import express from 'express';
import cors from 'cors';
import helmet from 'helmet';
import rateLimit from 'express-rate-limit';
import { createServer } from 'http';
import { Server, Socket } from 'socket.io';
import discoverRouter from './routes/discover';
import configRouter from './routes/config';
import statsRouter from './routes/stats';
import filesRouter from './routes/files';
import terminalRouter from './routes/terminal';
import authRouter from './routes/auth';
import topologyRouter from './routes/topology';
import hostsRouter from './routes/hosts';
import { requireAuth } from './middleware/auth';
import { getHostConfigs } from './config';
import { requestLogger, logger } from './middleware/requestLogger';
import { errorHandler } from './middleware/errorHandler';

const app = express();
const httpServer = createServer(app);
const PORT = 3001;

const allowedOrigins = ['http://localhost:3000', 'http://localhost:4173'];
const corsOrigin = process.env.CORS_ORIGIN ? [process.env.CORS_ORIGIN, ...allowedOrigins] : allowedOrigins;

// --- Socket.IO setup (websocket-engineer skill) ---
const io = new Server(httpServer, {
  cors: {
    origin: corsOrigin,
    credentials: true,
  },
  pingInterval: 25000,
  pingTimeout: 10000,
});

io.on('connection', (socket: Socket) => {
  logger.info({ socketId: socket.id }, 'Client connected via WebSocket');

  socket.on('disconnect', (reason: string) => {
    logger.info({ socketId: socket.id, reason }, 'Client disconnected');
  });
});

// Export io so routes can emit events
export { io };

// --- Security middleware (api-security-hardening skill) ---
app.use(helmet({
  contentSecurityPolicy: false, // Disable CSP for dev — configure per-environment in production
}));

// CORS — restrict to configured origins
app.use(cors({
  origin: corsOrigin,
  credentials: true,
}));

// Rate limiting — general API
app.use('/api/', rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 200,
  message: { status: 'error', message: 'Too many requests, please try again later' },
  standardHeaders: true,
  legacyHeaders: false,
}));

// Stricter rate limiting for discovery (expensive operation)
app.use('/api/discover', rateLimit({
  windowMs: 1 * 60 * 1000, // 1 minute
  max: 10,
  message: { status: 'error', message: 'Discovery rate limited — max 10 per minute' },
  standardHeaders: true,
  legacyHeaders: false,
}));

// --- Body parsing ---
app.use(express.json({ limit: '1mb' }));

// --- Observability (observability-monitoring skill) ---
app.use(requestLogger);

// --- Health check ---
app.get('/api/health', (_req, res) => {
  res.json({
    status: 'ok',
    uptime: process.uptime(),
    timestamp: new Date().toISOString(),
    connections: io.engine.clientsCount,
  });
});

// --- Debug endpoint (dev only) ---
if (process.env.NODE_ENV !== 'production') {
  app.get('/api/debug-config', async (_req, res) => {
    const hosts = await getHostConfigs();
    res.json({ hosts });
  });
}

// --- Public Routes ---
app.use('/api', authRouter);

// --- Protected Routes ---
app.use('/api', requireAuth, discoverRouter);
app.use('/api', requireAuth, configRouter);
app.use('/api', requireAuth, statsRouter);
app.use('/api', requireAuth, filesRouter);
app.use('/api', requireAuth, terminalRouter);
app.use('/api', requireAuth, topologyRouter);
app.use('/api', requireAuth, hostsRouter);

// --- Global error handler (must be last) ---
app.use(errorHandler);

// --- Start server ---
httpServer.listen(PORT, () => {
  logger.info(`Server running on http://localhost:${PORT}`);
});