Fix text direction auto format detection and undo

packages/fleather/lib/src/widgets/autoformats.dart

@@ -47,8 +47,9 @@ class AutoFormats {
   /// The position at which the active suggestion can be deactivated
   int get undoPosition => _activeSuggestion!.undoPositionCandidate;
 
-  /// `true` if there is an active suggestion; `false` otherwise
-  bool get hasActiveSuggestion => _activeSuggestion != null;
+  /// `true` if there is an active suggestion and undo delta is not empty;
+  /// `false` otherwise
+  bool get canUndo => _activeSuggestion?.undo.isNotEmpty == true;
 
   /// Perform detection of auto formats and apply changes to [document].
   ///
@@ -335,7 +336,7 @@ class _AutoTextDirection extends AutoFormat {
 
   bool _isBeforeEmptyLine(Operation next, String data) {
     final nextData = next.data;
-    return nextData is String ? nextData.startsWith('$data\n') : false;
+    return nextData is String ? nextData.startsWith('\n') : false;
   }
 
   bool _isInEmptyLine(Operation? previous, Operation next, String data) =>
@@ -348,6 +349,7 @@ class _AutoTextDirection extends AutoFormat {
     final documentDelta = document.toDelta();
     final iter = DeltaIterator(document.toDelta());
     final previous = iter.skip(position);
+    iter.skip(data.length);
     final next = iter.next();
 
     if (!_isInEmptyLine(previous, next, data)) return null;

packages/fleather/lib/src/widgets/controller.dart

@@ -171,7 +171,7 @@ class FleatherController extends ChangeNotifier {
   // document; `false` otherwise
   bool _captureAutoFormatCancellationOrUndo(
       ParchmentDocument document, int position, int length, Object data) {
-    if (!_autoFormats.hasActiveSuggestion) return true;
+    if (!_autoFormats.canUndo) return true;
 
     final isDeletionOfOneChar = data is String && data.isEmpty && length == 1;
     if (isDeletionOfOneChar) {

packages/fleather/test/widgets/autoformats_test.dart

@@ -45,7 +45,7 @@ void main() {
       ]);
       final performed = autoformats.run(document, 54, 'p');
       expect(performed, false);
-      expect(autoformats.hasActiveSuggestion, isFalse);
+      expect(autoformats.canUndo, isFalse);
     });
 
     test('Deleting at candidate position, undoes link formatting', () {
@@ -67,7 +67,7 @@ void main() {
       ]);
       autoformats.run(document, 54, ' ');
       autoformats.cancelActive();
-      expect(autoformats.hasActiveSuggestion, isFalse);
+      expect(autoformats.canUndo, isFalse);
     });
   });
 
@@ -138,7 +138,7 @@ void main() {
       ]);
       final performed = autoformats.run(document, 16, 'p');
       expect(performed, false);
-      expect(autoformats.hasActiveSuggestion, isFalse);
+      expect(autoformats.canUndo, isFalse);
     });
 
     test('Deleting at candidate position, undoes link formatting', () {
@@ -160,16 +160,16 @@ void main() {
       ]);
       autoformats.run(document, 54, ' ');
       autoformats.cancelActive();
-      expect(autoformats.hasActiveSuggestion, isFalse);
+      expect(autoformats.canUndo, isFalse);
     });
   });
 
   group('RTL detection', () {
-    test('Detection of RTL', () {
+    test('Detects RTL text when applied with no line style', () {
       final document = ParchmentDocument.fromJson([
-        {'insert': 'some ltr text\nש\n'}
+        {'insert': 'some ltr text\nب\n'},
       ]);
-      final performed = autoformats.run(document, 14, 'ש');
+      final performed = autoformats.run(document, 14, 'ب');
       expect(performed, true);
       expect(autoformats.selection, isNull);
       final attributes = document.toDelta().toList()[1].attributes;
@@ -178,5 +178,38 @@ void main() {
       expect(attributes[ParchmentAttribute.direction.key],
           ParchmentAttribute.direction.rtl.value);
     });
+
+    test('Detects RTL text when applied on an already styled line', () {
+      final document = ParchmentDocument.fromJson([
+        {'insert': 'some ltr text\nب'},
+        {
+          'insert': '\n',
+          'attributes': {'checked': true}
+        }
+      ]);
+      final performed = autoformats.run(document, 14, 'ب');
+      expect(performed, true);
+      expect(autoformats.selection, isNull);
+      final attributes = document.toDelta().toList()[1].attributes;
+      expect(attributes, isNotNull);
+      expect(attributes!.containsKey(ParchmentAttribute.direction.key), isTrue);
+      expect(attributes[ParchmentAttribute.direction.key],
+          ParchmentAttribute.direction.rtl.value);
+      expect(autoformats.canUndo, isTrue);
+    });
+
+    test('canUndo is false when line was already correctly styled', () {
+      final document = ParchmentDocument.fromJson([
+        {'insert': 'some ltr text\nب'},
+        {
+          'insert': '\n',
+          'attributes': {'direction': 'rtl', 'alignment': 'right'}
+        }
+      ]);
+      final performed = autoformats.run(document, 14, 'ب');
+      expect(performed, true);
+      expect(autoformats.selection, isNull);
+      expect(autoformats.canUndo, isFalse);
+    });
   });
 }