Refactor invoice PDF generation and VAT validation

- Updated PDF template to display a fixed software code instead of "SOFTWARE".
- Changed VAT label to include tax label dynamically and set to 0% for certain conditions.
- Enhanced JavaScript for VAT number validation with asynchronous checks against the VIES database.
- Implemented debounce for VAT number input to optimize validation calls.
- Updated country settings to include country codes for VAT validation.
- Modified email sending functions in webhook handlers to use dynamic attachment names for invoices.

assets/softwaretool.js

@@ -1482,6 +1482,48 @@ function showPaymentModal(option) {
     modal.appendChild(modalContent);
     document.body.appendChild(modal);
 
+    // VAT number validation state
+    let vatValidationInProgress = false;
+    let vatValidationResult = null;
+
+    // Function to check VAT number against VIES database (via server-side proxy)
+    async function checkVATNumber(countryCode, vatNumber) {
+        if (!countryCode || !vatNumber) {
+            return null;
+        }
+
+        // Use server-side proxy to avoid CORS issues
+        const serviceToken = document.getElementById("servicetoken")?.innerHTML || '';
+        const url = link + '/v2/vat_check';
+
+        try {
+            const response = await fetch(url, {
+                method: 'POST',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'Accept': 'application/json',
+                    'Authorization': 'Bearer ' + serviceToken
+                },
+                body: JSON.stringify({
+                    countryCode: countryCode,
+                    vatNumber: vatNumber
+                })
+            });
+
+            if (!response.ok) {
+                console.warn('VAT check HTTP error:', response.status);
+                return null;
+            }
+
+            const data = await response.json();
+            console.log('VIES response:', data);
+            return data;
+        } catch (error) {
+            console.error('Error checking VAT:', error);
+            return null;
+        }
+    }
+
     // Function to calculate and update tax
     function updateTaxDisplay() {
         const selectedCountry = document.getElementById("paymentCountry").value;
@@ -1500,12 +1542,12 @@ function showPaymentModal(option) {
                     // Netherlands: always take the tax percentage
                     taxRate = countryTaxRate;
                 } else if (isEU) {
-                    if (vatNumber) {
-                        // EU with VAT number: 0% VAT, reverse charge
+                    if (vatNumber && vatValidationResult && vatValidationResult.valid === true) {
+                        // EU with VALID VAT number: 0% VAT, reverse charge
                         taxRate = 0;
                         vatNote = 'Reverse charge VAT';
                     } else {
-                        // EU without VAT number: use country VAT
+                        // EU without VAT number or invalid VAT: use country VAT
                         taxRate = countryTaxRate;
                         vatNote = 'Local VAT';
                     }
@@ -1564,9 +1606,112 @@ function showPaymentModal(option) {
         }
     }
 
+    // Debounce timer for VAT validation
+    let vatValidationTimeout = null;
+
+    // Function to validate VAT number with visual feedback
+    async function validateVATNumber() {
+        const selectedCountry = document.getElementById("paymentCountry").value;
+        const vatNumber = document.getElementById("paymentVatNumber").value.trim();
+        const vatInput = document.getElementById("paymentVatNumber");
+
+        // Reset validation state
+        vatValidationResult = null;
+        vatInput.style.borderColor = '';
+
+        // Remove any existing validation message
+        const existingMessage = document.getElementById('vatValidationMessage');
+        if (existingMessage) {
+            existingMessage.remove();
+        }
+
+        if (!vatNumber) {
+            updateTaxDisplay();
+            return;
+        }
+
+        if (!selectedCountry || typeof COUNTRIES === 'undefined' || !COUNTRIES) {
+            updateTaxDisplay();
+            return;
+        }
+
+        const countryData = Object.values(COUNTRIES).find(c => c.country === selectedCountry);
+        if (!countryData || countryData.eu !== 1 || !countryData.country_code) {
+            updateTaxDisplay();
+            return;
+        }
+
+        // For Netherlands, don't validate VAT (always apply VAT)
+        if (selectedCountry === 'Netherlands') {
+            updateTaxDisplay();
+            return;
+        }
+
+        // Show validating state
+        vatInput.style.borderColor = '#ffc107';
+        vatValidationInProgress = true;
+
+        const validationMsg = document.createElement('div');
+        validationMsg.id = 'vatValidationMessage';
+        validationMsg.style.cssText = 'margin-top: 5px; font-size: 12px; color: #ffc107;';
+        validationMsg.innerHTML = '<i class="fa-solid fa-spinner fa-spin"></i> Validating VAT number...';
+        vatInput.parentNode.appendChild(validationMsg);
+
+        // Call VIES API
+        const result = await checkVATNumber(countryData.country_code, vatNumber);
+        vatValidationInProgress = false;
+
+        if (result && result.valid === true) {
+            // VAT number is valid
+            vatValidationResult = result;
+            vatInput.style.borderColor = '#28a745';
+            validationMsg.style.color = '#28a745';
+            validationMsg.innerHTML = '<i class="fa-solid fa-check-circle"></i> Valid VAT number';
+
+            // Format VAT number as CountryCode + VatNumber (e.g., DE115235681)
+            const formattedVAT = result.countryCode + result.vatNumber;
+            if (vatInput.value !== formattedVAT) {
+                vatInput.value = formattedVAT;
+            }
+        } else {
+            // VAT number is invalid or check failed
+            vatValidationResult = null;
+            vatInput.style.borderColor = '#dc3545';
+            validationMsg.style.color = '#dc3545';
+            validationMsg.innerHTML = '<i class="fa-solid fa-times-circle"></i> Invalid VAT number or validation failed';
+        }
+
+        // Update tax display with new validation result
+        updateTaxDisplay();
+    }
+
     // Add event listeners to country select and VAT number to update tax
-    document.getElementById("paymentCountry").addEventListener('change', updateTaxDisplay);
-    document.getElementById("paymentVatNumber").addEventListener('input', updateTaxDisplay);
+    document.getElementById("paymentCountry").addEventListener('change', () => {
+        vatValidationResult = null;
+        const vatInput = document.getElementById("paymentVatNumber");
+        vatInput.style.borderColor = '';
+        const existingMessage = document.getElementById('vatValidationMessage');
+        if (existingMessage) {
+            existingMessage.remove();
+        }
+        updateTaxDisplay();
+
+        // Validate VAT if already entered
+        if (vatInput.value.trim()) {
+            if (vatValidationTimeout) {
+                clearTimeout(vatValidationTimeout);
+            }
+            vatValidationTimeout = setTimeout(validateVATNumber, 500);
+        }
+    });
+
+    document.getElementById("paymentVatNumber").addEventListener('input', () => {
+        // Debounce VAT validation
+        if (vatValidationTimeout) {
+            clearTimeout(vatValidationTimeout);
+        }
+        vatValidationTimeout = setTimeout(validateVATNumber, 1000);
+    });
 
     // Close modal on cancel
     document.getElementById("cancelPayment").onclick = () => {