WooCommerce: Is this a gift + Validation + Email + Order Details

WooCommerce: Is this a gift + Validation + Email + Order Details

// add gift message on checkout after the "Order Notes"
add_action( 'woocommerce_after_order_notes', 'bdev_is_this_a_gift' );
function bdev_is_this_a_gift() {
    $domain = 'woocommerce';

    ?>
    <style>p#gift_field{display:none;}</style>
    <div id="message">
    <h3><i class="fa fa-gift"></i><?php _e( ' Is this a gift?', 'woocommerce' ); ?></h3>
    <?php

    woocommerce_form_field( 'gift_msg', array(
        'type'  => 'checkbox',
        'class' => array( 'gift-checkbox' ),
        'label' => __( 'To whom is this a gift?', 'woocommerce' ),
    ), WC()->checkout->get_value( 'cb_msg' ));

    woocommerce_form_field( 'gift', array(
        'type'              => 'text',
        'class'             => array('msg t_msg'),
        'label'             => __('Enter the recipient\'s e-mail address, nothing more. <a href="/privacy-policy" style="text-decoration: underline">More information here.</a>'),
        'placeholder'       => __('[email protected]'),
    ), WC()->checkout->get_value( 'gift' ));

    echo '</div>';

    ?><script>
    jQuery(document).ready(function($) {
        var a = '#gift_field';
        $('input#gift_msg').change( function(){
            if( $(this).is(':checked') )
                $(a).show();
            else
                $(a).hide();
        });
    });
    </script><?php
}

// validate the gift field and display error
add_action('woocommerce_after_checkout_validation', 'bdev_gift_validation', 20, 2 );
function bdev_gift_validation( $data, $errors ) {
    // valide "Gift" not empty if selected
    if( isset($_POST['gift_msg']) && isset($_POST['gift']) && empty($_POST['gift']) )
        $errors->add( 'gift', __( "You've chosen to send this product as a gift, but did not submit a recipient email address.", "woocommerce" ) );

    // validate "Gift" input email different from billing email
    if ( isset($_POST['gift']) && $data['billing_email'] === $_POST['gift'] ) {
        $errors->add( 'gift', __( "You cannot send a product as a gift to yourself. That defeats the purpose of this being a gift, does it not?", "woocommerce" ) );
    }
}

// update the gift field
add_action( 'woocommerce_checkout_update_order_meta', 'bdev_is_this_a_gift_save');
function bdev_is_this_a_gift_save( $order_id ) {
    $gift_recipient_address = $_POST['gift'];
    if ( ! empty( $gift_recipient_address ) )
        update_post_meta( $order_id, 'gift', sanitize_text_field( $gift_recipient_address ) );
}

// show if gift on the order page
add_action( 'woocommerce_admin_order_data_after_order_details', 'is_this_a_gift_order_display' );
function is_this_a_gift_order_display( $order ) {
    if( $value = $order->get_meta('gift') ) :
        echo '<div class="order_data_column">
        <h3>' . __( '<br>Gift For:', 'woocommerce' ) . '</h3>
        <p>' . $value . '</p>
        </div>';
    endif;
}

// send to the gift receiver if provided
add_filter( 'woocommerce_email_recipient_customer_completed_order', 'bdev_is_this_a_gift_replace_email_recipient', 10, 2 );
function bdev_is_this_a_gift_replace_email_recipient( $recipient, $order ) {
    $gift_recipient = $order->get_meta('gift');
    if ( is_a( $order, 'WC_Order' ) && $order->get_meta('gift') ) 
        $recipient = $order->get_meta('gift');
    return $recipient;
}

// add text to gift reciever email
add_action( 'woocommerce_email_before_order_table', 'bdev_this_was_a_gift', 20, 4 );
function bdev_this_was_a_gift( $order, $sent_to_admin, $plain_text, $email ) {
if ( $email->id == 'customer_completed_order'  && $order->get_meta('gift') == true ) {
echo '<h2 class="gift-h">Happy Days! You Got A GIFT!</h2><p class="gift-p">Your text here followed by "<strong>HAPPYCODE</strong>" and some more text at the end.</p>'; } }