import { Router, Response } from 'express';
import bcrypt from 'bcryptjs';
import db from '../database';
import { AuthRequest, generateToken, authMiddleware } from '../middleware/auth';
import { User } from '../types';

const router = Router();

router.post('/register', (req: AuthRequest, res: Response) => {
  try {
    const { username, password, displayName } = req.body;
    if (!username || !password) {
      return res.status(400).json({ error: 'Username and password required' });
    }

    // Only allow registration if no users exist (first-run setup)
    const userCount = db.prepare('SELECT COUNT(*) as count FROM users').get() as { count: number };
    if (userCount.count > 0) {
      return res.status(403).json({ error: 'Registration disabled. User already exists.' });
    }

    const hash = bcrypt.hashSync(password, 10);
    const result = db.prepare(
      'INSERT INTO users (username, password_hash, display_name) VALUES (?, ?, ?)'
    ).run(username, hash, displayName || null);

    const token = generateToken(result.lastInsertRowid as number);
    res.json({ token, user: { id: result.lastInsertRowid, username, displayName: displayName || null } });
  } catch (error: any) {
    if (error.code === 'SQLITE_CONSTRAINT_UNIQUE') {
      return res.status(409).json({ error: 'Username already exists' });
    }
    res.status(500).json({ error: error.message });
  }
});

router.post('/login', (req: AuthRequest, res: Response) => {
  try {
    const { username, password } = req.body;
    if (!username || !password) {
      return res.status(400).json({ error: 'Username and password required' });
    }

    const user = db.prepare('SELECT * FROM users WHERE username = ?').get(username) as User | undefined;
    if (!user || !bcrypt.compareSync(password, user.password_hash)) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    const token = generateToken(user.id);
    res.json({ token, user: { id: user.id, username: user.username, displayName: user.display_name } });
  } catch (error: any) {
    res.status(500).json({ error: error.message });
  }
});

router.get('/me', authMiddleware, (req: AuthRequest, res: Response) => {
  try {
    const user = db.prepare('SELECT id, username, display_name FROM users WHERE id = ?').get(req.userId) as User | undefined;
    if (!user) return res.status(404).json({ error: 'User not found' });
    res.json({ id: user.id, username: user.username, displayName: user.display_name });
  } catch (error: any) {
    res.status(500).json({ error: error.message });
  }
});

router.get('/setup-required', (_req: AuthRequest, res: Response) => {
  const userCount = db.prepare('SELECT COUNT(*) as count FROM users').get() as { count: number };
  res.json({ setupRequired: userCount.count === 0 });
});

export default router;