fix: indent padding from left when rtl

Also introduced last direction concept.

lib/src/editor/block_component/base_component/text_direction_mixin.dart

@@ -11,50 +11,103 @@ final _regex = RegExp(
 mixin BlockComponentTextDirectionMixin {
   Node get node;
 
+  TextDirection? lastDirection;
+
   /// Calculate the text direction of a block component.
+  // defaultTextDirection will be ltr if caller hasn't passed any value.
   TextDirection calculateTextDirection({
     TextDirection? defaultTextDirection,
   }) {
     defaultTextDirection = defaultTextDirection ?? TextDirection.ltr;
-    // if the block component has a text direction attribute, use it
-    final value = node.attributes[blockComponentTextDirection] as String?;
-    if (value != null && value != blockComponentTextDirectionAuto) {
-      return value.toTextDirection(fallback: defaultTextDirection);
-    }
 
-    // if the block component doesn't has a text direction attribute, but has a
-    // parent, use the text direction of the parent
-    final previousNodeContainsTextDirection = node.previousNodeWhere(
-      (element) => element.attributes.containsKey(blockComponentTextDirection),
+    final direction = calculateNodeDirection(
+      node: node,
+      defaultTextDirection: defaultTextDirection,
+      lastDirection: lastDirection,
     );
-    if (value == blockComponentTextDirectionAuto &&
-        previousNodeContainsTextDirection != null) {
-      final String previousValue = previousNodeContainsTextDirection
-          .attributes[blockComponentTextDirection];
-      defaultTextDirection =
-          previousValue.toTextDirection(fallback: defaultTextDirection);
-    }
 
-    // if the value is null or the text is null or empty,
-    // use the default text direction
-    final text = node.delta?.toPlainText();
-    if (value == null || text == null || text.isEmpty) {
-      return defaultTextDirection;
+    // node indent padding is added by parent node and the padding direction
+    // is equal to the node text direction. when the node direction is auto
+    // there is a special case which on typing text, the node direction could
+    // change without any change to parent node, because no attribute of the
+    // node changes as the direction attribute is auto but the calculated can
+    // change to rtl or ltr. in this cases we should notify parent node to
+    // recalculate the indent padding.
+    if (node.level > 1 &&
+        direction != lastDirection &&
+        node.attributes[blockComponentTextDirection] ==
+            blockComponentTextDirectionAuto) {
+      WidgetsBinding.instance
+          .addPostFrameCallback((_) => node.parent?.notify());
     }
+    lastDirection = direction;
+
+    return direction;
+  }
+}
+
+/// Calculate the text direction of a node.
+// If the textDirection attribute is not set we will use defaultTextDirection.
+// If the textDirection is ltr or rtl we will apply that.
+// If the textDirection is auto we go by these priorities:
+// 1. Determine the direction by first charachter with strong directionality
+// 2. lastDirection which is the node last determined direction
+// 3. previous line direction
+// 4. defaultTextDirection
+// We will move from first priority when for example the node text is empty or
+// it only has charachters without strong directionality e.g. '@'.
+TextDirection calculateNodeDirection({
+  required Node node,
+  required TextDirection defaultTextDirection,
+  TextDirection? lastDirection,
+}) {
+  defaultTextDirection = lastDirection ?? defaultTextDirection;
+
+  // if the block component has a text direction attribute which is not auto,
+  // use it
+  final value = node.attributes[blockComponentTextDirection] as String?;
+  if (value != null && value != blockComponentTextDirectionAuto) {
+    return value.toTextDirection(fallback: defaultTextDirection);
+  }
 
-    // if the value is auto and the text isn't null or empty,
-    //  calculate the text direction by the text
-    final matches = _regex.firstMatch(text);
-    if (matches != null) {
-      if (matches.group(1) != null) {
-        return TextDirection.rtl;
-      } else if (matches.group(2) != null) {
-        return TextDirection.ltr;
-      }
+  // previous line direction
+  final previousNodeContainsTextDirection = node.previousNodeWhere(
+    (element) => element.attributes.containsKey(blockComponentTextDirection),
+  );
+  if (lastDirection == null &&
+      value == blockComponentTextDirectionAuto &&
+      previousNodeContainsTextDirection != null) {
+    final String previousValue = previousNodeContainsTextDirection
+        .attributes[blockComponentTextDirection];
+    if (previousValue == blockComponentTextDirectionAuto) {
+      defaultTextDirection =
+          previousNodeContainsTextDirection.selectable?.textDirection() ??
+              defaultTextDirection;
+    } else {
+      defaultTextDirection =
+          previousValue.toTextDirection(fallback: defaultTextDirection);
     }
+  }
 
+  // if the value is null or the text is null or empty,
+  // use the default text direction
+  final text = node.delta?.toPlainText();
+  if (value == null || text == null || text.isEmpty) {
     return defaultTextDirection;
   }
+
+  // if the value is auto and the text isn't null or empty,
+  // calculate the text direction by the text
+  final matches = _regex.firstMatch(text);
+  if (matches != null) {
+    if (matches.group(1) != null) {
+      return TextDirection.rtl;
+    } else if (matches.group(2) != null) {
+      return TextDirection.ltr;
+    }
+  }
+
+  return defaultTextDirection;
 }
 
 extension on String {

lib/src/editor/block_component/bulleted_list_block_component/bulleted_list_block_component.dart

@@ -109,12 +109,17 @@ class _BulletedListBlockComponentWidgetState
   Node get node => widget.node;
 
   @override
-  EdgeInsets get indentPadding => configuration.indentPadding(
-        node,
-        calculateTextDirection(
-          defaultTextDirection: Directionality.maybeOf(context),
-        ),
+  EdgeInsets get indentPadding {
+    TextDirection direction =
+        Directionality.maybeOf(context) ?? TextDirection.ltr;
+    if (node.children.isNotEmpty) {
+      direction = calculateNodeDirection(
+        node: node.children.first,
+        defaultTextDirection: direction,
       );
+    }
+    return configuration.indentPadding(node, direction);
+  }
 
   @override
   Widget buildComponent(BuildContext context) {

lib/src/editor/block_component/numbered_list_block_component/numbered_list_block_component.dart

@@ -114,12 +114,17 @@ class _NumberedListBlockComponentWidgetState
   Node get node => widget.node;
 
   @override
-  EdgeInsets get indentPadding => configuration.indentPadding(
-        node,
-        calculateTextDirection(
-          defaultTextDirection: Directionality.maybeOf(context),
-        ),
+  EdgeInsets get indentPadding {
+    TextDirection direction =
+        Directionality.maybeOf(context) ?? TextDirection.ltr;
+    if (node.children.isNotEmpty) {
+      direction = calculateNodeDirection(
+        node: node.children.first,
+        defaultTextDirection: direction,
       );
+    }
+    return configuration.indentPadding(node, direction);
+  }
 
   @override
   Widget buildComponent(BuildContext context) {

lib/src/editor/block_component/text_block_component/text_block_component.dart

@@ -102,12 +102,17 @@ class _TextBlockComponentWidgetState extends State<TextBlockComponentWidget>
   Node get node => widget.node;
 
   @override
-  EdgeInsets get indentPadding => configuration.indentPadding(
-        node,
-        calculateTextDirection(
-          defaultTextDirection: Directionality.maybeOf(context),
-        ),
+  EdgeInsets get indentPadding {
+    TextDirection direction =
+        Directionality.maybeOf(context) ?? TextDirection.ltr;
+    if (node.children.isNotEmpty) {
+      direction = calculateNodeDirection(
+        node: node.children.first,
+        defaultTextDirection: direction,
       );
+    }
+    return configuration.indentPadding(node, direction);
+  }
 
   @override
   Widget buildComponent(BuildContext context) {

lib/src/editor/block_component/todo_list_block_component/todo_list_block_component.dart

@@ -123,12 +123,17 @@ class _TodoListBlockComponentWidgetState
   Node get node => widget.node;
 
   @override
-  EdgeInsets get indentPadding => configuration.indentPadding(
-        node,
-        calculateTextDirection(
-          defaultTextDirection: Directionality.maybeOf(context),
-        ),
+  EdgeInsets get indentPadding {
+    TextDirection direction =
+        Directionality.maybeOf(context) ?? TextDirection.ltr;
+    if (node.children.isNotEmpty) {
+      direction = calculateNodeDirection(
+        node: node.children.first,
+        defaultTextDirection: direction,
       );
+    }
+    return configuration.indentPadding(node, direction);
+  }
 
   bool get checked => widget.node.attributes[TodoListBlockKeys.checked];
 

test/new/block_component/text_direction_mixin_test.dart

@@ -2,6 +2,8 @@ import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../infra/testable_editor.dart';
+
 class TextDirectionTest with BlockComponentTextDirectionMixin {
   TextDirectionTest({
     required this.node,
@@ -40,13 +42,15 @@ void main() {
       expect(direction, TextDirection.ltr);
     });
 
-    test('auto empty text with lastDirection', () {
+    test('auto empty text with last direction', () {
       final node = paragraphNode(
         text: '',
         textDirection: blockComponentTextDirectionAuto,
       );
-      final direction = TextDirectionTest(node: node).calculateTextDirection(
-        defaultTextDirection: TextDirection.rtl,
+      final textDirectionTest = TextDirectionTest(node: node);
+      textDirectionTest.lastDirection = TextDirection.rtl;
+      final direction = textDirectionTest.calculateTextDirection(
+        defaultTextDirection: TextDirection.ltr,
       );
       expect(direction, TextDirection.rtl);
     });
@@ -115,6 +119,25 @@ void main() {
       expect(direction, TextDirection.rtl);
     });
 
+    test('use previous node direction (rtl) only when current is auto', () {
+      final node = pageNode(
+        children: [
+          paragraphNode(
+            text: 'سلام',
+            textDirection: blockComponentTextDirectionRTL,
+          ),
+          paragraphNode(
+            text: '\$',
+          ),
+        ],
+      );
+      final direction =
+          TextDirectionTest(node: node.children.last).calculateTextDirection(
+        defaultTextDirection: TextDirection.ltr,
+      );
+      expect(direction, TextDirection.ltr);
+    });
+
     test(
         'auto empty text don\'t use previous node direction because we can determine by the node text',
         () {
@@ -136,5 +159,55 @@ void main() {
       );
       expect(direction, TextDirection.ltr);
     });
+
+    test(
+        'auto empty text don\'t use previous node direction when we have last direction',
+        () {
+      final node = pageNode(
+        children: [
+          paragraphNode(
+            text: 'سلام',
+            textDirection: blockComponentTextDirectionRTL,
+          ),
+          paragraphNode(
+            text: '',
+            textDirection: blockComponentTextDirectionAuto,
+          ),
+        ],
+      );
+
+      final textDirectionTest = TextDirectionTest(node: node.children.last);
+      textDirectionTest.lastDirection = TextDirection.ltr;
+
+      final direction = textDirectionTest.calculateTextDirection(
+        defaultTextDirection: TextDirection.rtl,
+      );
+      expect(direction, TextDirection.ltr);
+    });
+  });
+
+  group('text_direction_mixin - widget test', () {
+    testWidgets('use previous node direction (auto) calculated value (rtl)',
+        (tester) async {
+      final editor = tester.editor
+        ..addNode(
+          paragraphNode(
+            text: 'سلام',
+            textDirection: blockComponentTextDirectionAuto,
+          ),
+        )
+        ..addNode(
+          paragraphNode(
+            text: '\$',
+            textDirection: blockComponentTextDirectionAuto,
+          ),
+        );
+      await editor.startTesting();
+
+      final node = editor.nodeAtPath([1])!;
+      expect(node.selectable?.textDirection(), TextDirection.rtl);
+
+      await editor.dispose();
+    });
   });
 }

test/new/service/shortcuts/command_shortcut_events/backspace_command_test.dart

@@ -467,5 +467,48 @@ void main() async {
 
       await editor.dispose();
     });
+
+    testWidgets("clear text but keep the old direction", (tester) async {
+      final editor = tester.editor
+        ..addNode(
+          paragraphNode(
+            text: 'Hello',
+            textDirection: blockComponentTextDirectionLTR,
+          ),
+        )
+        ..addNode(
+          paragraphNode(
+            text: 'س',
+            textDirection: blockComponentTextDirectionAuto,
+          ),
+        );
+      await editor.startTesting();
+
+      Node node = editor.nodeAtPath([1])!;
+      expect(
+        node.selectable?.textDirection().name,
+        blockComponentTextDirectionRTL,
+      );
+
+      final selection = Selection.collapsed(
+        Position(path: [1], offset: 1),
+      );
+      await editor.updateSelection(selection);
+
+      await simulateKeyDownEvent(LogicalKeyboardKey.backspace);
+      await tester.pumpAndSettle();
+
+      node = editor.nodeAtPath([1])!;
+      expect(
+        node.delta?.toPlainText().isEmpty,
+        true,
+      );
+      expect(
+        node.selectable?.textDirection().name,
+        blockComponentTextDirectionRTL,
+      );
+
+      await editor.dispose();
+    });
   });
 }