const express = require('express');
const helmet = require('helmet');
const rateLimit = require('express-rate-limit');
const path = require('path');
const { createSessionMiddleware, requireAuth } = require('./middleware/session');
const { registerLimiter, loginLimiter, routes: authRoutes } = require('./routes/auth');
const { routes: characterRoutes } = require('./routes/character');
const { routes: huntRoutes } = require('./routes/hunt');
const { routes: zonesRoutes } = require('./routes/zones');
const { routes: combatLogRoutes } = require('./routes/combatLog');
const { routes: inventoryRoutes } = require('./routes/inventory');
const { routes: shopRoutes } = require('./routes/shop');
const { routes: expeditionRoutes } = require('./routes/expeditions');
const { routes: leaderboardRoutes } = require('./routes/leaderboard');
const { routes: heroProfileRoutes } = require('./routes/heroProfile');
const { AppError } = require('./utils/errors');

// General API rate limiter: 120 req/min per IP (SECURITY.md).
const apiLimiter = rateLimit({
  windowMs: 60 * 1000, // 1 minute
  max: process.env.NODE_ENV === 'test' ? 1000 : 120,
  message: { ok: false, error: { code: 'RATE_LIMITED', message: 'Too many requests. Try again later.' } },
});

function createApp() {
  const app = express();

  // Security headers
  app.use(helmet());

  // Trust proxy (for rate limiting behind reverse proxy)
  app.set('trust proxy', 1);

  // JSON body parser with small limit
  app.use(express.json({ limit: '10kb' }));

  // Session middleware
  app.use(createSessionMiddleware());

  // Static files
  app.use(express.static('public'));

  // Health endpoint (no auth)
  app.get('/api/health', (_req, res) => {
    res.json({ ok: true });
  });

  // Auth routes (public)
  app.post('/api/auth/register', registerLimiter, authRoutes.postRegister);
  app.post('/api/auth/login', loginLimiter, authRoutes.postLogin);

  // Auth routes (require session)
  app.post('/api/auth/logout', requireAuth, authRoutes.postLogout);
  app.get('/api/auth/me', requireAuth, authRoutes.getMe);

  // General API rate limiter (applies to all non-auth routes below)
  app.use('/api', apiLimiter);

  // Character routes (require session)
  app.post('/api/character', requireAuth, characterRoutes.postCharacter);
  app.get('/api/character', requireAuth, characterRoutes.getCharacter);

  // Hunt routes (require session)
  app.post('/api/hunt', requireAuth, huntRoutes.postHunt);

  // Zone routes (require session)
  app.get('/api/zones', requireAuth, zonesRoutes.getZones);

  // Combat log routes (require session)
  app.get('/api/combat-log', requireAuth, combatLogRoutes.getCombatLog);

  // Inventory routes (require session)
  app.get('/api/inventory', requireAuth, inventoryRoutes.getInventory);
  app.post('/api/inventory/equip', requireAuth, inventoryRoutes.postEquip);
  app.post('/api/inventory/unequip', requireAuth, inventoryRoutes.postUnequip);
  app.post('/api/inventory/use', requireAuth, inventoryRoutes.postUse);

  // Shop routes (require session)
  app.get('/api/shop', requireAuth, shopRoutes.getShop);
  app.post('/api/shop/buy', requireAuth, shopRoutes.postBuy);
  app.post('/api/shop/sell', requireAuth, shopRoutes.postSell);

  // Expedition routes (require session)
  app.get('/api/expeditions/defs', requireAuth, expeditionRoutes.getDefs);
  app.post('/api/expeditions/start', requireAuth, expeditionRoutes.postStart);
  app.get('/api/expeditions/active', requireAuth, expeditionRoutes.getActive);
  app.post('/api/expeditions/claim', requireAuth, expeditionRoutes.postClaim);

  // Leaderboard route (require session)
  app.get('/api/leaderboard', requireAuth, leaderboardRoutes.getLeaderboard);

  // Hero profile route (public, no session required)
  app.get('/api/heroes/:name', heroProfileRoutes.getHeroProfile);

  // Catch-all: serve 404 page for unknown paths (HTML requests only).
  // API paths still return JSON errors via the central handler.
  // Placed before static files so it intercepts non-file paths.
  const PUBLIC_DIR = path.resolve(__dirname, '../public');
  app.use((req, res, next) => {
    // If a route already set headers, let it through (e.g., static file not found)
    if (res.headersSent) return next();
    if (req.accepts('html')) {
      return res.status(404).sendFile(path.join(PUBLIC_DIR, '404.html'));
    }
    return res.status(404).json({
      ok: false,
      error: { code: 'NOT_FOUND', message: 'Resource not found.' },
    });
  });

  // Static files (after catch-all for API paths, but static will still serve HTML pages)
  app.use(express.static('public'));
  app.use((err, _req, res, _next) => {
    // Log stack traces server-side only
    const fs = require('fs');
    fs.appendFileSync('/tmp/emberfall-errors.log', `ERROR: ${err.constructor.name} | ${err.message} | stack:${err.stack ? 'yes' : 'no'} | keys:${JSON.stringify(Object.keys(err))}\n${err.stack || ''}\n`);
    if (err.stack) {
      console.error(err.stack);
    }

    if (err instanceof AppError) {
      return res.status(err.status).json({
        ok: false,
        error: {
          code: err.code,
          message: err.message,
        },
      });
    }

    // Check for Zod-like validation errors
    if (err.name === 'ZodError' || (err.errors && Array.isArray(err.errors))) {
      return res.status(400).json({
        ok: false,
        error: {
          code: 'VALIDATION_ERROR',
          message: 'Request validation failed.',
        },
      });
    }

    // Generic error
    if (_req.accepts('html')) {
      return res.status(500).sendFile(path.join(PUBLIC_DIR, '500.html'));
    }
    res.status(500).json({
      ok: false,
      error: {
        code: 'INTERNAL_ERROR',
        message: 'Something went wrong.',
      },
    });
  });

  return app;
}

module.exports = { createApp };