Iconic WDS - Disable specific dates for specific products.

function.php

<?php
/**
 * Iconic WDS - Disable specific dates for specific products.
 *
 * @param array  $available_dates Available dates.
 * @param string $format          Date format.
 * @param bool   $ignore_slots    Ignore slots.
 *
 * @return array
 */
function iconic_wds_disable_specific_dates_for_specific_product( $available_dates, $format, $ignore_slots ) {
	if ( 'array' === $format || empty( WC()->cart ) ) {
		return $available_dates;
	}

	// Todo: add list of product IDs in this array.
	$for_products = array( 177 );

	// Check if any of the $for_products products are in the cart.
	$has_product = false;
	foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
		$product    = $cart_item['data'];
		$product_id = $product->get_parent_id() ? $product->get_parent_id() : $product->get_id();

		if ( in_array( $product_id, $for_products ) ) {
			$has_product = true;
			break;
		}
	}

	if ( ! $has_product ) {
		return $available_dates;
	}

	// If $for_products products are in the cart, remove dates after 21st December.
	$filtered_dates = array();
	foreach ( $available_dates as $date ) {
		$date_obj    = DateTime::createFromFormat( $format, $date );
		$first_march = DateTime::createFromFormat( 'Ymd', '20241221' );

		if ( $date_obj < $first_march ) {
			$filtered_dates[] = $date;
		}
	}

	return $filtered_dates;
}
add_filter( 'iconic_wds_available_dates', 'iconic_wds_disable_specific_dates_for_specific_product', 10, 3 );