add swipe to reply

Fixes #90

lib/controllers/settings_sections.dart

@@ -117,6 +117,21 @@ class SettingsSectionsController
                     .onError(showError),
               ),
             ),
+            .new(
+              title: "Swipe To Reply",
+              description: "Swipe a message to the right to reply to it.",
+              icon: Icons.swipe_right,
+              builder: (title, description, icon) => SwitchListTile(
+                title: Text(title),
+                subtitle: Text(description),
+                secondary: Icon(icon),
+                value: settings.swipeToReply,
+                onChanged: (value) => ref
+                    .read(SettingsController.provider.notifier)
+                    .set(settings.copyWith(swipeToReply: value))
+                    .onError(showError),
+              ),
+            ),
             if (!Platform.isAndroid && !Platform.isIOS)
               .new(
                 title: "Show Minimize Button",

lib/models/settings.dart

@@ -13,6 +13,7 @@ class const Settings({
   final bool linuxMobileMode = false,
   final bool showAllInHome = false,
   final bool showMinimizeButton = false,
+  final bool swipeToReply = false,
   final RoomOrder roomOrder = .unreadFirst,
 }) with _$Settings {
   Map<String, Object?> toJson() => _$SettingsToJson(this);

lib/widgets/renderers/event.dart

@@ -29,6 +29,7 @@ import "package:nexus/widgets/renderers/message.dart";
 import "package:nexus/widgets/reaction_row.dart";
 import "package:nexus/widgets/renderers/membership.dart";
 import "package:nexus/widgets/renderers/generic_event.dart";
+import "package:nexus/widgets/swipe_to_reply.dart";
 import "package:nexus/widgets/timestamp.dart";
 
 class const EventRenderer(
@@ -39,6 +40,9 @@ class const EventRenderer(
   final int? maxLines,
   final JumpToEvent? jumpToEvent,
   final IList<PopupMenuEntry> Function(Event event)? getEventOptions,
+
+  /// If set, events can be swiped, calling this
+  final VoidCallback? onSwipe,
   super.key,
 }) extends HookConsumerWidget {
   @override
@@ -239,18 +243,21 @@ class const EventRenderer(
                   child: GestureDetector(
                     onSecondaryTapUp: contextMenuCallback,
                     onLongPressStart: contextMenuCallback,
-                    child: Padding(
+                    child: SwipeToReply(
-                      padding: EdgeInsets.symmetric(horizontal: 8)
+                      onSwipe: onSwipe,
-                          .copyWith(top: isGrouped ? 0 : 8),
+                      Padding(
-                      child: Wrap(
+                        padding: EdgeInsets.symmetric(horizontal: 8)
-                        verticalDirection: .up,
+                            .copyWith(top: isGrouped ? 0 : 8),
-                        spacing: 6,
+                        child: Wrap(
-                        crossAxisAlignment: .center,
+                          verticalDirection: .up,
-                        children: [
+                          spacing: 6,
-                          child,
+                          crossAxisAlignment: .center,
-                          if (child is! MessageRenderer)
+                          children: [
-                            Timestamp(event.timestamp),
+                            child,
-                        ],
+                            if (child is! MessageRenderer)
+                              Timestamp(event.timestamp),
+                          ],
+                        ),
                       ),
                     ),
                   ),

lib/widgets/room_chat/chat_timeline.dart

@@ -13,6 +13,7 @@ class const ChatTimeline({
   required final IList<PopupMenuEntry> Function(Event) getEventOptions,
   required final int? highlightedEvent,
   required final double composerHeight,
+  final void Function(int rowId)? onSwipe,
   super.key,
 }) extends StatelessWidget {
   Widget eventRow(
@@ -26,6 +27,7 @@ class const ChatTimeline({
       roomId: roomId,
       jumpToEvent: jumpToEvent,
       getEventOptions: getEventOptions,
+      onSwipe: onSwipe == null ? null : () => onSwipe!(eventRowId),
     ),
     key: key,
     isHighlighted: highlightedEvent == eventRowId,

lib/widgets/room_chat/room_chat.dart

@@ -7,6 +7,8 @@ import "package:measure_size/measure_size.dart";
 import "package:nexus/controllers/client.dart";
 import "package:nexus/controllers/client_state.dart";
 import "package:nexus/controllers/member_list_opened.dart";
+import "package:nexus/controllers/power_level.dart";
+import "package:nexus/controllers/settings.dart";
 import "package:nexus/controllers/rooms.dart";
 import "package:nexus/controllers/room_chat.dart";
 import "package:nexus/helpers/hooks/chat_scroll.dart";
@@ -171,19 +173,30 @@ final class const RoomChat({
       return null;
     }, [jumpRowId]);
 
+    void onRelation(int rowId, RelationType type) {
+      relatedEvent.value = rowId;
+      relationType.value = type;
+      composerNode.requestFocus();
+    }
+
     IList<PopupMenuEntry> getEventOptions(Event event) =>
         event.buildEventOptions(
           context: context,
           ref: ref,
           roomId: roomId,
           userId: userId,
-          onRelation: (rowId, type) {
+          onRelation: onRelation,
-            relatedEvent.value = rowId;
-            relationType.value = type;
-            composerNode.requestFocus();
-          },
         );
 
+    final swipeToReply = ref.watch(
+      SettingsController.provider.select(
+        (settings) => settings.value?.swipeToReply ?? false,
+      ),
+    );
+    final canReply = ref.watch(
+      PowerLevelController.provider(.new(eventType: .message, roomId: roomId)),
+    );
+
     return Scaffold(
       endDrawer: PinnedEventsDrawer(
         roomId,
@@ -224,6 +237,9 @@ final class const RoomChat({
                                   roomId: roomId,
                                   jumpToEvent: jumpToEvent,
                                   getEventOptions: getEventOptions,
+                                  onSwipe: swipeToReply && canReply
+                                      ? (rowId) => onRelation(rowId, .reply)
+                                      : null,
                                   highlightedEvent: highlightedEvent.value,
                                   composerHeight: composerSize.value,
                                 ),

lib/widgets/swipe_to_reply.dart

@@ -0,0 +1,58 @@
+import "package:flutter/services.dart";
+import "package:flutter_hooks/flutter_hooks.dart";
+import "package:material_ui/material_ui.dart";
+
+class const SwipeToReply(
+  final Widget child, {
+  required final VoidCallback? onSwipe,
+  super.key,
+}) extends HookWidget {
+  static const maxDrag = 64.0;
+  static const threshold = 0.75;
+
+  @override
+  Widget build(BuildContext context) {
+    final controller = useAnimationController(duration: Durations.short4);
+    useListenable(controller);
+
+    if (onSwipe == null) return child;
+
+    final progress = controller.value;
+
+    return GestureDetector(
+      onHorizontalDragUpdate: (details) {
+        final previous = controller.value;
+        controller.value = previous + details.primaryDelta! / maxDrag;
+
+        if (previous < threshold && controller.value >= threshold) {
+          HapticFeedback.lightImpact();
+        }
+      },
+      onHorizontalDragEnd: (_) {
+        if (controller.value >= threshold) onSwipe!();
+        controller.animateBack(0, curve: Curves.easeOut);
+      },
+      onHorizontalDragCancel: () =>
+          controller.animateBack(0, curve: Curves.easeOut),
+      child: Stack(
+        alignment: .centerLeft,
+        children: [
+          Positioned(
+            left: 16,
+            child: Opacity(
+              opacity: (progress / threshold).clamp(0, 1),
+              child: Transform.scale(
+                scale: progress >= threshold ? 1 : 0.75,
+                child: const Icon(Icons.reply),
+              ),
+            ),
+          ),
+          Transform.translate(
+            offset: .new(progress * maxDrag, 0),
+            child: child,
+          ),
+        ],
+      ),
+    );
+  }
+}