Files
voidraft/frontend/src/views/editor/extensions/codeblock/cursorProtection.ts
2025-11-17 22:11:16 +08:00

152 lines
4.8 KiB
TypeScript

/**
* 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';
import { Block } from './types';
import { USER_EVENTS } from './annotation';
/**
* 二分查找:找到包含指定位置的块
* blocks 数组按位置排序,使用二分查找 O(log n)
*/
function findBlockAtPos(blocks: Block[], pos: number): Block | null {
let left = 0;
let right = blocks.length - 1;
while (left <= right) {
const mid = Math.floor((left + right) / 2);
const block = blocks[mid];
if (pos < block.range.from) {
// 位置在当前块之前
right = mid - 1;
} else if (pos > block.range.to) {
// 位置在当前块之后
left = mid + 1;
} else {
// 位置在当前块范围内
return block;
}
}
return null;
}
/**
* 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 || blocks.length === 0) return false;
const block = findBlockAtPos(blocks, pos);
if (!block) return false;
// 检查是否在该块的分隔符区域内
return pos >= block.delimiter.from && pos < block.delimiter.to;
} 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;
const block = findBlockAtPos(blocks, pos);
if (!block) return pos;
// 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 {
// 找到前一个块的索引
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: USER_EVENTS.SELECT
});
// 阻止默认行为
event.preventDefault();
return true;
}
return false;
}
});
}