emoji: Make emoji picker return the selected emoji, for reuse

Instead of using the selected emoji deep down the widget tree, simply
return it where the emoji picker sheet is opened, to use it for
different purposes.

Author: sm-sayedi

lib/widgets/action_sheet.dart

@@ -738,14 +738,22 @@ class ReactionButtons extends StatelessWidget {
         : zulipLocalizations.errorReactionAddingFailedTitle);
   }
 
-  void _handleTapMore() {
+  void _handleTapMore() async {
     // TODO(design): have emoji picker slide in from right and push
     //   action sheet off to the left
 
     // Dismiss current action sheet before opening emoji picker sheet.
     Navigator.of(pageContext).pop();
 
-    showEmojiPickerSheet(pageContext: pageContext, message: message);
+    final emoji = await showEmojiPickerSheet(pageContext: pageContext);
+    if (emoji == null || !pageContext.mounted) return;
+    unawaited(doAddOrRemoveReaction(
+      context: pageContext,
+      doRemoveReaction: false,
+      messageId: message.id,
+      emoji: emoji,
+      errorDialogTitle:
+        ZulipLocalizations.of(pageContext).errorReactionAddingFailedTitle));
   }
 
   Widget _buildButton({

lib/widgets/emoji_reaction.dart

@@ -398,12 +398,11 @@ Future<void> doAddOrRemoveReaction({
 }
 
 /// Opens a browsable and searchable emoji picker bottom sheet.
-void showEmojiPickerSheet({
+Future<EmojiCandidate?> showEmojiPickerSheet({
   required BuildContext pageContext,
-  required Message message,
-}) {
+}) async {
   final store = PerAccountStoreWidget.of(pageContext);
-  showModalBottomSheet<void>(
+  return showModalBottomSheet<EmojiCandidate>(
     context: pageContext,
     // Clip.hardEdge looks bad; Clip.antiAliasWithSaveLayer looks pixel-perfect
     // on my iPhone 13 Pro but is marked as "much slower":
@@ -423,20 +422,15 @@ void showEmojiPickerSheet({
         // For _EmojiPickerItem, and RealmContentNetworkImage used in ImageEmojiWidget.
         child: PerAccountStoreWidget(
           accountId: store.accountId,
-          child: EmojiPicker(pageContext: pageContext, message: message)));
+          child: EmojiPicker(pageContext: pageContext)));
     });
 }
 
 @visibleForTesting
 class EmojiPicker extends StatefulWidget {
-  const EmojiPicker({
-    super.key,
-    required this.pageContext,
-    required this.message,
-  });
+  const EmojiPicker({super.key, required this.pageContext});
 
   final BuildContext pageContext;
-  final Message message;
 
   @override
   State<EmojiPicker> createState() => _EmojiPickerState();
@@ -534,8 +528,7 @@ class _EmojiPickerState extends State<EmojiPicker> with PerAccountStoreAwareStat
                   itemCount: _resultsToDisplay.length,
                   itemBuilder: (context, i) => EmojiPickerListEntry(
                     pageContext: widget.pageContext,
-                    emoji: _resultsToDisplay[i].candidate,
-                    message: widget.message)))),
+                    emoji: _resultsToDisplay[i].candidate)))),
           ]))),
     ]);
   }
@@ -547,27 +540,15 @@ class EmojiPickerListEntry extends StatelessWidget {
     super.key,
     required this.pageContext,
     required this.emoji,
-    required this.message,
   });
 
   final BuildContext pageContext;
   final EmojiCandidate emoji;
-  final Message message;
 
   static const _emojiSize = 24.0;
 
   void _onPressed() {
-    // Dismiss the enclosing action sheet immediately,
-    // for swift UI feedback that the user's selection was received.
-    Navigator.pop(pageContext);
-
-    doAddOrRemoveReaction(
-      context: pageContext,
-      doRemoveReaction: false,
-      messageId: message.id,
-      emoji: emoji,
-      errorDialogTitle:
-        ZulipLocalizations.of(pageContext).errorReactionAddingFailedTitle);
+    Navigator.pop(pageContext, emoji);
   }
 
   @override