const express = require('express');
const fs = require('fs');
const path = require('path');
const sharp = require('sharp');
const session = require('express-session');
const app = express();
const port = 3001;

const comicsRoot = '/www/comics'; // 修改为你的漫画主目录

app.use(require('cors')({
  origin: true,
  credentials: true // 允许跨域携带cookie（前端用 credentials: 'include'）
}));
app.use(express.json());
app.use(session({
  secret: 'comic-viewer-2024', // 建议改成强随机字符串
  resave: false,
  saveUninitialized: false,
  cookie: { httpOnly: true, maxAge: 30 * 24 * 3600 * 1000 }
}));

// ==========================
// 用户管理
// ==========================

// users.txt 格式: 每行  username:password
function loadUsers() {
  const file = path.join(__dirname, 'users.txt');
  if (!fs.existsSync(file)) return {};
  const users = {};
  fs.readFileSync(file, 'utf8').split(/\r?\n/).forEach(line => {
    if (!line.trim() || line.trim().startsWith('#')) return;
    const [u, p] = line.split(':');
    if (u && p) users[u.trim()] = p.trim();
  });
  return users;
}

// 登录
app.post('/api/login', (req, res) => {
  const { username, password } = req.body;
  const users = loadUsers();
  if (users[username] && users[username] === password) {
    req.session.login = true;
    req.session.username = username;
    res.json({ ok: true });
  } else {
    res.status(401).json({ ok: false, msg: '用户名或密码错误' });
  }
});
// 登出
app.post('/api/logout', (req, res) => {
  req.session.destroy(() => res.json({ ok: true }));
});
// 检查登录状态
app.get('/api/check', (req, res) => {
  res.json({ login: !!req.session.login, username: req.session.username });
});

// 认证中间件
function auth(req, res, next) {
  if (req.session.login) return next();
  res.status(401).json({ ok: false, msg: '请先登录' });
}

// ==========================
// 业务API（所有加auth保护）
// ==========================

// 文件类型判定
function isImage(fn) { return /\.(jpe?g|png|webp|gif)$/i.test(fn); }
function isHtml(fn) { return /\.html?$/i.test(fn); }
function isVideo(fn) { return /\.(mp4|webm|mov|avi|mkv|ogg)$/i.test(fn); }

// 只列出非空文件夹
app.get('/api/folders', auth, (req, res) => {
  fs.readdir(comicsRoot, { withFileTypes: true }, (err, files) => {
    if (err) return res.status(500).json([]);
    const dirs = files.filter(f => f.isDirectory()).map(f => f.name);
    Promise.all(
      dirs.map(d =>
        new Promise(resolve => {
          fs.readdir(path.join(comicsRoot, d), (e, fls) => {
            const nonHidden = (fls || []).filter(f => !f.startsWith('.'));
            resolve(nonHidden.length > 0 ? d : null);
          });
        })
      )
    ).then(results => {
      res.json(results.filter(Boolean));
    });
  });
});

// 文件夹下所有文件（图片/html/视频/其它）
app.get('/api/list/:folder', auth, (req, res) => {
  const folder = path.basename(req.params.folder);
  const dir = path.join(comicsRoot, folder);
  fs.readdir(dir, (err, files) => {
    if (err) return res.status(404).json([]);
    const filtered = files.filter(f => !f.startsWith('.'));
    res.json(filtered.sort((a, b) => a.localeCompare(b, 'zh', { numeric: true })));
  });
});

// 文件夹下所有图片（按文件名排序）
app.get('/api/images/:folder', auth, (req, res) => {
  const folder = path.basename(req.params.folder);
  const dir = path.join(comicsRoot, folder);
  fs.readdir(dir, (err, files) => {
    if (err) return res.status(404).json([]);
    const imgs = files.filter(isImage).sort((a, b) => a.localeCompare(b, 'zh', { numeric: true }));
    res.json(imgs);
  });
});

// 图片/视频/其它原始文件
app.get('/api/image/:folder/:img', auth, (req, res) => {
  const folder = path.basename(req.params.folder);
  const img = path.basename(req.params.img);
  const file = path.join(comicsRoot, folder, img);
  fs.access(file, fs.constants.R_OK, (err) => {
    if (err) return res.status(404).end();
    res.sendFile(file);
  });
});

// 图片缩略图（只对图片调用）
app.get('/api/image-thumb/:folder/:img', auth, (req, res) => {
  const folder = path.basename(req.params.folder);
  const img = path.basename(req.params.img);
  const file = path.join(comicsRoot, folder, img);
  fs.access(file, fs.constants.R_OK, (err) => {
    if (err) return res.status(404).end();
    sharp(file).resize({ height: 128 }).toBuffer()
      .then(buf => res.type('image/jpeg').send(buf))
      .catch(() => res.status(404).end());
  });
});

// HTML 文件（iframe方式）
app.get('/api/html/:folder/:file', auth, (req, res) => {
  const folder = path.basename(req.params.folder);
  const file = path.basename(req.params.file);
  const filePath = path.join(comicsRoot, folder, file);
  fs.access(filePath, fs.constants.R_OK, (err) => {
    if (err) return res.status(404).end();
    res.sendFile(filePath);
  });
});

app.listen(port, () => console.log('Comic backend running at port', port));