#!/usr/bin/env node
/**
 * ui-picker-server.js —— 极简「页面元素拾取」服务（零依赖）
 *
 * 干什么：给浏览器里的拾取器提供一个落脚点 ——
 *         页面点选元素后，把「选择器 / 网页 / 文本 / class / 关键样式 / HTML 片段」
 *         追加写进本技能目录下的 marks/_ui-marks.json，供 AI 读取后精确改代码。
 *
 * 起法：  node ui-picker-server.js [端口]                      （在本目录下执行，默认 8890）
 * 页面：  <script src="http://127.0.0.1:8890/picker.js"></script>
 *         URL 带 ?pick 才激活；按 Z 切拾取模式；点元素 → 确认窗 → 「确认」
 *
 * 端点：
 *   GET  /picker.js        注入脚本
 *   POST /mark             存一条标记（追加写盘）
 *   GET  /marks            读回全部标记（JSON）
 *   POST /clear            清空标记
 *   GET  /health           存活检查
 */
const http = require('http');
const fs = require('fs');
const path = require('path');

const PORT = parseInt(process.argv[2], 10) || 8890;
// 存档跟技能一起放，搬到哪都自洽
const OUT_DIR = path.join(__dirname, 'marks');
const OUT_FILE = path.join(OUT_DIR, '_ui-marks.json');

function readMarks() {
  try {
    const raw = fs.readFileSync(OUT_FILE, 'utf8');
    const obj = JSON.parse(raw);
    return Array.isArray(obj.marks) ? obj : { updated: '', marks: [] };
  } catch {
    return { updated: '', marks: [] };
  }
}

function writeMarks(obj) {
  fs.mkdirSync(OUT_DIR, { recursive: true });
  obj.updated = new Date().toISOString();
  fs.writeFileSync(OUT_FILE, JSON.stringify(obj, null, 2), 'utf8');
}

function send(res, code, body, type) {
  res.writeHead(code, {
    'Content-Type': type || 'application/json; charset=utf-8',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Headers': 'Content-Type',
    'Access-Control-Allow-Methods': 'GET,POST,OPTIONS',
    'Cache-Control': 'no-store',
  });
  res.end(body);
}

function readBody(req) {
  return new Promise((resolve, reject) => {
    let buf = '';
    req.on('data', (c) => {
      buf += c;
      if (buf.length > 8 * 1024 * 1024) reject(new Error('body too large'));
    });
    req.on('end', () => resolve(buf));
    req.on('error', reject);
  });
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, `http://127.0.0.1:${PORT}`);

  if (req.method === 'OPTIONS') return send(res, 204, '');

  if (req.method === 'GET' && url.pathname === '/health') {
    return send(res, 200, JSON.stringify({ ok: true, skill: __dirname, file: OUT_FILE, count: readMarks().marks.length }));
  }

  if (req.method === 'GET' && url.pathname === '/picker.js') {
    return send(res, 200, fs.readFileSync(path.join(__dirname, 'picker.js'), 'utf8'), 'application/javascript; charset=utf-8');
  }

  if (req.method === 'GET' && url.pathname === '/marks') {
    return send(res, 200, fs.readFileSync(OUT_FILE, 'utf8').toString());
  }

  if (req.method === 'POST' && url.pathname === '/mark') {
    try {
      const body = JSON.parse(await readBody(req));
      const store = readMarks();
      const item = {
        id: store.marks.length + 1,
        at: new Date().toISOString(),
        page: body.page || '',
        note: body.note || '',
        selector: body.selector || '',
        breadcrumb: body.breadcrumb || '',
        tag: body.tag || '',
        classes: body.classes || [],
        text: body.text || '',
        attrs: body.attrs || {},
        rect: body.rect || null,
        styles: body.styles || {},
        html: body.html || '',
      };
      store.marks.push(item);
      writeMarks(store);
      console.log(`[mark #${item.id}] ${item.selector}  ← ${item.note}`);
      return send(res, 200, JSON.stringify({ ok: true, id: item.id, total: store.marks.length }));
    } catch (e) {
      return send(res, 400, JSON.stringify({ ok: false, error: String(e.message || e) }));
    }
  }

  if (req.method === 'POST' && url.pathname === '/clear') {
    writeMarks({ updated: '', marks: [] });
    return send(res, 200, JSON.stringify({ ok: true, total: 0 }));
  }

  return send(res, 404, JSON.stringify({ ok: false, error: 'not found' }));
});

server.listen(PORT, '127.0.0.1', () => {
  console.log(`元素拾取服务已启动: http://127.0.0.1:${PORT}`);
  console.log(`页面引入: <script src="http://127.0.0.1:${PORT}/picker.js"></script>`);
  console.log(`标记落盘: ${OUT_FILE}`);
});