woo-func.php

<?php
/*
 * Save current single product to cookies
 * To display those products in single product 'Recentrly searched' section
 */
add_action('wp', 'matat_save_current_single_product_to_cookies');
function matat_save_current_single_product_to_cookies() {

	if( get_field('recently_viewed_cookie_num', 'options') ) {
		$number_of_products = get_field('recently_viewed_cookie_num', 'options');
	} else {
		$number_of_products = 10;
	}

	if( is_singular('product') ) {
		global $post;
		$product_id = $post->ID;

		if( !matat_check_if_current_product_id_is_in_cookie( $product_id ) ) {
			
			if( isset($_COOKIE['recently_viewed']) && !empty($_COOKIE['recently_viewed']) ) {
				$cookie         = $_COOKIE['recently_viewed'];
				$products_array = unserialize( $cookie );
				$length         = count( $products_array );
				echo $length;
				echo '<br>';
				echo $number_of_products;
				if ( $length <= $number_of_products ) {
					$products_array[] = $product_id;
				} else {
					array_unshift( $products_array, $product_id );
				}
				setcookie( 'recently_viewed', serialize( $products_array ), time() + 60 * 60 * 24 * 30 ); // set cookie for 30 days
			}
		}

	}
}

/*
 * Check if current product id include within the cookies for 'recently searched' section
 */
function matat_check_if_current_product_id_is_in_cookie( $product_id ) {

	if( isset($_COOKIE['recently_viewed']) && !empty($_COOKIE['recently_viewed']) ) {
		$cookie         = $_COOKIE['recently_viewed'];
		$products_array = unserialize( $cookie );
		if( in_array( $product_id, $products_array ) ) {
			return true;
		} else {
			return false;
		}

	} else {
		$products_array = [];
		setcookie( 'recently_viewed', serialize( $products_array ), time() + 60 * 60 * 24 * 30 ); // set cookie for 30 days
		return false;
	}
}

/*
 * get products from cookie
 */
function matat_get_recently_viewed_from_cookie() {
	if( isset($_COOKIE['recently_viewed']) && !empty($_COOKIE['recently_viewed']) ) {
		$cookie         = $_COOKIE['recently_viewed'];
		$products_array = unserialize( $cookie );

		return $products_array;
	} else {
		return false;
	}
}