/* ═══════════════════════════════════════════════════════════
   巨子测肤 · 1'me — 后端服务(零依赖,Node ≥ 18)
   1) 静态托管 h5/ 目录
   2) POST /api/skin-analyze:图片中转 Face++ 高阶版测肤
      密钥只存在服务端(SKIN_API_KEY / SKIN_API_SECRET),
      前端永远接触不到 api_secret。
   启动: node server.js   (默认 8080,可用 PORT 环境变量改)
   ═══════════════════════════════════════════════════════════ */
'use strict';

const http = require('http');
const fs = require('fs');
const path = require('path');

const PORT = Number(process.env.PORT) || 8080;
const ROOT = __dirname;
const FACEPP_URL = 'https://api-cn.faceplusplus.com/facepp/v1/skinanalyze_advanced';

/* ─── 密钥加载:环境变量优先,其次解析项目根的 apikey.bash ─── */
function loadCredentials() {
  if (process.env.SKIN_API_KEY && process.env.SKIN_API_SECRET) {
    return { key: process.env.SKIN_API_KEY, secret: process.env.SKIN_API_SECRET };
  }
  try {
    const txt = fs.readFileSync(path.join(ROOT, '..', 'apikey.bash'), 'utf8');
    const key = (txt.match(/SKIN_API_KEY\s*=\s*["']?([A-Za-z0-9_-]+)/) || [])[1];
    const secret = (txt.match(/SKIN_API_SECRET\s*=\s*["']?([A-Za-z0-9_-]+)/) || [])[1];
    if (key && secret) return { key, secret };
  } catch (e) { /* 文件不存在则走下面的报错 */ }
  console.error('[启动失败] 找不到密钥:请设置 SKIN_API_KEY / SKIN_API_SECRET 环境变量,');
  console.error('           或在项目根目录放置 apikey.bash(内容为 export SKIN_API_KEY=... 等)');
  process.exit(1);
}
const CRED = loadCredentials();

/* ─── 静态文件 ─── */
const MIME = {
  '.html': 'text/html; charset=utf-8', '.css': 'text/css; charset=utf-8',
  '.js': 'application/javascript; charset=utf-8', '.json': 'application/json; charset=utf-8',
  '.png': 'image/png', '.jpg': 'image/jpeg', '.jpeg': 'image/jpeg', '.svg': 'image/svg+xml',
  '.ico': 'image/x-icon', '.webp': 'image/webp', '.woff2': 'font/woff2'
};
function serveStatic(req, res, pathname) {
  let p = decodeURIComponent(pathname);
  if (p === '/') p = '/index.html';
  const file = path.normalize(path.join(ROOT, p));
  if (file !== ROOT && !file.startsWith(ROOT + path.sep)) { res.writeHead(403); return res.end('Forbidden'); }
  fs.readFile(file, (err, data) => {
    if (err) { res.writeHead(404, { 'Content-Type': 'text/plain; charset=utf-8' }); return res.end('Not Found'); }
    res.writeHead(200, { 'Content-Type': MIME[path.extname(file)] || 'application/octet-stream' });
    res.end(data);
  });
}

/* ─── Face++ 错误 → 用户可读提示 ─── */
const ERR_MSG = {
  'NO_FACE_FOUND': '未检测到人脸,请正对镜头、露出完整五官后重试',
  'INVALID_IMAGE_FACE': '照片中人脸不完整或检测到多张人脸,请单人正脸出镜',
  'INVALID_FACE_SIZE': '距离太远啦,请靠近镜头一些',
  'INVALID_IMAGE_SIZE': '照片尺寸不符合要求,请重试',
  'IMAGE_FILE_TOO_LARGE': '照片过大,请重试',
  'IMAGE_ERROR_UNSUPPORTED_FORMAT': '照片格式不支持,请重试',
  'AUTHENTICATION_ERROR': '检测服务配置有误,请联系管理员',
  'AUTHORIZATION_ERROR': '检测服务额度或权限异常,请联系管理员',
  'CONCURRENCY_LIMIT_EXCEEDED': '当前检测人数较多,请稍候重试',
  'INTERNAL_ERROR': '检测服务开小差了,请稍候重试'
};

function readBody(req, limitBytes) {
  return new Promise((resolve, reject) => {
    let size = 0; const chunks = [];
    req.on('data', c => {
      size += c.length;
      if (size > limitBytes) { reject(new Error('TOO_LARGE')); req.destroy(); return; }
      chunks.push(c);
    });
    req.on('end', () => resolve(Buffer.concat(chunks)));
    req.on('error', reject);
  });
}

async function handleAnalyze(req, res) {
  try {
    const body = JSON.parse((await readBody(req, 12 * 1024 * 1024)).toString('utf8'));
    const b64 = (body.image_base64 || '').replace(/^data:image\/\w+;base64,/, '');
    if (!b64) { res.writeHead(400, { 'Content-Type': 'application/json; charset=utf-8' }); return res.end(JSON.stringify({ ok: false, code: 'NO_IMAGE', message: '缺少图片' })); }

    const form = new FormData();
    form.append('api_key', CRED.key);
    form.append('api_secret', CRED.secret);
    form.append('image_base64', b64);
    form.append('face_quality_control', '0');
    form.append('return_rect_confidence', '1');
    form.append('return_maps', 'red_area');

    const fpRes = await fetch(FACEPP_URL, { method: 'POST', body: form, signal: AbortSignal.timeout(30000) });
    const fpJson = await fpRes.json().catch(() => ({}));

    if (fpJson.error_message) {
      const code = fpJson.error_message.split(':')[0];
      console.log(`[analyze] Face++ 错误: ${code}`);
      res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
      return res.end(JSON.stringify({ ok: false, code, message: ERR_MSG[code] || '检测失败,请重试' }));
    }
    if (!fpJson.result) {
      res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
      return res.end(JSON.stringify({ ok: false, code: 'INTERNAL_ERROR', message: ERR_MSG.INTERNAL_ERROR }));
    }
    // 只回传前端需要的字段,不透传密钥相关内容
    res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
    res.end(JSON.stringify({ ok: true, result: fpJson.result, face_rectangle: fpJson.face_rectangle || null }));
  } catch (e) {
    const code = e.message === 'TOO_LARGE' ? 'IMAGE_FILE_TOO_LARGE' : 'NETWORK_ERROR';
    res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
    res.end(JSON.stringify({ ok: false, code, message: code === 'NETWORK_ERROR' ? '网络异常,请检查网络后重试' : ERR_MSG[code] }));
  }
}

http.createServer((req, res) => {
  if (req.method === 'POST' && req.url.split('?')[0] === '/api/skin-analyze') return handleAnalyze(req, res);
  if (req.method === 'GET' && req.url.split('?')[0] === '/api/health') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    return res.end(JSON.stringify({ ok: true }));
  }
  return serveStatic(req, res, req.url.split('?')[0]);
}).listen(PORT, '0.0.0.0', () => {
  console.log(`[server] 巨子测肤 H5 已启动: http://127.0.0.1:${PORT}  (静态 + /api/skin-analyze)`);
});