keep message drafts on room switches

this is for you courge

lib/helpers/extensions/with_latest_edit.dart

@@ -0,0 +1,20 @@
+import "package:nexus/models/event.dart";
+import "package:nexus/models/room.dart";
+
+extension WithLatestEdit on Room {
+  Event? withLatestEdit(int rowId) {
+    final event = events[rowId];
+    if (event == null) return null;
+
+    final edited = event.lastEditRowId == 0
+        ? null
+        : events[event.lastEditRowId];
+
+    return edited == null
+        ? event
+        : event.copyWith(
+            content: edited.content,
+            localContent: edited.localContent,
+          );
+  }
+}

lib/helpers/hooks/chat_composer.dart

@@ -1,40 +1,50 @@
 import "package:flutter/services.dart";
 import "package:flutter_hooks/flutter_hooks.dart";
+import "package:hooks_riverpod/hooks_riverpod.dart";
 import "package:material_ui/material_ui.dart";
+import "package:nexus/controllers/composer_draft.dart";
+import "package:nexus/models/composer_params.dart";
 import "package:nexus/models/relation_type.dart";
 
 final class ChatComposer({
-  required final ValueNotifier<int?> relatedEvent,
-  required final ValueNotifier<RelationType> relationType,
+  required final int? relatedEvent,
+  required final RelationType relationType,
+  required final ComposerDraftController notifier,
   required final FocusNode node,
 }) {
-  factory use() {
-    final relatedEvent = useState<int?>(null);
-    final relationType = useState(RelationType.reply);
+  factory use(WidgetRef ref, ComposerParams composer) {
+    final provider = ComposerDraftController.provider(composer);
     final node = useFocusNode(
-      onKeyEvent: (_, event) {
+      onKeyEvent: (node, event) {
         if (event is KeyDownEvent && event.logicalKey == .escape) {
-          relatedEvent.value = null;
+          ref.read(provider.notifier).dismiss();
+          // Ending an edit replaces the text field, losing its focus
+          WidgetsBinding.instance.addPostFrameCallback(
+            (_) => node.requestFocus(),
+          );
           return .handled;
         }
 
         return .ignored;
       },
     );
+    final (relatedEvent, relationType) = ref.watch(
+      provider.select((draft) => (draft.relatedEvent, draft.relationType)),
+    );
 
     return .new(
       relatedEvent: relatedEvent,
       relationType: relationType,
+      notifier: ref.watch(provider.notifier),
       node: node,
     );
   }
 
-  int? get repliedEventRowId =>
-      relationType.value == .reply ? relatedEvent.value : null;
+  int? get repliedEventRowId => relationType == .reply ? relatedEvent : null;
 
   void relate(int rowId, RelationType type) {
-    relatedEvent.value = rowId;
-    relationType.value = type;
-    node.requestFocus();
+    notifier.relate(rowId, type);
+    // Starting an edit replaces the text field, losing its focus
+    WidgetsBinding.instance.addPostFrameCallback((_) => node.requestFocus());
   }
 }