import { Router, Request, Response, NextFunction } from 'express';
import bcrypt from 'bcryptjs';
import jwt from 'jsonwebtoken';
import { z } from 'zod';
import prisma from '../lib/prisma';
import { authenticate } from '../middleware/auth';
import { AppError } from '../lib/errors';

const router = Router();

const JWT_SECRET = process.env.JWT_SECRET || 'change-me-in-production';
const JWT_REFRESH_SECRET = process.env.JWT_REFRESH_SECRET || 'change-me-too';
const ACCESS_TOKEN_EXPIRY = '15m';
const REFRESH_TOKEN_EXPIRY = '7d';

// Store for invalidated refresh tokens (in production, use Redis)
const invalidatedTokens = new Set<string>();

const loginSchema = z.object({
  email: z.string().email('Invalid email format'),
  password: z.string().min(1, 'Password is required'),
});

const refreshSchema = z.object({
  refreshToken: z.string().min(1, 'Refresh token is required'),
});

function generateTokens(user: { id: string; email: string; role: string; tenantId: string | null; firstName: string; lastName: string }) {
  const payload = {
    id: user.id,
    email: user.email,
    role: user.role,
    tenantId: user.tenantId,
    firstName: user.firstName,
    lastName: user.lastName,
  };

  const accessToken = jwt.sign(payload, JWT_SECRET, { expiresIn: ACCESS_TOKEN_EXPIRY });
  const refreshToken = jwt.sign({ id: user.id, type: 'refresh' }, JWT_REFRESH_SECRET, { expiresIn: REFRESH_TOKEN_EXPIRY });

  return { accessToken, refreshToken };
}

// POST /api/auth/login
router.post('/login', async (req: Request, res: Response, next: NextFunction) => {
  try {
    const parsed = loginSchema.safeParse(req.body);
    if (!parsed.success) {
      res.status(400).json({
        error: 'Validation error',
        details: parsed.error.flatten().fieldErrors,
      });
      return;
    }

    const { email, password } = parsed.data;

    const user = await prisma.user.findUnique({
      where: { email },
      include: { tenant: true },
    });

    if (!user || !user.active) {
      res.status(401).json({ error: 'Invalid credentials' });
      return;
    }

    const validPassword = await bcrypt.compare(password, user.passwordHash);
    if (!validPassword) {
      res.status(401).json({ error: 'Invalid credentials' });
      return;
    }

    const tokens = generateTokens(user);

    res.json({
      ...tokens,
      user: {
        id: user.id,
        email: user.email,
        firstName: user.firstName,
        lastName: user.lastName,
        role: user.role,
        tenantId: user.tenantId,
        tenant: user.tenant ? { id: user.tenant.id, name: user.tenant.name, slug: user.tenant.slug } : null,
      },
    });
  } catch (err) {
    next(err);
  }
});

// POST /api/auth/refresh
router.post('/refresh', async (req: Request, res: Response, next: NextFunction) => {
  try {
    const parsed = refreshSchema.safeParse(req.body);
    if (!parsed.success) {
      res.status(400).json({
        error: 'Validation error',
        details: parsed.error.flatten().fieldErrors,
      });
      return;
    }

    const { refreshToken } = parsed.data;

    if (invalidatedTokens.has(refreshToken)) {
      res.status(401).json({ error: 'Token has been invalidated' });
      return;
    }

    let decoded: any;
    try {
      decoded = jwt.verify(refreshToken, JWT_REFRESH_SECRET);
    } catch {
      res.status(401).json({ error: 'Invalid refresh token' });
      return;
    }

    if (decoded.type !== 'refresh') {
      res.status(401).json({ error: 'Invalid token type' });
      return;
    }

    const user = await prisma.user.findUnique({
      where: { id: decoded.id },
    });

    if (!user || !user.active) {
      res.status(401).json({ error: 'User not found or inactive' });
      return;
    }

    // Invalidate old refresh token
    invalidatedTokens.add(refreshToken);

    const tokens = generateTokens(user);

    res.json(tokens);
  } catch (err) {
    next(err);
  }
});

// POST /api/auth/logout
router.post('/logout', authenticate, async (req: Request, res: Response, next: NextFunction) => {
  try {
    const refreshToken = req.body.refreshToken;
    if (refreshToken) {
      invalidatedTokens.add(refreshToken);
    }
    res.json({ message: 'Logged out successfully' });
  } catch (err) {
    next(err);
  }
});

// GET /api/auth/me
router.get('/me', authenticate, async (req: Request, res: Response, next: NextFunction) => {
  try {
    const user = await prisma.user.findUnique({
      where: { id: req.user!.id },
      include: { tenant: true },
    });

    if (!user) {
      res.status(404).json({ error: 'User not found' });
      return;
    }

    res.json({
      id: user.id,
      email: user.email,
      firstName: user.firstName,
      lastName: user.lastName,
      role: user.role,
      tenantId: user.tenantId,
      tenant: user.tenant ? { id: user.tenant.id, name: user.tenant.name, slug: user.tenant.slug, logo: user.tenant.logo } : null,
      createdAt: user.createdAt,
      updatedAt: user.updatedAt,
    });
  } catch (err) {
    next(err);
  }
});

export default router;