WooCommerce Buy 3 get 1 Free For Variations/Attributes

wcb3g1fv.php

/**
 * @snippet       WooCommerce Buy 3 get 1 Free For Variations/Attributes
 * @how-to        https://insomniainc.com/code-snippets/woocommerce/woocommerce-buy-3-get-1-free-for-variations-attributes/
 * @author        u/acephaliax
 * @compatiblity  Last tested on WooCommerce 8.9.2
 * @community     r/wordpress, r/woocommerce
 * @caffeinate    https://buymeacoffee.com/acephaliax
 */

// Hook to calculate fees in the cart
add_action( 'woocommerce_cart_calculate_fees', 'insomniainc_variation_party_discount' );

// Function to calculate attribute discount
function insomniainc_variation_party_discount( $cart ) {
    // Define the attribute name (e.g. "Colour")
    $attribute_name = 'Colour';
    
    // Define the term names for the attribute (e.g. "Blue", "Black", "White")
    $terms = array('Blue', 'Black', 'White');
    
    // Loop through each term
    foreach ( $terms as $term ) {
        $term_count = 0;
        $term_product = null;
        $discount_count = 0;
        
        // Loop through each item in the cart
        foreach ( $cart->get_cart() as $cart_item ) {
            $product = $cart_item['data'];
            $product_name = $product->get_name();
            
            // Check if the product name contains the term
            if ( strpos( $product_name, $term )!== false ) {
                $term_count++;
                $term_product = $product; // store the product for later use
            }
        }
        
        // If the term count is greater than or equal to the threshold, apply the discount
        if ( $term_count >= 4 ) { // Change this number to adjust the threshold (e.g. 3, 5, etc.)
            $discount_count = floor( $term_count / 4 ); // Change this number to adjust the discount ratio (e.g. 3, 5, etc.)
            $product_price = $term_product->get_price(); // Get price of one product with the term
            
            // Dynamic discount text with plural support
            if ( $discount_count > 1 ) {
                $discount_text = $discount_count. ' Free '. $term.'s'; // Append 's' for plural
            } else {
                $discount_text = $discount_count. ' Free '. $term; // Singular
            }
            
            $cart->add_fee( $discount_text, -$product_price * $discount_count );
        }
    }
}

For reddit request: https://www.reddit.com/r/Wordpress/comments/1d7wyux/buy_2_get_1_free_plugin_for_woocommerce/