if ( ! isset( $this->requests[ $index ] ) || self::ACTION_DELETE !== $this->requests[ $index ] ) {
				$this->requests[ $index ] = self::ACTION_UPDATE;
			}
		}
	}


	/**
	 * Adds the given retailer IDs to the requests array to be deleted.
	 *
	 * @since 2.0.0
	 *
	 * @param int[] $retailer_ids retailer IDs to delete
	 */
	public function delete_products( array $retailer_ids ) {

		foreach ( $retailer_ids as $retailer_id ) {
			$this->requests[ $this->get_product_index( $retailer_id ) ] = self::ACTION_DELETE;
		}
	}


	/**
	 * Adds the products with stock changes to the requests array to be updated.
	 *
	 * @since 3.5.8
	 *
	 * @param \WC_Product $product product object
	 */
	public function handle_stock_update( \WC_Product $product ) {

		// bail if not connected
		if ( ! facebook_for_woocommerce()->get_connection_handler()->is_connected() ) {
			return;
		}

		// bail if admin and not AJAX
		if ( is_admin() && ! wp_doing_ajax() ) {
			return;
		}

		try {
			// handle variable products - sync children only, not the parent
			if ( $product->is_type( 'variable' ) ) {
				$variation_ids = $product->get_children();
				if ( ! empty( $variation_ids ) ) {
					$this->create_or_update_products( $variation_ids );
				}
			} else {
				// add the product to the list of products to be updated
				$this->create_or_update_products( array( $product->get_id() ) );
			}
		} catch ( Exception $e ) {
			// Silently handle any sync errors - Facebook sync should not break stock updates.
			unset( $e ); // phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedCatch
		}
	}


	/**
	 * Handles product imports from WooCommerce import functionality.
	 *
	 * @since 3.5.8
	 *
	 * @param \WC_Product $product The product object that was imported
	 * @param array       $data    The import data
	 */
	// phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter
	public function handle_product_import_update( $product, $data ) {

		// bail if not connected
		if ( ! facebook_for_woocommerce()->get_connection_handler()->is_connected() ) {
			return;
		}

		// Process ALL products (both new and updates) during import
		try {
			facebook_for_woocommerce()->get_product_sync_validator( $product )->validate();
			$this->create_or_update_products( array( $product->get_id() ) );
		} catch ( \Exception $e ) {
			return;
		}
	}

	/**
	 * Creates a background job to sync the products in the requests array.
	 *
	 * @since 2.0.0
	 *
	 * @return \stdClass|object|null
	 */
	public function schedule_sync() {

		if ( ! empty( $this->requests ) ) {

			$job_handler = facebook_for_woocommerce()->get_products_sync_background_handler();
			$job         = $job_handler->create_job( array( 'requests' => $this->requests ) );

			$job_handler->dispatch();

			return $job;
		}
	}


	/**
	 * Gets the prefixed product ID used as the array index.
	 *
	 * @since 2.0.0
	 *
	 * @param int|string $product_id product ID
	 * @return string prefixed product index
	 */
	private function get_product_index( $product_id ) {

		return self::PRODUCT_INDEX_PREFIX . $product_id;
	}


	/**
	 * Determines whether a sync is currently in progress.
	 *
	 * This method uses caching to avoid expensive database queries.
	 * The cache is automatically invalidated when jobs are created, updated, or completed.
	 * On frontend requests, this always returns false to avoid expensive queries.
	 *
	 * @since 2.0.0
	 *
	 * @return bool
	 */
	public static function is_sync_in_progress() {
		// On frontend, skip the check entirely - visitors don't need sync status
		if ( ! is_admin() && ! wp_doing_ajax() && ! wp_doing_cron() ) {
			return false;
		}

		// Check cache first
		$cache_key = 'wc_facebook_sync_in_progress';
		$cached    = get_transient( $cache_key );
		if ( false !== $cached ) {
			return 'yes' === $cached;
		}

		// Query for processing jobs
		$jobs = facebook_for_woocommerce()->get_products_sync_background_handler()->get_jobs(
			array(
				'status' => 'processing',
			)
		);

		$in_progress = ! empty( $jobs );

		// Cache the result - invalidated when job status changes
		set_transient( $cache_key, $in_progress ? 'yes' : 'no', 0 );

		return $in_progress;
	}
}