// PayPal Referral Reward Payout Handler
const paypal = require('@paypal/checkout-server-sdk');

// PayPal environment setup
const environment = process.env.NODE_ENV === 'production'
  ? new paypal.core.LiveEnvironment(process.env.PAYPAL_CLIENT_ID, process.env.PAYPAL_SECRET)
  : new paypal.core.SandboxEnvironment(process.env.PAYPAL_CLIENT_ID, process.env.PAYPAL_SECRET);
const paypalClient = new paypal.core.PayPalHttpClient(environment);

async function sendPayout(recipientEmail, amount, referralId) {
  const axios = require('axios');

  // Get PayPal access token
  const authResponse = await axios.post(
    `${process.env.PAYPAL_API_URL}/v1/oauth2/token`,
    'grant_type=client_credentials',
    {
      auth: {
        username: process.env.PAYPAL_CLIENT_ID,
        password: process.env.PAYPAL_SECRET
      }
    }
  );
  const accessToken = authResponse.data.access_token;

  // Create payout
  const payoutResponse = await axios.post(
    `${process.env.PAYPAL_API_URL}/v1/payments/payouts`,
    {
      sender_batch_header: {
        sender_batch_id: `growsurf-${referralId}-${Date.now()}`,
        email_subject: 'You received a referral reward!',
        email_message: 'Thanks for referring friends! Here is your reward.'
      },
      items: [{
        recipient_type: 'EMAIL',
        amount: { value: amount.toFixed(2), currency: 'USD' },
        receiver: recipientEmail,
        note: `Referral reward for referral ${referralId}`,
        sender_item_id: `ref-${referralId}`
      }]
    },
    { headers: { 'Authorization': `Bearer ${accessToken}` } }
  );

  return payoutResponse.data;
}

app.post('/webhooks/growsurf/payout', async (req, res) => {
  const { event, participant } = req.body;

  if (event !== 'PARTICIPANT_REACHED_REWARD') {
    return res.json({ skipped: true });
  }

  // Check idempotency
  const existing = await db.payouts.findByReferralId(participant.id);
  if (existing) return res.json({ message: 'Already processed' });

  const paypalEmail = participant.metadata?.paypalEmail || participant.email;
  const rewardAmount = 10.00; // $10 per referral

  try {
    const payout = await sendPayout(paypalEmail, rewardAmount, participant.id);
    await db.payouts.create({
      participantId: participant.id,
      paypalBatchId: payout.batch_header.payout_batch_id,
      amount: rewardAmount,
      status: 'pending'
    });
    res.json({ success: true, batchId: payout.batch_header.payout_batch_id });
  } catch (error) {
    console.error('Payout failed:', error);
    res.status(500).json({ error: error.message });
  }
});