Drupal Commerce Line Items: alter the price?

Question

I have to add to my cart some line items with a custom amount. The commerce product is saved with price = 0, and my module compute the price and add the line item to the cart/order, but i dont understand how to set programmatically the price.

I've read about using Rules, but I need my module to be able to set/alter the price, without invoking rules.

I've tryed with an entity wrapper, i tryed to alter the line item created with commerce_product_line_item_new(), but nothing, when the line item gets into the cart always has the original product price (in my case, 0).

How to alter a line item price programmatically?

My code so far looks like:

// For debugging, this function is called by hook_menu()
function mymodule_test($product_id)
{
    global $user;
    $user = user_load($user->uid);

    $order = commerce_cart_order_load($user->uid);
    $order_wrapper = entity_metadata_wrapper('commerce_order', $order);

    $product = commerce_product_load($product_id);

    $line_item = commerce_product_line_item_new(
            $product,
            1,
            0,
            array(
            ),
            'cover'
    );

    $line_item_wrapper = entity_metadata_wrapper("commerce_line_item", $line_item);

    $line_item_wrapper->commerce_unit_price->data = commerce_price_component_add(
            $line_item_wrapper->commerce_unit_price->value(),
            'base_price',
            array(
                            'amount' => 1234,
                            'currency_code' => 'EUR',
                            'data' => array(),
            ),
            TRUE
    );

    $insert_line_item = commerce_cart_product_add($user->uid, $line_item_wrapper->value(), FALSE);

    return 'done';
}

The strange thing, is that I tryed to adapt the code of commerce_line_item_unit_price_amount() found in commerce/modules/line_item/commerce_line_item.rules.inc, but this test:

<?php
    global $user;
    $product = commerce_product_load(4); // my commerce product for test

    $line_item = commerce_product_line_item_new(
        $product,
        1,
        0,
        array(
        ),
        'cover' // I do have this line_items type
    );

    // manually set amount and component name
    $amount = 1234;
    $component_name = 'base_price'; // tryed with discount, nothing change

    $wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);
    $unit_price = commerce_price_wrapper_value($wrapper, 'commerce_unit_price', TRUE);

    // Calculate the updated amount and create a price array representing the
    // difference between it and the current amount.
    $current_amount = $unit_price['amount'];
    $updated_amount = commerce_round(COMMERCE_ROUND_HALF_UP, $amount);

    $difference = array(
        'amount' => $updated_amount - $current_amount, 
        'currency_code' => $unit_price['currency_code'], 
        'data' => array(),
    );

    // Set the amount of the unit price and add the difference as a component.
    $wrapper->commerce_unit_price->amount = $updated_amount;

    $wrapper->commerce_unit_price->data = commerce_price_component_add(
        $wrapper->commerce_unit_price->value(), 
        $component_name, 
        $difference, 
        TRUE
    );

    $insert_line_item = commerce_cart_product_add($user->uid, $line_item, FALSE);
?>

still fail, the line_item get into the cart but with the original price of the referenced product.

Any idea?

Answer 1

For those people who don't want to use rules and hope to alter the price directly. Here is my solution:

// Alter the price in list and single product page.
function my_module_commerce_product_calculate_sell_price_line_item_alter($line_item){

    $price = 100; //1 dollar
    $line_item->commerce_unit_price[LANGUAGE_NONE]['0']['amount'] = $price;

}

// Alter the price in cart & order.
function my_module_commerce_cart_line_item_refresh($line_item, $order_wrapper){

    $price = 100; //1 dollar
    $line_item->commerce_unit_price[LANGUAGE_NONE]['0']['amount'] = $price;
    // Alter the base_price component.
    $line_item->commerce_unit_price[LANGUAGE_NONE]['0']['data']['components']['0']['price']['amount'] = $price;

}