Fix pricing calculation by passing pricePerTon from frontend to backend

The backend was using a hardcoded PORTFOLIO_PRICING map that only had prices
for portfolios 1, 2, 3 (defaulting to $18/ton for others). When Wren API
returns Portfolio ID 37 at $237/ton, the backend was calculating with $18/ton
instead, causing massive pricing discrepancies.

Changes:
- Frontend now passes pricePerTon (from Wren API) in checkout request
- Backend uses the received pricePerTon instead of lookup table
- Removed dependency on hardcoded PORTFOLIO_PRICING map
- Added validation for pricePerTon parameter

Example fix:
- Before: 0.03 tons × $18/ton = $0.54 (wrong!)
- After: 0.03 tons × $237/ton = $7.11 (correct!)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

server/routes/checkout.js

@@ -17,11 +17,10 @@ const PROCESSING_FEE_PERCENT = 0.03; // 3%
 /**
  * Calculate pricing with processing fee
  * @param {number} tons - Number of tons
- * @param {number} portfolioId - Portfolio ID
+ * @param {number} pricePerTon - Price per ton from Wren API
  * @returns {Object} Pricing breakdown
  */
-function calculatePricing(tons, portfolioId) {
-  const pricePerTon = PORTFOLIO_PRICING[portfolioId] || 18; // Default to $18/ton
+function calculatePricing(tons, pricePerTon) {
   const baseAmount = Math.round(tons * pricePerTon * 100); // Convert to cents
   const processingFee = Math.round(baseAmount * PROCESSING_FEE_PERCENT);
   const totalAmount = baseAmount + processingFee;
@@ -40,7 +39,7 @@ function calculatePricing(tons, portfolioId) {
  */
 router.post('/create-session', async (req, res) => {
   try {
-    const { tons, portfolioId, customerEmail } = req.body;
+    const { tons, portfolioId, pricePerTon, customerEmail } = req.body;
 
     // Validation
     if (!tons || tons <= 0) {
@@ -53,10 +52,16 @@ router.post('/create-session', async (req, res) => {
       return res.status(400).json({ error: 'Invalid portfolio ID' });
     }
 
-    console.log(`📦 Creating checkout for portfolio ID: ${portfolioId}, tons: ${tons}`);
+    // Validate price per ton
+    if (!pricePerTon || pricePerTon <= 0) {
+      console.error('❌ Invalid pricePerTon received:', pricePerTon);
+      return res.status(400).json({ error: 'Invalid price per ton' });
+    }
 
-    // Calculate pricing
-    const { baseAmount, processingFee, totalAmount, pricePerTon } = calculatePricing(tons, portfolioId);
+    console.log(`📦 Creating checkout for portfolio ID: ${portfolioId}, tons: ${tons}, price: $${pricePerTon}/ton`);
+
+    // Calculate pricing using the price from frontend (Wren API)
+    const { baseAmount, processingFee, totalAmount } = calculatePricing(tons, pricePerTon);
 
     // Create line items for Stripe
     const lineItems = [

src/api/checkoutClient.ts

@@ -17,6 +17,7 @@ const getApiBaseUrl = (): string => {
 export interface CreateCheckoutSessionParams {
   tons: number;
   portfolioId: number;
+  pricePerTon: number; // Price per ton from Wren API
   customerEmail?: string;
 }
 

src/components/OffsetOrder.tsx

@@ -150,6 +150,7 @@ export function OffsetOrder({ tons, monetaryAmount, onBack, calculatorType }: Pr
       const checkoutSession = await createCheckoutSession({
         tons: actualOffsetTons,
         portfolioId: portfolio.id,
+        pricePerTon: portfolio.pricePerTon || 18, // Pass the actual price from Wren
       });
 
       logger.info('[OffsetOrder] Checkout session created:', checkoutSession.sessionId);