import express from 'express';
import path from 'path';
import cors from 'cors';
import helmet from 'helmet';
import morgan from 'morgan';
import config from './config';
import { VERSION as version } from "./version";
import { checkStartup } from './config/startup-validator';
import { getDb } from './database/database';
import { connectRedis, disconnectRedis, reconnectRedis, testRedisConnection } from './middleware/cache';
import rateLimiter from './middleware/rate-limit';
import routes from './routes';
import { pansouWebProxy } from './proxy/pansou-web';
import { checkAndRunScheduledCleanup } from './cloud/cleanup.service';
import { refreshAllStorageInfo } from './cloud/cloud.service';

const app = express();

// ============ Middleware ============
app.set('trust proxy', true);

// CORS — 生产环境必须配置真实域名（空值或占位符用 * 并打警告日志）
const corsOrigin = process.env.CORS_ORIGIN || '';
const isPlaceholder = !corsOrigin || corsOrigin === 'https://your-domain.com';
if (config.nodeEnv === 'production' && isPlaceholder) {
  console.error('[FATAL] CORS_ORIGIN 未配置或使用了占位符 https://your-domain.com，生产环境必须设置真实域名。应用拒绝启动。');
  process.exit(1);
}
if (config.nodeEnv === 'production' && !isPlaceholder) {
  app.use(cors({ origin: corsOrigin, credentials: true }));
} else {
  app.use(cors({ origin: '*', credentials: false }));
}

app.use(helmet({ contentSecurityPolicy: false }));

// morgan 日志格式：不记录 IP，避免隐私合规问题
app.use(morgan(':method :url :status :res[content-length] - :response-time ms'));

app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true, limit: '10mb' }));
// ============ 前端静态文件 ============
const frontendDist = path.join(__dirname, 'frontend');
// Cache control: HTML no-cache, hashed assets immutable
app.use((req, res, next) => {
  if (req.path.endsWith('.html')) {
    res.setHeader('Cache-Control', 'no-cache, no-store, must-revalidate');
  } else if (req.path.startsWith('/assets/')) {
    res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
  }
  next();
});
app.use(express.static(frontendDist));

// ============ Rate Limiting (after static files — only API routes are limited)
app.use(rateLimiter);

// ============ Routes ============
app.use('/api/uploads', express.static('/app/uploads'));
app.use('/api', routes);

// ============ Health Check（增强版：覆盖 Redis / PanSou / VideoParser 状态） ============
app.get('/health', async (_req, res) => {
  const dbOk = (() => {
    try { getDb(); return true; } catch { return false; }
  })();

  const redisStatus = await (async () => {
    try {
      const { getRedis } = require('./middleware/cache');
      const redis = getRedis();
      if (!redis) return 'disconnected';
      const pong = await redis.ping().catch(() => null);
      return pong === 'PONG' ? 'connected' : 'error';
      // eslint-disable-next-line no-unused-vars
    } catch { return 'unknown'; }
  })();

  const pansouStatus = await (async () => {
    try {
      // Native fetch available in Node 20+
      const url = (config.pansouUrl || 'http://pansou:80').replace(/\/+$/, '') + '/api/search';
      const controller = new AbortController();
      const t = setTimeout(() => controller.abort(), 3000);
      const r = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ kw: 'health', page: 1 }), signal: controller.signal });
      clearTimeout(t);
      return r.ok ? 'ok' : 'degraded';
      // eslint-disable-next-line no-unused-vars
    } catch { return 'unreachable'; }
  })();

  const videoParserStatus = await (async () => {
    try {
      // Native fetch available in Node 20+
      const url = (config.videoParserUrl || 'http://video-parser:3001').replace(/\/+$/, '');
      const controller = new AbortController();
      const t = setTimeout(() => controller.abort(), 3000);
      const r = await fetch(url, { signal: controller.signal });
      clearTimeout(t);
      return r.ok ? 'ok' : 'degraded';
      // eslint-disable-next-line no-unused-vars
    } catch { return 'unreachable'; }
  })();

  const overall = dbOk && redisStatus === 'connected' && pansouStatus === 'ok' && videoParserStatus === 'ok'
    ? 'ok'
    : dbOk && redisStatus !== 'unknown' && pansouStatus !== 'unreachable'
      ? 'degraded'
      : 'unhealthy';

  res.json({
    version,
    status: overall,
    timestamp: new Date().toISOString(),
    uptime: Math.floor(process.uptime()),
    memory: process.memoryUsage().rss,
    components: {
      db: dbOk ? 'connected' : 'error',
      redis: redisStatus,
      pansou: pansouStatus,
      videoParser: videoParserStatus,
    },
  });
});

// ============ PanSou Web UI Proxy ============
app.use('/pansou', pansouWebProxy);

// SPA fallback
app.use((req, res, next) => {
  if (req.path.startsWith('/api/') || req.path === '/health') return next();
  res.sendFile(path.join(frontendDist, 'index.html'), (err) => { if (err) next(); });
});

// Global error handler
app.use((err: any, _req: express.Request, res: express.Response, _next: express.NextFunction) => {
  console.error('[Error]', err);
  res.status(err.status || 500).json({
    error: config.nodeEnv === 'production' ? 'Internal server error' : err.message,
    code: err.status || 500,
  });
});

// ============ Server Start ============
async function start(): Promise<void> {
  // Startup config validation
  if (!checkStartup()) {
    console.error('[Server] 配置校验未通过，进程退出');
    process.exit(1);
  }

  try {
    getDb();
    console.log('[DB] SQLite database initialized');
    try {
      const { getSystemConfig } = require('./admin/system-config.service');
      const tz = getSystemConfig('timezone');
      if (tz) { process.env.TZ = tz; console.log(`[Config] Timezone set to: ${tz}`); }
    } catch { console.warn('[Config] Could not set timezone, using default'); }
  } catch (err) {
    console.error('[DB] Failed to initialize database:', err);
    process.exit(1);
  }

  try {
    const { getSystemConfig } = require('./admin/system-config.service');
    const redisUrl = process.env.REDIS_URL || getSystemConfig('redis_url');
    if (redisUrl) {
      const ok = await reconnectRedis(redisUrl);
      if (ok) console.log('[Redis] Connected to', redisUrl);
    } else {
      await connectRedis();
    }
  } catch { console.warn('[Redis] Redis not available, continuing without cache'); }

  // Cleanup scheduler
  const CLEANUP_INTERVAL = 10 * 60 * 1000;
  setInterval(() => { checkAndRunScheduledCleanup().catch(err => console.error('[Cleanup] Scheduler error:', err.message)); }, CLEANUP_INTERVAL);
  setTimeout(() => { checkAndRunScheduledCleanup().catch(err => console.error('[Cleanup] Initial check error:', err.message)); }, 30000);

  // Storage info refresh scheduler — every 60 minutes
  const STORAGE_REFRESH_INTERVAL = 60 * 60 * 1000;
  setInterval(() => { refreshAllStorageInfo().catch(err => console.error('[Storage] Refresh error:', err.message)); }, STORAGE_REFRESH_INTERVAL);
  setTimeout(() => { refreshAllStorageInfo().catch(err => console.error('[Storage] Initial refresh error:', err.message)); }, 60000);

  const server = app.listen(config.port, () => {
    console.log(`[Server] CloudSearch Backend running on port ${config.port} (${config.nodeEnv})`);
  });

  const shutdown = async (signal: string) => {
    console.log(`\n[Server] Received ${signal}, shutting down gracefully...`);
    server.close(async () => { await disconnectRedis(); console.log('[Server] Closed'); process.exit(0); });
    setTimeout(() => { console.error('[Server] Force shutdown'); process.exit(1); }, 10000);
  };

  process.on('SIGTERM', () => shutdown('SIGTERM'));
  process.on('SIGINT', () => shutdown('SIGINT'));
  process.on('uncaughtException', (err) => { console.error('[FATAL] Uncaught Exception:', err); setTimeout(() => process.exit(1), 1000); });
  process.on('unhandledRejection', (reason) => { const msg = reason instanceof Error ? reason.message : String(reason); console.error('[FATAL] Unhandled Rejection:', msg); });
}

start().catch((err) => { console.error('[Server] Failed to start:', err); process.exit(1); });

export default app;