import { Router } from 'express';
import bcrypt from 'bcryptjs';
import jwt from 'jsonwebtoken';
import { z } from 'zod';
import { pool } from '../db/connection.js';

const router = Router();

const registerSchema = z.object({
  email: z.string().email(),
  password: z.string().min(8),
  displayName: z.string().min(2).max(120)
});

const loginSchema = z.object({
  email: z.string().email(),
  password: z.string().min(1)
});

// Middleware für Validierung
const validateRegister = (req, res, next) => {
  try {
    const parsed = registerSchema.safeParse(req.body);
    if (!parsed.success) {
      return res.status(400).json({ 
        error: 'Validation failed',
        details: parsed.error.flatten() 
      });
    }
    req.validatedData = parsed.data;
    next();
  } catch (err) {
    console.error('Validation error:', err);
    return res.status(500).json({ error: 'Internal server error during validation' });
  }
};

const validateLogin = (req, res, next) => {
  try {
    const parsed = loginSchema.safeParse(req.body);
    if (!parsed.success) {
      return res.status(400).json({ 
        error: 'Validation failed',
        details: parsed.error.flatten() 
      });
    }
    req.validatedData = parsed.data;
    next();
  } catch (err) {
    console.error('Validation error:', err);
    return res.status(500).json({ error: 'Internal server error during validation' });
  }
};

router.post('/register', validateRegister, async (req, res) => {
  try {
    const { email, password, displayName } = req.validatedData;
    const passwordHash = await bcrypt.hash(password, 12);

    const [result] = await pool.query(
      'INSERT INTO users (email, password_hash, display_name) VALUES (?, ?, ?)',
      [email, passwordHash, displayName]
    );

    const token = jwt.sign({ userId: result.insertId, email }, process.env.JWT_SECRET, { expiresIn: '7d' });
    return res.status(201).json({ token });
  } catch (err) {
    console.error('Registration error:', err);
    if (err.code === 'ER_DUP_ENTRY') {
      return res.status(409).json({ error: 'Email already exists' });
    }
    return res.status(500).json({ error: 'Registration failed' });
  }
});

router.post('/login', validateLogin, async (req, res) => {
  try {
    const { email, password } = req.validatedData;
    const [rows] = await pool.query('SELECT id, email, password_hash FROM users WHERE email = ? LIMIT 1', [email]);
    const user = rows[0];

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

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

    const token = jwt.sign({ userId: user.id, email: user.email }, process.env.JWT_SECRET, { expiresIn: '7d' });
    return res.status(200).json({ token });
  } catch (err) {
    console.error('Login error:', err);
    return res.status(500).json({ error: 'Login failed' });
  }
});

export default router;