How can I change the Total of price existing in WooCommerce - wordpress

Question

How Can I change the Total price of the cart using hook.
I have tried many hooks without result.
i'm probably arrived to find the result .
This is what I have tried.
add_action('woocommerce_checkout_process', 'wh_getCartItemBeforePayment', 10);
function wh_getCartItemBeforePayment(){
if($_POST['percent']){
if($_POST['percent']==1){
/*WC()->cart->total*0.25;
WC()->cart->calculate_totals();
woocommerce_cart_totals();*/
/*
add_action('woocommerce_cart_calculate_fees','woocommerce_custom_surcharge' );
function woocommerce_custom_surcharge() {
global $woocommerce;
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
$percentage = 0.01;
$surcharge = ( $woocommerce->cart->cart_contents_total + $woocommerce->cart->shipping_total ) * $percentage;
$woocommerce->cart->add_fee( 'Surcharge', $surcharge, true, '' );
}
throw new Exception( __( WC()->cart->total ) );*/
//$items = WC()->cart->get_cart();
$cupom_value=-1;
foreach ($items as $item => $values)
{
$_product = $values['data']->post;
$product_title = $_product->post_title;
$qty = $values['quantity'];
$price = get_post_meta($values['product_id'], '_price', true);
$post_id = $value['product_id'];
$regular_price = get_post_meta( $post_id, '_regular_price', true);
$sale_price = get_post_meta( $post_id, '_sale_price', true);
$cupom_value = ($regular_price - $sale_price) *0.25;
$price = $cupom_value;
$value['data']->price = $price;
}
//$price=3*0.25;
wc_add_notice($cupom_value, 'error' );
}}}

Answer 1

add_action( 'woocommerce_calculate_totals', 'action_cart_calculate_totals', 10, 1 );
function action_cart_calculate_totals( $cart_object ) {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
if ( !WC()->cart->is_empty() ):
$cart_object->cart_contents_total += 10; // add 10 to cart total
endif;
}