}

				return $this->array_merge_recursive_replace_non_array_properties( $acc, $query );
			},
			array()
		);

		// Perform any necessary special merges.
		$merged_query['post__in'] = $this->merge_post__in( ...$special_query_vars['post__in'] );

		return $merged_query;
	}

	/**
	 * Return query params to support custom sort values
	 *
	 * @param string $orderby  Sort order option.
	 *
	 * @return array
	 */
	private function get_custom_orderby_query( $orderby ) {
		if ( ! in_array( $orderby, $this->custom_order_opts, true ) || 'post__in' === $orderby ) {
			return array( 'orderby' => $orderby );
		}

		if ( 'price' === $orderby ) {
			add_filter( 'posts_clauses', array( $this, 'add_price_sorting_posts_clauses' ), 10, 2 );
			return array(
				'isProductCollection' => true,
				'orderby'             => $orderby,
			);
		}

		// The popularity orderby value here is for backwards compatibility as we have since removed the filter option.
		if ( 'sales' === $orderby || 'popularity' === $orderby ) {
			add_filter( 'posts_clauses', array( $this, 'add_sales_sorting_posts_clauses' ), 10, 2 );
			return array(
				'isProductCollection' => true,
				'orderby'             => $orderby,
			);
		}

		if ( 'menu_order' === $orderby ) {
			return array(
				'orderby' => 'menu_order',
				'order'   => 'ASC',
			);
		}

		if ( 'random' === $orderby ) {
			return array(
				'orderby' => 'rand',
			);
		}

		$meta_keys = array(
			'rating' => '_wc_average_rating',
		);

		return array(
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
			'meta_key' => $meta_keys[ $orderby ],
			'orderby'  => 'meta_value_num',
		);
	}

	/**
	 * Add the `posts_clauses` filter to add price-based sorting
	 *
	 * @param array    $clauses The list of clauses for the query.
	 * @param WP_Query $query   The WP_Query instance.
	 * @return array   Modified list of clauses.
	 */
	public function add_price_sorting_posts_clauses( $clauses, $query ) {
		$query_vars                  = $query->query_vars;
		$is_product_collection_block = $query_vars['isProductCollection'] ?? false;

		if ( ! $is_product_collection_block ) {
			return $clauses;
		}

		$orderby = $query_vars['orderby'] ?? null;
		if ( 'price' !== $orderby ) {
			return $clauses;
		}

		$clauses['join']    = $this->append_product_sorting_table_join( $clauses['join'] );
		$is_ascending_order = 'asc' === strtolower( $query_vars['order'] ?? 'desc' );

		$clauses['orderby'] = $is_ascending_order ?
			'wc_product_meta_lookup.min_price ASC, wc_product_meta_lookup.product_id ASC' :
			'wc_product_meta_lookup.max_price DESC, wc_product_meta_lookup.product_id DESC';

		return $clauses;
	}

	/**
	 * Add the `posts_clauses` filter to add sales-based sorting
	 *
	 * @param array    $clauses The list of clauses for the query.
	 * @param WP_Query $query   The WP_Query instance.
	 * @return array   Modified list of clauses.
	 */
	public function add_sales_sorting_posts_clauses( $clauses, $query ) {
		$query_vars                  = $query->query_vars;
		$is_product_collection_block = $query_vars['isProductCollection'] ?? false;

		if ( ! $is_product_collection_block ) {
			return $clauses;
		}

		$orderby = $query_vars['orderby'] ?? null;

		// The popularity orderby value here is for backwards compatibility as we have since removed the filter option.
		if ( 'sales' !== $orderby && 'popularity' !== $orderby ) {
			return $clauses;
		}

		$clauses['join']    = $this->append_product_sorting_table_join( $clauses['join'] );
		$is_ascending_order = 'asc' === strtolower( $query_vars['order'] ?? 'desc' );

		$clauses['orderby'] = $is_ascending_order ?
			'wc_product_meta_lookup.total_sales ASC, wc_product_meta_lookup.product_id ASC' :
			'wc_product_meta_lookup.total_sales DESC, wc_product_meta_lookup.product_id DESC';

		return $clauses;
	}

	/**
	 * Join wc_product_meta_lookup to posts if not already joined.
	 *
	 * @param string $sql SQL join.
	 * @return string
	 */
	protected function append_product_sorting_table_join( $sql ) {
		global $wpdb;

		if ( ! strstr( $sql, 'wc_product_meta_lookup' ) ) {
			$sql .= " LEFT JOIN {$wpdb->wc_product_meta_lookup} wc_product_meta_lookup ON $wpdb->posts.ID = wc_product_meta_lookup.product_id ";
		}
		return $sql;
	}

	/**
	 * Merge all of the 'post__in' values and return an array containing only values that are present in all arrays.
	 *
	 * @param int[][] ...$post__in The 'post__in' values to be merged.
	 *
	 * @return int[] The merged 'post__in' values.
	 */
	private function merge_post__in( ...$post__in ) {
		if ( empty( $post__in ) ) {
			return array();
		}

		// Since we're using array_intersect, any array that is empty will result
		// in an empty output array. To avoid this we need to make sure every
		// argument is a non-empty array.
		$post__in = array_filter(
			$post__in,
			function ( $val ) {
				return is_array( $val ) && ! empty( $val );
			}
		);
		if ( empty( $post__in ) ) {
			return array();
		}

		// Since the 'post__in' filter is exclusionary we need to use an intersection of
		// all of the arrays. This ensures one query doesn't add options that another
		// has otherwise excluded from the results.
		if ( count( $post__in ) > 1 ) {
			$post__in = array_intersect( ...$post__in );
			// An empty array means that there was no overlap between the filters and so
			// the query should return no results.
			if ( empty( $post__in ) ) {
				return array( -1 );
			}
		} else {
			$post__in = reset( $post__in );
		}

		return array_values( array_unique( $post__in, SORT_NUMERIC ) );
	}
}