* Get our sample schema for a post.
	 *
	 * @return array The sample schema for a post
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			// Since WordPress 5.3, the schema can be cached in the $schema property.
			return $this->schema;
		}

		$this->schema = [
			// This tells the spec of JSON Schema we are using which is draft 4.
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			// The title property marks the identity of the resource.
			'title'      => $this->endpoint,
			'type'       => 'object',
			// In JSON Schema you can specify object properties in the properties attribute.
			'properties' => [
				'id' => [
					'description' => esc_html__( 'Unique identifier for the object.', 'surecart' ),
					'type'        => 'string',
					'context'     => [ 'view', 'edit', 'embed' ],
					'readonly'    => true,
				],
			],
		];

		return $this->schema;
	}

	/**
	 * Process the callback for the route.
	 *
	 * @param string $class Class name.
	 * @param string $method Class method.
	 * @return callback
	 */
	public function callback( $class, $method ) {
		// litespeed caching bypass.
		do_action( 'litespeed_control_set_nocache', 'surecart api request' );

		return function ( $request ) use ( $class, $method ) {
			// check and filter context.
			$context = ! empty( $request['context'] ) ? $request['context'] : 'view';

			// should we convert currency?
			$converts_currency = $this->converts_currency && 'edit' !== $context;

			// allow override of currency conversion in a per-request basis.
			if ( isset( $request['currency_conversion'] ) ) {
				$converts_currency = wp_validate_boolean( $request['currency_conversion'] );
			}

			// convert currency if needed.
			\SureCart::currency()->convert( $converts_currency );

			// get and call controller with request.
			$controller = \SureCart::closure()->method( $class, $method );
			$model      = $controller( apply_filters( "rest_{$this->endpoint}_request", $request, $method ) );

			if ( is_wp_error( $model ) ) {
				return $model;
			}

			// remove wp_created_by to prevent user ids from being leaked.
			if ( 'edit' !== $context && ! empty( $model->metadata->wp_created_by ) ) {
				unset( $model->metadata->wp_created_by );
			}

			$response = rest_ensure_response( $this->filter_response_by_context( is_a( $model, Model::class ) ? $model->toArray() : $model, $context ) );

			if ( is_a( $model, Model::class ) && ! empty( $model->getCacheStatus() ) ) {
				$response->header( 'X-SURECART-CACHE-STATUS', $model->getCacheStatus() );
			}

			return $response;
		};
	}

	/**
	 * Check permissions for specific properties of the request.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 * @param array            $keys Keys to check.
	 *
	 * @return boolean
	 */
	protected function requestOnlyHasKeys( $request, $keys ) {
		$keys = array_merge( $keys, [ 'context', '_locale', 'rest_route', 'id', 'expand' ] );
		foreach ( $request->get_params() as $key => $value ) {
			if ( ! in_array( $key, $keys, true ) ) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Retrieves the query params for collections.
	 *
	 * @return array
	 */
	public function get_collection_params() {
		return [];
	}

	/**
	 * Set these all as false by default
	 * in case parent class doesn't implement them.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 *
	 * @return false
	 */
	public function get_item_permissions_check( $request ) {
		return false;
	}

	/**
	 * Set these all as false by default
	 * in case parent class doesn't implement them.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 *
	 * @return false
	 */
	public function get_items_permissions_check( $request ) {
		return false;
	}

	/**
	 * Set these all as false by default
	 * in case parent class doesn't implement them.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 *
	 * @return false
	 */
	public function create_item_permissions_check( $request ) {
		return false;
	}

	/**
	 * Set these all as false by default
	 * in case parent class doesn't implement them.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 *
	 * @return false
	 */
	public function update_item_permissions_check( $request ) {
		return false;
	}

	/**
	 * Set these all as false by default
	 * in case parent class doesn't implement them.
	 *
	 * @param \WP_REST_Request $request Full details about the request.
	 *
	 * @return false
	 */
	public function delete_item_permissions_check( $request ) {
		return false;
	}
}