feat: introduce new MSC library architecture

- migrated to more useful MSC directory structure
- migrate Widgets API into new structure
- add recent emoji API into new structure

The recent emoji API is non-standard and should be compatible with Element.

Signed-off-by: Lanna Michalke <l.michalke@famedly.com>

lib/msc_extensions/README.md

@@ -0,0 +1,21 @@
+# MSC extensions
+
+This folder contains non-spec feature implementations, usually proposed in Matrix Specification Changes (MSCs).
+
+Please try to cover the following conventions:
+
+- name your implementation `/lib/msc_extensions/msc_NUMER_short_name/whatsoever.dart`,
+  e.g. `/lib/msc_extensions/msc_3588_stories/stories.dart`
+- please link the MSC in a comment in the first line:
+  ```dart
+  /// MSC3588: Stories As Rooms (https://github.com/matrix-org/matrix-spec-proposals/blob/d818877504cfda00ac52430ba5b9e8423c878b77/proposals/3588-stories-as-rooms.md)
+  ```
+- the implementation should provide an `extension NAME on ...` (usually `Client`)
+- proprietary implementations without MSC should be given a useful name and 
+  corresponding, useful documentation comments, e.g. `/lib/msc_extensions/extension_recent_emoji/recent_emoji.dart`
+- Moreover, all implemented non-spec features should be listed below:
+
+## Implemented non-spec features
+
+- MSC 1236 - Widget API V2
+- `io.element.recent_emoji` - recent emoji sync in account data

lib/msc_extensions/extension_recent_emoji/recent_emoji.dart

@@ -0,0 +1,51 @@
+library extension_recent_emoji;
+
+import 'package:matrix/matrix.dart';
+
+/// Syncs recent emojis in account data
+///
+/// Keeps recently used emojis stored in account data by
+///
+/// ```js
+/// { // the account data
+///   "io.element.recent_emoji": {
+///     "recent_emoji" : {
+///       "emoji character": n, // number used
+///     }
+///   }
+/// }
+/// ```
+///
+/// Proprietary extension by New Vector Ltd.
+extension RecentEmojiExtension on Client {
+  /// returns the recently used emojis from the account data
+  ///
+  /// There's no corresponding standard or MSC, it's just the reverse-engineered
+  /// API from New Vector Ltd.
+  Map<String, int> get recentEmojis => Map.fromEntries(
+        (accountData['io.element.recent_emoji']?.content['recent_emoji']
+                    as List<dynamic>? ??
+                [])
+            .map(
+          (e) => MapEntry(e[0] as String, e[1] as int),
+        ),
+      );
+
+  /// +1 the stated emoji in the account data
+  Future<void> addRecentEmoji(String emoji) async {
+    final data = recentEmojis;
+    if (data.containsKey(emoji)) {
+      data[emoji] = data[emoji]! + 1;
+    } else {
+      data[emoji] = 1;
+    }
+    return setRecentEmojiData(data);
+  }
+
+  /// sets the raw recent emoji account data. Use [addRecentEmoji] instead
+  Future<void> setRecentEmojiData(Map<String, int> data) async {
+    final content = List.from(data.entries.map((e) => [e.key, e.value]));
+    return setAccountData(
+        userID!, 'io.element.recent_emoji', {'recent_emoji': content});
+  }
+}

lib/msc_extensions/msc_1236_widgets/msc_1236_widgets.dart

@@ -0,0 +1,43 @@
+library msc_1236_widgets;
+
+import 'package:matrix/matrix.dart';
+
+export 'src/widget.dart';
+
+extension MatrixWidgets on Room {
+  /// Returns all present Widgets in the room.
+  List<MatrixWidget> get widgets => {
+        ...states['m.widget'] ?? states['im.vector.modular.widgets'] ?? {},
+      }.values.expand((e) {
+        try {
+          return [MatrixWidget.fromJson(e.content, this)];
+        } catch (_) {
+          return <MatrixWidget>[];
+        }
+      }).toList();
+
+  Future<String> addWidget(MatrixWidget widget) {
+    final user = client.userID;
+    final widgetId =
+        widget.name!.toLowerCase().replaceAll(RegExp(r'\W'), '_') + '_' + user!;
+
+    final json = widget.toJson();
+    json['creatorUserId'] = user;
+    json['id'] = widgetId;
+    return client.setRoomStateWithKey(
+      id,
+      'im.vector.modular.widgets',
+      widgetId,
+      json,
+    );
+  }
+
+  Future<String> deleteWidget(String widgetId) {
+    return client.setRoomStateWithKey(
+      id,
+      'im.vector.modular.widgets',
+      widgetId,
+      {},
+    );
+  }
+}

lib/msc_extensions/msc_1236_widgets/src/widget.dart

@@ -0,0 +1,128 @@
+import 'package:matrix/src/room.dart';
+
+class MatrixWidget {
+  final Room room;
+  final String? creatorUserId;
+  final Map<String, dynamic>? data;
+  final String? id;
+  final String? name;
+  final String type;
+
+  /// use [buildWidgetUrl] instead
+  final String url;
+  final bool waitForIframeLoad;
+
+  MatrixWidget({
+    required this.room,
+    this.creatorUserId,
+    this.data = const {},
+    this.id,
+    required this.name,
+    required this.type,
+    required this.url,
+    this.waitForIframeLoad = false,
+  });
+
+  factory MatrixWidget.fromJson(Map<String, dynamic> json, Room room) =>
+      MatrixWidget(
+        room: room,
+        creatorUserId:
+            json.containsKey('creatorUserId') ? json['creatorUserId'] : null,
+        data: json.containsKey('data') ? json['data'] : {},
+        id: json.containsKey('id') ? json['id'] : null,
+        name: json['name'],
+        type: json['type'],
+        url: json['url'],
+        waitForIframeLoad: json.containsKey('waitForIframeLoad')
+            ? json['waitForIframeLoad']
+            : false,
+      );
+
+  /// creates an `m.etherpad` [MatrixWidget]
+  factory MatrixWidget.etherpad(Room room, String name, Uri url) =>
+      MatrixWidget(
+        room: room,
+        name: name,
+        type: 'm.etherpad',
+        url: url.toString(),
+        data: {
+          'url': url.toString(),
+        },
+      );
+
+  /// creates an `m.jitsi` [MatrixWidget]
+  factory MatrixWidget.jitsi(Room room, String name, Uri url,
+          {bool isAudioOnly = false}) =>
+      MatrixWidget(
+        room: room,
+        name: name,
+        type: 'm.jitsi',
+        url: url.toString(),
+        data: {
+          'domain': url.host,
+          'conferenceId': url.pathSegments.last,
+          'isAudioOnly': isAudioOnly,
+        },
+      );
+
+  /// creates an `m.video` [MatrixWidget]
+  factory MatrixWidget.video(Room room, String name, Uri url) => MatrixWidget(
+        room: room,
+        name: name,
+        type: 'm.video',
+        url: url.toString(),
+        data: {
+          'url': url.toString(),
+        },
+      );
+
+  /// creates an `m.custom` [MatrixWidget]
+  factory MatrixWidget.custom(Room room, String name, Uri url) => MatrixWidget(
+        room: room,
+        name: name,
+        type: 'm.custom',
+        url: url.toString(),
+        data: {
+          'url': url.toString(),
+        },
+      );
+
+  Future<Uri> buildWidgetUrl() async {
+    // See https://github.com/matrix-org/matrix-doc/issues/1236 for a
+    // description, specifically the section
+    // `What does the other stuff in content mean?`
+    final userProfile = await room.client.ownProfile;
+    var parsedUri = url;
+
+    // a key-value map with the strings to be replaced
+    final replaceMap = {
+      r'$matrix_user_id': userProfile.userId,
+      r'$matrix_room_id': room.id,
+      r'$matrix_display_name': userProfile.displayName ?? '',
+      r'$matrix_avatar_url': userProfile.avatarUrl?.toString() ?? '',
+      // removing potentially dangerous keys containing anything but
+      // `[a-zA-Z0-9_-]` as well as non string values
+      if (data != null)
+        ...Map.from(data!)
+          ..removeWhere((key, value) =>
+              !RegExp(r'^[\w-]+$').hasMatch(key) || !value is String)
+          ..map((key, value) => MapEntry('\$key', value)),
+    };
+
+    replaceMap.forEach((key, value) {
+      parsedUri = parsedUri.replaceAll(key, Uri.encodeComponent(value));
+    });
+
+    return Uri.parse(parsedUri);
+  }
+
+  Map<String, dynamic> toJson() => {
+        'creatorUserId': creatorUserId,
+        'data': data,
+        'id': id,
+        'name': name,
+        'type': type,
+        'url': url,
+        'waitForIframeLoad': waitForIframeLoad,
+      };
+}

test/client_test.dart

@@ -322,6 +322,15 @@ void main() {
       await matrix.setAvatar(testFile);
     });
 
+    test('recentEmoji', () async {
+      final client = await getClient();
+      final emojis = client.recentEmojis;
+      expect(emojis.isEmpty, isTrue);
+
+      await client.addRecentEmoji('🦙');
+      expect(client.recentEmojis['🦙'], 1);
+    });
+
     test('setMuteAllPushNotifications', () async {
       await matrix.setMuteAllPushNotifications(false);
     });

test/fake_matrix_api.dart

@@ -2121,6 +2121,8 @@ class FakeMatrixApi extends MockClient {
       '/client/unstable/room_keys/version': (var reqI) => {'version': '5'},
     },
     'PUT': {
+      '/client/r0/user/${Uri.encodeComponent('@alice:example.com')}/account_data/io.element.recent_emoji}':
+          (var req) => {},
       '/client/r0/user/%40test%3AfakeServer.notExisting/account_data/m.ignored_user_list':
           (var req) => {},
       '/client/r0/presence/${Uri.encodeComponent('@alice:example.com')}/status':