Feat: support for customize copy and cut Embeddables to Clipboard (#2067)

* Feat: custom behavior while copying or cutting a embeddable

* dart fixes

* fix: removed unnecessary optional return for CopyCutAction

* fix: invalid null_aware_operator

* added doc comments

---------

Co-authored-by: CatHood0 <santiagowmar@gmail.com>

lib/flutter_quill.dart

@@ -28,6 +28,9 @@ export 'src/editor/style_widgets/style_widgets.dart';
 export 'src/editor/widgets/cursor.dart';
 export 'src/editor/widgets/default_styles.dart';
 export 'src/editor/widgets/link.dart';
+export 'src/editor_toolbar_controller_shared/copy_cut_service/copy_cut_service.dart';
+export 'src/editor_toolbar_controller_shared/copy_cut_service/copy_cut_service_provider.dart';
+export 'src/editor_toolbar_controller_shared/copy_cut_service/default_copy_cut_service.dart';
 export 'src/editor_toolbar_controller_shared/quill_configurations.dart';
 export 'src/editor_toolbar_shared/quill_configurations_ext.dart';
 export 'src/toolbar/base_toolbar.dart';

lib/src/document/nodes/line.dart

@@ -5,6 +5,7 @@ import 'package:collection/collection.dart';
 import '../../../../quill_delta.dart';
 import '../../common/structs/offset_value.dart';
 import '../../editor/embed/embed_editor_builder.dart';
+import '../../editor_toolbar_controller_shared/copy_cut_service/copy_cut_service_provider.dart';
 import '../attribute.dart';
 import '../style.dart';
 import 'block.dart';
@@ -520,7 +521,21 @@ base class Line extends QuillContainer<Leaf?> {
   int _getNodeText(Leaf node, StringBuffer buffer, int offset, int remaining) {
     final text = node.toPlainText();
     if (text == Embed.kObjectReplacementCharacter) {
-      buffer.write(Embed.kObjectReplacementCharacter);
+      final embed = node.value as Embeddable;
+      final provider = CopyCutServiceProvider.instance;
+      // By default getCopyCutAction just return the same operation
+      // returning Embed.kObjectReplacementCharacter for the buffer
+      final action = provider.getCopyCutAction(embed.type);
+      final data = action.call(embed.data);
+      // This conditional avoid an issue where the plain data copied
+      // to the clipboard, when it is pasted on the editor
+      // the content has a unexpected behaviors
+      if (data != Embed.kObjectReplacementCharacter) {
+        buffer.write(data);
+        return remaining;
+      } else {
+        buffer.write(action.call(data));
+      }
       return remaining - node.length;
     }
 

lib/src/editor_toolbar_controller_shared/copy_cut_service/copy_cut_service.dart

@@ -0,0 +1,13 @@
+import 'package:flutter/foundation.dart';
+
+typedef CopyCutAction = Object? Function(dynamic data);
+
+/// An abstraction to make it easy to provide different implementations
+/// For copy or cut actions from a Line (just for embeddable blocks)
+@immutable
+abstract class CopyCutService {
+  /// Get the CopyCutAction by the type
+  /// of the embeddable (this type is decided by
+  /// the property type of that class)
+  CopyCutAction getCopyCutAction(String type);
+}

lib/src/editor_toolbar_controller_shared/copy_cut_service/copy_cut_service_provider.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/foundation.dart' show immutable;
+import 'copy_cut_service.dart';
+import 'default_copy_cut_service.dart';
+
+@immutable
+class CopyCutServiceProvider {
+  const CopyCutServiceProvider._();
+  static CopyCutService _instance = DefaultCopyCutService();
+
+  static CopyCutService get instance => _instance;
+
+  static void setInstance(CopyCutService service) {
+    _instance = service;
+  }
+
+  static void setInstanceToDefault() {
+    _instance = DefaultCopyCutService();
+  }
+}

lib/src/editor_toolbar_controller_shared/copy_cut_service/default_copy_cut_service.dart

@@ -0,0 +1,14 @@
+import '../../document/nodes/leaf.dart';
+import 'copy_cut_service.dart';
+
+/// Default implementation for [CopyCutService]
+///
+/// This implementation always return the default embed character
+/// replacemenet ([\uFFFC]) to work with the embeds from the internal
+/// flutter quill plugins
+class DefaultCopyCutService extends CopyCutService {
+  @override
+  CopyCutAction getCopyCutAction(String type) {
+    return (data) => Embed.kObjectReplacementCharacter;
+  }
+}