Add stream language filter and fix directory infinite scroll.

Settings multi-select filters Top/category/tag lists via Helix (with over-fetch for multiple languages). Larger Helix pages, safer cursors, and scroll near-end loading restore pagination; GQL page-2 integrity failures end the list cleanly.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/apis/twitch_gql_api.dart

@@ -38,10 +38,16 @@ class TwitchGqlApi extends BaseApiClient {
       headers: _gqlHeaders,
     );
     final errors = response['errors'];
-    if (errors is List && errors.isNotEmpty && response['data'] == null) {
-      final message = (errors.first as JsonMap)['message'] as String? ??
-          'Twitch GQL error';
-      throw ApiException(message);
+    if (errors is List && errors.isNotEmpty) {
+      final data = response['data'];
+      final dataEmpty = data == null ||
+          (data is Map &&
+              data.values.every((value) => value == null));
+      if (dataEmpty) {
+        final message = (errors.first as JsonMap)['message'] as String? ??
+            'Twitch GQL error';
+        throw ApiException(message);
+      }
     }
     return response;
   }
@@ -205,28 +211,42 @@ class TwitchGqlApi extends BaseApiClient {
         .toList();
   }
 
-  /// Live streams matching optional [freeformTags], sorted by viewer count.
+  /// Live streams matching optional [freeformTags] / [languages], sorted by viewers.
+  ///
+  /// Twitch caps `first` at 30 for this connection. Cursor pagination often
+  /// fails with `IntegrityCheckFailed` without a web integrity token — callers
+  /// should treat a failed page-2 as end-of-list.
   Future<StreamsTwitch> getStreams({
     List<String>? freeformTags,
+    List<String>? languages,
     StreamViewerSort sort = StreamViewerSort.viewersDesc,
     String? cursor,
     int first = 30,
   }) async {
+    final cappedFirst = first.clamp(1, 30);
+    final gqlLangs = languages == null || languages.isEmpty
+        ? null
+        : languages
+              .map((l) => l.trim().toUpperCase())
+              .where((l) => l.isNotEmpty)
+              .toList();
+
     final response = await _gql({
       'operationName': 'FrostyTopStreams',
       'query':
-          r'query FrostyTopStreams($first: Int, $after: Cursor, $tags: [String!], $sort: StreamSort) {'
-          r' streams(first: $first, after: $after, options: { sort: $sort, freeformTags: $tags }) {'
+          r'query FrostyTopStreams($first: Int, $after: Cursor, $tags: [String!], $sort: StreamSort, $langs: [Language!]) {'
+          r' streams(first: $first, after: $after, options: { sort: $sort, freeformTags: $tags, languages: $langs }) {'
           r' edges { cursor node {'
-          r' id title viewersCount createdAt'
+          r' id title viewersCount createdAt language'
           r' game { id name }'
           r' broadcaster { id login displayName }'
           r' } } pageInfo { hasNextPage } } }',
       'variables': {
-        'first': first,
+        'first': cappedFirst,
         'after': cursor,
         'tags': freeformTags,
         'sort': sort.gqlValue,
+        'langs': gqlLangs,
       },
     });
 
@@ -235,28 +255,38 @@ class TwitchGqlApi extends BaseApiClient {
     return _streamsFromConnection(connection);
   }
 
-  /// Live streams under a category/game, with viewer sort (Helix has no asc).
+  /// Live streams under a category/game, with viewer sort and optional languages.
   Future<StreamsTwitch> getGameStreams({
     required String gameId,
+    List<String>? languages,
     StreamViewerSort sort = StreamViewerSort.viewersDesc,
     String? cursor,
     int first = 30,
   }) async {
+    final cappedFirst = first.clamp(1, 30);
+    final gqlLangs = languages == null || languages.isEmpty
+        ? null
+        : languages
+              .map((l) => l.trim().toUpperCase())
+              .where((l) => l.isNotEmpty)
+              .toList();
+
     final response = await _gql({
       'operationName': 'FrostyGameStreams',
       'query':
-          r'query FrostyGameStreams($id: ID!, $first: Int, $after: Cursor, $sort: StreamSort) {'
-          r' game(id: $id) { streams(first: $first, after: $after, options: { sort: $sort }) {'
+          r'query FrostyGameStreams($id: ID!, $first: Int, $after: Cursor, $sort: StreamSort, $langs: [Language!]) {'
+          r' game(id: $id) { streams(first: $first, after: $after, options: { sort: $sort, languages: $langs }) {'
           r' edges { cursor node {'
-          r' id title viewersCount createdAt'
+          r' id title viewersCount createdAt language'
           r' game { id name }'
           r' broadcaster { id login displayName }'
           r' } } pageInfo { hasNextPage } } } }',
       'variables': {
         'id': gameId,
-        'first': first,
+        'first': cappedFirst,
         'after': cursor,
         'sort': sort.gqlValue,
+        'langs': gqlLangs,
       },
     });
 
@@ -270,7 +300,8 @@ class TwitchGqlApi extends BaseApiClient {
   StreamsTwitch _streamsFromConnection(JsonMap connection) {
     final edges = (connection['edges'] as List?) ?? const [];
     final pageInfo = connection['pageInfo'] as JsonMap?;
-    final hasNext = pageInfo?['hasNextPage'] as bool? ?? false;
+    // Prefer explicit pageInfo; if missing, assume more when we got a full page.
+    final hasNext = pageInfo?['hasNextPage'] as bool? ?? edges.length >= 30;
 
     final streams = <StreamTwitch>[];
     String? nextCursor;
@@ -285,7 +316,9 @@ class TwitchGqlApi extends BaseApiClient {
 
     return StreamsTwitch(
       streams,
-      hasNext && nextCursor != null ? {'cursor': nextCursor} : const {},
+      hasNext && nextCursor != null && nextCursor.isNotEmpty
+          ? {'cursor': nextCursor}
+          : const {},
     );
   }
 
@@ -293,6 +326,7 @@ class TwitchGqlApi extends BaseApiClient {
     final broadcaster = node['broadcaster'] as JsonMap? ?? const {};
     final game = node['game'] as JsonMap? ?? const {};
     final login = broadcaster['login'] as String? ?? '';
+    final language = (node['language'] as String? ?? '').toLowerCase();
 
     return StreamTwitch(
       broadcaster['id'] as String? ?? '',
@@ -305,6 +339,7 @@ class TwitchGqlApi extends BaseApiClient {
       node['createdAt'] as String? ?? '',
       // Helix-style placeholder so existing thumbnail widgets keep working.
       'https://static-cdn.jtvnw.net/previews-ttv/live_user_$login-{width}x{height}.jpg',
+      language,
     );
   }
 }