Add simple client switcher buttons for within a bundle next to the input bar

lib/pages/chat.dart

@@ -222,6 +222,10 @@ class ChatController extends State<Chat> {
 
   TextEditingController sendController = TextEditingController();
 
+  void setActiveClient(Client c) => setState(() {
+        Matrix.of(context).setActiveClient(c);
+      });
+
   Future<void> send() async {
     if (sendController.text.trim().isEmpty) return;
     var parseCommands = true;

lib/pages/views/chat_view.dart

@@ -37,9 +37,9 @@ class ChatView extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    controller.matrix = Matrix.of(context);
+    controller.matrix ??= Matrix.of(context);
     final client = controller.matrix.client;
-    controller.room ??= client.getRoomById(controller.roomId);
+    controller.room = client.getRoomById(controller.roomId);
     if (controller.room == null) {
       return Scaffold(
         appBar: AppBar(
@@ -680,6 +680,14 @@ class ChatView extends StatelessWidget {
                                     alignment: Alignment.center,
                                     child: EncryptionButton(controller.room),
                                   ),
+                                  if (controller.matrix.isMultiAccount &&
+                                      controller.matrix.currentBundle.length >
+                                          1)
+                                    Container(
+                                      height: 56,
+                                      alignment: Alignment.center,
+                                      child: _ChatAccountPicker(controller),
+                                    ),
                                   Expanded(
                                     child: Padding(
                                       padding: const EdgeInsets.symmetric(
@@ -792,3 +800,55 @@ class _EditContent extends StatelessWidget {
     );
   }
 }
+
+class _ChatAccountPicker extends StatelessWidget {
+  final ChatController controller;
+
+  const _ChatAccountPicker(this.controller, {Key key}) : super(key: key);
+
+  void _popupMenuButtonSelected(String mxid) {
+    final client = controller.matrix.currentBundle
+        .firstWhere((cl) => cl.userID == mxid, orElse: () => null);
+    if (client == null) {
+      Logs().w('Attempted to switch to a non-existing client $mxid');
+      return;
+    }
+    controller.setActiveClient(client);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    controller.matrix ??= Matrix.of(context);
+    final clients = controller.matrix.currentBundle;
+    clients.removeWhere((c) => c.getRoomById(controller.roomId) == null);
+    return FutureBuilder<Profile>(
+      future: controller.matrix.client.ownProfile,
+      builder: (context, snapshot) => PopupMenuButton<String>(
+        onSelected: _popupMenuButtonSelected,
+        itemBuilder: (BuildContext context) => clients
+            .map((client) => PopupMenuItem<String>(
+                  value: client.userID,
+                  child: FutureBuilder<Profile>(
+                    future: client.ownProfile,
+                    builder: (context, snapshot) => ListTile(
+                      leading: Avatar(
+                        snapshot.data?.avatarUrl,
+                        snapshot.data?.displayName ?? client.userID.localpart,
+                        size: 20,
+                      ),
+                      title: Text(snapshot.data?.displayName ?? client.userID),
+                      contentPadding: EdgeInsets.all(0),
+                    ),
+                  ),
+                ))
+            .toList(),
+        child: Avatar(
+          snapshot.data?.avatarUrl,
+          snapshot.data?.displayName ??
+              controller.matrix.client.userID.localpart,
+          size: 20,
+        ),
+      ),
+    );
+  }
+}

lib/widgets/matrix.dart

@@ -80,6 +80,23 @@ class MatrixState extends State<Matrix> with WidgetsBindingObserver {
     return activeClient;
   }
 
+  void setActiveClient(Client cl) {
+    final i = widget.clients.indexWhere((c) => c == cl);
+    if (i != null) {
+      activeClient = i;
+    } else {
+      Logs().w('Tried to set an unknown client ${cl.userID} as active');
+    }
+  }
+
+  List<Client> get currentBundle {
+    final bundles = accountBundles;
+    if (bundles.containsKey(activeBundle)) {
+      return bundles[activeBundle];
+    }
+    return bundles.values.first;
+  }
+
   Map<String, List<Client>> get accountBundles {
     final resBundles = <String, List<_AccountBundleWithClient>>{};
     for (var i = 0; i < widget.clients.length; i++) {