Refactor authorization and token refresh logic; update tax handling and invoice generation

- Changed variable name from `$stmt_service` to `$stmt_refreshkey` for clarity in `authorization.php` and `token_refresh.php`.
- Added null coalescing operator to ensure criteria are set to an empty string if not provided in `products_software_versions.php`.
- Modified SQL script to add `eu` column to `taxes` table and update tax rates based on EU membership.
- Enhanced invoice generation logic in `functions.php` to include VAT notes based on customer country and VAT number.
- Updated email and PDF templates to display VAT notes and percentages correctly.
- Adjusted JavaScript tax calculation logic to handle VAT based on country and VAT number.
- Fixed API URL in `index.php` for token refresh endpoint.
- Updated countries data structure in `countries.php` to include EU membership status.

assets/softwaretool.js

@@ -1485,12 +1485,35 @@ function showPaymentModal(option) {
     // Function to calculate and update tax
     function updateTaxDisplay() {
         const selectedCountry = document.getElementById("paymentCountry").value;
+        const vatNumber = document.getElementById("paymentVatNumber").value.trim();
         let taxRate = 0;
+        let vatNote = '';
 
         if (selectedCountry && typeof COUNTRIES !== 'undefined' && COUNTRIES) {
             const countryData = Object.values(COUNTRIES).find(c => c.country === selectedCountry);
             if (countryData) {
-                taxRate = parseFloat(countryData.taxes) || 0;
+                const isEU = countryData.eu === 1;
+                const isNetherlands = selectedCountry === 'Netherlands';
+                const countryTaxRate = parseFloat(countryData.taxes) || 0;
+
+                if (isNetherlands) {
+                    // Netherlands: always take the tax percentage
+                    taxRate = countryTaxRate;
+                } else if (isEU) {
+                    if (vatNumber) {
+                        // EU with VAT number: 0% VAT, reverse charge
+                        taxRate = 0;
+                        vatNote = 'Reverse charge VAT';
+                    } else {
+                        // EU without VAT number: use country VAT
+                        taxRate = countryTaxRate;
+                        vatNote = 'Local VAT';
+                    }
+                } else {
+                    // Non-EU: use country tax percentage (usually 0)
+                    taxRate = countryTaxRate;
+                    vatNote = 'Out of scope of EU VAT. Buyer is responsible for local taxes and duties';
+                }
             }
         }
 
@@ -1503,13 +1526,13 @@ function showPaymentModal(option) {
 
         if (taxRate > 0) {
             taxDisplay.innerHTML = `
-                <span>VAT (${taxRate}%):</span>
+                <span>VAT (${taxRate}%)${vatNote ? ' <small style="font-size: 9px; color: #888;">(' + vatNote + ')</small>' : ''}:</span>
                 <span style="font-weight: 600;">${currency} ${taxAmount.toFixed(2)}</span>
             `;
         } else {
             taxDisplay.innerHTML = `
-                <span>VAT:</span>
-                <span style="font-weight: 600;">-</span>
+                <span>VAT${vatNote ? ' <small style="font-size: 9px; color: #888;">(' + vatNote + ')</small>' : ''}:</span>
+                <span style="font-weight: 600;">${vatNote ? '0%' : '-'}</span>
             `;
         }
 
@@ -1541,8 +1564,9 @@ function showPaymentModal(option) {
         }
     }
 
-    // Add event listener to country select to update tax
+    // Add event listeners to country select and VAT number to update tax
     document.getElementById("paymentCountry").addEventListener('change', updateTaxDisplay);
+    document.getElementById("paymentVatNumber").addEventListener('input', updateTaxDisplay);
 
     // Close modal on cancel
     document.getElementById("cancelPayment").onclick = () => {