import { Engine } from '../Engine';
import { ScheduledCallbackTiming } from './Clock';
export type CoroutineGenerator = () => Generator<any | number | Promise<any> | undefined, void, number>;
export interface CoroutineOptions {
    /**
     * Coroutines run preframe in the clock by default.
     */
    timing?: ScheduledCallbackTiming;
    /**
     * Coroutines auto start by default, set to false to require play();
     */
    autostart?: boolean;
}
type Thenable = PromiseLike<void>['then'];
export interface CoroutineInstance extends PromiseLike<void> {
    isRunning(): boolean;
    isComplete(): boolean;
    done: Promise<void>;
    generator: Generator<CoroutineInstance | number | Promise<any> | undefined, void, number>;
    start: () => CoroutineInstance;
    cancel: () => void;
    then: Thenable;
    [Symbol.iterator]: () => Generator<CoroutineInstance | number | Promise<any> | undefined, void, number>;
}
/**
 * Excalibur coroutine helper, returns a [[CoroutineInstance]] which is promise-like when complete. Coroutines run before frame update by default.
 *
 * Each coroutine yield is 1 excalibur frame. Coroutines get passed the elapsed time our of yield. Coroutines
 * run internally on the excalibur clock.
 *
 * If you yield a promise it will be awaited before resumed
 * If you yield a number it will wait that many ms before resumed
 * @param thisArg set the "this" context of the generator, by default is globalThis
 * @param engine pass a specific engine to use for running the coroutine
 * @param coroutineGenerator coroutine generator function
 * @param {CoroutineOptions} options optionally schedule coroutine pre/post update
 */
export declare function coroutine(thisArg: any, engine: Engine, coroutineGenerator: CoroutineGenerator, options?: CoroutineOptions): CoroutineInstance;
/**
 * Excalibur coroutine helper, returns a promise when complete. Coroutines run before frame update.
 *
 * Each coroutine yield is 1 excalibur frame. Coroutines get passed the elapsed time our of yield. Coroutines
 * run internally on the excalibur clock.
 *
 * If you yield a promise it will be awaited before resumed
 * If you yield a number it will wait that many ms before resumed
 * @param engine pass a specific engine to use for running the coroutine
 * @param coroutineGenerator coroutine generator function
 * @param {CoroutineOptions} options optionally schedule coroutine pre/post update
 */
export declare function coroutine(engine: Engine, coroutineGenerator: CoroutineGenerator, options?: CoroutineOptions): CoroutineInstance;
/**
 * Excalibur coroutine helper, returns a promise when complete. Coroutines run before frame update.
 *
 * Each coroutine yield is 1 excalibur frame. Coroutines get passed the elapsed time our of yield. Coroutines
 * run internally on the excalibur clock.
 *
 * If you yield a promise it will be awaited before resumed
 * If you yield a number it will wait that many ms before resumed
 * @param coroutineGenerator coroutine generator function
 * @param {CoroutineOptions} options optionally schedule coroutine pre/post update
 */
export declare function coroutine(coroutineGenerator: CoroutineGenerator, options?: CoroutineOptions): CoroutineInstance;
/**
 * Excalibur coroutine helper, returns a promise when complete. Coroutines run before frame update.
 *
 * Each coroutine yield is 1 excalibur frame. Coroutines get passed the elapsed time our of yield. Coroutines
 * run internally on the excalibur clock.
 *
 * If you yield a promise it will be awaited before resumed
 * If you yield a number it will wait that many ms before resumed
 * @param thisArg set the "this" context of the generator, by default is globalThis
 * @param coroutineGenerator coroutine generator function
 * @param {CoroutineOptions} options optionally schedule coroutine pre/post update
 */
export declare function coroutine(thisArg: any, coroutineGenerator: CoroutineGenerator, options?: CoroutineOptions): CoroutineInstance;
export {};