WooCommerce: Add a discount based on individual items quantity - php

Question

In my WooCommerce website I have a few products with the same price of 80$.
I want to add a Discount by the products quantity.
The logic is like that:
if (Products Quantity is 2){
// the original product price change from 80$ to 75$ each.
}
if(Products Quantity is 3 or more){
//the original product price change from 80$ to 70$ each.
}
for example,
if a customer pick 2 products, the original price will be (80$ x 2) => 160$.
But after the discount, it will be: (75$ x 2) => 150$.
And…
if visitor pick 3 products, the original price will be (80$ x 3) => 240$.
But after the fee, it will be: (70$ x 3) => 210$.
Any help, please?
Thanks

Answer 1

This custom hooked function should do what you expect. You can set in it your progressive discount limit based on individual item quantity.
Here is the code
## Tested and works on WooCommerce 2.6.x and 3.0+
add_action( 'woocommerce_cart_calculate_fees', 'progressive_discount_by_item_quantity', 10, 1 );
function progressive_discount_by_item_quantity( $cart ) {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
# Progressive quantity until quantity 3 is reached (here)
# After this quantity limit, the discount by item is fixed
# No discount is applied when item quantity is equal to 1
// Set HERE the progressive limit quantity discount
$progressive_limit_qty = 3; // <== <== <== <== <== <== <== <== <== <== <==
$discount = 0;
foreach( $cart->get_cart() as $cart_item_key => $cart_item ){
$qty = $cart_item['quantity'];
if( $qty <= $progressive_limit_qty )
$param = $qty; // Progressive
else
$param = $progressive_limit_qty; // Fixed
## Calculation ##
$discount -= 5 * $qty * ($param - 1);
}
if( $discount < 0 )
$cart->add_fee( __( 'Quantity discount' ), $discount); // Discount
}
Code goes in function.php file of your active child theme (or theme) or also in any plugin file.
Tested and works on WooCommerce 2.6.x and 3.0+