const express = require('express');
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const http = require('http');
const https = require('https');
const multer = require('multer');

const DATA_DIR = process.env.DATA_DIR || path.join(__dirname, 'data');
const PHOTO_DIR = path.join(DATA_DIR, 'photos');
const VIDEO_DIR = path.join(DATA_DIR, 'videos');
const SELF_CERT_DIR = path.join(DATA_DIR, 'certs'); // 自簽憑證存放處（找不到外部憑證時的備援）
const EXTERNAL_CERT_DIR = process.env.CERT_DIR || ''; // 外掛正式憑證目錄（例如掛載 /certs）
const TMP_DIR = path.join(DATA_DIR, 'tmp');
for (const d of [DATA_DIR, PHOTO_DIR, VIDEO_DIR, SELF_CERT_DIR, TMP_DIR]) {
  fs.mkdirSync(d, { recursive: true });
}

const DB_FILE = path.join(DATA_DIR, 'pairs.json');
const TARGETS_META_FILE = path.join(DATA_DIR, 'targets.json');
const TARGETS_MIND_FILE = path.join(DATA_DIR, 'targets.mind');

const ADMIN_PORT = Number(process.env.ADMIN_PORT) || 3510; // 管理頁（HTTP）
const VIEWER_PORT = Number(process.env.VIEWER_PORT) || 3511; // 掃描頁（HTTPS，相機需要安全連線）

const PHOTO_EXTS = new Set(['.jpg', '.jpeg', '.png']);
const VIDEO_EXTS = new Set(['.mp4', '.m4v', '.mov', '.webm']);

function timestampName(d = new Date()) {
  const p = (n) => String(n).padStart(2, '0');
  return (
    `${d.getFullYear()}${p(d.getMonth() + 1)}${p(d.getDate())}` +
    `_${p(d.getHours())}${p(d.getMinutes())}${p(d.getSeconds())}`
  );
}

function loadJson(file, fallback) {
  try {
    return JSON.parse(fs.readFileSync(file, 'utf8'));
  } catch {
    return fallback;
  }
}

function saveJson(file, obj) {
  fs.writeFileSync(file, JSON.stringify(obj, null, 2));
}

let db = loadJson(DB_FILE, { pairs: [], updatedAt: 0 });

function persistDb() {
  db.updatedAt = Date.now();
  saveJson(DB_FILE, db);
}

const upload = multer({
  dest: TMP_DIR,
  limits: { fileSize: 2 * 1024 * 1024 * 1024 },
});

// 共用路由（API 與資料檔），掛在管理與掃描兩個 app 上
const shared = express.Router();
shared.use('/vendor', express.static(path.join(__dirname, 'public', 'vendor')));
shared.use('/data/photos', express.static(PHOTO_DIR));
shared.use('/data/videos', express.static(VIDEO_DIR));

shared.get('/data/targets.mind', (req, res) => {
  if (!fs.existsSync(TARGETS_MIND_FILE)) return res.status(404).json({ error: 'no targets' });
  res.sendFile(TARGETS_MIND_FILE);
});

function getState() {
  const targets = loadJson(TARGETS_META_FILE, null);
  const needsCompile =
    db.pairs.length > 0
      ? !targets || (targets.compiledAt || 0) < db.updatedAt
      : !!(targets && targets.targets.length > 0);
  return {
    pairs: db.pairs,
    targets,
    needsCompile,
    ports: { admin: ADMIN_PORT, viewer: VIEWER_PORT },
  };
}

shared.get('/api/state', (req, res) => {
  res.json(getState());
});

function cleanupTmp(req) {
  const files = [];
  if (req.file) files.push(req.file);
  if (req.files) for (const list of Object.values(req.files)) files.push(...list);
  for (const f of files) fs.rm(f.path, { force: true }, () => {});
}

shared.post(
  '/api/pairs',
  upload.fields([
    { name: 'photo', maxCount: 1 },
    { name: 'video', maxCount: 1 },
  ]),
  (req, res) => {
    const photo = req.files && req.files.photo && req.files.photo[0];
    const video = req.files && req.files.video && req.files.video[0];
    if (!photo || !video) {
      cleanupTmp(req);
      return res.status(400).json({ error: '需要同時上傳照片與影片' });
    }
    const photoExt = path.extname(photo.originalname).toLowerCase();
    const videoExt = path.extname(video.originalname).toLowerCase();
    if (!PHOTO_EXTS.has(photoExt)) {
      cleanupTmp(req);
      return res.status(400).json({ error: `照片格式僅支援 ${[...PHOTO_EXTS].join(' / ')}` });
    }
    if (!VIDEO_EXTS.has(videoExt)) {
      cleanupTmp(req);
      return res.status(400).json({ error: `影片格式僅支援 ${[...VIDEO_EXTS].join(' / ')}` });
    }

    const id = Date.now().toString(36) + crypto.randomBytes(3).toString('hex');
    const photoFile = id + photoExt;
    const videoFile = id + videoExt;
    fs.renameSync(photo.path, path.join(PHOTO_DIR, photoFile));
    fs.renameSync(video.path, path.join(VIDEO_DIR, videoFile));

    const pair = {
      id,
      name: timestampName(),
      photo: photoFile,
      video: videoFile,
      createdAt: Date.now(),
    };
    db.pairs.push(pair);
    persistDb();
    res.json({ ok: true, pair });
  }
);

// 裁切框（相對座標 0~1，null 表示用整張照片）。只影響編譯輸入，照片檔不動
function isValidCrop(c) {
  if (c === null) return true;
  if (!c || typeof c !== 'object') return false;
  const nums = [c.x, c.y, c.w, c.h];
  if (!nums.every((n) => typeof n === 'number' && Number.isFinite(n))) return false;
  return c.x >= 0 && c.y >= 0 && c.w > 0 && c.h > 0 && c.x + c.w <= 1.0001 && c.y + c.h <= 1.0001;
}

shared.put('/api/pairs/:id/crop', express.json(), (req, res) => {
  const pair = db.pairs.find((p) => p.id === req.params.id);
  if (!pair) return res.status(404).json({ error: '找不到這組配對' });
  const crop = req.body ? req.body.crop : undefined;
  if (crop === undefined || !isValidCrop(crop)) {
    return res.status(400).json({ error: 'crop 格式錯誤（需為 null 或 {x,y,w,h} 相對座標）' });
  }
  if (crop === null) delete pair.crop;
  else pair.crop = { x: +crop.x.toFixed(4), y: +crop.y.toFixed(4), w: +crop.w.toFixed(4), h: +crop.h.toFixed(4) };
  persistDb();
  res.json({ ok: true, pair });
});

shared.delete('/api/pairs/:id', (req, res) => {
  const idx = db.pairs.findIndex((p) => p.id === req.params.id);
  if (idx === -1) return res.status(404).json({ error: '找不到這組配對' });
  const [pair] = db.pairs.splice(idx, 1);
  fs.rm(path.join(PHOTO_DIR, pair.photo), { force: true }, () => {});
  fs.rm(path.join(VIDEO_DIR, pair.video), { force: true }, () => {});
  persistDb();
  res.json({ ok: true });
});

// 管理頁在瀏覽器端把所有照片編譯成 .mind 特徵檔後上傳到這裡
shared.post('/api/targets', upload.single('mind'), (req, res) => {
  let mapping;
  try {
    mapping = JSON.parse(req.body.mapping);
    if (!Array.isArray(mapping.targets)) throw new Error('bad mapping');
  } catch {
    cleanupTmp(req);
    return res.status(400).json({ error: 'mapping 格式錯誤' });
  }
  if (!req.file) return res.status(400).json({ error: '缺少 .mind 檔' });

  const known = new Set(db.pairs.map((p) => p.id));
  for (const t of mapping.targets) {
    if (!known.has(t.pairId)) {
      cleanupTmp(req);
      return res.status(400).json({ error: `pairId ${t.pairId} 不存在，請重新整理後再編譯` });
    }
  }

  fs.renameSync(req.file.path, TARGETS_MIND_FILE);
  saveJson(TARGETS_META_FILE, { compiledAt: Date.now(), targets: mapping.targets });
  res.json({ ok: true, state: getState() });
});

function errorHandler(err, req, res, next) {
  console.error(err);
  res.status(500).json({ error: err.message || 'server error' });
}

// HTML 一律不快取，避免手機拿到舊版頁面
function sendPage(file) {
  return (req, res) =>
    res.sendFile(path.join(__dirname, 'public', file), {
      headers: { 'Cache-Control': 'no-store' },
    });
}

// 管理 app（3510，HTTP）：root 是管理頁
const adminApp = express();
adminApp.get('/', sendPage('admin.html'));
adminApp.get('/admin', (req, res) => res.redirect('/'));
adminApp.use(shared);
adminApp.use(errorHandler);

// 掃描 app（3511，HTTPS）：root 是掃描頁
const viewerApp = express();
viewerApp.get('/', sendPage('index.html'));
viewerApp.use(shared);
viewerApp.use(errorHandler);

function ensureCerts() {
  // 1. 明確指定的憑證檔（環境變數 SSL_KEY / SSL_CERT 為完整路徑）
  if (process.env.SSL_KEY && process.env.SSL_CERT) {
    console.log('使用指定憑證:', process.env.SSL_CERT);
    return { key: fs.readFileSync(process.env.SSL_KEY), cert: fs.readFileSync(process.env.SSL_CERT) };
  }
  // 2. 外掛憑證目錄（CERT_DIR），依常見檔名組合搜尋
  if (EXTERNAL_CERT_DIR) {
    const candidates = [
      ['privkey.pem', 'fullchain.pem'], // Let's Encrypt / Synology 匯出
      ['privkey.pem', 'cert.pem'],
      ['server.key', 'server.crt'],
      ['key.pem', 'cert.pem'],
      ['ssl.key', 'ssl.crt'],
    ];
    for (const [k, c] of candidates) {
      const keyFile = path.join(EXTERNAL_CERT_DIR, k);
      const certFile = path.join(EXTERNAL_CERT_DIR, c);
      if (fs.existsSync(keyFile) && fs.existsSync(certFile)) {
        console.log(`使用外掛憑證: ${certFile} + ${keyFile}`);
        return { key: fs.readFileSync(keyFile), cert: fs.readFileSync(certFile) };
      }
    }
    console.warn(`在 ${EXTERNAL_CERT_DIR} 找不到憑證（試過: ${candidates.map((p) => p.join('+')).join(', ')}），改用自簽憑證`);
  }
  // 3. 備援：自動產生自簽憑證
  const keyFile = path.join(SELF_CERT_DIR, 'server.key');
  const certFile = path.join(SELF_CERT_DIR, 'server.crt');
  if (fs.existsSync(keyFile) && fs.existsSync(certFile)) {
    return { key: fs.readFileSync(keyFile), cert: fs.readFileSync(certFile) };
  }
  const selfsigned = require('selfsigned');
  const pems = selfsigned.generate([{ name: 'commonName', value: 'photo-live' }], {
    days: 3650,
    keySize: 2048,
    extensions: [
      {
        name: 'subjectAltName',
        altNames: [{ type: 2, value: 'localhost' }, { type: 2, value: 'photo-live' }],
      },
    ],
  });
  fs.writeFileSync(keyFile, pems.private);
  fs.writeFileSync(certFile, pems.cert);
  console.log('已產生自簽 HTTPS 憑證於', SELF_CERT_DIR);
  return { key: pems.private, cert: pems.cert };
}

http.createServer(adminApp).listen(ADMIN_PORT, () => {
  console.log(`管理頁 (HTTP):  http://0.0.0.0:${ADMIN_PORT}`);
});
https.createServer(ensureCerts(), viewerApp).listen(VIEWER_PORT, () => {
  console.log(`掃描頁 (HTTPS): https://0.0.0.0:${VIEWER_PORT} （手機請走這個）`);
});