Centralize GIF parsing in a helper like for reactions

lib/helpers/gif_helper.dart

@@ -0,0 +1,33 @@
+class GifHelper {
+  /// Parse a known GIF format, which can be any of:
+  /// g:GIFID
+  /// https://media.giphy.com/media/GIFID/giphy.gif
+  /// https://giphy.com/gifs/Optional-title-with-dashes-GIFID
+  ///
+  /// GIFID is a Giphy GIF ID. The https:// is optional (and
+  /// can also be http://). The giphy.com/gifs form can also
+  /// include a trailing slash.
+  ///
+  /// Returns null if text is not a valid GIF format
+  static String? parseGifId(String text) {
+    final trimmed = text.trim();
+    final match = RegExp(r'^g:([A-Za-z0-9_-]+)$').firstMatch(trimmed);
+    if (match != null) {
+      return match.group(1);
+    }
+    final directUrlMatch = RegExp(
+      r'^(?:https?:\/\/)?media\.giphy\.com\/media\/([A-Za-z0-9_-]+)\/giphy\.gif$',
+    ).firstMatch(trimmed);
+    if (directUrlMatch != null) {
+      return directUrlMatch.group(1);
+    }
+    // Giphy understands page URLs with just the ID, or any string and a
+    // dash before the ID, and redirects to a page with a dash-separated
+    // title, a dash, and the ID. IDs in this form *probably* can't
+    // contain dashes.
+    final pageMatch = RegExp(
+      r'^(?:https?:\/\/)?giphy\.com\/gifs\/(?:[^/?]*-)?([A-Za-z0-9_]+)\/?$',
+    ).firstMatch(trimmed);
+    return pageMatch?.group(1);
+  }
+}

lib/screens/channel_chat_screen.dart

@@ -11,6 +11,7 @@ import '../connector/meshcore_connector.dart';
 import '../utils/platform_info.dart';
 import '../helpers/chat_scroll_controller.dart';
 import '../connector/meshcore_protocol.dart';
+import '../helpers/gif_helper.dart';
 import '../helpers/reaction_helper.dart';
 import '../helpers/utf8_length_limiter.dart';
 import '../l10n/l10n.dart';
@@ -355,7 +356,7 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     final settingsService = context.watch<AppSettingsService>();
     final enableTracing = settingsService.settings.enableMessageTracing;
     final isOutgoing = message.isOutgoing;
-    final gifId = _parseGifId(message.text);
+    final gifId = GifHelper.parseGifId(message.text);
     final poi = _parsePoiMessage(message.text);
     final translatedDisplayText =
         message.translatedText != null &&
@@ -699,7 +700,7 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     final colorScheme = Theme.of(context).colorScheme;
     final previewTextColor = colorScheme.onSurface.withValues(alpha: 0.7);
 
-    final gifId = _parseGifId(replyText);
+    final gifId = GifHelper.parseGifId(replyText);
     final poi = _parsePoiMessage(replyText);
 
     Widget contentPreview;
@@ -811,12 +812,6 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     );
   }
 
-  String? _parseGifId(String text) {
-    final trimmed = text.trim();
-    final match = RegExp(r'^g:([A-Za-z0-9_-]+)$').firstMatch(trimmed);
-    return match?.group(1);
-  }
-
   _PoiInfo? _parsePoiMessage(String text) {
     final trimmed = text.trim();
     final match = RegExp(
@@ -1053,7 +1048,7 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
                 child: ValueListenableBuilder<TextEditingValue>(
                   valueListenable: _textController,
                   builder: (context, value, child) {
-                    final gifId = _parseGifId(value.text);
+                    final gifId = GifHelper.parseGifId(value.text);
                     if (gifId != null) {
                       return Focus(
                         autofocus: true,

lib/screens/chat_screen.dart

@@ -16,6 +16,7 @@ import '../connector/meshcore_protocol.dart';
 import '../helpers/reaction_helper.dart';
 import '../widgets/message_status_icon.dart';
 import '../helpers/chat_scroll_controller.dart';
+import '../helpers/gif_helper.dart';
 import '../helpers/path_helper.dart';
 import '../helpers/utf8_length_limiter.dart';
 import '../models/channel_message.dart';
@@ -523,7 +524,7 @@ class _ChatScreenState extends State<ChatScreen> {
               child: ValueListenableBuilder<TextEditingValue>(
                 valueListenable: _textController,
                 builder: (context, value, child) {
-                  final gifId = _parseGifId(value.text);
+                  final gifId = GifHelper.parseGifId(value.text);
                   if (gifId != null) {
                     return Focus(
                       autofocus: true,
@@ -598,28 +599,6 @@ class _ChatScreenState extends State<ChatScreen> {
     );
   }
 
-  String? _parseGifId(String text) {
-    final trimmed = text.trim();
-    final match = RegExp(r'^g:([A-Za-z0-9_-]+)$').firstMatch(trimmed);
-    if (match != null) {
-      return match.group(1);
-    }
-    final directUrlMatch = RegExp(
-      r'^(?:https?:\/\/)?media\.giphy\.com\/media\/([A-Za-z0-9_-]+)\/giphy\.gif$',
-    ).firstMatch(trimmed);
-    if (directUrlMatch != null) {
-      return directUrlMatch.group(1);
-    }
-    // Giphy understands page URLs with just the ID, or any string and a
-    // dash before the ID, and redirects to a page with a dash-separated
-    // title, a dash, and the ID. IDs in this form *probably* can't
-    // contain dashes.
-    final pageMatch = RegExp(
-      r'^(?:https?:\/\/)?giphy\.com\/gifs\/(?:[^/?]*-)?([A-Za-z0-9_]+)\/?$',
-    ).firstMatch(trimmed);
-    return pageMatch?.group(1);
-  }
-
   void _showGifPicker(BuildContext context) {
     showModalBottomSheet(
       context: context,
@@ -1589,7 +1568,7 @@ class _MessageBubble extends StatelessWidget {
     final enableTracing = settingsService.settings.enableMessageTracing;
     final isOutgoing = message.isOutgoing;
     final colorScheme = Theme.of(context).colorScheme;
-    final gifId = _parseGifId(message.text);
+    final gifId = GifHelper.parseGifId(message.text);
     final poi = _parsePoiMessage(message.text);
     final isFailed = message.status == MessageStatus.failed;
     final bubbleColor = isFailed
@@ -1863,12 +1842,6 @@ class _MessageBubble extends StatelessWidget {
     );
   }
 
-  String? _parseGifId(String text) {
-    final trimmed = text.trim();
-    final match = RegExp(r'^g:([A-Za-z0-9_-]+)$').firstMatch(trimmed);
-    return match?.group(1);
-  }
-
   _PoiInfo? _parsePoiMessage(String text) {
     final trimmed = text.trim();
     final match = RegExp(