Add Iranian National Code In The Woocommerce Checkout (Save & Display In Admin)

add-iranian-national-code-in-woocommerce-1.php

/**
 * @snippet       Add iranian national code in the checkout with display in admin
 * @author        Rasool Vahdati
 * @compatible    WooCommerce 6
 */
 
/**
 * Check the validity of an Iranian national code
 *
 * @param string $code The national code to be validated.
 * @return bool True if the code is valid, false otherwise.
 */
function check_national_code( $code )
{
    // Check if the input code is a 10-digit number
    if (!preg_match('/^[0-9]{10}$/', $code)) {
        return false;
    }

    // Check for repetitive patterns like "0000000000"
    for ($i = 0; $i < 10; $i++) {
        if (preg_match('/^'.$i.'{10}$/', $code)) {
            return false;
        }
    }

    // Calculate the sum based on the algorithm
    for ($i = 0, $sum = 0; $i < 9; $i++) {
        $sum += ((10 - $i) * intval(substr($code, $i, 1)));
    }

    // Validate the code using modulus operation
    $ret = $sum % 11;
    $parity = intval(substr($code, 9, 1));

    if (($ret < 2 && $ret == $parity) || ($ret >= 2 && $ret == 11 - $parity)) {
        return true;
    }

    return false;
}

/**
 * Add custom national code field to WooCommerce payment page
 * This function adds an input field for users to enter their national code during checkout.
 */
function add_custom_national_code_field()
{
    echo '<div class="form-row form-row-wide woocommerce-additional-fields__field-wrapper">
            <label for="billing_national_code">' . __('National Code', 'woocommerce') . ' <span class="required">*</span></label>
                <span class="woocommerce-input-wrapper"><input type="text" class="input-text" name="billing_national_code" id="billing_national_code" value="' . esc_attr( isset( $_POST['billing_national_code'] ) ? $_POST['billing_national_code'] : '') . '" /></span>
        </div>';
}

add_action('woocommerce_after_checkout_billing_form', 'add_custom_national_code_field');

/**
 * Validate custom national code field during checkout process
 * This function validates the entered national code during the checkout process.
 */
function validate_custom_national_code_field()
{
    $national_code = isset( $_POST['billing_national_code'] ) ? sanitize_text_field( $_POST['billing_national_code'] ) : '';

    if (!empty( $national_code ) && !check_national_code( $national_code ) ) {
        wc_add_notice( __('The entered national code is not valid.', 'woocommerce'), 'error');
    }
}

add_action('woocommerce_checkout_process', 'validate_custom_national_code_field');

/**
 * Save custom national code field in the order meta
 *
 * @param int $order_id The ID of the order to which the national code belongs.
 */
function save_custom_national_code_field( $order_id )
{
    if ( !empty( $_POST['billing_national_code'] ) ) {
        update_post_meta( $order_id, 'billing_national_code', sanitize_text_field( $_POST['billing_national_code'] ) );
    }
}

add_action('woocommerce_checkout_update_order_meta', 'save_custom_national_code_field');

/**
 * Display the national code in the admin order meta
 *
 * @param WC_Order $order The order object for which the national code is displayed.
 */
function checkout_field_display_admin_order_meta( $order )
{
    echo '<p><strong>' . __('National Code', 'woocommerce') . ':</strong> ' . get_post_meta( $order->get_id(), 'billing_national_code', true ) . '</p>';
}

add_action('woocommerce_admin_order_data_after_billing_address', 'checkout_field_display_admin_order_meta', 10, 1);