export interface EngineAPI {
    /**
     * Returns a timestamp representing the last time Engine.play() was called.
     * @since 2.0.0
     */
    readonly lastPlay: number;

    /**
     * Returns the current state of the engine ("idle", "playing", "rendering").
     * States:
     * * "idle": The engine is idle, awaiting the triggering of passage navigation—the default state.
     * * "playing": Passage navigation has been triggered and a turn is being processed.
     * * "rendering": The incoming passage is being rendered and added to the page—takes place during turn processing,
     *   so implies "playing".
     * @since 2.7.0
     */
    readonly state: "idle" | "playing" | "rendering";

    /**
     * Moves backward one moment within the full history (past + future), if possible, activating and showing the
     * moment moved to. Returns whether the history navigation was successful (should only fail if already at the
     * beginning of the full history).
     * @since 2.0.0
     */
    backward(): boolean;

    /**
     * Moves forward one moment within the full history (past + future), if possible, activating and showing the moment
     * moved to. Returns whether the history navigation was successful (should only fail if already at the end of the
     * full history).
     * @since 2.0.0
     */
    forward(): boolean;

    /**
     * Activates the moment at the given offset from the active (present) moment within the full state history and show
     * it. Returns whether the history navigation was successful (should only fail if the offset from the active
     * (present) moment is not within the bounds of the full history).
     * @param offset The offset from the active (present) moment of the moment to go to.
     * @since 2.0.0
     */
    go(offset: number): boolean;

    /**
     * Activates the moment at the given index within the full state history and show it. Returns whether the history
     * navigation was successful (should only fail if the index is not within the bounds of the full history).
     * @param index The index of the moment to go to.
     * @since 2.0.0
     * @example
     * Engine.goTo(0) // Goes to the first moment
     * Engine.goTo(9) // Goes to the tenth moment
     */
    goTo(index: number): boolean;

    /**
     * Returns whether the engine is idle.
     * @since 2.16.0
     */
    isIdle(): boolean;

    /**
     * Returns whether the engine is processing a turn — i.e. passage navigation has been triggered.
     * @since 2.16.0
     */
    isPlaying(): boolean;

    /**
     * Returns whether the engine is rendering the incoming passage.
     * @since 2.16.0
     */
    isRendering(): boolean;

    /**
     * Renders and displays the passage referenced by the given title, optionally without adding a new moment to the
     * history.
     * @param passageTitle The title of the passage to play.
     * @param noHistory Disables the update of the history (i.e. no moment is added to the history).
     * @since 2.0.0
     */
    play(passageTitle: string, noHistory?: boolean): HTMLElement;

    /**
     * Restarts the story.
     *
     * WARNING: The player will not be prompted and all unsaved state will be lost.
     * NOTE: In general, you should not call this method directly. Instead, call the UI.restart() static method, which
     * prompts the player with an OK/Cancel dialog before itself calling Engine.restart(), if they accept.
     * @since 2.0.0
     */
    restart(): void;

    /**
     * Renders and displays the active (present) moment's associated passage without adding a new moment to the history.
     * @since 2.0.0
     */
    show(): HTMLElement;
}

export {};