import { Request, Response, NextFunction } from 'express';
import jwt from 'jsonwebtoken';
import { JWT_CONFIG } from '../config/env.config';
import { getRedisClient } from '../util/redis.util';

declare global {
  namespace Express {
    interface Request {
      userId?: string;
      user?: any;
    }
  }
}

const auth = async (req: Request, res: Response, next: NextFunction) => {
  const authHeader = req.headers.authorization;

  if (!authHeader || !authHeader.startsWith('Bearer ')) {
    return res.status(401).json({ message: 'No token provided.' });
  }

  const token = authHeader.split(' ')[1];

  try {
    const decoded = jwt.verify(token, JWT_CONFIG.secret);

    if (typeof decoded === 'string' || !('userId' in decoded)) {
      return res.status(401).json({ message: 'Invalid token structure.' });
    }

    // Check if session exists in Redis (for logout/invalidation)
    const redis = await getRedisClient();
    const sessionKey = `session:${decoded.userId}:${token.substring(0, 10)}`;
    const sessionExists = await redis.exists(sessionKey);

    if (!sessionExists) {
      return res.status(401).json({ message: 'Session expired or invalid.' });
    }

    // Fetch user to check 2FA status
    const User = (await import('../model/user.model')).default;
    const user = await User.findById(decoded.userId);

    if (!user) {
      return res.status(401).json({ message: 'User not found.' });
    }

    req.userId = decoded.userId;
    req.user = user;

    // Enforce 2FA
    // Allow 2FA setup routes even if 2FA is not enabled
    const is2FASetupRoute = req.originalUrl.includes('/auth/2fa/');

    if (!user.isTwoFactorEnabled && !is2FASetupRoute) {
      return res.status(403).json({
        message: '2FA setup required.',
        code: '2fa_setup_required'
      });
    }

    // Enforce document upload for trainers and organizations
    // Allow document upload routes and verification status check routes
    const isDocumentUploadRoute = req.originalUrl.includes('/users/upload-documents');
    const isVerificationRoute = req.originalUrl.includes('/users/me') ||
      req.originalUrl.includes('/users/reapply-verification');

    const requiresDocumentUpload = (user.role === 'trainer' || user.role === 'organization') && !user.documentsUploaded;

    if (requiresDocumentUpload && !isDocumentUploadRoute && !isVerificationRoute && !is2FASetupRoute) {
      return res.status(403).json({
        message: 'Document upload required.',
        code: 'document_upload_required'
      });
    }

    // Extend session TTL on each request (sliding expiration)
    await redis.expire(sessionKey, 7 * 24 * 60 * 60); // 7 days

    next();
  } catch (err) {
    return res.status(401).json({ message: 'Invalid token.' });
  }
};

export default auth;