import { type Context, FrameEvent } from "./engine_context.js";
import { ContextEvent } from "./engine_context_registry.js";
export declare type Event = ContextEvent | FrameEvent;
declare type LifecycleHookContext = {
    context: Context;
};
/**
 * A function that can be called during the Needle Engine frame event at a specific point
 * @link https://engine.needle.tools/docs/scripting.html#special-lifecycle-hooks
 */
export declare type LifecycleMethod = (this: LifecycleHookContext, ctx: Context) => void;
/**
 * Options for `onStart(()=>{})` etc event hooks
 * @link https://engine.needle.tools/docs/scripting.html#special-lifecycle-hooks
 */
export declare type LifecycleMethodOptions = {
    /**
     * If true, the callback will only be called once
     */
    once?: boolean;
};
/** register a function to be called during the Needle Engine frame event at a specific point
 * @param cb the function to call
 * @param evt the event to call the function at
 */
export declare function registerFrameEventCallback(cb: LifecycleMethod, evt: Event, opts?: LifecycleMethodOptions): void;
/**
 * unregister a function to be called during the Needle Engine frame event at a specific point
 */
export declare function unregisterFrameEventCallback(cb: LifecycleMethod, evt: Event): void;
export declare function invokeLifecycleFunctions(ctx: Context, evt: Event): void;
export {};