import { Router } from 'express';
import { PrismaClient } from '@prisma/client';

const router = Router();
const prisma = new PrismaClient();

// Helper to generate a VPN IP for a new device
async function getNextVpnIp(): Promise<string> {
  const baseIp = '10.10.0.';
  // Find the highest VPN IP currently in use
  const lastDevice = await prisma.device.findFirst({
    where: { vpnIp: { startsWith: baseIp } },
    orderBy: { vpnIp: 'desc' }
  });

  if (!lastDevice || !lastDevice.vpnIp) {
    return `${baseIp}1`; // Start with 10.10.0.1
  }

  const lastOctet = parseInt(lastDevice.vpnIp.split('.')[3], 10);
  if (lastOctet >= 254) {
    throw new Error('VPN IP pool exhausted in this subnet');
  }

  return `${baseIp}${lastOctet + 1}`;
}

// Get all devices
router.get('/', async (req, res) => {
  try {
    const devices = await prisma.device.findMany({ include: { tenant: true } });
    res.json(devices);
  } catch (error) {
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Create device for a tenant
router.post('/', async (req, res) => {
  try {
    const { tenantId, name, macAddress, opnsenseUrl, apiKey, apiSecret } = req.body;
    
    // Automatically generate the VPN IP for this customer device
    const nextVpnIp = await getNextVpnIp();

    const newDevice = await prisma.device.create({
      data: { 
        tenantId, 
        name, 
        macAddress, 
        vpnIp: nextVpnIp,
        opnsenseUrl, 
        apiKey, 
        apiSecret 
      },
    });

    // TODO: Actually trigger OpenVPN config generation via SSH or scripts to the VPN Server (10.0.1.150)
    // generateVpnConfig(nextVpnIp, macAddress);

    res.status(201).json(newDevice);
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

export default router;