Auto add coupon in woocommerce with sample attribute variation

gistfile1.txt

add_action( 'woocommerce_before_cart', 'cs_apply_matched_coupons' );

function cs_apply_matched_coupons() {
    global $woocommerce;

    $coupon1 = 'coupon 1'; // your coupon code here
    $coupon2 = 'coupon 2'; // your coupon code here
    $coupon3 = 'coupon 3'; // your coupon code here
    $coupon4 = 'coupon 4'; // your coupon code here
    $coupon5 = 'coupon 5'; // your coupon code here

		$sample_count = 0;
		$cartData = $woocommerce->cart->cart_contents;

		foreach ( $cartData as $cart_item ) {
			$attribute = $cart_item['data']->get_variation_attributes();
			if( !empty($attribute['attribute_pa_product-type']) &&  $attribute['attribute_pa_product-type'] == 'sample') {
				$sample_count += $cart_item['quantity'];
			}
		}
		$sample_count = (int) $sample_count;
		if ( $sample_count == 1 ) {
			$woocommerce->cart->add_discount( $coupon1 );
		} elseif ( $sample_count == 2 ) {
				$woocommerce->cart->add_discount( $coupon2 );
		} elseif ( $sample_count == 3 ) {
				$woocommerce->cart->add_discount( $coupon3 );
		} elseif ( $sample_count == 4 ) {
				$woocommerce->cart->add_discount( $coupon4 );
		} elseif ( $sample_count >= 5 ) {
				$woocommerce->cart->add_discount( $coupon5 );
		}
}
?>