✨ Added cursor protection extension

frontend/src/views/editor/extensions/codeblock/cursorProtection.ts

@@ -0,0 +1,123 @@
+/**
+ * 光标保护扩展
+ * 防止光标通过方向键移动到分隔符区域
+ */
+
+import { EditorView } from '@codemirror/view';
+import { EditorSelection } from '@codemirror/state';
+import { blockState } from './state';
+
+/**
+ * 检查位置是否在分隔符区域内
+ */
+function isInDelimiter(view: EditorView, pos: number): boolean {
+    try {
+        const blocks = view.state.field(blockState, false);
+        if (!blocks) return false;
+
+        for (const block of blocks) {
+            if (pos >= block.delimiter.from && pos < block.delimiter.to) {
+                return true;
+            }
+        }
+        return false;
+    } catch {
+        return false;
+    }
+}
+
+/**
+ * 调整光标位置，跳过分隔符区域
+ */
+function adjustPosition(view: EditorView, pos: number, forward: boolean): number {
+    try {
+        const blocks = view.state.field(blockState, false);
+        if (!blocks || blocks.length === 0) return pos;
+
+        for (const block of blocks) {
+            // 如果位置在分隔符内
+            if (pos >= block.delimiter.from && pos < block.delimiter.to) {
+                // 向前移动：跳到该块内容的开始
+                // 向后移动：跳到前一个块的内容末尾
+                if (forward) {
+                    return block.content.from;
+                } else {
+                    // 找到前一个块
+                    const blockIndex = blocks.indexOf(block);
+                    if (blockIndex > 0) {
+                        const prevBlock = blocks[blockIndex - 1];
+                        return prevBlock.content.to;
+                    }
+                    return block.delimiter.from;
+                }
+            }
+        }
+
+        return pos;
+    } catch {
+        return pos;
+    }
+}
+
+/**
+ * 光标保护扩展
+ * 拦截方向键移动，防止光标进入分隔符区域
+ */
+export function createCursorProtection() {
+    return EditorView.domEventHandlers({
+        keydown(event, view) {
+            // 只处理方向键
+            if (!['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown'].includes(event.key)) {
+                return false;
+            }
+
+            // 获取当前光标位置
+            const selection = view.state.selection.main;
+            const currentPos = selection.head;
+
+            // 计算目标位置
+            let targetPos = currentPos;
+            
+            if (event.key === 'ArrowLeft') {
+                targetPos = Math.max(0, currentPos - 1);
+            } else if (event.key === 'ArrowRight') {
+                targetPos = Math.min(view.state.doc.length, currentPos + 1);
+            } else if (event.key === 'ArrowUp') {
+                const line = view.state.doc.lineAt(currentPos);
+                if (line.number > 1) {
+                    const prevLine = view.state.doc.line(line.number - 1);
+                    const col = currentPos - line.from;
+                    targetPos = Math.min(prevLine.from + col, prevLine.to);
+                }
+            } else if (event.key === 'ArrowDown') {
+                const line = view.state.doc.lineAt(currentPos);
+                if (line.number < view.state.doc.lines) {
+                    const nextLine = view.state.doc.line(line.number + 1);
+                    const col = currentPos - line.from;
+                    targetPos = Math.min(nextLine.from + col, nextLine.to);
+                }
+            }
+
+            // 检查目标位置是否在分隔符内
+            if (isInDelimiter(view, targetPos)) {
+                // 调整位置
+                const forward = event.key === 'ArrowRight' || event.key === 'ArrowDown';
+                const adjustedPos = adjustPosition(view, targetPos, forward);
+
+                // 移动光标到调整后的位置
+                view.dispatch({
+                    selection: EditorSelection.cursor(adjustedPos),
+                    scrollIntoView: true,
+                    userEvent: 'select'
+                });
+
+                // 阻止默认行为
+                event.preventDefault();
+                return true;
+            }
+
+            return false;
+        }
+    });
+}
+

frontend/src/views/editor/extensions/codeblock/index.ts

@@ -25,6 +25,7 @@ import {getCodeBlockLanguageExtension} from './lang-parser';
 import {createLanguageDetection} from './lang-detect';
 import {SupportedLanguage} from './types';
 import {getMathBlockExtensions} from './mathBlock';
+import {createCursorProtection} from './cursorProtection';
 
 /**
  * 代码块扩展配置选项
@@ -108,6 +109,9 @@ export function createCodeBlockExtension(options: CodeBlockOptions = {}): Extens
             showBackground
         }),
 
+        // 光标保护（防止方向键移动到分隔符上）
+        createCursorProtection(),
+
         // 块选择功能
         ...getBlockSelectExtensions(),
 
@@ -207,6 +211,11 @@ export {
     getMathBlockExtensions
 } from './mathBlock';
 
+// 光标保护功能
+export {
+    createCursorProtection
+} from './cursorProtection';
+
 /**
  * 默认导出
  */