header", span = { GridItemSpan(maxLineSpan) }) {
-            Rise(0) { LibraryHeader(s, a, total, searchCleared, source == Store.XBOX.id, showUninstalled, onShowUninstalled) }
+            Rise(0) { LibraryHeader(s, a, total, searchCleared, source == Store.XBOX.id, showUninstalled, onShowUninstalled, collections = source == Store.ITCH.id) }
         }
         item(key = "filters", span = { GridItemSpan(maxLineSpan) }) {
             Rise(1) { LibraryFilters(sources, source, onSource) }
@@ -430,7 +451,7 @@ private fun LazyGridScope.libraryGrid(entries: List<LibraryEntry>, empty: Int, t
 @Composable
 private fun LibraryHeader(
     s: FrontEndState, a: FrontEndActions, total: Int, searchCleared: Boolean, xbox: Boolean,
-    showUninstalled: Boolean?, onShowUninstalled: (Boolean) -> Unit,
+    showUninstalled: Boolean?, onShowUninstalled: (Boolean) -> Unit, collections: Boolean,
 ) {
     val colors = MaterialTheme.colorScheme
     val narrow = LocalNarrowPane.current
@@ -447,6 +468,7 @@ private fun LibraryHeader(
         },
     ) {
         if (showUninstalled != null || xbox) LibraryFilterButton(showUninstalled, onShowUninstalled, xbox)
+        if (collections) CollectionsButton()
         SortButton(s, a)
         ViewButton(s, a)
         GameFileFolderActions(s, a)
@@ -700,6 +722,39 @@ private fun LibraryFilterButton(showUninstalled: Boolean?, onShowUninstalled: (B
     }
 }
 
+@Composable
+private fun CollectionsButton() {
+    val pal = LocalPalette.current
+    val ctx = LocalContext.current
+    val title = stringResource(R.string.itch_collections)
+    val all = stringResource(R.string.stores_tab_all)
+    var at by remember { mutableStateOf<Rect?>(null) }
+    Box(Modifier.onGloballyPositioned { at = it.boundsInRoot() }) {
+        HeaderIconButton(title + " · " + (ItchCollections.chosen()?.title ?: all), CollectionsIcon, "itch-collections") {
+            val from = at ?: return@HeaderIconButton
+            val choices = listOf<ItchCollection?>(null) + ItchCollections.list
+            Steps.ask(StepAsk(
+                anchor = from, side = StepSide.Left, accent = pal.signal, pillCorner = 8.dp, items = choices.size,
+                handle = { Icon(CollectionsIcon, null, tint = pal.signal, modifier = Modifier.size(18.dp)) },
+            ) {
+                StepTitle(title)
+                StepList {
+                    choices.forEachIndexed { i, c ->
+                        val picked = c?.id == ItchCollections.selected
+                        StepChoice(
+                            c?.let { it.title + " (" + it.count + ")" } ?: all, selected = picked, enabled = open,
+                            modifier = Modifier.fillMaxWidth().stepItem(i).then(if (picked) Modifier.focusRequester(first) else Modifier),
+                        ) {
+                            ItchCollections.select(ctx, c?.id)
+                            Steps.fold()
+                        }
+                    }
+                }
+            })
+        }
+    }
+}
+
 @Composable
 private fun SortButton(s: FrontEndState, a: FrontEndActions) {
     val pal = LocalPalette.current

app/src/main/res/values-ar/strings.xml

@@ -3219,6 +3219,7 @@
     <string name="library_remove">إزالة من المكتبة</string>
     <string name="library_in">في المكتبة</string>
     <string name="xbox_filter_show">عرض</string>
+    <string name="itch_collections">المجموعات</string>
     <string name="xbox_filter_cloud">سحابية</string>
     <string name="stores_xbox_cloud_settings">إعدادات السحابة</string>
 </resources>

app/src/main/res/values-b+es+419/strings.xml

@@ -3069,6 +3069,7 @@
     <string name="library_remove">Quitar de Biblioteca</string>
     <string name="library_in">En Biblioteca</string>
     <string name="xbox_filter_show">Mostrar</string>
+    <string name="itch_collections">Colecciones</string>
     <string name="xbox_filter_cloud">Nube</string>
     <string name="stores_xbox_cloud_settings">Configuración de nube</string>
 </resources>

app/src/main/res/values-bg/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Премахни от Библиотека</string>
     <string name="library_in">В Библиотека</string>
     <string name="xbox_filter_show">Показване</string>
+    <string name="itch_collections">Колекции</string>
     <string name="xbox_filter_cloud">Облак</string>
     <string name="stores_xbox_cloud_settings">Настройки на облака</string>
 </resources>

app/src/main/res/values-cs/strings.xml

@@ -3151,6 +3151,7 @@
     <string name="library_remove">Odebrat z knihovny</string>
     <string name="library_in">V knihovně</string>
     <string name="xbox_filter_show">Zobrazit</string>
+    <string name="itch_collections">Kolekce</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Nastavení cloudu</string>
 </resources>

app/src/main/res/values-da/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Fjern fra Bibliotek</string>
     <string name="library_in">I Bibliotek</string>
     <string name="xbox_filter_show">Vis</string>
+    <string name="itch_collections">Samlinger</string>
     <string name="xbox_filter_cloud">Sky</string>
     <string name="stores_xbox_cloud_settings">Skyindstillinger</string>
 </resources>

app/src/main/res/values-de/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Aus der Bibliothek entfernen</string>
     <string name="library_in">In der Bibliothek</string>
     <string name="xbox_filter_show">Anzeigen</string>
+    <string name="itch_collections">Sammlungen</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Cloud-Einstellungen</string>
 </resources>

app/src/main/res/values-el/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Αφαίρεση από τη Βιβλιοθήκη</string>
     <string name="library_in">Στη Βιβλιοθήκη</string>
     <string name="xbox_filter_show">Εμφάνιση</string>
+    <string name="itch_collections">Συλλογές</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Ρυθμίσεις cloud</string>
 </resources>

app/src/main/res/values-es/strings.xml

@@ -3119,6 +3119,7 @@
     <string name="library_remove">Quitar de la Biblioteca</string>
     <string name="library_in">En la Biblioteca</string>
     <string name="xbox_filter_show">Mostrar</string>
+    <string name="itch_collections">Colecciones</string>
     <string name="xbox_filter_cloud">Nube</string>
     <string name="stores_xbox_cloud_settings">Ajustes de nube</string>
 </resources>

app/src/main/res/values-fi/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Poista kirjastosta</string>
     <string name="library_in">Kirjastossa</string>
     <string name="xbox_filter_show">Näytä</string>
+    <string name="itch_collections">Kokoelmat</string>
     <string name="xbox_filter_cloud">Pilvi</string>
     <string name="stores_xbox_cloud_settings">Pilviasetukset</string>
 </resources>

app/src/main/res/values-fr/strings.xml

@@ -3119,6 +3119,7 @@
     <string name="library_remove">Retirer de la Bibliothèque</string>
     <string name="library_in">Dans la Bibliothèque</string>
     <string name="xbox_filter_show">Afficher</string>
+    <string name="itch_collections">Collections</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Paramètres cloud</string>
 </resources>

app/src/main/res/values-hi/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">लाइब्रेरी से हटाएँ</string>
     <string name="library_in">लाइब्रेरी में</string>
     <string name="xbox_filter_show">दिखाएँ</string>
+    <string name="itch_collections">संग्रह</string>
     <string name="xbox_filter_cloud">क्लाउड</string>
     <string name="stores_xbox_cloud_settings">क्लाउड सेटिंग्स</string>
 </resources>

app/src/main/res/values-hu/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Eltávolítás a könyvtárból</string>
     <string name="library_in">A könyvtárban</string>
     <string name="xbox_filter_show">Megjelenítés</string>
+    <string name="itch_collections">Gyűjtemények</string>
     <string name="xbox_filter_cloud">Felhő</string>
     <string name="stores_xbox_cloud_settings">Felhőbeállítások</string>
 </resources>

app/src/main/res/values-in/strings.xml

@@ -3073,6 +3073,7 @@
     <string name="library_remove">Hapus dari Pustaka</string>
     <string name="library_in">Di Pustaka</string>
     <string name="xbox_filter_show">Tampilkan</string>
+    <string name="itch_collections">Koleksi</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Pengaturan cloud</string>
 </resources>

app/src/main/res/values-it/strings.xml

@@ -3117,6 +3117,7 @@
     <string name="library_remove">Rimuovi dalla Libreria</string>
     <string name="library_in">Nella Libreria</string>
     <string name="xbox_filter_show">Mostra</string>
+    <string name="itch_collections">Raccolte</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Impostazioni cloud</string>
 </resources>

app/src/main/res/values-ja/strings.xml

@@ -3060,6 +3060,7 @@
     <string name="library_remove">ライブラリから削除</string>
     <string name="library_in">ライブラリにあります</string>
     <string name="xbox_filter_show">表示</string>
+    <string name="itch_collections">コレクション</string>
     <string name="xbox_filter_cloud">クラウド</string>
     <string name="stores_xbox_cloud_settings">クラウド設定</string>
 </resources>

app/src/main/res/values-ko/strings.xml

@@ -3060,6 +3060,7 @@
     <string name="library_remove">라이브러리에서 제거</string>
     <string name="library_in">라이브러리에 있음</string>
     <string name="xbox_filter_show">표시</string>
+    <string name="itch_collections">컬렉션</string>
     <string name="xbox_filter_cloud">클라우드</string>
     <string name="stores_xbox_cloud_settings">클라우드 설정</string>
 </resources>

app/src/main/res/values-ms/strings.xml

@@ -3058,6 +3058,7 @@
     <string name="library_remove">Alih keluar dari Pustaka</string>
     <string name="library_in">Dalam Pustaka</string>
     <string name="xbox_filter_show">Tunjukkan</string>
+    <string name="itch_collections">Koleksi</string>
     <string name="xbox_filter_cloud">Awan</string>
     <string name="stores_xbox_cloud_settings">Tetapan awan</string>
 </resources>

app/src/main/res/values-nb/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Fjern fra Bibliotek</string>
     <string name="library_in">I Bibliotek</string>
     <string name="xbox_filter_show">Vis</string>
+    <string name="itch_collections">Samlinger</string>
     <string name="xbox_filter_cloud">Sky</string>
     <string name="stores_xbox_cloud_settings">Skyinnstillinger</string>
 </resources>

app/src/main/res/values-nl/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Verwijderen uit Bibliotheek</string>
     <string name="library_in">In Bibliotheek</string>
     <string name="xbox_filter_show">Weergeven</string>
+    <string name="itch_collections">Collecties</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Cloudinstellingen</string>
 </resources>

app/src/main/res/values-pl/strings.xml

@@ -3154,6 +3154,7 @@
     <string name="library_remove">Usuń z biblioteki</string>
     <string name="library_in">W bibliotece</string>
     <string name="xbox_filter_show">Pokaż</string>
+    <string name="itch_collections">Kolekcje</string>
     <string name="xbox_filter_cloud">Chmura</string>
     <string name="stores_xbox_cloud_settings">Ustawienia chmury</string>
 </resources>

app/src/main/res/values-pt-rPT/strings.xml

@@ -3117,6 +3117,7 @@
     <string name="library_remove">Remover da Biblioteca</string>
     <string name="library_in">Na Biblioteca</string>
     <string name="xbox_filter_show">Mostrar</string>
+    <string name="itch_collections">Coleções</string>
     <string name="xbox_filter_cloud">Nuvem</string>
     <string name="stores_xbox_cloud_settings">Definições da nuvem</string>
 </resources>

app/src/main/res/values-pt/strings.xml

@@ -3117,6 +3117,7 @@
     <string name="library_remove">Remover da Biblioteca</string>
     <string name="library_in">Na Biblioteca</string>
     <string name="xbox_filter_show">Mostrar</string>
+    <string name="itch_collections">Coleções</string>
     <string name="xbox_filter_cloud">Nuvem</string>
     <string name="stores_xbox_cloud_settings">Configurações da nuvem</string>
 </resources>

app/src/main/res/values-ro/strings.xml

@@ -3117,6 +3117,7 @@
     <string name="library_remove">Elimină din Bibliotecă</string>
     <string name="library_in">În Bibliotecă</string>
     <string name="xbox_filter_show">Afișează</string>
+    <string name="itch_collections">Colecții</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Setări cloud</string>
 </resources>

app/src/main/res/values-ru/strings.xml

@@ -3153,6 +3153,7 @@
     <string name="library_remove">Убрать из библиотеки</string>
     <string name="library_in">В библиотеке</string>
     <string name="xbox_filter_show">Показать</string>
+    <string name="itch_collections">Коллекции</string>
     <string name="xbox_filter_cloud">Облако</string>
     <string name="stores_xbox_cloud_settings">Настройки облака</string>
 </resources>

app/src/main/res/values-sv/strings.xml

@@ -3083,6 +3083,7 @@
     <string name="library_remove">Ta bort från Bibliotek</string>
     <string name="library_in">I Bibliotek</string>
     <string name="xbox_filter_show">Visa</string>
+    <string name="itch_collections">Samlingar</string>
     <string name="xbox_filter_cloud">Moln</string>
     <string name="stores_xbox_cloud_settings">Molninställningar</string>
 </resources>

app/src/main/res/values-th/strings.xml

@@ -3058,6 +3058,7 @@
     <string name="library_remove">นำออกจากไลบรารี</string>
     <string name="library_in">อยู่ในไลบรารี</string>
     <string name="xbox_filter_show">แสดง</string>
+    <string name="itch_collections">คอลเลกชัน</string>
     <string name="xbox_filter_cloud">คลาวด์</string>
     <string name="stores_xbox_cloud_settings">การตั้งค่าคลาวด์</string>
 </resources>

app/src/main/res/values-tr/strings.xml

@@ -3085,6 +3085,7 @@
     <string name="library_remove">Kütüphane içinden kaldır</string>
     <string name="library_in">Kütüphane içinde</string>
     <string name="xbox_filter_show">Göster</string>
+    <string name="itch_collections">Koleksiyonlar</string>
     <string name="xbox_filter_cloud">Bulut</string>
     <string name="stores_xbox_cloud_settings">Bulut ayarları</string>
 </resources>

app/src/main/res/values-uk/strings.xml

@@ -3151,6 +3151,7 @@
     <string name="library_remove">Прибрати з бібліотеки</string>
     <string name="library_in">У бібліотеці</string>
     <string name="xbox_filter_show">Показати</string>
+    <string name="itch_collections">Колекції</string>
     <string name="xbox_filter_cloud">Хмара</string>
     <string name="stores_xbox_cloud_settings">Налаштування хмари</string>
 </resources>

app/src/main/res/values-vi/strings.xml

@@ -3058,6 +3058,7 @@
     <string name="library_remove">Xóa khỏi Thư viện</string>
     <string name="library_in">Trong Thư viện</string>
     <string name="xbox_filter_show">Hiển thị</string>
+    <string name="itch_collections">Bộ sưu tập</string>
     <string name="xbox_filter_cloud">Đám mây</string>
     <string name="stores_xbox_cloud_settings">Cài đặt đám mây</string>
 </resources>

app/src/main/res/values-zh-rCN/strings.xml

@@ -3062,6 +3062,7 @@
     <string name="library_remove">从游戏库移除</string>
     <string name="library_in">已在游戏库</string>
     <string name="xbox_filter_show">显示</string>
+    <string name="itch_collections">收藏集</string>
     <string name="xbox_filter_cloud">云</string>
     <string name="stores_xbox_cloud_settings">云设置</string>
 </resources>

app/src/main/res/values-zh-rHK/strings.xml

@@ -3061,6 +3061,7 @@
     <string name="library_remove">從收藏庫移除</string>
     <string name="library_in">已在收藏庫</string>
     <string name="xbox_filter_show">顯示</string>
+    <string name="itch_collections">收藏集</string>
     <string name="xbox_filter_cloud">雲端</string>
     <string name="stores_xbox_cloud_settings">雲端設定</string>
 </resources>

app/src/main/res/values-zh-rTW/strings.xml

@@ -3061,6 +3061,7 @@
     <string name="library_remove">從收藏庫移除</string>
     <string name="library_in">已在收藏庫</string>
     <string name="xbox_filter_show">顯示</string>
+    <string name="itch_collections">收藏集</string>
     <string name="xbox_filter_cloud">雲端</string>
     <string name="stores_xbox_cloud_settings">雲端設定</string>
 </resources>

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

@@ -3236,6 +3236,7 @@
     <string name="library_remove">Remove from Library</string>
     <string name="library_in">In Library</string>
     <string name="xbox_filter_show">Show</string>
+    <string name="itch_collections">Collections</string>
     <string name="xbox_filter_cloud">Cloud</string>
     <string name="stores_xbox_cloud_settings">Cloud settings</string>
     <string name="xbox_cloud_gaming" translatable="false">Xbox Cloud Gaming</string>

app/src/test/java/com/droiddeck/launcher/stores/itch/ItchCollectionsTest.kt

@@ -0,0 +1,31 @@
+package com.droiddeck.launcher.stores.itch
+
+import org.json.JSONArray
+import org.json.JSONObject
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+@org.junit.runner.RunWith(org.robolectric.RobolectricTestRunner::class)
+@org.robolectric.annotation.Config(sdk = [33], application = android.app.Application::class)
+class ItchCollectionsTest {
+    @Test fun collectionsKeepTheirIdTitleAndCount() {
+        val body = JSONArray()
+            .put(JSONObject().put("id", 8356509).put("title", "library").put("games_count", 12))
+            .put(JSONObject().put("id", 7).put("title", "").put("games_count", 3))
+            .put(JSONObject().put("title", "no id"))
+        val list = ItchCollections.parseCollections(body)
+        assertEquals(listOf("8356509"), list.map { it.id })
+        assertEquals("library", list.single().title)
+        assertEquals(12, list.single().count)
+    }
+
+    @Test fun collectionGamesReadBothKeyStylesAndSkipRowsWithoutAGame() {
+        val game = JSONObject().put("id", 99).put("title", "Celeste 64").put("url", "https://noel.itch.io/celeste64")
+        val snake = JSONObject().put("collection_games", JSONArray().put(JSONObject().put("game", game)).put(JSONObject().put("position", 1)))
+        val camel = JSONObject().put("collectionGames", JSONArray().put(JSONObject().put("game", game)))
+        assertEquals(listOf("noel.itch.io/celeste64"), ItchCollections.parseGames(snake).map { it.id })
+        assertEquals(1, ItchCollections.parseGames(camel).size)
+        assertEquals(false, ItchCollections.parseGames(snake).single().owned)
+        assertEquals(0, ItchCollections.parseGames(JSONObject()).size)
+    }
+}

app/src/test/java/com/droiddeck/launcher/ui/LibraryEntriesTest.kt

@@ -94,4 +94,23 @@ class LibraryEntriesTest {
         GameRef.parse("xbox:9NBLGGH4R315").let { assertEquals(Store.XBOX, it.store); assertEquals("9NBLGGH4R315", it.storeId) }
         GameRef.parse("app:nope:1").let { assertNull(it.store); assertNull(it.appId) }
     }
+
+    @Test fun aCollectionKeepsItsInstalledGamesAndListsTheRestAsNotInstalled() {
+        val games = listOf(
+            Library.SteamGame(440, "Team Fortress 2", null, "Steam library"),
+            Library.SteamGame(-5, "Celeste", null, Library.ADDED, source = "itch", storeId = "a/celeste"),
+            Library.SteamGame(-6, "Other", null, Library.ADDED, source = "itch", storeId = "a/other"),
+        )
+        val library = mapOf(Store.ITCH to listOf(owned(Store.ITCH, "a/celeste"), owned(Store.ITCH, "a/other"), owned(Store.ITCH, "b/owned")))
+        val all = libraryEntries(games, library, setOf("itch:a/celeste", "itch:a/other"))
+        val collection = listOf(owned(Store.ITCH, "a/celeste"), owned(Store.ITCH, "b/owned"), owned(Store.ITCH, "c/new"))
+        val out = collectionEntries(all, collection)
+        assertEquals(listOf("app:-5", "app:itch:b/owned", "app:itch:c/new"), out.map { it.key })
+        assertEquals(listOf(true, false, false), out.map { it.installed })
+    }
+
+    @Test fun anEmptyCollectionHidesEveryGame() {
+        val all = libraryEntries(listOf(Library.SteamGame(440, "Team Fortress 2", null, "Steam library")), emptyMap(), emptySet())
+        assertEquals(emptyList<String>(), collectionEntries(all, emptyList()).map { it.key })
+    }
 }

docs/development/itch-collections.md

@@ -0,0 +1,26 @@
+# itch.io collections
+
+On the Library's itch tab a Collections button in the header lists the collections of the signed-in
+itch account. Picking one hides every game that is not in it; the games of the collection that are not
+installed show in the existing "Not installed" section, and All brings the full library back. The button
+exists only while the itch chip is selected.
+
+## Data
+
+`ItchCollections` (`stores/itch/ItchCollections.kt`) asks itch with the account's API key:
+
+```
+GET /profile/collections                          -> collections[{id, title, games_count}]
+GET /collections/<id>/collection-games?page=N     -> collection_games[{game{...}}]
+```
+
+Pages are read until one comes back empty. Each game goes through `ItchLibrary.item`, the reader the
+library and shelves share, so it looks the same everywhere. The selection and the loaded games live in
+memory; the list is asked again whenever the itch tab opens. Counts are logged
+(`itch.io: <n> collections`, `itch.io: collection <id> has <n> games`).
+
+## Filtering
+
+`collectionEntries` keeps the itch entries whose store key is in the collection, then adds the
+collection games the library has no entry for as not installed ones. Their game page resolves through
+`StoresState.detailItem`, which also looks at the collection games.