Adding VAT to WooCommerce

WooCommerce_nif

<?php 

/**
 * Plugin Name: WooCommerce NIF
 * Description:       Adds NIF fields to WooCommerce
 * Version:           1.0
 * Author:            Daniel Pereyra Costas
 * Author URI:        https://charrua.es
 * License:           GPL v2 or later
 * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
 * Text Domain:       woocommerce-nif
 */

/*
 * Add VAT field to WooCommerce billing fields
 * Show after Company Name field (priority 30)
 */

add_filter('woocommerce_billing_fields', 'charrua_add_vat_to_billing_fields');

function charrua_add_vat_to_billing_fields($billing_fields)
{
    $billing_fields['billing_vat'] = array(
        'type' => 'text',
        'label' => __('NIF/CIF', 'woocommerce-nif'),
        'class' => array('form-row-wide'),
        'required' => false,
        'clear' => true,
        'priority' => 31,
    );

    return $billing_fields;
}

/*
 * Add VAT field value under addresses tab on My Account
 * Frontend -> My Account -> Addresses
 */

add_filter('woocommerce_my_account_my_address_formatted_address', 'charrua_my_account_my_address_formatted_address', 10, 3);

function charrua_my_account_my_address_formatted_address($fields, $customer_id, $type)
{
    if ($type == 'billing') {
        $fields['vat'] = get_user_meta($customer_id, 'billing_vat', true);
    }

    return $fields;
}

/*
 * Add VAT field value when printing billing address on:
 * Emails, order details (backend) and customer order details (after purchasing, frontend) 
 */

add_filter('woocommerce_order_formatted_billing_address', 'charrua_add_vat_formatted_billing_address', 10, 2);

function charrua_add_vat_formatted_billing_address($fields, $order)
{
    $fields['vat'] = $order->billing_vat;

    return $fields;
}


/*
 * Creating merger VAT variables for printing formatting
 * We will use this later when formatting the address on Spain
 */ 

add_filter('woocommerce_formatted_address_replacements', 'charrua_formatted_address_replacements', 10, 2);

function charrua_formatted_address_replacements($address, $args)
{
    $address['{vat}'] = '';
    $address['{vat_upper}'] = '';

    if (!empty($args['vat'])) {
        $address['{vat}'] = $args['vat'];
        $address['{vat_upper}'] = strtoupper($args['vat']);
    }

    return $address;
}


/*
 * Defining the Spanish (Spain) formatting to print the address plus including VAT value.
 */

add_filter('woocommerce_localisation_address_formats', 'charrua_localisation_address_format');

function charrua_localisation_address_format($formats)
{
    $formats['ES'] = "{name}\n{company}\n{vat_upper}\n{address_1}\n{address_2}\n{postcode} {city}\n{state}\n{country}";

    return $formats;
}

/*
 * Add VAT form meta field on Wordpress Admin -> User Profile -> Billing
 */

add_filter('woocommerce_customer_meta_fields', 'charrua_customer_meta_fields');

function charrua_customer_meta_fields($fields)
{
    $fields['billing']['fields']['billing_vat'] = array(
        'label' => __('VAT', 'woocommerce'),
    );

    return $fields;
}

/*
 * Copy VAT user meta field value stored, to the order when creating a new order and selecting a client (ajax request)
 * Or when using the pencil on the Order Edit Page "Use billing address" (ajax request)
 * Both cases, creating a new order and selecting a client or copying billing data from stored client data use the same filter.
 *
 * On Wordpress Admin -> Order -> New Order or Order Edit Page (same page)
 */

add_filter('woocommerce_ajax_get_customer_details', 'charrua_found_customer_details');

function charrua_found_customer_details($customer_data)
{
    $customer_data['billing']['vat'] = get_user_meta($_POST['user_id'], 'billing_vat', true);

    return $customer_data;
}