How to programmatically remove applied discount coupons in Woocommerce?

Question

I've been searching for a while but I can't find how to remove woocommerce coupons programmatically.

I'm trying to make discounts based on cart total. I need to apply remove coupons because If you have products worth 1000 € (15% discount coupon applied) and remove products and leave only products worth 50 €, you still get this 15% discount because my code isn't removing the already applied coupon.

So here is my code for now:

    add_action( 'woocommerce_before_cart', 'apply_matched_coupons' );

function apply_matched_coupons() {
    global $woocommerce;

$coupon_code5 = '5p'; // your coupon code here
$coupon_code10 = '10p'; // your coupon code here
$coupon_code15 = '15p'; // your coupon code here
$coupon_code20 = '20p'; // your coupon code here
$coupon_code25 = '25p'; // your coupon code here

   if ( $woocommerce->cart->has_discount( $coupon_code ) ){ 
return;
}

   if ( $woocommerce->cart->cart_contents_total >= 4000 ) {
        $woocommerce->cart->add_discount( $coupon_code25 );
        $woocommerce->show_messages();
    }
else if ( $woocommerce->cart->cart_contents_total >= 2000 ) {
        $woocommerce->cart->add_discount( $coupon_code20 );
        $woocommerce->show_messages();
    }
else if ( $woocommerce->cart->cart_contents_total >= 1000 ) {
        $woocommerce->cart->add_discount( $coupon_code15 );
        $woocommerce->show_messages();
    }
else if ( $woocommerce->cart->cart_contents_total >= 500 ) {
        $woocommerce->cart->add_discount( $coupon_code10 );
        $woocommerce->show_messages();
    }
else if ( $woocommerce->cart->cart_contents_total >= 200 ) {
        $woocommerce->cart->add_discount( $coupon_code5 );
        $woocommerce->show_messages();
    }
}

Answer 1

To remove a single coupon from the cart using its coupon code use WC_Cart->remove_coupon( $code ).

To remove all coupons from the cart you would use WC_Cart->remove_coupons( $type ) - $type defaults to null for all, pass in "cart" to remove before tax coupons, "order" for after tax coupons.

To get all of the coupons in the cart as an array you can loop over and optionally remove, use WC_Cart->get_coupons().

foreach ( WC()->cart->get_coupons() as $code => $coupon ){
   $valid = ? // decide to remove or not
   if ( ! $valid ){
       WC()->cart->remove_coupon( $code );
   }
}

Answer 2

The cart method remove_coupons() has been since updated such that a type is no longer required. Now, to remove all coupons, this will do the trick:

WC()->cart->remove_coupons();

For more information, check out the documentation for the WC_Cart class here.