[State] Add state event class

lib/src/State.dart

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2019 Zender & Kurtz GbR.
+ *
+ * Authors:
+ *   Christian Pauly <krille@famedly.com>
+ *   Marcel Radzio <mtrnord@famedly.com>
+ *
+ * This file is part of famedlysdk.
+ *
+ * famedlysdk is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * famedlysdk is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with famedlysdk.  If not, see <http://www.gnu.org/licenses/>.
+ */
+import 'package:famedlysdk/src/utils/ChatTime.dart';
+
+import './Room.dart';
+import './RawEvent.dart';
+
+class State extends RawEvent {
+  /// Optional. The previous content for this state.
+  /// This will be present only for state events appearing in the timeline.
+  /// If this is not a state event, or there is no previous content, this key will be null.
+  final Map<String, dynamic> prevContent;
+
+  /// Optional. This key will only be present for state events. A unique key which defines
+  /// the overwriting semantics for this piece of room state.
+  final String stateKey;
+
+  State(
+      {this.prevContent,
+      this.stateKey,
+      dynamic content,
+      String typeKey,
+      String eventId,
+      String roomId,
+      String sender,
+      ChatTime time,
+      dynamic unsigned,
+      Room room})
+      : super(
+            content: content,
+            typeKey: typeKey,
+            eventId: eventId,
+            roomId: roomId,
+            sender: sender,
+            time: time,
+            unsigned: unsigned,
+            room: room);
+
+  /// Get a State event from a table row or from the event stream.
+  factory State.fromJson(Map<String, dynamic> jsonPayload, Room room) {
+    final Map<String, dynamic> content =
+        RawEvent.getMapFromPayload(jsonPayload['content']);
+    final Map<String, dynamic> unsigned =
+        RawEvent.getMapFromPayload(jsonPayload['unsigned']);
+    final Map<String, dynamic> prevContent =
+        RawEvent.getMapFromPayload(jsonPayload['prev_content']);
+    return State(
+        stateKey: jsonPayload['state_key'],
+        prevContent: prevContent,
+        content: content,
+        typeKey: jsonPayload['type'],
+        eventId: jsonPayload['event_id'],
+        roomId: jsonPayload['room_id'],
+        sender: jsonPayload['sender'],
+        time: ChatTime(jsonPayload['origin_server_ts']),
+        unsigned: unsigned,
+        room: room);
+  }
+
+  /// The unique key of this event. For events with a [stateKey], it will be the
+  /// stateKey. Otherwise it will be the [type] as a string.
+  String get key => stateKey != null || stateKey.isEmpty ? type : stateKey;
+}