Managing conditional coupons and additional fees on cart/checkout Woocommerce - woocommerce

Question

I am having problems in managing contemporarly disocunt coupons and custom additional fields on the cart and checkout page.
I created a function that adds a discount only if a product is present in the cart with more than a variation and the discount is applied only on the second (or third) variation, NOT on the first one. You can find my final code here Woocommerce conditional part cart discount on the same product present with > 1 variation
However I had to go further on, as I have a particular tricky situation. Normally the condition described above cannot be applied when other discounts are in the cart (i.e. standard discount coupons). I hence added these two lines just after getting the cart
$has_coupons = count(WC()->cart->applied_coupons)>0?true:false;
if(!$has_coupons) {
//here goes the function that I did
} else return;
Everything is fine, and it works. However there is a particular situation in which I have to apply a coupon to the cart (not %) that detracts to teh whole cart a specific amount. This particular coupon CAN go with the discount created in the function I wrote!
/* get coupon code*/
function get_coupon_code() {
global $woocommerce;
if ( !empty( $woocommerce->cart->applied_coupons ) ) {
$my_coupon_code = $woocommerce->cart->get_coupons() ;
foreach($my_coupon_code as $coupon){
if ( $post = get_post( $coupon->id ) ) {
$coupon_code= $coupon->code;
}
}
}
return $coupon_code;
}
/* get coupon amount*/
function get_coupon_amount() {
global $woocommerce;
if ( ! empty( $woocommerce->cart->applied_coupons ) ) {
$my_coupon_amount = $woocommerce->cart->get_coupons() ;
foreach($my_coupon_amount as $coupon){
$coupon_amount =$coupon->coupon_amount;
}
}
return $coupon_amount;
}
function cart_discount() {
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
global $woocommerce;
//get the code and amount of the coupon applied
$coupon_code = get_coupon_code();
$coupon_amount = get_coupon_amount();
//check if the code corresponds to the coupon exception I want to accept
if ($coupon_code == 'wa-1'){
//if it is the code I need to apply, then I remove it from the cart
WC()->cart->remove_coupon($coupon_code);
//I use the amount to add it as additional fee at negative
$coupon_discount = -($coupon_amount);
//I add the ex-coupon amount to an additional field
$discount_agency_text = __( 'Detracted agency fee', 'woocommerce' );
WC()->cart->add_fee( $discount_agency_text, $coupon_discount, false );
}
//and following the function previously mentioned
$cart = WC()->cart->get_cart();
$has_coupons = count(WC()->cart->applied_coupons)>0?true:false;
//check if there are other coupons or if the coupon applied are the case I want to pass through my function
if(!$has_coupons || $coupon == 'wa-1') {
//here follows the strings to apply a 10% discount on the second (third) variation of the product and not on the first one
foreach($cart as $cart_item_key => $values) {
$product_id = $values['product_id']; // product ID
$variation_id = $values['variation_id']; // product quantity
$cart_lines_total = $values["line_total"];
$cart_lines_quantity = $values["quantity"];
//product id to be considered for this discount
//$product = 1394 = Spedizioni CSR eng
//$product = 1389 = Spedizioni IDP eng
//$product = 13888 = Spedizioni CSR ita
//$product = 13910 = Spedizioni IDP ita
if($product_id == '1394' || $product_id == '1389' || $product_id == '13888' || $product_id == '13910')
{
$cart_array []= array( $product_id , $variation_id, $cart_lines_quantity, $cart_lines_total);
}
}
$conteggio = count($cart_array); //counts the number of items in teh cart
// percent is 5%
$percent = -0.10;
if ($conteggio < 3 && $cart_array[0][0] == $cart_array[1][0])
{
$discount = $percent * $cart_array[1][3];
$discount_text = __( '10% discount on subsequent week(s)', 'woocommerce' );
WC()->cart->add_fee( $discount_text, $discount, false );
}
if ($conteggio < 4 && $cart_array[0][0] == $cart_array[1][0] && $cart_array[0][0] == $cart_array[2][0])
{
$discount = ($percent * $cart_array[1][3]) + ($percent * $cart_array[2][3]);
$discount_text = __( '10% discount on subsequent week(s)', 'woocommerce' );
WC()->cart->add_fee( $discount_text, $discount, false );
}
if ($conteggio < 5 && $cart_array[0][0] == $cart_array[1][0] && $cart_array[0][0] == $cart_array[2][0] && $cart_array[0][0] == $cart_array[3][0])
{
$discount = ($percent * $cart_array[1][3]) + ($percent * $cart_array[2][3]) + ($percent * $cart_array[3][3]);
$discount_text = __( '10% discount on subsequent week(s)', 'woocommerce' );
WC()->cart->add_fee( $discount_text, $discount, false );
}
} else return;
}
add_action( 'woocommerce_cart_calculate_fees','cart_discount' );
The problem I have is that part concernign the management of teh discount coupon doesn't work. It gets the $coupon_code and $coupon_amount, but doesn't add it to the additional fields section.
Anybody can help me please?

Answer 1

Nicely presented !
This plugin may solve the problem easy, it allows you to charge extra fees in cart, based on the combination of multiple conditional rules that you configure in your woocommerce store.
I hope it may help!
WooCommerce Conditional Product Fees For Checkout

Answer 2

I am still stuck on the argument but I try now to make it simpler.
I can actually simply use a coupon discount that works together with my function (which, in case I have a product with > then a variation, it adds 10% discount only the following variation and not on the first one).
The problem is that if I use a coupon (=80€) applied on the cart, it anyway spread over the various items and the 10% discount is calculated on a lower price (not on the regular price).
My problem would be solved if I can apply the coupon on the final cart total, instead of being spread over the single items. Is that possible?
Just to give you an example, my $cart_array before applying the coupon is
Array
(
[0] => Array
(
[0] => 1394 //product_id
[1] => 1851 //variation_id
[2] => 1 //quantity
[3] => 906 //regular price
)
[1] => Array
(
[0] => 1394 //product_id
[1] => 1852 //variation_id
[2] => 1 //quantity
[3] => 906 //regular price
)
)
If at this point I apply the coupon, the array changes in:
Array
(
[0] => Array
(
[0] => 1394
[1] => 1851
[2] => 1
[3] => 866 //price after coupon
)
[1] => Array
(
[0] => 1394
[1] => 1852
[2] => 1
[3] => 866 //price after coupon
)
)
As you see the second item is no more 906 but 866 and thus the 10% discount is less.
Is there a way to apply the coupon only to the first item of the array? Or apply it at the final total (after the additional fee has been calculated)?