public function update_favorite( $request ) {
		$activity = $this->get_activity_object( $request );

		if ( empty( $activity->id ) ) {
			return new WP_Error(
				'bp_rest_invalid_id',
				__( 'Invalid activity ID.', 'buddypress' ),
				array(
					'status' => 404,
				)
			);
		}

		$user_id = get_current_user_id();

		$result = false;
		if ( in_array( $activity->id, $this->get_user_favorites(), true ) ) {
			$result  = bp_activity_remove_user_favorite( $activity->id, $user_id );
			$message = __( 'Sorry, you cannot remove the activity from your favorites.', 'buddypress' );

			// Update the user favorites, removing the activity ID.
			$this->user_favorites = array_diff( $this->get_user_favorites(), array( $activity->id ) );
		} else {
			$result  = bp_activity_add_user_favorite( $activity->id, $user_id );
			$message = __( 'Sorry, you cannot add the activity to your favorites.', 'buddypress' );

			// Update the user favorites, adding the activity ID.
			$this->user_favorites[] = (int) $activity->id;
		}

		if ( ! $result ) {
			return new WP_Error(
				'bp_rest_user_cannot_update_activity_favorite',
				$message,
				array(
					'status' => 500,
				)
			);
		}

		// Setting context.
		$request->set_param( 'context', 'edit' );

		// Prepare the response now the user favorites has been updated.
		$retval = array(
			$this->prepare_response_for_collection(
				$this->prepare_item_for_response( $activity, $request )
			),
		);

		$response = rest_ensure_response( $retval );

		/**
		 * Fires after user favorited activities has been updated via the REST API.
		 *
		 * @since 5.0.0
		 *
		 * @param BP_Activity_Activity $activity       The updated activity.
		 * @param array                $user_favorites The updated user favorites.
		 * @param WP_REST_Response     $response       The response data.
		 * @param WP_REST_Request      $request        The request sent to the API.
		 */
		do_action( 'bp_rest_activity_update_favorite', $activity, $this->get_user_favorites(), $response, $request );

		return $response;
	}