From 6cd43c4db676999e7591840b0b8ab50d78093df9 Mon Sep 17 00:00:00 2001
From: Amir Panahandeh <amirpanahandeh@yahoo.com>
Date: Sun, 10 Dec 2023 14:57:40 +0330
Subject: [PATCH] Fix text direction auto format detection and undo (#191)

* Fix text direction auto format detection and undo
---
 .../fleather/lib/src/widgets/autoformats.dart |  7 +++-
 .../fleather/lib/src/widgets/controller.dart  | 18 +++++----
 .../test/widgets/autoformats_test.dart        | 39 +++++++++++++++++--
 3 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/packages/fleather/lib/src/widgets/autoformats.dart b/packages/fleather/lib/src/widgets/autoformats.dart
index aa563f6e..99144a2d 100644
--- a/packages/fleather/lib/src/widgets/autoformats.dart
+++ b/packages/fleather/lib/src/widgets/autoformats.dart
@@ -50,6 +50,10 @@ class AutoFormats {
   /// `true` if there is an active suggestion; `false` otherwise
   bool get hasActiveSuggestion => _activeSuggestion != null;
 
+  /// `true` if hasActiveSuggestion and undo delta is not empty;
+  /// `false` otherwise
+  bool get canUndo => hasActiveSuggestion && _activeSuggestion!.undo.isNotEmpty;
+
   /// Perform detection of auto formats and apply changes to [document].
   ///
   /// Inserted data must be of type [String].
@@ -335,7 +339,7 @@ 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 +352,7 @@ 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;
diff --git a/packages/fleather/lib/src/widgets/controller.dart b/packages/fleather/lib/src/widgets/controller.dart
index d3f998d0..a28c15ac 100644
--- a/packages/fleather/lib/src/widgets/controller.dart
+++ b/packages/fleather/lib/src/widgets/controller.dart
@@ -173,15 +173,17 @@ class FleatherController extends ChangeNotifier {
       ParchmentDocument document, int position, int length, Object data) {
     if (!_autoFormats.hasActiveSuggestion) return true;
 
-    final isDeletionOfOneChar = data is String && data.isEmpty && length == 1;
-    if (isDeletionOfOneChar) {
-      // Undo if deleting 1 character after retain of auto-format
-      if (position == _autoFormats.undoPosition) {
-        final undoSelection = _autoFormats.undoActive(document);
-        if (undoSelection != null) {
-          _updateSelectionSilent(undoSelection, source: ChangeSource.local);
+    if (_autoFormats.canUndo) {
+      final isDeletionOfOneChar = data is String && data.isEmpty && length == 1;
+      if (isDeletionOfOneChar) {
+        // Undo if deleting 1 character after retain of auto-format
+        if (position == _autoFormats.undoPosition) {
+          final undoSelection = _autoFormats.undoActive(document);
+          if (undoSelection != null) {
+            _updateSelectionSilent(undoSelection, source: ChangeSource.local);
+          }
+          return false;
         }
-        return false;
       }
     }
     // Cancel active nevertheless
diff --git a/packages/fleather/test/widgets/autoformats_test.dart b/packages/fleather/test/widgets/autoformats_test.dart
index 1e440e30..b0e971ea 100644
--- a/packages/fleather/test/widgets/autoformats_test.dart
+++ b/packages/fleather/test/widgets/autoformats_test.dart
@@ -165,11 +165,11 @@ void main() {
   });
 
   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);
+    });
   });
 }