Set a custom calculated item price in Woocommerce

Question

Currently i have some custom calculation of product price based on different situation. When customer added a product in to cart then the custom price is set in session data , cart_item_data['my-price'] and i implemented using add_filter( 'woocommerce_add_cart_item') function and everything seems to working now .

Now the price in view cart page, checkout page is correct with my cart_item_data['my-price'].

But the only problem i am facing is the price is not updated in woocommerce mini cart that is appeared in the menu ,How can i change this ?

When i google i see a filter

add_filter('woocommerce_cart_item_price');

but i can't understand how to use this i do the following

    add_filter('woocommerce_cart_item_price','modify_cart_product_price',10,3);

function modify_cart_product_price( $price, $cart_item, $cart_item_key){
  if($cart_item['my-price']!==0){
      $price =$cart_item['my-price'];
    }
    return $price;
    //exit;
}

Here individual price is getting correct , but total price is wrong

Answer 1

Updated (october 2018)

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:

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