add support for creating rooms

Fixes #81

lib/helpers/extensions/create_room.dart

@@ -0,0 +1,111 @@
+import "dart:async";
+
+import "package:collection/collection.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:material_ui/material_ui.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/rooms.dart";
+import "package:nexus/controllers/sidebar_page.dart";
+import "package:nexus/controllers/spaces.dart";
+import "package:nexus/helpers/extensions/focus_room.dart";
+import "package:nexus/helpers/extensions/get_all_child_rooms.dart";
+import "package:nexus/helpers/extensions/with_progress_snackbar.dart";
+import "package:nexus/models/requests/create_room.dart";
+
+extension CreateRoom on BuildContext {
+  /// Creates a room, showing progress and errors in snackbars, and opens it
+  /// once it has synced. [request] may be a future, so any lookups needed to
+  /// build it happen while the progress snackbar is shown.
+  ///
+  /// Returns the created room's ID, or null if creating it failed.
+  Future<String?> createRoom(
+    CreateRoomRequest request, {
+    required String name,
+  }) async {
+    final container = ProviderScope.containerOf(this);
+    final messenger = ScaffoldMessenger.of(this);
+
+    final result = await withProgressSnackbar("Creating $name...", () async {
+      final roomId = await container
+          .read(ClientController.provider.notifier)
+          .createRoom(request);
+
+      // Wait for the room to show up in the room list (under DMs, if it's
+      // one) before opening it.
+      final synced = Completer<bool>();
+      final subscription = container.listen(
+        SpacesController.provider.select(
+          (async) =>
+              async.value?.any(
+                (space) =>
+                    space.id == roomId ||
+                    ((!request.isDirect || space.id == "dms") &&
+                        space.allChildRooms.any(
+                          (room) => room.metadata?.id == roomId,
+                        )),
+              ) ??
+              false,
+        ),
+        (_, found) {
+          if (found && !synced.isCompleted) synced.complete(true);
+        },
+        fireImmediately: true,
+      );
+
+      return (
+        roomId,
+        await synced.future
+            .timeout(const .new(seconds: 15), onTimeout: () => false)
+            .whenComplete(subscription.close),
+      );
+    });
+    if (result == null) return null;
+
+    final (roomId, synced) = result;
+    if (synced && await container.focusRoom(roomId)) {
+      container.read(SidebarPageController.provider.notifier).set(.rooms);
+    } else {
+      messenger.showSnackBar(
+        .new(
+          content: Text("Created $name, but it hasn't finished syncing yet."),
+        ),
+      );
+    }
+
+    return roomId;
+  }
+
+  /// Opens the existing DM with [userId], or creates one if there isn't one.
+  Future<void> startDirectMessage(
+    String userId, {
+    required String name,
+    bool encrypted = true,
+    String? inviteReason,
+  }) async {
+    final container = ProviderScope.containerOf(this);
+    final existing = container
+        .read(RoomsController.provider)
+        .values
+        .firstWhereOrNull((room) => room.metadata?.dmUserId == userId)
+        ?.metadata
+        ?.id;
+
+    if (existing != null) {
+      if (await container.focusRoom(existing)) {
+        container.read(SidebarPageController.provider.notifier).set(.rooms);
+      }
+      return;
+    }
+
+    await createRoom(
+      .new(
+        isDirect: true,
+        preset: .trustedPrivateChat,
+        invite: .new([userId]),
+        inviteReason: inviteReason,
+        initialState: encrypted ? .new([.encryption]) : const .empty(),
+      ),
+      name: "a DM with $name",
+    );
+  }
+}

lib/helpers/extensions/get_localpart.dart

@@ -1,3 +1,8 @@
 extension GetLocalpart on String {
   String get localpart => length > 1 ? substring(1).split(":").first : "?";
+
+  String? get serverName {
+    final index = indexOf(":");
+    return index == -1 ? null : substring(index + 1);
+  }
 }

lib/helpers/extensions/join_room.dart

@@ -3,6 +3,7 @@ import "package:material_ui/material_ui.dart";
 import "package:nexus/controllers/client.dart";
 import "package:nexus/controllers/sidebar_page.dart";
 import "package:nexus/helpers/extensions/focus_room.dart";
+import "package:nexus/helpers/extensions/with_progress_snackbar.dart";
 import "package:nexus/models/requests/join_room.dart";
 
 extension JoinRoom on BuildContext {
@@ -16,56 +17,27 @@ extension JoinRoom on BuildContext {
   }) async {
     final container = ProviderScope.containerOf(this);
     final messenger = ScaffoldMessenger.of(this);
-    final colorScheme = Theme.of(this).colorScheme;
 
-    final joining = messenger.showSnackBar(
-      .new(content: Text("Joining $name..."), duration: const .new(days: 1)),
+    final roomId = await withProgressSnackbar(
+      "Joining $name...",
+      () =>
+          container.read(ClientController.provider.notifier).joinRoom(request),
+    );
+    if (roomId == null) return null;
+
+    messenger.showSnackBar(
+      .new(
+        content: Text("Joined $name."),
+        action: .new(
+          label: "Open",
+          onPressed: () async {
+            await container.focusRoom(roomId);
+            container.read(SidebarPageController.provider.notifier).set(.rooms);
+          },
+        ),
+      ),
     );
 
-    try {
-      final roomId = await container
-          .read(ClientController.provider.notifier)
-          .joinRoom(request);
-
-      joining.close();
-      messenger.showSnackBar(
-        .new(
-          content: Text("Joined $name."),
-          action: .new(
-            label: "Open",
-            onPressed: () async {
-              if (await container.focusRoom(roomId)) {
-                container
-                    .read(SidebarPageController.provider.notifier)
-                    .set(.rooms);
-              } else {
-                messenger.showSnackBar(
-                  .new(
-                    content: Text(
-                      "$name hasn't finished syncing yet, try again in a moment.",
-                    ),
-                  ),
-                );
-              }
-            },
-          ),
-        ),
-      );
-
-      return roomId;
-    } catch (error) {
-      joining.close();
-      messenger.showSnackBar(
-        .new(
-          backgroundColor: colorScheme.errorContainer,
-          content: Text(
-            error.toString(),
-            style: .new(color: colorScheme.onErrorContainer),
-          ),
-        ),
-      );
-
-      return null;
-    }
+    return roomId;
   }
 }

lib/helpers/extensions/show_adaptive_sheet.dart

@@ -4,8 +4,8 @@ import "package:nexus/helpers/extensions/is_desktop.dart";
 extension ShowAdaptiveSheet on BuildContext {
   /// Shows the widget from [builder] in a dialog on desktop, or a bottom sheet
   /// on mobile. Use the context passed to [builder] to close it.
-  Future<void> showAdaptiveSheet(WidgetBuilder builder) => isDesktop
-      ? showDialog(
+  Future<T?> showAdaptiveSheet<T>(WidgetBuilder builder) => isDesktop
+      ? showDialog<T>(
           context: this,
           builder: (context) => Dialog(
             clipBehavior: .antiAlias,
@@ -15,7 +15,7 @@ extension ShowAdaptiveSheet on BuildContext {
             ),
           ),
         )
-      : showModalBottomSheet(
+      : showModalBottomSheet<T>(
           context: this,
           isScrollControlled: true,
           constraints: .new(maxHeight: MediaQuery.sizeOf(this).height - 80),

lib/helpers/extensions/with_progress_snackbar.dart

@@ -0,0 +1,37 @@
+import "package:material_ui/material_ui.dart";
+
+extension WithProgressSnackbar on BuildContext {
+  /// Shows [progress] in a snackbar while [action] runs, and shows any error
+  /// it throws in an error snackbar.
+  ///
+  /// Returns the result of [action], or null if it failed.
+  Future<T?> withProgressSnackbar<T>(
+    String progress,
+    Future<T> Function() action,
+  ) async {
+    final messenger = ScaffoldMessenger.of(this);
+    final colorScheme = Theme.of(this).colorScheme;
+
+    final snackbar = messenger.showSnackBar(
+      .new(content: Text(progress), duration: const .new(days: 1)),
+    );
+
+    try {
+      return await action();
+    } catch (error) {
+      messenger.showSnackBar(
+        .new(
+          backgroundColor: colorScheme.errorContainer,
+          content: Text(
+            error.toString(),
+            style: .new(color: colorScheme.onErrorContainer),
+          ),
+        ),
+      );
+
+      return null;
+    } finally {
+      snackbar.close();
+    }
+  }
+}