const express = require('express');
const cors = require('cors');
const rateLimit = require('express-rate-limit');
const Database = require('better-sqlite3');
const path = require('path');
const http = require('http');
const { WebSocketServer } = require('ws');

const app = express();
const PORT = process.env.PORT || 3001;
const server = http.createServer(app);

// Trust the first proxy (nginx) so that express-rate-limit can correctly
// identify clients by their real IP from the X-Forwarded-For header.
app.set('trust proxy', 1);

app.use(cors());
app.use(express.json());

// Serve the built frontend (production mode)
const distPath = path.join(__dirname, '..', 'frontend', 'dist');
app.use(express.static(distPath));

// Apply rate limiting to all API routes
const apiLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 300, // limit each IP to 300 requests per windowMs
  standardHeaders: true,
  legacyHeaders: false,
  message: { error: 'リクエストが多すぎます。しばらくしてから再試行してください。' },
});
app.use('/api', apiLimiter);

const dbPath = path.join(__dirname, 'data.db');
const db = new Database(dbPath);

// Initialize database schema
db.exec(`
  CREATE TABLE IF NOT EXISTS cars (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    description TEXT DEFAULT ''
  );

  CREATE TABLE IF NOT EXISTS reservations (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    car_id INTEGER NOT NULL,
    start_date TEXT NOT NULL,
    end_date TEXT NOT NULL,
    customer_name TEXT DEFAULT '',
    notes TEXT DEFAULT '',
    FOREIGN KEY (car_id) REFERENCES cars(id) ON DELETE CASCADE
  );
`);

// Migrate: add new car fields if they don't exist yet
const carCols = db.prepare("PRAGMA table_info(cars)").all().map((c) => c.name);
if (!carCols.includes('inspection_expiry')) {
  db.exec("ALTER TABLE cars ADD COLUMN inspection_expiry TEXT DEFAULT ''");
}
if (!carCols.includes('has_etc')) {
  db.exec('ALTER TABLE cars ADD COLUMN has_etc INTEGER DEFAULT 0');
}
if (!carCols.includes('tire_type')) {
  db.exec("ALTER TABLE cars ADD COLUMN tire_type TEXT DEFAULT 'ノーマル'");
}
db.prepare("UPDATE cars SET tire_type = 'スタッドレス' WHERE tire_type = 'スタットレス'").run();

// Seed some initial cars if none exist
const carCount = db.prepare('SELECT COUNT(*) as cnt FROM cars').get();
if (carCount.cnt === 0) {
  const insertCar = db.prepare('INSERT INTO cars (name, description) VALUES (?, ?)');
  insertCar.run('代車 A', '');
  insertCar.run('代車 B', '');
  insertCar.run('代車 C', '');
}

// --- WebSocket Server ---
const wss = new WebSocketServer({ server, path: '/api/ws' });

function broadcast(message) {
  const data = JSON.stringify(message);
  wss.clients.forEach((client) => {
    if (client.readyState === client.OPEN) {
      client.send(data);
    }
  });
}

function normalizeTireType(value) {
  return value === 'スタットレス' ? 'スタッドレス' : value;
}

function normalizeCar(car) {
  if (!car) {
    return car;
  }
  return {
    ...car,
    tire_type: normalizeTireType(car.tire_type),
  };
}

wss.on('connection', (ws) => {
  ws.on('error', () => {}); // suppress unhandled error events
});

// --- Cars API ---
app.get('/api/cars', (req, res) => {
  const cars = db.prepare('SELECT * FROM cars ORDER BY id').all().map(normalizeCar);
  res.json(cars);
});

app.post('/api/cars', (req, res) => {
  const { name, description = '', inspection_expiry = '', has_etc = 0, tire_type = 'ノーマル' } = req.body;
  if (!name || !name.trim()) {
    return res.status(400).json({ error: '車名は必須です' });
  }
  const result = db.prepare(
    'INSERT INTO cars (name, description, inspection_expiry, has_etc, tire_type) VALUES (?, ?, ?, ?, ?)'
  ).run(name.trim(), description, inspection_expiry, has_etc ? 1 : 0, tire_type);
  const car = normalizeCar(db.prepare('SELECT * FROM cars WHERE id = ?').get(result.lastInsertRowid));
  broadcast({ type: 'data_changed', entity: 'cars' });
  res.status(201).json(car);
});

app.put('/api/cars/:id', (req, res) => {
  const { name, description, inspection_expiry, has_etc, tire_type } = req.body;
  if (!name || !name.trim()) {
    return res.status(400).json({ error: '車名は必須です' });
  }
  const result = db.prepare(
    'UPDATE cars SET name = ?, description = ?, inspection_expiry = ?, has_etc = ?, tire_type = ? WHERE id = ?'
  ).run(name.trim(), description ?? '', inspection_expiry ?? '', has_etc ? 1 : 0, tire_type ?? 'ノーマル', req.params.id);
  if (result.changes === 0) {
    return res.status(404).json({ error: '車が見つかりません' });
  }
  const car = normalizeCar(db.prepare('SELECT * FROM cars WHERE id = ?').get(req.params.id));
  broadcast({ type: 'data_changed', entity: 'cars' });
  res.json(car);
});

app.delete('/api/cars/:id', (req, res) => {
  const result = db.prepare('DELETE FROM cars WHERE id = ?').run(req.params.id);
  if (result.changes === 0) {
    return res.status(404).json({ error: '車が見つかりません' });
  }
  broadcast({ type: 'data_changed', entity: 'all' });
  res.json({ success: true });
});

// --- Reservations API ---
app.get('/api/reservations', (req, res) => {
  const reservations = db.prepare('SELECT * FROM reservations ORDER BY start_date').all();
  res.json(reservations);
});

app.post('/api/reservations', (req, res) => {
  const { car_id, start_date, end_date, customer_name = '', notes = '' } = req.body;
  if (!car_id || !start_date || !end_date) {
    return res.status(400).json({ error: 'car_id, start_date, end_date は必須です' });
  }
  if (start_date > end_date) {
    return res.status(400).json({ error: '開始日は終了日以前である必要があります' });
  }
  const result = db.prepare(
    'INSERT INTO reservations (car_id, start_date, end_date, customer_name, notes) VALUES (?, ?, ?, ?, ?)'
  ).run(car_id, start_date, end_date, customer_name, notes);
  const reservation = db.prepare('SELECT * FROM reservations WHERE id = ?').get(result.lastInsertRowid);
  broadcast({ type: 'data_changed', entity: 'reservations' });
  res.status(201).json(reservation);
});

app.put('/api/reservations/:id', (req, res) => {
  const { car_id, start_date, end_date, customer_name, notes } = req.body;
  if (!car_id || !start_date || !end_date) {
    return res.status(400).json({ error: 'car_id, start_date, end_date は必須です' });
  }
  if (start_date > end_date) {
    return res.status(400).json({ error: '開始日は終了日以前である必要があります' });
  }
  const result = db.prepare(
    'UPDATE reservations SET car_id = ?, start_date = ?, end_date = ?, customer_name = ?, notes = ? WHERE id = ?'
  ).run(car_id, start_date, end_date, customer_name ?? '', notes ?? '', req.params.id);
  if (result.changes === 0) {
    return res.status(404).json({ error: '予約が見つかりません' });
  }
  const reservation = db.prepare('SELECT * FROM reservations WHERE id = ?').get(req.params.id);
  broadcast({ type: 'data_changed', entity: 'reservations' });
  res.json(reservation);
});

app.delete('/api/reservations/:id', (req, res) => {
  const result = db.prepare('DELETE FROM reservations WHERE id = ?').run(req.params.id);
  if (result.changes === 0) {
    return res.status(404).json({ error: '予約が見つかりません' });
  }
  broadcast({ type: 'data_changed', entity: 'reservations' });
  res.json({ success: true });
});

// SPA fallback: serve index.html for any non-API route
app.get('/*path', apiLimiter, (req, res) => {
  res.sendFile(path.join(distPath, 'index.html'));
});

server.listen(PORT, () => {
  console.log(`Server running on http://localhost:${PORT}`);
});