Fixing for multiline messages

packages/stream_chat_flutter/lib/src/utils/extensions.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:diacritic/diacritic.dart';
 import 'package:file_picker/file_picker.dart';
 import 'package:flutter/foundation.dart';
@@ -12,6 +13,16 @@ extension StringExtension on String {
   String capitalize() =>
       isNotEmpty ? '${this[0].toUpperCase()}${substring(1).toLowerCase()}' : '';
 
+  /// Returns the biggest line of a text.
+  String biggestLine() {
+    if (contains('\n')) {
+      return split('\n')
+          .reduce((curr, next) => curr.length > next.length ? curr : next);
+    } else {
+      return this;
+    }
+  }
+
   /// Returns whether the string contains only emoji's or not.
   ///
   ///  Emojis guidelines
@@ -353,6 +364,24 @@ extension MessageX on Message {
     return copyWith(text: messageTextToRender);
   }
 
+  /// Returns an approximation of message size
+  double roughMessageSize(double? fontSize) {
+    var messageTextLength = text!.biggestLine().length;
+
+    if (quotedMessage != null) {
+      var quotedMessageLength =
+          (quotedMessage!.text?.biggestLine().length ?? 0) + 40;
+      if (quotedMessage!.attachments.isNotEmpty) {
+        quotedMessageLength += 40;
+      }
+      if (quotedMessageLength > messageTextLength) {
+        messageTextLength = quotedMessageLength;
+      }
+    }
+
+    return messageTextLength * (fontSize ?? 1) * 1.2;
+  }
+
   /// It returns the message with the translated text if available locally
   Message translate(String language) =>
       copyWith(text: i18n?['${language}_text'] ?? text);