Woocommerce change price based on quantity and variation - php

Question

I am currently creating my first site using woocommerce for a client, and they are requesting for me to have a price increase per variation and quantity, however i am not sure how to do it. Here is an example of what they are asking for:
Product Type: Limestone
Variations:
Product Size:
10kg bag
20kg bag
40kg bag
Quantity:
1-20
TL;DR
if the customer wants multiple 10kg bags, the price increases by £36 at a time, if they want multiple 20kg bags, the price increases by £30 at a time, and if they want multiple 40kg bags, the price doubles every time.
I have used woocommerce variations and attributes so far but now it would require modifying having 3x20 variations all of which require a different price, which would be easier to change if a statement is possible as follows:
if ($productsize === '10kg') {
$quantity = 2; //get quantity from textbox $_POST
$initial_price = 36; //get inital price from woocommerce global variable
$total_price = $inital_price * $quantity;
update_price($total_price); //a function to update the price in woocommerce when adding to cart
}
Obviously the code above does not use any woocommerce variables, however doing this for only 3 variations would be easier than manually entering 60 variations on one product for which we have >60 on our site.

Answer 1

I don't know if you need it anymore, however try it
add_action( 'woocommerce_before_calculate_totals', 'IG_recalculate_price',5,1 );
function IG_recalculate_price( $cart_object ) {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
$quantity = 0;
foreach ( $cart_object->get_cart() as $key => $value ) {
// count q.ty
$quantity += $value['quantity'];
// delta q.ty
if( $quantity > 24 ) {
// get price by custom field but you can use a simple var
$newprice = get_post_meta( $value['data']->get_id(), 'custom_field2', true);
$value['data']->set_price( $newprice );
// reset q.ty for check every item in the cart
$quantity = 0;
}else{
$newprice = get_post_meta( $value['data']->get_id(), 'custom_field', true);
$value['data']->set_price( $newprice );
$quantity = 0;
}
}
}