feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

frontend/packages/common/chat-area/text-grab/src/utils/helper/get-selection-direction.ts

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+ 
+import { Direction } from '../../types/selection';
+import { compareNodePosition } from './compare-node-position';
+
+export const getSelectionDirection = (selection: Selection): Direction => {
+  // 确保有选区存在
+  if (!selection || selection.isCollapsed) {
+    return Direction.Unknown; // 没有选区或选区未展开
+  }
+
+  const { anchorNode } = selection;
+  const { focusNode } = selection;
+
+  // 确保 anchorNode 和 focusNode 都不为 null
+  if (!anchorNode || !focusNode) {
+    return Direction.Unknown; // 无法确定方向
+  }
+
+  const { anchorOffset } = selection;
+  const { focusOffset } = selection;
+  // 比较 anchor 和 focus 的位置
+  if (anchorNode === focusNode) {
+    // 如果 anchor 和 focus 在同一个节点，通过偏移量判断方向
+    return anchorOffset <= focusOffset ? Direction.Forward : Direction.Backward;
+  } else {
+    // 如果不在同一个节点，使用 Document Position 来判断
+    const position = compareNodePosition(anchorNode, focusNode);
+
+    if (position === 'before') {
+      return Direction.Forward;
+    } else if (position === 'after') {
+      return Direction.Backward;
+    }
+  }
+
+  // 如果无法确定方向，返回 'unknown'
+  return Direction.Unknown;
+};