feat: Nicer design for abandonded DM rooms

assets/l10n/intl_en.arb

@@ -2515,5 +2515,6 @@
     "sorryThatsNotPossible": "Sorry... that is not possible",
     "deviceKeys": "Device keys:",
     "letsStart": "Let's start",
-    "enterInviteLinkOrMatrixId": "Enter invite link or Matrix ID..."
+    "enterInviteLinkOrMatrixId": "Enter invite link or Matrix ID...",
+    "reopenChat": "Reopen chat"
 }

lib/pages/chat/chat.dart

@@ -133,6 +133,37 @@ class ChatController extends State<Chat> {
 
   bool showEmojiPicker = false;
 
+  bool get isLeftDMRoom {
+    final room = this.room;
+    final userId = room?.directChatMatrixID;
+    if (room == null || userId == null) return false;
+    return room.isDirectChat &&
+        room.unsafeGetUserFromMemoryOrFallback(userId).membership ==
+            Membership.leave;
+  }
+
+  void recreateChat() async {
+    final room = this.room;
+    final userId = room?.directChatMatrixID;
+    if (room == null || userId == null) {
+      throw Exception(
+          'Try to recreate a room with is not a DM room. This should not be possible from the UI!');
+    }
+    final success = await showFutureLoadingDialog(
+        context: context,
+        future: () async {
+          final client = room.client;
+          final waitForSync = client.onSync.stream
+              .firstWhere((s) => s.rooms?.leave?.containsKey(room.id) ?? false);
+          await room.leave();
+          await waitForSync;
+          return await client.startDirectChat(userId);
+        });
+    final roomId = success.result;
+    if (roomId == null) return;
+    VRouter.of(context).toSegments(['rooms', roomId]);
+  }
+
   EmojiPickerType emojiPickerType = EmojiPickerType.keyboard;
 
   void requestHistory() async {

lib/pages/chat/chat_view.dart

@@ -277,7 +277,38 @@ class ChatView extends StatelessWidget {
                                           Brightness.light
                                       ? Colors.white
                                       : Colors.black,
-                                  child: Column(
+                                  child: controller.isLeftDMRoom
+                                      ? Row(
+                                          mainAxisAlignment:
+                                              MainAxisAlignment.spaceEvenly,
+                                          children: [
+                                            TextButton.icon(
+                                              style: TextButton.styleFrom(
+                                                foregroundColor:
+                                                    Theme.of(context)
+                                                        .colorScheme
+                                                        .error,
+                                              ),
+                                              icon: const Icon(
+                                                Icons.archive_outlined,
+                                              ),
+                                              onPressed: () {},
+                                              label: Text(
+                                                L10n.of(context)!.leave,
+                                              ),
+                                            ),
+                                            TextButton.icon(
+                                              icon: const Icon(
+                                                Icons.chat_outlined,
+                                              ),
+                                              onPressed:
+                                                  controller.recreateChat,
+                                              label: Text(
+                                                  L10n.of(context)!.reopenChat),
+                                            ),
+                                          ],
+                                        )
+                                      : Column(
                                           mainAxisSize: MainAxisSize.min,
                                           children: [
                                             const ConnectionStatusHeader(),