WooCommmerce - Custom coupon logic

gistfile1.aw

/*
 * This code goes into your theme's functions.php
 */
add_filter( 'woocommerce_coupon_is_valid', 'custom_woocommerce_coupon_is_valid', 1, 2 );

function custom_woocommerce_coupon_is_valid( $valid, $coupon ) {

	if ($coupon=='YOURCOUPONCODE') {
     
 		$min_quantity = 12;

		if (sizeof( $this->product_ids )>0) {
			$valid = false;
			if (sizeof($woocommerce->cart->get_cart())>0) {
				foreach ($woocommerce->cart->get_cart() as $cart_item_key => $cart_item) {
					if (in_array($cart_item['product_id'], $coupon->product_ids) || in_array($cart_item['variation_id'], $coupon->product_ids)) {
				
						if ( $cart_item['qty'] > $min_quantity ) $valid = true;

					}

				}
			}
		}

 	}

	return $valid;
}

Hi, I can't get the code work.