chore: renaming

lib/src/editor/editor_component/service/shortcuts/character_shortcut_events/format_by_wrapping_with_single_char/format_by_wrapping_with_single_char.dart

@@ -7,4 +7,4 @@
 export 'format_code.dart';
 export 'format_italic.dart';
 export 'format_strikethrough.dart';
-export 'handle_single_character_format.dart';
+export 'handle_format_by_wrapping_with_single_char.dart';

lib/src/editor/editor_component/service/shortcuts/character_shortcut_events/format_by_wrapping_with_single_char/handle_format_by_wrapping_with_single_char.dart

@@ -0,0 +1,95 @@
+import 'package:appflowy_editor/appflowy_editor.dart';
+
+enum FormatStyleByWrappingWithSingleChar {
+  code,
+  italic,
+  strikethrough,
+}
+
+Future<bool> Function(EditorState) handleFormatByWrappingWithSingleChar({
+  required String char,
+  required FormatStyleByWrappingWithSingleChar formatStyle,
+}) {
+  assert(char.length == 1);
+  return (editorState) async {
+    final selection = editorState.selection;
+    // if the selection is not collapsed,
+    // we should return false to let the IME handle it.
+    if (selection == null || !selection.isCollapsed) {
+      return false;
+    }
+
+    final path = selection.end.path;
+    final node = editorState.getNodeAtPath(path);
+    final delta = node?.delta;
+    // if the node doesn't contain the delta(which means it isn't a text)
+    // we don't need to format it.
+    if (node == null || delta == null) {
+      return false;
+    }
+
+    final plainText = delta.toPlainText();
+
+    final headCharIndex = plainText.indexOf(char);
+    final endCharIndex = plainText.lastIndexOf(char);
+
+    // Determine if a 'Character' already exists in the node and only once.
+    // 1. This is no 'Character' in the plainText: indexOf returns -1.
+    // 2. More than one 'Character' in the plainText: the headCharIndex and endCharIndex are supposed to be the same, if not, which means plainText has more than one character. For example: when plainText is '_abc', it will trigger formatting(remind:the last char is used to trigger the formatting,so it won't be counted in the plainText.). But adding '_' after 'a__ab' won't trigger formatting.
+    // 3. there're two characters connecting together, like adding '_' after 'abc_' won't trigger formatting.
+    if (headCharIndex == -1 ||
+        headCharIndex != endCharIndex ||
+        headCharIndex == selection.end.offset - 1) {
+      return false;
+    }
+
+    // if all the conditions are met, we should format the text to italic.
+    // 1. delete the previous 'Character',
+    // 2. update the style of the text surrounded by the two 'Character's to [formatStyle]
+    // 3. update the cursor position.
+
+    final deletion = editorState.transaction
+      ..deleteText(
+        node,
+        headCharIndex,
+        char.length,
+      );
+    editorState.apply(deletion);
+
+    // To minimize errors, retrieve the format style from an enum that is specific to single characters.
+    final String style;
+
+    switch (formatStyle) {
+      case FormatStyleByWrappingWithSingleChar.code:
+        style = 'code';
+        break;
+      case FormatStyleByWrappingWithSingleChar.italic:
+        style = 'italic';
+        break;
+      case FormatStyleByWrappingWithSingleChar.strikethrough:
+        style = 'strikethrough';
+        break;
+      default:
+        style = '';
+        assert(false, 'Invalid format style');
+    }
+
+    final format = editorState.transaction
+      ..formatText(
+        node,
+        headCharIndex,
+        selection.end.offset - headCharIndex - 1,
+        {
+          style: true,
+        },
+      )
+      ..afterSelection = Selection.collapsed(
+        Position(
+          path: path,
+          offset: selection.end.offset - 1,
+        ),
+      );
+    editorState.apply(format);
+    return true;
+  };
+}