/**
 * API: Push Notification Subscription Endpoint
 * POST /api/notifications/subscribe - Subscribe to push notifications
 * DELETE /api/notifications/subscribe - Unsubscribe from push notifications
 * GET /api/notifications/subscribe - Get VAPID public key
 */

import type { NextApiRequest, NextApiResponse } from 'next';
import { PushChannel } from '../../../lib/notifications/channels/push';

// Create push channel instance for subscription management
const pushChannel = new PushChannel({
  vapidPublicKey: process.env.VAPID_PUBLIC_KEY || '',
  vapidPrivateKey: process.env.VAPID_PRIVATE_KEY || '',
  vapidSubject: process.env.VAPID_SUBJECT || 'mailto:admin@localgreenchain.local'
});

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  // In production, get userId from session/auth
  const userId = req.query.userId as string || req.body?.userId || 'demo-user';

  if (req.method === 'GET') {
    try {
      // Return VAPID public key for client subscription
      const publicKey = pushChannel.getPublicKey();
      const hasSubscription = pushChannel.hasSubscription(userId);

      return res.status(200).json({
        success: true,
        data: {
          publicKey,
          subscribed: hasSubscription
        }
      });
    } catch (error: any) {
      return res.status(500).json({
        success: false,
        error: error.message
      });
    }
  }

  if (req.method === 'POST') {
    try {
      const { endpoint, keys } = req.body;

      if (!endpoint || !keys?.p256dh || !keys?.auth) {
        return res.status(400).json({
          success: false,
          error: 'Invalid subscription data. Required: endpoint, keys.p256dh, keys.auth'
        });
      }

      const subscription = pushChannel.subscribe(userId, { endpoint, keys });

      return res.status(201).json({
        success: true,
        data: {
          subscribed: true,
          subscription: {
            endpoint: subscription.endpoint,
            createdAt: subscription.createdAt
          }
        }
      });
    } catch (error: any) {
      return res.status(500).json({
        success: false,
        error: error.message
      });
    }
  }

  if (req.method === 'DELETE') {
    try {
      const { endpoint } = req.body;

      const success = pushChannel.unsubscribe(userId, endpoint);

      return res.status(200).json({
        success: true,
        data: {
          unsubscribed: success
        }
      });
    } catch (error: any) {
      return res.status(500).json({
        success: false,
        error: error.message
      });
    }
  }

  return res.status(405).json({ error: 'Method not allowed' });
}