wpgens auto apply coupon when product is added to cart

functions.php

<?php


add_action( 'woocommerce_add_to_cart', 'wpgens_auto_apply_coupons_on_add_to_cart', 10, 6 );
function wpgens_auto_apply_coupons_on_add_to_cart( $cart_item_key, $product_id, $quantity, $variation_id, $variation, $cart_item_data ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if ( ! is_user_logged_in() )
        return;

    if ( WC()->cart === null )
        return;

    $user_info  = get_userdata( get_current_user_id() );
    $user_email = $user_info->user_email;

    $args = array(
        'posts_per_page' => 10,
        'post_type'      => 'shop_coupon',
        'post_status'    => 'publish',
        'meta_query'     => array(
            'relation' => 'AND',
            array(
                'key'     => 'customer_email',
                'value'   => $user_email,
                'compare' => 'LIKE',
            ),
            array(
                'key'     => 'usage_count',
                'value'   => '0',
                'compare' => '=',
            ),
        ),
    );

    $coupons = get_posts( $args );

    if ( $coupons ) {
        foreach ( $coupons as $coupon ) {
            if ( ! WC()->cart->has_discount( $coupon->post_title ) && substr( $coupon->post_title, 0, 3 ) === 'RAF' ) {
                WC()->cart->add_discount( $coupon->post_title );
            }
        }
    }
}