Progressive percent discount based on cart amount - php

Question

I am trying to make a simple discount code for WooCommerce that gives you a percent discount before buying. Lets say that if you add products worth $100 you get 2% discount and if you add products worth $250 you get 4%, etc.
The only thing I found was this:
// Hook before calculate fees
add_action('woocommerce_cart_calculate_fees' , 'add_custom_fees');
/**
* Add custom fee if more than three article
* #param WC_Cart $cart
*/
function add_custom_fees( WC_Cart $cart ){
if( $cart->cart_contents_count < 3 ){
return;
}
// Calculate the amount to reduce
$discount = $cart->subtotal * 0.1;
$cart->add_fee( 'You have more than 3 items in your cart, a 10% discount has been added.', -$discount);
}
But could not manage to make it work with the modifying the hooks with those for the price.
How can I achieve this?

Answer 1

Here is the way to do it using conditions based on cart subtotal excl tax amount to add this progressive percentage as a negative fee, so a discount:
add_action( 'woocommerce_cart_calculate_fees','cart_price_progressive_discount' );
function cart_price_progressive_discount() {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
$has_discount = false;
$stotal_ext = WC()->cart->subtotal_ex_tax;
// Discount percent based on cart amount conditions
if( $stotal_ext >= 100 && $stotal_ext < 250 ) {
$percent = -0.02;
$percent_text = ' 2%';
$has_discount =true;
} elseif( $stotal_ext >= 250 ) {
$percent = -0.04;
$percent_text = ' 4%';
$has_discount =true;
}
// Calculation
$discount = $stotal_ext * $percent;
// Displayed text
$discount_text = __('Discount', 'woocommerce') . $percent_text;
if( $has_discount ) {
WC()->cart->add_fee( $discount_text, $discount, false );
}
// Last argument in add fee method enable tax on calculation if "true"
}
This goes in function.php file of your active child theme (or theme) or also in any plugin file.
This code is tested and works.
Similar: WooCommerce - Conditional Progressive Discount based on number of items in cart
Reference: WooCommerce class - WC_Cart - add_fee() method