Code-Snippets-Functions/Execute a function on a child site/WooCommerce/automatically-add-product-to-cart-on-visit.txt

add_action( 'template_redirect', 'add_product_to_cart' );
function add_product_to_cart() {
	if ( ! is_admin() ) {
		$product_id = 64; //replace with your own product id
		$found = false;
		//check if product already in cart
		if ( sizeof( WC()->cart->get_cart() ) > 0 ) {
			foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
				$_product = $values['data'];
				if ( $_product->get_id() == $product_id )
					$found = true;
			}
			// if product not found, add it
			if ( ! $found )
				WC()->cart->add_to_cart( $product_id );
		} else {
			// if no products in cart, add it
			WC()->cart->add_to_cart( $product_id );
		}
	}
}