feat: Implement ignore list

lib/src/client.dart

@@ -1519,6 +1519,52 @@ sort order of ${prevState.sortOrder}. This should never happen...''');
     }
   }
 
+  /// Clear all local cached messages and perform a new clean sync.
+  Future<void> clearLocalCachedMessages() async {
+    prevBatch = null;
+    rooms.forEach((r) => r.prev_batch = null);
+    await database?.clearCache(id);
+  }
+
+  /// A list of mxids of users who are ignored.
+  List<String> get ignoredUsers =>
+      accountData.containsKey('m.ignored_user_list')
+          ? accountData['m.ignored_user_list'].content['ignored_users']
+          : [];
+
+  /// Ignore another user. This will clear the local cached messages to
+  /// hide all previous messages from this user.
+  Future<void> ignoreUser(String userId) async {
+    if (!userId.isValidMatrixId) {
+      throw Exception('$userId is not a valid mxid!');
+    }
+    await setAccountData(
+      userID,
+      'm.ignored_user_list',
+      {'ignored_users': ignoredUsers..add(userId)},
+    );
+    await clearLocalCachedMessages();
+    return;
+  }
+
+  /// Unignore a user. This will clear the local cached messages and request
+  /// them again from the server to avoid gaps in the timeline.
+  Future<void> unignoreUser(String userId) async {
+    if (!userId.isValidMatrixId) {
+      throw Exception('$userId is not a valid mxid!');
+    }
+    if (!ignoredUsers.contains(userId)) {
+      throw Exception('$userId is not in the ignore list!');
+    }
+    await setAccountData(
+      userID,
+      'm.ignored_user_list',
+      {'ignored_users': ignoredUsers..remove(userId)},
+    );
+    await clearLocalCachedMessages();
+    return;
+  }
+
   bool _disposed = false;
   Future _currentTransaction = Future.sync(() => {});
 

test/client_test.dart

@@ -421,6 +421,18 @@ void main() {
     test('changePassword', () async {
       await matrix.changePassword('1234', oldPassword: '123456');
     });
+    test('ignoredUsers', () async {
+      expect(matrix.ignoredUsers, []);
+      matrix.accountData['m.ignored_user_list'] =
+          BasicEvent(type: 'm.ignored_user_list', content: {
+        'ignored_users': ['@charley:stupid.abc']
+      });
+      expect(matrix.ignoredUsers, ['@charley:stupid.abc']);
+    });
+    test('ignoredUsers', () async {
+      await matrix.ignoreUser('@charley2:stupid.abc');
+      await matrix.unignoreUser('@charley:stupid.abc');
+    });
 
     test('dispose', () async {
       await matrix.dispose(closeDatabase: true);

test/fake_matrix_api.dart

@@ -1982,6 +1982,8 @@ class FakeMatrixApi extends MockClient {
       '/client/unstable/room_keys/version': (var reqI) => {'version': '5'},
     },
     'PUT': {
+      '/client/r0/user/%40test%3AfakeServer.notExisting/account_data/m.ignored_user_list':
+          (var req) => {},
       '/client/r0/presence/${Uri.encodeComponent('@alice:example.com')}/status':
           (var req) => {},
       '/client/r0/pushrules/global/content/nocake/enabled': (var req) => {},