implemented shared items view for Talk chats with tabbed categories and on-scroll pagination

lib/api/marianumcloud/talk/get_shared_items/get_shared_items.dart

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+import 'package:http/http.dart' as http;
+
+import '../../nextcloud_ocs.dart';
+import '../talk_api.dart';
+import 'get_shared_items_response.dart';
+
+/// Fetches the messages that shared an item of a given [objectType] in a chat
+/// (Talk's `GET /chat/{token}/share`). Paginated via [lastKnownMessageId] using
+/// the `X-Chat-Last-Given` response header (see
+/// [GetSharedItemsResponse.lastGivenMessageId]).
+///
+/// Known [objectType]s: `media`, `file`, `audio`, `voice`, `location`,
+/// `deckcard`, `recording`, `other`.
+class GetSharedItems extends TalkApi<GetSharedItemsResponse> {
+  GetSharedItems(
+    String token, {
+    required String objectType,
+    int limit = 20,
+    int? lastKnownMessageId,
+  }) : super(
+         'v1/chat/$token/share',
+         null,
+         getParameters: {
+           'objectType': objectType,
+           'limit': limit,
+           'lastKnownMessageId': ?lastKnownMessageId,
+         },
+       );
+
+  @override
+  GetSharedItemsResponse assemble(String raw) =>
+      GetSharedItemsResponse.fromOcs(NextcloudOcs.decode(raw));
+
+  @override
+  Future<http.Response> request(
+    Uri uri,
+    Object? body,
+    Map<String, String>? headers,
+  ) => http.get(uri, headers: headers);
+}

lib/api/marianumcloud/talk/get_shared_items/get_shared_items_overview.dart

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+import 'package:http/http.dart' as http;
+
+import '../../nextcloud_ocs.dart';
+import '../talk_api.dart';
+import 'get_shared_items_overview_response.dart';
+
+/// Fetches the latest shared items of every type at once (Talk's
+/// `GET /chat/{token}/share/overview`). Used to decide which category tabs to
+/// show and to seed their first page. [limit] caps the items returned per type.
+class GetSharedItemsOverview extends TalkApi<GetSharedItemsOverviewResponse> {
+  GetSharedItemsOverview(String token, {int limit = 20})
+    : super(
+        'v1/chat/$token/share/overview',
+        null,
+        getParameters: {'limit': limit},
+      );
+
+  @override
+  GetSharedItemsOverviewResponse assemble(String raw) =>
+      GetSharedItemsOverviewResponse.fromOcs(NextcloudOcs.decode(raw));
+
+  @override
+  Future<http.Response> request(
+    Uri uri,
+    Object? body,
+    Map<String, String>? headers,
+  ) => http.get(uri, headers: headers);
+}

lib/api/marianumcloud/talk/get_shared_items/get_shared_items_overview_response.dart

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+import '../../../api_response.dart';
+import '../chat/get_chat_response.dart';
+
+/// Response of Talk's `GET /chat/{token}/share/overview`: the latest shared
+/// items grouped by object type (`media`, `file`, `voice`, `audio`, `location`,
+/// `recording`, `deckcard`, `other`). Reuses [GetChatResponseObject] for the
+/// message structure.
+class GetSharedItemsOverviewResponse extends ApiResponse {
+  final Map<String, List<GetChatResponseObject>> itemsByType;
+
+  GetSharedItemsOverviewResponse(this.itemsByType);
+
+  factory GetSharedItemsOverviewResponse.fromOcs(Map<String, dynamic> ocs) {
+    final data = ocs['data'];
+    final result = <String, List<GetChatResponseObject>>{};
+    if (data is Map<String, dynamic>) {
+      for (final entry in data.entries) {
+        final value = entry.value;
+        final raw = switch (value) {
+          List<dynamic> list => list,
+          Map<dynamic, dynamic> map => map.values,
+          _ => const <dynamic>[],
+        };
+        result[entry.key] = raw
+            .whereType<Map<String, dynamic>>()
+            .map(GetChatResponseObject.fromJson)
+            .toList();
+      }
+    }
+    return GetSharedItemsOverviewResponse(result);
+  }
+}

lib/api/marianumcloud/talk/get_shared_items/get_shared_items_response.dart

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+import '../../../api_response.dart';
+import '../chat/get_chat_response.dart';
+
+/// Response of Talk's shared-items endpoints. The message objects carry the
+/// same structure as regular chat messages, so we reuse [GetChatResponseObject]
+/// (the shared file lives in `messageParameters['file']`).
+///
+/// The server returns `data` either as a list or as a message-id-keyed map
+/// depending on version; [fromOcs] normalises both to a list.
+class GetSharedItemsResponse extends ApiResponse {
+  final List<GetChatResponseObject> items;
+
+  GetSharedItemsResponse(this.items);
+
+  factory GetSharedItemsResponse.fromOcs(Map<String, dynamic> ocs) {
+    final data = ocs['data'];
+    final raw = switch (data) {
+      List<dynamic> list => list,
+      Map<dynamic, dynamic> map => map.values,
+      _ => const <dynamic>[],
+    };
+    final items = raw
+        .whereType<Map<String, dynamic>>()
+        .map(GetChatResponseObject.fromJson)
+        .toList();
+    return GetSharedItemsResponse(items);
+  }
+
+  /// Offset for the next page, taken from the `X-Chat-Last-Given` header.
+  /// Null when the header is absent (older server) — treat that as "stop".
+  int? get lastGivenMessageId {
+    final value = headers?['x-chat-last-given'];
+    return value == null ? null : int.tryParse(value);
+  }
+}