puffin-app/server/routes/checkout.js

import express from 'express';
import { stripe } from '../config/stripe.js';
import { Order } from '../models/Order.js';

const router = express.Router();

// Portfolio pricing configuration (price per ton in USD)
const PORTFOLIO_PRICING = {
  1: 15, // Balanced portfolio
  2: 18, // High-impact portfolio
  3: 20  // Premium portfolio
};

// Processing fee percentage
const PROCESSING_FEE_PERCENT = 0.03; // 3%

/**
 * Calculate pricing with processing fee
 * @param {number} tons - Number of tons
 * @param {number} portfolioId - Portfolio ID
 * @returns {Object} Pricing breakdown
 */
function calculatePricing(tons, portfolioId) {
  const pricePerTon = PORTFOLIO_PRICING[portfolioId] || 18; // Default to $18/ton
  const baseAmount = Math.round(tons * pricePerTon * 100); // Convert to cents
  const processingFee = Math.round(baseAmount * PROCESSING_FEE_PERCENT);
  const totalAmount = baseAmount + processingFee;

  return {
    baseAmount,
    processingFee,
    totalAmount,
    pricePerTon
  };
}

/**
 * POST /api/checkout/create-session
 * Create a Stripe Checkout Session
 */
router.post('/create-session', async (req, res) => {
  try {
    const { tons, portfolioId, customerEmail } = req.body;

    // Validation
    if (!tons || tons <= 0) {
      return res.status(400).json({ error: 'Invalid tons value' });
    }

    if (!portfolioId || ![1, 2, 3].includes(portfolioId)) {
      return res.status(400).json({ error: 'Invalid portfolio ID' });
    }

    // Calculate pricing
    const { baseAmount, processingFee, totalAmount, pricePerTon } = calculatePricing(tons, portfolioId);

    // Create line items for Stripe
    const lineItems = [
      {
        price_data: {
          currency: 'usd',
          product_data: {
            name: `Carbon Offset - ${tons} tons`,
            description: `Portfolio ${portfolioId} at $${pricePerTon}/ton`,
            images: ['https://puffin-app.example.com/images/carbon-offset.png'], // Optional: Add your logo
          },
          unit_amount: baseAmount, // Base amount in cents
        },
        quantity: 1,
      },
      {
        price_data: {
          currency: 'usd',
          product_data: {
            name: 'Processing Fee (3%)',
            description: 'Transaction processing fee',
          },
          unit_amount: processingFee, // Processing fee in cents
        },
        quantity: 1,
      },
    ];

    // Create Stripe Checkout Session
    const session = await stripe.checkout.sessions.create({
      payment_method_types: ['card'],
      line_items: lineItems,
      mode: 'payment',
      success_url: `${process.env.FRONTEND_URL}/checkout/success?session_id={CHECKOUT_SESSION_ID}`,
      cancel_url: `${process.env.FRONTEND_URL}/checkout/cancel`,
      customer_email: customerEmail,
      metadata: {
        tons: tons.toString(),
        portfolioId: portfolioId.toString(),
        baseAmount: baseAmount.toString(),
        processingFee: processingFee.toString(),
      },
    });

    // Store order in database
    const order = Order.create({
      stripeSessionId: session.id,
      customerEmail: customerEmail || null,
      tons,
      portfolioId,
      baseAmount,
      processingFee,
      totalAmount,
      currency: 'USD',
    });

    console.log(`✅ Created checkout session: ${session.id}`);
    console.log(`   Order ID: ${order.id}`);
    console.log(`   Amount: $${(totalAmount / 100).toFixed(2)} (${tons} tons @ $${pricePerTon}/ton + 3% fee)`);

    res.json({
      sessionId: session.id,
      url: session.url,
      orderId: order.id,
    });

  } catch (error) {
    console.error('❌ Checkout session creation error:', error);
    res.status(500).json({
      error: 'Failed to create checkout session',
      message: error.message,
    });
  }
});

/**
 * GET /api/checkout/session/:sessionId
 * Retrieve checkout session details
 */
router.get('/session/:sessionId', async (req, res) => {
  try {
    const { sessionId } = req.params;

    // Get order from database
    const order = Order.findBySessionId(sessionId);

    if (!order) {
      return res.status(404).json({ error: 'Order not found' });
    }

    // Get Stripe session (optional - for additional details)
    const session = await stripe.checkout.sessions.retrieve(sessionId);

    res.json({
      order: {
        id: order.id,
        tons: order.tons,
        portfolioId: order.portfolio_id,
        baseAmount: order.base_amount,
        processingFee: order.processing_fee,
        totalAmount: order.total_amount,
        currency: order.currency,
        status: order.status,
        wrenOrderId: order.wren_order_id,
        createdAt: order.created_at,
      },
      session: {
        paymentStatus: session.payment_status,
        customerEmail: session.customer_details?.email,
      },
    });

  } catch (error) {
    console.error('❌ Session retrieval error:', error);
    res.status(500).json({
      error: 'Failed to retrieve session',
      message: error.message,
    });
  }
});

export default router;