PHP Sums minus value - php

Question

I have the following sum
$item_shipping_cost += (float) $this->get_fee( $this->fee, $item_shipping_cost ) * (int) $product_data['quantity'];
This adds up like the this:
Product Price + Item Shipping Cost + Fee * Qty
So if the product price is set at £1.00 and Item Shipping is at £1.00 and the fee is £0.50 and I want 2 items the cost will be a total of £4.00. However, I would like to subtract the value of 'fee' as I only want the fee to be charge on addition products. How would I do this?
This line of code belongs to a WooCommerce Shipping Per Product plugin. The full code is:
class WC_Shipping_Per_Product extends WC_Shipping_Method {
const METHOD_ID = 'per_product';
/**
* Default product shipping cost.
*
* #var int
*/
private $cost;
/**
* Handling fee applied to entire order.
*
* #var int
*/
private $order_fee;
/**
* Constructor.
*
* #param int $instance_id Instance Id for method in zone config.
*/
public function __construct( $instance_id = 0 ) {
parent::__construct( $instance_id );
$this->id = self::METHOD_ID;
$this->method_title = __( 'Per-product', 'woocommerce-shipping-per-product' );
$this->method_description = __( 'Per product shipping allows you to define different shipping costs for products, based on customer location. These costs will be displayed and charged separately from any other shipping methods.', 'woocommerce-shipping-per-product' );
$this->supports = array(
'shipping-zones',
'instance-settings',
'instance-settings-modal',
);
// Load the form fields.
$this->init_form_fields();
// Define user set variables.
$this->title = $this->get_option( 'title' );
$this->tax_status = $this->get_option( 'tax_status' );
$this->cost = $this->get_option( 'cost' );
$this->fee = $this->get_option( 'fee' );
$this->order_fee = $this->get_option( 'order_fee' );
// Actions.
add_action( 'woocommerce_update_options_shipping_' . $this->id, array( $this, 'process_admin_options' ) );
}
/**
* Initialise Gateway Settings Form Fields.
*/
public function init_form_fields() {
$this->instance_form_fields = array(
'title' => array(
'title' => __( 'Method Title', 'woocommerce-shipping-per-product' ),
'type' => 'text',
'description' => __( 'This controls the title which the user sees during checkout.', 'woocommerce-shipping-per-product' ),
'default' => __( 'Product Shipping', 'woocommerce-shipping-per-product' ),
'desc_tip' => true,
),
'tax_status' => array(
'title' => __( 'Tax Status', 'woocommerce-shipping-per-product' ),
'type' => 'select',
'description' => '',
'default' => 'taxable',
'options' => array(
'taxable' => __( 'Taxable', 'woocommerce-shipping-per-product' ),
'none' => __( 'None', 'woocommerce-shipping-per-product' ),
),
),
'cost' => array(
'title' => __( 'Default Product Cost', 'woocommerce-shipping-per-product' ),
'type' => 'text',
'description' => __( 'Cost excluding tax (per product) for products without defined costs. Enter an amount, e.g. 2.50. Entering an amount here will apply a global shipping cost for all products, effectively disabling all other shipping methods', 'woocommerce-shipping-per-product' ),
'default' => '',
'placeholder' => __( 'Disabled, Enter an amount, e.g. 2.50.', 'woocommerce-shipping-per-product' ),
'desc_tip' => true,
),
'fee' => array(
'title' => __( 'Handling Fee (per product)', 'woocommerce-shipping-per-product' ),
'type' => 'text',
'description' => __( 'Fee excluding tax. Enter an amount, e.g. 2.50, or a percentage, e.g. 5%. Leave blank to disable.', 'woocommerce-shipping-per-product' ),
'default' => '',
'placeholder' => __( 'Disabled, Enter an amount, e.g. 2.50, or a percentage, e.g. 5%.', 'woocommerce-shipping-per-product' ),
'desc_tip' => true,
),
'order_fee' => array(
'title' => __( 'Handling Fee (per order)', 'woocommerce-shipping-per-product' ),
'type' => 'text',
'description' => __( 'Fee excluding tax. Enter an amount, e.g. 2.50, or a percentage, e.g. 5%. Leave blank to disable.', 'woocommerce-shipping-per-product' ),
'default' => '',
'placeholder' => __( 'Disabled, Enter an amount, e.g. 2.50, or a percentage, e.g. 5%.', 'woocommerce-shipping-per-product' ),
'desc_tip' => true,
),
);
}
/**
* Check is per product shipping is enabled for the product.
*
* #param array $product_data The product data form the package array.
* #param array $package Shipping package array.
*
* #return bool
*/
public function is_per_product_shipping_product( array $product_data, array $package ) {
if ( $product_data['quantity'] > 0 ) {
if ( $product_data['data']->needs_shipping() ) {
if ( false !== $this->calculate_product_shipping_cost( $product_data, $package ) ) {
return true;
}
}
}
return false;
}
/**
* Calculate the per product shipping cost if enabled for the product.
*
* #param array $product_data The product data form the package array.
* #param array $package Shipping package array.
*
* #return float|bool
*/
private function calculate_product_shipping_cost( array $product_data, array $package ) {
$rule = false;
$item_shipping_cost = 0;
if ( $product_data['variation_id'] ) {
$rule = woocommerce_per_product_shipping_get_matching_rule( $product_data['variation_id'], $package );
}
if ( false === $rule ) {
$rule = woocommerce_per_product_shipping_get_matching_rule( $product_data['product_id'], $package );
}
if ( $rule ) {
$item_shipping_cost += (float) $rule->rule_item_cost * (int) $product_data['quantity'];
$item_shipping_cost += (float) $rule->rule_cost;
} elseif ( '0' === $this->cost || $this->cost > 0 ) {
// Use default shipping cost.
$item_shipping_cost += (float) $this->cost * (int) $product_data['quantity'];
} else {
// NO default and nothing found - abort.
return false;
}
// Fee.
$item_shipping_cost += (float) $this->get_fee( $this->fee, $item_shipping_cost ) * (int) $product_data['quantity'];
return $item_shipping_cost;
}
/**
* Calculate shipping when this method is used standalone.
*
* #param array $package information.
*/
public function calculate_shipping( $package = array() ) {
$_tax = new WC_Tax();
$taxes = array();
$shipping_cost = 0;
if ( empty( $package['ship_via'] ) || ! in_array( $this->id, $package['ship_via'], true ) ) {
return; // must be a package mark as per product shipping in split_shipping_packages_per_product.
}
// This shipping method loops through products, adding up the cost.
if ( count( $package['contents'] ) > 0 ) {
foreach ( $package['contents'] as $item_id => $values ) {
if ( $values['quantity'] > 0 ) {
if ( $values['data']->needs_shipping() ) {
$item_shipping_cost = $this->calculate_product_shipping_cost( $values, $package );
$shipping_cost += $item_shipping_cost;
if ( 'yes' === get_option( 'woocommerce_calc_taxes' ) && 'taxable' === $this->tax_status ) {
$rates = $_tax->get_shipping_tax_rates( $values['data']->get_tax_class() );
$item_taxes = $_tax->calc_shipping_tax( $item_shipping_cost, $rates );
// Sum the item taxes.
foreach ( array_keys( $taxes + $item_taxes ) as $key ) {
$taxes[ $key ] = ( isset( $item_taxes[ $key ] ) ? $item_taxes[ $key ] : 0 ) + ( isset( $taxes[ $key ] ) ? $taxes[ $key ] : 0 );
}
}
}
}
}
}
// Add order shipping cost + tax.
if ( $this->order_fee ) {
$order_fee = (float) $this->get_fee( $this->order_fee, $shipping_cost );
$shipping_cost += $order_fee;
if ( 'yes' === get_option( 'woocommerce_calc_taxes' ) && 'taxable' === $this->tax_status ) {
$rates = $_tax->get_shipping_tax_rates();
$item_taxes = $_tax->calc_shipping_tax( $order_fee, $rates );
// Sum the item taxes.
foreach ( array_keys( $taxes + $item_taxes ) as $key ) {
$taxes[ $key ] = ( isset( $item_taxes[ $key ] ) ? $item_taxes[ $key ] : 0 ) + ( isset( $taxes[ $key ] ) ? $taxes[ $key ] : 0 );
}
}
}
// Add rate.
$this->add_rate(
array(
'id' => $this->id,
'label' => $this->title,
'cost' => $shipping_cost,
'taxes' => $taxes, // We calc tax in the method.
)
);
}
}

Answer 1

I suppose you mean:
$item_shipping_cost -= ($product_data['quantity'] - 1) * $this->fee;
This will remove fees from all products except one.
Add my line of code after your line:
$item_shipping_cost += (float) $this->get_fee( $this->fee, $item_shipping_cost ) * (int) $product_data['quantity'];
When there is only 1 product, then no fee will be subtracted.