import { EffectCallback } from 'react';
export declare type TimerHookStatus = 'idle' | 'running' | 'paused' | 'expired';
export interface TimerHook {
    /**
     * Starts the timer. If the timer is currently in a paused state, then it will
     * resume based on the original remaining length.
     */
    start: () => void;
    /**
     * Pauses the timer. This function has no effect if the timer has not yet
     * started ticking.
     */
    pause: () => void;
    /**
     * Resumes the timer. This function has no effect if the timer has not yet
     * started ticking.
     */
    resume: () => void;
    /**
     * Restarts the timer with new parameters.
     *
     * @param newLength - Optionally provide a new timer length (in milliseconds).
     * @param newTick - Optionally provide a new tick length (in milliseconds).
     */
    restart: (options?: RestartTimerOptions) => void;
    /**
     * A function returning the amount of time (in milliseconds) remaining in the
     * timer. If the timer is idle, this function returns `0`.
     */
    getRemaining: () => number;
    /**
     * A function returning the number of ticks that have accumulated since the
     * start of the currently-running timer.
     */
    getTickCount: () => number;
    /**
     * Returns a string enum indicating the current timer state
     * (one of: `"idle"`, `"running"`, `"paused"`, or `"expired"`).
     */
    getStatus: () => TimerHookStatus;
    /**
     * A static value that updates whenever the underlying timer state changes.
     * You can give this value to the dependency list `React.useEffect` to trigger
     * an effect.
     */
    key: number;
}
export interface RestartTimerOptions {
    length?: number;
    tick?: number;
}
export interface UseTimerOptions {
    length: number;
    tick?: number;
    autoStart?: boolean;
}
/**
 * Returns a timer that works inside the React lifecycle.
 *
 * @param length - The total length of the timer (in milliseconds).
 * @param tick - The interval at which to update the timer (in milliseconds).
 * @param autoStart - If `true`, the timer will immediately start ticking using
 * the initially-provided `length` and `tick` values.
 */
export declare function useTimer(options: UseTimerOptions): TimerHook;
/**
 * Execute an effect if the supplied timer ticks.
 *
 * @param timer - The `TimerHook` object from which to trigger the effect.
 * @param effect - Imperative function that can return a cleanup function.
 */
export declare function useTimerTick(timer: TimerHook, effect: EffectCallback): void;
/**
 * Execute an effect if the supplied timer expires (completes its countdown).
 *
 * @param timer - The `TimerHook` object from which to trigger the effect.
 * @param effect - Imperative function that can return a cleanup function.
 */
export declare function useTimerExpire(timer: TimerHook, effect: EffectCallback): void;