refactor: move node to core/document

frontend/app_flowy/packages/appflowy_editor/example/lib/plugin/code_block_node_widget.dart

@@ -60,7 +60,7 @@ SelectionMenuItem codeBlockMenuItem = SelectionMenuItem(
     if (selection == null || textNodes.isEmpty) {
       return;
     }
-    if (textNodes.first.toRawString().isEmpty) {
+    if (textNodes.first.toPlainText().isEmpty) {
       TransactionBuilder(editorState)
         ..updateNode(textNodes.first, {
           'subtype': 'code_block',
@@ -74,7 +74,6 @@ SelectionMenuItem codeBlockMenuItem = SelectionMenuItem(
         ..insertNode(
           selection.end.path.next,
           TextNode(
-            type: 'text',
             children: LinkedList(),
             attributes: {
               'subtype': 'code_block',
@@ -149,7 +148,7 @@ class __CodeBlockNodeWidgeState extends State<_CodeBlockNodeWidge>
 
   Widget _buildCodeBlock(BuildContext context) {
     final result = highlight.highlight.parse(
-      widget.textNode.toRawString(),
+      widget.textNode.toPlainText(),
       language: _language,
       autoDetection: _language == null,
     );

frontend/app_flowy/packages/appflowy_editor/example/lib/plugin/horizontal_rule_node_widget.dart

@@ -17,7 +17,7 @@ ShortcutEventHandler _insertHorzaontalRule = (editorState, event) {
     return KeyEventResult.ignored;
   }
   final textNode = textNodes.first;
-  if (textNode.toRawString() == '--') {
+  if (textNode.toPlainText() == '--') {
     TransactionBuilder(editorState)
       ..deleteText(textNode, 0, 2)
       ..insertNode(
@@ -53,7 +53,7 @@ SelectionMenuItem horizontalRuleMenuItem = SelectionMenuItem(
       return;
     }
     final textNode = textNodes.first;
-    if (textNode.toRawString().isEmpty) {
+    if (textNode.toPlainText().isEmpty) {
       TransactionBuilder(editorState)
         ..insertNode(
           textNode.path,
@@ -71,7 +71,6 @@ SelectionMenuItem horizontalRuleMenuItem = SelectionMenuItem(
         ..insertNode(
           selection.end.path.next,
           TextNode(
-            type: 'text',
             children: LinkedList(),
             attributes: {
               'subtype': 'horizontal_rule',

frontend/app_flowy/packages/appflowy_editor/example/lib/plugin/tex_block_node_widget.dart

@@ -21,7 +21,7 @@ SelectionMenuItem teXBlockMenuItem = SelectionMenuItem(
       return;
     }
     final Path texNodePath;
-    if (textNodes.first.toRawString().isEmpty) {
+    if (textNodes.first.toPlainText().isEmpty) {
       texNodePath = selection.end.path;
       TransactionBuilder(editorState)
         ..insertNode(

frontend/app_flowy/packages/appflowy_editor/example/lib/plugin/underscore_to_italic.dart

@@ -18,7 +18,7 @@ ShortcutEventHandler _underscoreToItalicHandler = (editorState, event) {
   }
 
   final textNode = textNodes.first;
-  final text = textNode.toRawString();
+  final text = textNode.toPlainText();
   // Determine if an 'underscore' already exists in the text node and only once.
   final firstUnderscore = text.indexOf('_');
   final lastUnderscore = text.lastIndexOf('_');

frontend/app_flowy/packages/appflowy_editor/lib/appflowy_editor.dart

@@ -3,7 +3,7 @@ library appflowy_editor;
 
 export 'src/infra/log.dart';
 export 'src/render/style/editor_style.dart';
-export 'src/document/node.dart';
+export 'src/core/document/node.dart';
 export 'src/document/path.dart';
 export 'src/document/position.dart';
 export 'src/document/selection.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/commands/edit_text.dart

@@ -1,7 +1,7 @@
 import 'dart:async';
 
 import 'package:appflowy_editor/src/commands/text_command_infra.dart';
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/editor_state.dart';
 import 'package:appflowy_editor/src/operation/transaction_builder.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/commands/format_built_in_text.dart

@@ -2,7 +2,7 @@ import 'package:appflowy_editor/src/commands/format_text.dart';
 import 'package:appflowy_editor/src/commands/text_command_infra.dart';
 import 'package:appflowy_editor/src/document/attributes.dart';
 import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
 import 'package:appflowy_editor/src/editor_state.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/commands/format_text.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 
 import 'package:appflowy_editor/src/commands/text_command_infra.dart';
 import 'package:appflowy_editor/src/document/attributes.dart';
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
 import 'package:appflowy_editor/src/editor_state.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/commands/text_command_infra.dart

@@ -1,4 +1,4 @@
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
 import 'package:appflowy_editor/src/editor_state.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/core/document/node.dart

@@ -0,0 +1,278 @@
+import 'dart:collection';
+
+import 'package:flutter/material.dart';
+
+import 'package:appflowy_editor/src/document/attributes.dart';
+import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
+import 'package:appflowy_editor/src/document/path.dart';
+import 'package:appflowy_editor/src/document/text_delta.dart';
+
+class Node extends ChangeNotifier with LinkedListEntry<Node> {
+  Node({
+    required this.type,
+    Attributes? attributes,
+    this.parent,
+    LinkedList<Node>? children,
+  })  : children = children ?? LinkedList<Node>(),
+        _attributes = attributes ?? {} {
+    for (final child in this.children) {
+      child.parent = this;
+    }
+  }
+
+  factory Node.fromJson(Map<String, Object> json) {
+    assert(json['type'] is String);
+
+    final jType = json['type'] as String;
+    final jChildren = json['children'] as List?;
+    final jAttributes = json['attributes'] != null
+        ? Attributes.from(json['attributes'] as Map)
+        : Attributes.from({});
+
+    final children = LinkedList<Node>();
+    if (jChildren != null) {
+      children.addAll(
+        jChildren.map(
+          (jChild) => Node.fromJson(
+            Map<String, Object>.from(jChild),
+          ),
+        ),
+      );
+    }
+
+    Node node;
+
+    if (jType == 'text') {
+      final jDelta = json['delta'] as List<dynamic>?;
+      final delta = jDelta == null ? Delta() : Delta.fromJson(jDelta);
+      node = TextNode(
+        children: children,
+        attributes: jAttributes,
+        delta: delta,
+      );
+    } else {
+      node = Node(
+        type: jType,
+        children: children,
+        attributes: jAttributes,
+      );
+    }
+
+    for (final child in children) {
+      child.parent = node;
+    }
+
+    return node;
+  }
+
+  final String type;
+  final LinkedList<Node> children;
+  Node? parent;
+  Attributes _attributes;
+
+  // Renderable
+  GlobalKey? key;
+  final layerLink = LayerLink();
+
+  Attributes get attributes => {..._attributes};
+
+  String get id {
+    if (subtype != null) {
+      return '$type/$subtype';
+    }
+    return type;
+  }
+
+  String? get subtype {
+    if (attributes[BuiltInAttributeKey.subtype] is String) {
+      return attributes[BuiltInAttributeKey.subtype] as String;
+    }
+    return null;
+  }
+
+  Path get path => _computePath();
+
+  void updateAttributes(Attributes attributes) {
+    final oldAttributes = this.attributes;
+
+    _attributes = composeAttributes(this.attributes, attributes) ?? {};
+
+    // Notifies the new attributes
+    // if attributes contains 'subtype', should notify parent to rebuild node
+    // else, just notify current node.
+    bool shouldNotifyParent =
+        this.attributes['subtype'] != oldAttributes['subtype'];
+    shouldNotifyParent ? parent?.notifyListeners() : notifyListeners();
+  }
+
+  Node? childAtIndex(int index) {
+    if (children.length <= index || index < 0) {
+      return null;
+    }
+
+    return children.elementAt(index);
+  }
+
+  Node? childAtPath(Path path) {
+    if (path.isEmpty) {
+      return this;
+    }
+
+    return childAtIndex(path.first)?.childAtPath(path.sublist(1));
+  }
+
+  void insert(Node entry, {int? index}) {
+    final length = children.length;
+    index ??= length;
+
+    if (children.isEmpty) {
+      entry.parent = this;
+      children.add(entry);
+      notifyListeners();
+      return;
+    }
+
+    // If index is out of range, insert at the end.
+    // If index is negative, insert at the beginning.
+    // If index is positive, insert at the index.
+    if (index >= length) {
+      children.last.insertAfter(entry);
+    } else if (index <= 0) {
+      children.first.insertBefore(entry);
+    } else {
+      childAtIndex(index)?.insertBefore(entry);
+    }
+  }
+
+  @override
+  void insertAfter(Node entry) {
+    entry.parent = parent;
+    super.insertAfter(entry);
+
+    // Notifies the new node.
+    parent?.notifyListeners();
+  }
+
+  @override
+  void insertBefore(Node entry) {
+    entry.parent = parent;
+    super.insertBefore(entry);
+
+    // Notifies the new node.
+    parent?.notifyListeners();
+  }
+
+  @override
+  void unlink() {
+    super.unlink();
+
+    parent?.notifyListeners();
+    parent = null;
+  }
+
+  Map<String, Object> toJson() {
+    var map = <String, Object>{
+      'type': type,
+    };
+    if (children.isNotEmpty) {
+      map['children'] =
+          children.map((node) => node.toJson()).toList(growable: false);
+    }
+    if (attributes.isNotEmpty) {
+      map['attributes'] = attributes;
+    }
+    return map;
+  }
+
+  Node copyWith({
+    String? type,
+    LinkedList<Node>? children,
+    Attributes? attributes,
+  }) {
+    final node = Node(
+      type: type ?? this.type,
+      attributes: attributes ?? {...this.attributes},
+      children: children,
+    );
+    if (children == null && this.children.isNotEmpty) {
+      for (final child in this.children) {
+        node.children.add(
+          child.copyWith()..parent = node,
+        );
+      }
+    }
+    return node;
+  }
+
+  Path _computePath([Path previous = const []]) {
+    if (parent == null) {
+      return previous;
+    }
+    var index = 0;
+    for (final child in parent!.children) {
+      if (child == this) {
+        break;
+      }
+      index += 1;
+    }
+    return parent!._computePath([index, ...previous]);
+  }
+}
+
+class TextNode extends Node {
+  TextNode({
+    required Delta delta,
+    LinkedList<Node>? children,
+    Attributes? attributes,
+  })  : _delta = delta,
+        super(
+          type: 'text',
+          children: children,
+          attributes: attributes ?? {},
+        );
+
+  TextNode.empty({Attributes? attributes})
+      : _delta = Delta([TextInsert('')]),
+        super(
+          type: 'text',
+          attributes: attributes ?? {},
+        );
+
+  Delta _delta;
+  Delta get delta => _delta;
+  set delta(Delta v) {
+    _delta = v;
+    notifyListeners();
+  }
+
+  @override
+  Map<String, Object> toJson() {
+    final map = super.toJson();
+    map['delta'] = delta.toJson();
+    return map;
+  }
+
+  @override
+  TextNode copyWith({
+    String? type = 'text',
+    LinkedList<Node>? children,
+    Attributes? attributes,
+    Delta? delta,
+  }) {
+    final textNode = TextNode(
+      children: children,
+      attributes: attributes ?? this.attributes,
+      delta: delta ?? this.delta,
+    );
+    if (children == null && this.children.isNotEmpty) {
+      for (final child in this.children) {
+        textNode.children.add(
+          child.copyWith()..parent = textNode,
+        );
+      }
+    }
+    return textNode;
+  }
+
+  String toPlainText() => _delta.toPlainText();
+}

frontend/app_flowy/packages/appflowy_editor/lib/src/document/attributes.dart

@@ -1,42 +1,45 @@
+/// Attributes is used to describe the Node's information.
+///
+/// Please note: The keywords in [BuiltInAttributeKey] are reserved.
 typedef Attributes = Map<String, dynamic>;
 
-int hashAttributes(Attributes attributes) {
-  return Object.hashAllUnordered(
-      attributes.entries.map((e) => Object.hash(e.key, e.value)));
-}
-
-Attributes invertAttributes(Attributes? attr, Attributes? base) {
-  attr ??= {};
+Attributes? composeAttributes(
+  Attributes? base,
+  Attributes? other, {
+  keepNull = false,
+}) {
   base ??= {};
-  final Attributes baseInverted = base.keys.fold({}, (memo, key) {
-    if (base![key] != attr![key] && attr.containsKey(key)) {
-      memo[key] = base[key];
-    }
-    return memo;
-  });
-  return attr.keys.fold(baseInverted, (memo, key) {
-    if (attr![key] != base![key] && !base.containsKey(key)) {
-      memo[key] = null;
-    }
-    return memo;
-  });
-}
-
-Attributes? composeAttributes(Attributes? a, Attributes? b,
-    [bool keepNull = false]) {
-  a ??= {};
-  b ??= {};
-  Attributes attributes = {...b};
+  other ??= {};
+  Attributes attributes = {
+    ...base,
+    ...other,
+  };
 
   if (!keepNull) {
-    attributes = Map.from(attributes)..removeWhere((_, value) => value == null);
-  }
-
-  for (final entry in a.entries) {
-    if (!b.containsKey(entry.key)) {
-      attributes[entry.key] = entry.value;
-    }
+    attributes = Attributes.from(attributes)
+      ..removeWhere((_, value) => value == null);
   }
 
   return attributes.isNotEmpty ? attributes : null;
 }
+
+Attributes invertAttributes(Attributes? base, Attributes? other) {
+  base ??= {};
+  other ??= {};
+  final Attributes attributes = base.keys.fold({}, (previousValue, key) {
+    if (other!.containsKey(key) && other[key] != base![key]) {
+      previousValue[key] = base[key];
+    }
+    return previousValue;
+  });
+  return other.keys.fold(attributes, (previousValue, key) {
+    if (!base!.containsKey(key) && other![key] != base[key]) {
+      previousValue[key] = null;
+    }
+    return previousValue;
+  });
+}
+
+int hashAttributes(Attributes base) => Object.hashAllUnordered(
+      base.entries.map((e) => Object.hash(e.key, e.value)),
+    );

frontend/app_flowy/packages/appflowy_editor/lib/src/document/node_iterator.dart

@@ -1,4 +1,4 @@
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 
 import './state_tree.dart';
 

frontend/app_flowy/packages/appflowy_editor/lib/src/document/state_tree.dart

@@ -1,6 +1,6 @@
 import 'dart:math';
 
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/text_delta.dart';
 import './attributes.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/document/text_delta.dart

@@ -47,7 +47,9 @@ class TextInsert extends TextOperation {
     final contentHash = content.hashCode;
     final attrs = _attributes;
     return Object.hash(
-        contentHash, attrs == null ? null : hashAttributes(attrs));
+      contentHash,
+      attrs != null ? hashAttributes(attrs) : null,
+    );
   }
 
   @override
@@ -101,7 +103,10 @@ class TextRetain extends TextOperation {
   @override
   int get hashCode {
     final attrs = _attributes;
-    return Object.hash(_length, attrs == null ? null : hashAttributes(attrs));
+    return Object.hash(
+      _length,
+      attrs != null ? hashAttributes(attrs) : null,
+    );
   }
 
   @override
@@ -401,7 +406,11 @@ class Delta extends Iterable<TextOperation> {
         final thisOp = thisIter._next(length);
         final otherOp = otherIter._next(length);
         final attributes = composeAttributes(
-            thisOp.attributes, otherOp.attributes, thisOp is TextRetain);
+          thisOp.attributes,
+          otherOp.attributes,
+          keepNull: thisOp is TextRetain,
+        );
+
         if (otherOp is TextRetain && otherOp.length > 0) {
           TextOperation? newOp;
           if (thisOp is TextRetain) {
@@ -480,8 +489,10 @@ class Delta extends Iterable<TextOperation> {
           if (op is TextDelete) {
             inverted.add(baseOp);
           } else if (op is TextRetain && op.attributes != null) {
-            inverted.retain(baseOp.length,
-                invertAttributes(op.attributes, baseOp.attributes));
+            inverted.retain(
+              baseOp.length,
+              invertAttributes(baseOp.attributes, op.attributes),
+            );
           }
         }
         return previousValue + length;
@@ -520,7 +531,7 @@ class Delta extends Iterable<TextOperation> {
   ///
   /// This method can help you to compute the position of the next character.
   int nextRunePosition(int pos) {
-    final stringContent = toRawString();
+    final stringContent = toPlainText();
     if (pos >= stringContent.length - 1) {
       return stringContent.length;
     }
@@ -535,7 +546,7 @@ class Delta extends Iterable<TextOperation> {
     return stringContent.length;
   }
 
-  String toRawString() {
+  String toPlainText() {
     _rawString ??=
         _operations.whereType<TextInsert>().map((op) => op.content).join();
     return _rawString!;

frontend/app_flowy/packages/appflowy_editor/lib/src/extensions/node_extensions.dart

@@ -1,4 +1,4 @@
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
 import 'package:appflowy_editor/src/extensions/object_extensions.dart';
 import 'package:appflowy_editor/src/extensions/path_extensions.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/extensions/text_node_extensions.dart

@@ -1,4 +1,4 @@
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/position.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
@@ -171,7 +171,7 @@ extension TextNodesExtension on List<TextNode> {
         if (i == 0 && pathEquals(node.path, selection.start.path)) {
           if (selection.isBackward) {
             newSelection = selection.copyWith(
-              end: Position(path: node.path, offset: node.toRawString().length),
+              end: Position(path: node.path, offset: node.toPlainText().length),
             );
           } else {
             newSelection = selection.copyWith(
@@ -187,13 +187,13 @@ extension TextNodesExtension on List<TextNode> {
           } else {
             newSelection = selection.copyWith(
               start:
-                  Position(path: node.path, offset: node.toRawString().length),
+                  Position(path: node.path, offset: node.toPlainText().length),
             );
           }
         } else {
           newSelection = Selection(
             start: Position(path: node.path, offset: 0),
-            end: Position(path: node.path, offset: node.toRawString().length),
+            end: Position(path: node.path, offset: node.toPlainText().length),
           );
         }
         if (!node.allSatisfyInSelection(newSelection, styleKey, test)) {

frontend/app_flowy/packages/appflowy_editor/lib/src/infra/html_converter.dart

@@ -2,7 +2,7 @@ import 'dart:collection';
 import 'dart:ui';
 
 import 'package:appflowy_editor/src/document/attributes.dart';
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/text_delta.dart';
 import 'package:appflowy_editor/src/extensions/color_extension.dart';
 import 'package:flutter/material.dart';
@@ -89,7 +89,7 @@ class HTMLToNodesConverter {
       }
     }
     if (delta.isNotEmpty) {
-      result.add(TextNode(type: "text", delta: delta));
+      result.add(TextNode(delta: delta));
     }
     return result;
   }
@@ -134,7 +134,7 @@ class HTMLToNodesConverter {
       final delta = Delta();
       delta.insert(element.text);
       if (delta.isNotEmpty) {
-        return [TextNode(type: "text", delta: delta)];
+        return [TextNode(delta: delta)];
       }
     }
     return [];
@@ -271,8 +271,7 @@ class HTMLToNodesConverter {
       }
     }
 
-    final textNode =
-        TextNode(type: "text", delta: delta, attributes: attributes);
+    final textNode = TextNode(delta: delta, attributes: attributes);
     if (isCheckbox) {
       textNode.attributes["subtype"] = BuiltInAttributeKey.checkbox;
       textNode.attributes["checkbox"] = checked;
@@ -315,7 +314,6 @@ class HTMLToNodesConverter {
     final delta = Delta();
     delta.insert(element.text);
     return TextNode(
-        type: "text",
         attributes: {"subtype": "heading", "heading": headingStyle},
         delta: delta);
   }

frontend/app_flowy/packages/appflowy_editor/lib/src/infra/infra.dart

@@ -1,4 +1,4 @@
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 
 class Infra {
 // find the forward nearest text node

frontend/app_flowy/packages/appflowy_editor/lib/src/operation/transaction_builder.dart

@@ -2,7 +2,7 @@ import 'dart:collection';
 import 'dart:math';
 
 import 'package:appflowy_editor/src/document/attributes.dart';
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/document/path.dart';
 import 'package:appflowy_editor/src/document/position.dart';
 import 'package:appflowy_editor/src/document/selection.dart';
@@ -42,8 +42,7 @@ class TransactionBuilder {
   /// Updates the attributes of nodes.
   updateNode(Node node, Attributes attributes) {
     beforeSelection = state.cursorSelection;
-
-    final inverted = invertAttributes(attributes, node.attributes);
+    final inverted = invertAttributes(node.attributes, attributes);
     add(UpdateOperation(
       node.path,
       {...attributes},

frontend/app_flowy/packages/appflowy_editor/lib/src/render/editor/editor_entry.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 
-import 'package:appflowy_editor/src/document/node.dart';
+import 'package:appflowy_editor/src/core/document/node.dart';
 import 'package:appflowy_editor/src/editor_state.dart';
 import 'package:appflowy_editor/src/service/render_plugin_service.dart';