Updated (october 2021)
For testing this successfully (and as I don't know how you make calculations), I have added a custom hidden field in product add to cart form with the following:
// The hidden product custom field
add_action( 'woocommerce_before_add_to_cart_button', 'add_gift_wrap_field' );
function add_gift_wrap_field() {
global $product;
// The fake calculated price
?>
<input type="hidden" id="my-price" name="my-price" value="115">
<?php
}
When product is added to cart, this my-price
custom field is also submitted (posted). To set this value in cart object I use the following function:
add_filter( 'woocommerce_add_cart_item', 'custom_cart_item_prices', 20, 2 );
function custom_cart_item_prices( $cart_item_data, $cart_item_key ) {
// Get and set your price calculation
if( isset( $_POST['my-price'] ) ){
$cart_item_data['my-price'] = $_POST['my-price'];
// Every add to cart action is set as a unique line item
$cart_item_data['unique_key'] = md5( microtime().rand() );
}
return $cart_item_data;
}
Now to apply (set) the new calculated price my-price
to the cart item, I use this last function:
// For mini cart *(cart item displayed price)*
add_action( 'woocommerce_cart_item_price', 'filter_cart_item_price', 10, 2 );
function filter_cart_item_price( $price, $cart_item ) {
if ( ! is_checkout() && isset($cart_item['my-price']) ) {
$args = array( 'price' => floatval( $cart_item['my-price'] ) );
if ( WC()->cart->display_prices_including_tax() ) {
$product_price = wc_get_price_including_tax( $cart_item['data'], $args );
} else {
$product_price = wc_get_price_excluding_tax( $cart_item['data'], $args );
}
return wc_price( $product_price );
}
return $price;
}
add_action( 'woocommerce_before_calculate_totals', 'set_calculated_cart_item_price', 20, 1 );
function set_calculated_cart_item_price( $cart ) {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
return;
// Loop through cart items
foreach ( $cart->get_cart() as $cart_item ){
if( isset( $cart_item['my-price'] ) && ! empty( $cart_item['my-price'] ) || $cart_item['my-price'] != 0 ){
// Set the calculated item price (if there is one)
$cart_item['data']->set_price( $cart_item['my-price'] );
}
}
}
All code goes in function.php file of your active child theme (or active theme).
Tested and works