Reference: Error Codes

connexpay.on('error', (error) => {
  if (error.category === 'VALIDATION_ERROR') {
    const cardNumberError = error.fields?.find(f => f.field === 'cardNumber');
    if (cardNumberError) {
      showFieldError('card-number', cardNumberError.message);
    }
  }
});

function handleExpirationError(fieldError) {
  const input = document.getElementById('expiry-input');
  const errorDiv = document.getElementById('expiry-error');
  
  errorDiv.textContent = fieldError.message;
  errorDiv.style.display = 'block';
  input.classList.add('error');
  
  // Show format hint for format errors
  if (fieldError.message.includes('Invalid expiration date')) {
    errorDiv.textContent += ' (Use MM/YY format)';
  }
}

function showCVVHelp(cardType) {
  const helpText = cardType === 'amex' 
    ? 'Enter the 4-digit code on the front of your card'
    : 'Enter the 3-digit code on the back of your card';
    
  showTooltip('cvv-help', helpText);
}

function handlePaymentError(error) {
  switch (error.message) {
    case 'No payment method has been selected':
      showPaymentMethodSelection();
      break;
    case 'Payment already performed':
      // Create new checkout session
      window.location.reload();
      break;
    case 'ConnexPay SDK is not ready':
      // Wait for SDK to be ready
      connexpay.on('ready', () => processPayment());
      break;
    case 'Apple Pay: User canceled.':
    case 'Google Pay: User canceled.':
      // Don't show error for user cancellation
      resetPaymentForm();
      break;
    default:
      showGenericError('Payment error: ' + error.message);
  }
}

let paymentInProgress = false;

async function processPayment() {
  if (paymentInProgress) {
    console.log('Payment already in progress');
    return;
  }
  
  try {
    paymentInProgress = true;
    const result = await connexpay.confirmPayment();
    // Handle success
  } catch (error) {
    if (error.message === 'Payment already performed') {
      // Create new checkout session
      window.location.reload();
    }
  } finally {
    paymentInProgress = false;
  }
}

function handleWalletError(error) {
  switch (error.message) {
    case 'Apple Pay: User canceled.':
    case 'Google Pay: User canceled.':
      // Don't show error for user cancellation
      resetPaymentForm();
      break;
      
    default:
      showError('Payment method error: ' + error.message);
  }
}

interface UserError extends Error {
  category: 'VALIDATION_ERROR' | 'PAYMENT_ERROR';
  message: string;         // Human-readable error message
  fields?: FieldError[];   // Field-specific errors (validation only)
}

interface FieldError {
  field: 'cardNumber' | 'expirationDate' | 'securityCode';
  message: string;
}

{
  "category": "VALIDATION_ERROR",
  "message": "Please correct the following errors",
  "fields": [
    {
      "field": "cardNumber",
      "message": "Invalid card number"
    },
    {
      "field": "expirationDate", 
      "message": "Card has expired"
    }
  ]
}

{
  "category": "PAYMENT_ERROR",
  "message": "No payment method has been selected"
}