feat: enable toggling and canceling of the formatting with shortcuts

lib/src/core/transform/transaction.dart

@@ -195,6 +195,7 @@ extension TextTransaction on Transaction {
     int index,
     String text, {
     Attributes? attributes,
+    Attributes? toggledAttributes,
   }) {
     final delta = node.delta;
     if (delta == null) {
@@ -207,7 +208,11 @@ extension TextTransaction on Transaction {
       'The index($index) is out of range or negative.',
     );
 
-    final newAttributes = attributes ?? delta.sliceAttributes(index);
+    final newAttributes = attributes ?? delta.sliceAttributes(index) ?? {};
+
+    if (toggledAttributes != null) {
+      newAttributes.addAll(toggledAttributes);
+    }
 
     final insert = Delta()
       ..retain(index)
@@ -316,6 +321,7 @@ extension TextTransaction on Transaction {
       return;
     }
     afterSelection = beforeSelection;
+
     final format = Delta()
       ..retain(index)
       ..retain(length, attributes: attributes);

lib/src/editor/block_component/rich_text/appflowy_rich_text_keys.dart

@@ -19,4 +19,13 @@ class AppFlowyRichTextKeys {
     textColor,
     highlightColor,
   ];
+
+  // The values supported toggled even if the selection is collapsed.
+  static List<String> supportToggled = [
+    bold,
+    italic,
+    underline,
+    strikethrough,
+    code,
+  ];
 }

lib/src/editor/command/text_commands.dart

@@ -1,3 +1,5 @@
+import 'dart:math';
+
 import 'package:appflowy_editor/appflowy_editor.dart';
 
 extension TextTransforms on EditorState {
@@ -185,18 +187,37 @@ extension TextTransforms on EditorState {
     if (selection == null) {
       return;
     }
+
     final nodes = getNodesInSelection(selection);
-    final isHighlight = nodes.allSatisfyInSelection(selection, (delta) {
-      return delta.everyAttributes(
-        (attributes) => attributes[key] == true,
+    if (selection.isCollapsed) {
+      // get the attributes from the previous one character.
+      selection = selection.copyWith(
+        start: selection.start.copyWith(
+          offset: max(
+            selection.startIndex - 1,
+            0,
+          ),
+        ),
       );
-    });
-    await formatDelta(
-      selection,
-      {
-        key: !isHighlight,
-      },
-    );
+      final toggled = nodes.allSatisfyInSelection(selection, (delta) {
+        return delta.everyAttributes(
+          (attributes) => attributes[key] == true,
+        );
+      });
+      toggledStyle[key] = !toggled;
+    } else {
+      final isHighlight = nodes.allSatisfyInSelection(selection, (delta) {
+        return delta.everyAttributes(
+          (attributes) => attributes[key] == true,
+        );
+      });
+      await formatDelta(
+        selection,
+        {
+          key: !isHighlight,
+        },
+      );
+    }
   }
 
   /// format the node at the given selection.

lib/src/editor/editor_component/service/ime/delta_input_on_insert_impl.dart

@@ -1,5 +1,6 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/editor/editor_component/service/ime/character_shortcut_event_helper.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 Future<void> onInsert(
@@ -42,11 +43,21 @@ Future<void> onInsert(
   }
   assert(node.delta != null);
 
+  if (kDebugMode) {
+    // verify the toggled keys are supported.
+    assert(
+      editorState.toggledStyle.keys.every(
+        (element) => AppFlowyRichTextKeys.supportToggled.contains(element),
+      ),
+    );
+  }
+
   final transaction = editorState.transaction
     ..insertText(
       node,
       selection.startIndex,
       insertion.textInserted,
+      toggledAttributes: editorState.toggledStyle,
     );
   return editorState.apply(transaction);
 }

lib/src/editor/editor_component/service/shortcuts/command_shortcut_events/markdown_commands.dart

@@ -24,35 +24,50 @@ final CommandShortcutEvent toggleBoldCommand = CommandShortcutEvent(
   key: 'toggle bold',
   command: 'ctrl+b',
   macOSCommand: 'cmd+b',
-  handler: (editorState) => _toggleAttribute(editorState, 'bold'),
+  handler: (editorState) => _toggleAttribute(
+    editorState,
+    AppFlowyRichTextKeys.bold,
+  ),
 );
 
 final CommandShortcutEvent toggleItalicCommand = CommandShortcutEvent(
   key: 'toggle italic',
   command: 'ctrl+i',
   macOSCommand: 'cmd+i',
-  handler: (editorState) => _toggleAttribute(editorState, 'italic'),
+  handler: (editorState) => _toggleAttribute(
+    editorState,
+    AppFlowyRichTextKeys.italic,
+  ),
 );
 
 final CommandShortcutEvent toggleUnderlineCommand = CommandShortcutEvent(
   key: 'toggle underline',
   command: 'ctrl+u',
   macOSCommand: 'cmd+u',
-  handler: (editorState) => _toggleAttribute(editorState, 'underline'),
+  handler: (editorState) => _toggleAttribute(
+    editorState,
+    AppFlowyRichTextKeys.underline,
+  ),
 );
 
 final CommandShortcutEvent toggleStrikethroughCommand = CommandShortcutEvent(
   key: 'toggle strikethrough',
   command: 'ctrl+shift+s',
   macOSCommand: 'cmd+shift+s',
-  handler: (editorState) => _toggleAttribute(editorState, 'strikethrough'),
+  handler: (editorState) => _toggleAttribute(
+    editorState,
+    AppFlowyRichTextKeys.strikethrough,
+  ),
 );
 
 final CommandShortcutEvent toggleCodeCommand = CommandShortcutEvent(
   key: 'toggle code',
   command: 'ctrl+e',
   macOSCommand: 'cmd+e',
-  handler: (editorState) => _toggleAttribute(editorState, 'code'),
+  handler: (editorState) => _toggleAttribute(
+    editorState,
+    AppFlowyRichTextKeys.code,
+  ),
 );
 
 KeyEventResult _toggleAttribute(

lib/src/editor_state.dart

@@ -100,6 +100,9 @@ class EditorState {
 
   /// Sets the selection of the editor.
   set selection(Selection? value) {
+    // clear the toggled style when the selection is changed.
+    toggledStyle.clear();
+
     selectionNotifier.value = value;
   }
 
@@ -145,6 +148,13 @@ class EditorState {
     sync: true,
   );
 
+  /// Store the toggled format style, like bold, italic, etc.
+  /// All the values must be the key from [AppFlowyRichTextKeys.supportToggled].
+  ///
+  /// NOTES: It only works once;
+  ///   after the selection is changed, the toggled style will be cleared.
+  final toggledStyle = <String, bool>{};
+
   final UndoManager undoManager = UndoManager();
 
   Transaction get transaction {

test/new/command/text_commands_test.dart

@@ -1,6 +1,10 @@
+import 'dart:io';
+
 import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../infra/testable_editor.dart';
 import '../util/util.dart';
 
 void main() async {
@@ -313,4 +317,65 @@ void main() async {
       expect(texts, ['come', 'To', 'App']);
     });
   });
+
+  group('toggle style', () {
+    testWidgets('toggle the style if the previous character isn\'t formatted',
+        (tester) async {
+      const text = '';
+      final editor = tester.editor..addParagraph(initialText: text);
+
+      await editor.startTesting();
+      await editor.updateSelection(
+        Selection.single(path: [0], startOffset: text.length),
+      );
+
+      // toggle bold, italic, underline
+      final keys = [
+        LogicalKeyboardKey.keyB,
+        LogicalKeyboardKey.keyI,
+        LogicalKeyboardKey.keyU,
+      ];
+      for (final key in keys) {
+        await editor.pressKey(
+          key: key,
+          isControlPressed: !Platform.isMacOS,
+          isMetaPressed: Platform.isMacOS,
+        );
+      }
+
+      await editor.ime.insertText('Hello');
+      final delta1 = editor.nodeAtPath([0])!.delta!;
+      expect(delta1.toJson(), [
+        {
+          "insert": "Hello",
+          "attributes": {"bold": true, "italic": true, "underline": true}
+        }
+      ]);
+
+      // cancel the toggled style
+      for (final key in keys) {
+        await editor.pressKey(
+          key: key,
+          isControlPressed: !Platform.isMacOS,
+          isMetaPressed: Platform.isMacOS,
+        );
+      }
+
+      await editor.ime.insertText('World');
+      final delta2 = editor.nodeAtPath([0])!.delta!;
+      expect(delta2.toJson(), [
+        {
+          "insert": "Hello",
+          "attributes": {"bold": true, "italic": true, "underline": true}
+        },
+        {
+          "insert": "World",
+          "attributes": {"bold": false, "italic": false, "underline": false}
+        },
+      ]);
+
+      expect(editor.editorState.toggledStyle, isEmpty);
+      await editor.dispose();
+    });
+  });
 }