fix: integrate the replace function in the ai writer cubit

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/ai/operations/ai_writer_cubit.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:appflowy/ai/ai.dart';
 import 'package:appflowy/workspace/application/view/view_service.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
+import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-ai/protobuf.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_result/appflowy_result.dart';
@@ -15,6 +16,11 @@ import 'ai_writer_block_operations.dart';
 import 'ai_writer_entities.dart';
 import 'ai_writer_node_extension.dart';
 
+/// Enable the debug log for the AiWriterCubit.
+///
+/// This is useful for debugging the AI writer cubit.
+const _aiWriterCubitDebugLog = false;
+
 class AiWriterCubit extends Cubit<AiWriterState> {
   AiWriterCubit({
     required this.documentId,
@@ -95,6 +101,10 @@ class AiWriterCubit extends Cubit<AiWriterState> {
     final command = node.aiWriterCommand;
     final (run, prompt) = await _addSelectionTextToRecords(command);
 
+    _aiWriterCubitLog(
+      'command: $command, run: $run, prompt: $prompt',
+    );
+
     if (!run) {
       await exit();
       return;
@@ -215,23 +225,22 @@ class AiWriterCubit extends Cubit<AiWriterState> {
     //
     // If the user clicks accept, we need to replace the selection with the AI's response
     if (action case SuggestionAction.accept) {
-      await _textRobot.persist();
+      // trim the markdown text to avoid extra new lines
+      final trimmedMarkdownText = _textRobot.markdownText.trim();
 
-      // Clear the format of the selected text.
-      // From grey color to the original color.
-      await formatSelection(
-        editorState,
-        selection,
-        ApplySuggestionFormatType.clear,
+      _aiWriterCubitLog(
+        'trigger accept action, markdown text: $trimmedMarkdownText',
       );
 
-      final nodes = editorState.getNodesInSelection(selection);
-      final transaction = editorState.transaction..deleteNodes(nodes);
-      await editorState.apply(
-        transaction,
-        withUpdateSelection: false,
+      await _textRobot.deleteAINodes();
+
+      await _textRobot.replace(
+        selection: selection,
+        markdownText: trimmedMarkdownText,
       );
+
       await exit(withDiscard: false, withUnformat: false);
+
       return;
     }
 
@@ -283,17 +292,24 @@ class AiWriterCubit extends Cubit<AiWriterState> {
     AiWriterCommand command,
   ) async {
     final node = aiWriterNode;
+
+    // check the node is registered
     if (node == null) {
       return (false, '');
     }
+
+    // check the selection is valid
     final selection = node.aiWriterSelection?.normalized;
     if (selection == null) {
       return (false, '');
     }
 
+    // if the command is continue writing, we don't need to get the selection text
     if (command == AiWriterCommand.continueWriting) {
       return (true, '');
     }
+
+    // if the selection is collapsed, we don't need to get the selection text
     if (selection.isCollapsed) {
       return (true, '');
     }
@@ -304,6 +320,7 @@ class AiWriterCubit extends Cubit<AiWriterState> {
       records.add(
         AiWriterRecord.user(content: selectionText, format: null),
       );
+
       return (true, '');
     } else {
       return (true, selectionText);
@@ -547,6 +564,10 @@ class AiWriterCubit extends Cubit<AiWriterState> {
           attributes: ApplySuggestionFormatType.replace.attributes,
         );
         onAppendToDocument?.call();
+
+        _aiWriterCubitLog(
+          'received message: $text',
+        );
       },
       processAssistMessage: (text) async {
         if (state case final GeneratingAiWriterState generatingState) {
@@ -558,6 +579,10 @@ class AiWriterCubit extends Cubit<AiWriterState> {
             ),
           );
         }
+
+        _aiWriterCubitLog(
+          'received assist message: $text',
+        );
       },
       onEnd: () async {
         if (state case final GeneratingAiWriterState generatingState) {
@@ -574,6 +599,10 @@ class AiWriterCubit extends Cubit<AiWriterState> {
           records.add(
             AiWriterRecord.ai(content: _textRobot.markdownText),
           );
+
+          _aiWriterCubitLog(
+            'returned response: ${_textRobot.markdownText}',
+          );
         }
       },
       onError: (error) async {
@@ -665,6 +694,12 @@ class AiWriterCubit extends Cubit<AiWriterState> {
       );
     }
   }
+
+  void _aiWriterCubitLog(String message) {
+    if (_aiWriterCubitDebugLog) {
+      Log.debug('[AiWriterCubit] $message');
+    }
+  }
 }
 
 mixin RegisteredAiWriter {

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/ai/operations/ai_writer_node_extension.dart

@@ -57,11 +57,27 @@ extension AiWriterNodeExtension on EditorState {
       slicedNodes.add(copiedNode);
     }
 
+    for (final (i, node) in slicedNodes.indexed) {
+      final childNodesShouldBeDeleted = <Node>[];
+      for (final child in node.children) {
+        if (!child.path.inSelection(selection)) {
+          childNodesShouldBeDeleted.add(child);
+        }
+      }
+      for (final child in childNodesShouldBeDeleted) {
+        slicedNodes[i] = node.copyWith(
+          children: node.children.where((e) => e.id != child.id).toList(),
+          type: selection.startIndex != 0 ? ParagraphBlockKeys.type : node.type,
+        );
+      }
+    }
+
     final markdown = await customDocumentToMarkdown(
       Document.blank()..insert([0], slicedNodes),
     );
 
-    return markdown;
+    // trim the last \n if it exists
+    return markdown.trimRight();
   }
 
   List<String> getPlainTextInSelection(Selection? selection) {

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/base/markdown_text_robot.dart

@@ -145,6 +145,16 @@ class MarkdownTextRobot {
     }
   }
 
+  /// Delete the temporary inserted AI nodes
+  Future<void> deleteAINodes() async {
+    final nodes = getInsertedNodes();
+    final transaction = editorState.transaction..deleteNodes(nodes);
+    await editorState.apply(
+      transaction,
+      options: const ApplyOptions(recordUndo: false),
+    );
+  }
+
   /// Discard the inserted content
   Future<void> discard() async {
     final start = _insertPosition;
@@ -333,8 +343,38 @@ class MarkdownTextRobot {
     }
 
     // Convert the markdown text to delta.
+    // Question: Why we need to convert the markdown to document first?
+    // Answer: Because the markdown text may contain the list item,
+    // if we convert the markdown to delta directly, the list item will be
+    // treated as a normal text node, and the delta will be incorrect.
+    // For example, the markdown text is:
+    // ```
+    // 1. item1
+    // ```
+    // if we convert the markdown to delta directly, the delta will be:
+    // ```
+    // [
+    //   {
+    //     "insert": "1. item1"
+    //   }
+    // ]
+    // ```
+    // if we convert the markdown to document first, the document will be:
+    // ```
+    // [
+    //   {
+    //     "type": "numbered_list",
+    //     "children": [
+    //       {
+    //         "insert": "item1"
+    //       }
+    //     ]
+    //   }
+    // ]
+    final document = customMarkdownToDocument(markdownText);
     final decoder = DeltaMarkdownDecoder();
-    final markdownDelta = decoder.convert(markdownText);
+    final markdownDelta =
+        document.nodeAtPath([0])?.delta ?? decoder.convert(markdownText);
 
     // Replace the delta of the selected node.
     final transaction = editorState.transaction;
@@ -366,6 +406,7 @@ class MarkdownTextRobot {
     // Get the selected nodes.
     final nodes = editorState.getNodesInSelection(selection);
 
+    // Note: Don't change its order, otherwise the delta will be incorrect.
     // step 1. merge the first selected node and the first node from the ai response
     // step 2. merge the last selected node and the last node from the ai response
     // step 3. insert the middle nodes from the ai response
@@ -398,9 +439,12 @@ class MarkdownTextRobot {
         lastMarkdownNode != null &&
         lastMarkdownDelta != null) {
       final endIndex = selection.endIndex;
-      transaction
-        ..deleteText(lastNode, 0, endIndex)
-        ..insertTextDelta(lastNode, 0, lastMarkdownDelta);
+      transaction.deleteText(lastNode, 0, endIndex);
+      // if the last node is same as the first node, it means we have replaced the
+      // selected text in the first node.
+      if (lastMarkdownNode.id != firstMarkdownNode?.id) {
+        transaction.insertTextDelta(lastNode, 0, lastMarkdownDelta);
+      }
     }
 
     // step 3

frontend/appflowy_flutter/lib/shared/markdown_to_document.dart

@@ -41,6 +41,7 @@ Future<String> customDocumentToMarkdown(
   try {
     markdown = documentToMarkdown(
       document,
+      lineBreak: '\n\n',
       customParsers: [
         const MathEquationNodeParser(),
         const CalloutNodeParser(),

frontend/appflowy_flutter/pubspec.lock

@@ -98,8 +98,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: "552f95f"
-      resolved-ref: "552f95fd15627e10a138c6db2a6d0a8089bc9a25"
+      ref: "361b99c38370abeeb19656f89e8c31cb3666623b"
+      resolved-ref: "361b99c38370abeeb19656f89e8c31cb3666623b"
       url: "https://github.com/AppFlowy-IO/appflowy-editor.git"
     source: git
     version: "5.1.0"

frontend/appflowy_flutter/pubspec.yaml

@@ -184,7 +184,7 @@ dependency_overrides:
   appflowy_editor:
     git:
       url: https://github.com/AppFlowy-IO/appflowy-editor.git
-      ref: "552f95f"
+      ref: "361b99c38370abeeb19656f89e8c31cb3666623b"
 
   appflowy_editor_plugins:
     git:

frontend/appflowy_flutter/test/unit_test/document/text_robot/markdown_text_robot_test.dart

@@ -732,6 +732,75 @@ Email became **widely prevalent**, and instant messaging services like *ICQ* and
         expect(d7.attributes, null);
       }
     });
+
+    test(
+        'the length of the returned response less than the length of the selected text',
+        () async {
+      final document = buildTestDocument();
+      final editorState = EditorState(document: document);
+
+      editorState.selection = Selection(
+        start: Position(
+          path: [0],
+          offset: 'The introduction of the World Wide Web'.length,
+        ),
+        end: Position(
+          path: [2],
+          offset:
+              'Email became widespread, and instant messaging services like ICQ and AOL Instant Messenger gained popularity'
+                  .length,
+        ),
+      );
+
+      final markdownText =
+          ''' in the **early 1990s** marked a *significant turning point* in technological history.''';
+      final markdownTextRobot = MarkdownTextRobot(
+        editorState: editorState,
+      );
+      await markdownTextRobot.replace(
+        selection: editorState.selection!,
+        markdownText: markdownText,
+      );
+
+      final afterNodes = editorState.document.root.children;
+      expect(afterNodes.length, 2);
+
+      {
+        // first paragraph
+        final delta1 = afterNodes[0].delta!.toList();
+        expect(delta1.length, 5);
+
+        final d1 = delta1[0] as TextInsert;
+        expect(d1.text, "The introduction of the World Wide Web in the ");
+        expect(d1.attributes, null);
+
+        final d2 = delta1[1] as TextInsert;
+        expect(d2.text, "early 1990s");
+        expect(d2.attributes, {AppFlowyRichTextKeys.bold: true});
+
+        final d3 = delta1[2] as TextInsert;
+        expect(d3.text, " marked a ");
+        expect(d3.attributes, null);
+
+        final d4 = delta1[3] as TextInsert;
+        expect(d4.text, "significant turning point");
+        expect(d4.attributes, {AppFlowyRichTextKeys.italic: true});
+
+        final d5 = delta1[4] as TextInsert;
+        expect(d5.text, " in technological history.");
+        expect(d5.attributes, null);
+      }
+
+      {
+        // second paragraph
+        final delta2 = afterNodes[1].delta!.toList();
+        expect(delta2.length, 1);
+
+        final d1 = delta2[0] as TextInsert;
+        expect(d1.text, ", allowing for real-time text communication.");
+        expect(d1.attributes, null);
+      }
+    });
   });
 }