export {};

interface CancelOptions {
    upcomingOnly?: boolean;
}

interface Cancel {
    cancel: (options?: CancelOptions) => void;
}

interface NoReturn<T extends (...args: any[]) => any> {
    (...args: Parameters<T>): void;
}

export type throttle<T extends (...args: any[]) => any> = NoReturn<T> & Cancel;
export type debounce<T extends (...args: any[]) => any> = NoReturn<T> & Cancel;

interface ThrottleOptions {
    noTrailing?: boolean;
    noLeading?: boolean;
    debounceMode?: boolean;
}

interface DebounceOptions {
    atBegin?: boolean;
}

/**
 * Throttle execution of a function. Especially useful for rate limiting
 * execution of handlers on events like resize and scroll.
 *
 * @param delay
 * A zero-or-greater delay in milliseconds. For event callbacks, values around
 * 100 or 250 (or even higher) are most useful.
 *
 * @param callback
 * A function to be executed after delay milliseconds. The `this` context and
 * all arguments are passed through, as-is, to `callback` when the
 * throttled-function is executed.
 *
 * @param options
 * An object to configure options.
 *
 * @param options.noTrailing
 * Optional, defaults to false. If noTrailing is true, callback will only execute
 * every `delay` milliseconds while the throttled-function is being called. If
 * noTrailing is false or unspecified, callback will be executed one final time
 * after the last throttled-function call. (After the throttled-function has not
 * been called for `delay` milliseconds, the internal counter is reset)
 *
 * @param options.noLeading
 * Optional, defaults to false. If noLeading is false, the first throttled-function
 * call will execute callback immediately. If noLeading is true, the first the
 * callback execution will be skipped. It should be noted that callback will never
 * executed if both noLeading = true and noTrailing = true.
 *
 * @param options.debounceMode If `debounceMode` is true (at begin), schedule
 * `callback` to execute after `delay` ms. If `debounceMode` is false (at end),
 * schedule `callback` to execute after `delay` ms.
 *
 * @return
 * A new, throttled, function.
 */
export function throttle<T extends (...args: any[]) => any>(
    delay: number,
    callback: T,
    options?: ThrottleOptions,
): throttle<T>;

/**
 * Debounce execution of a function. Debouncing, unlike throttling,
 * guarantees that a function is only executed a single time, either at the
 * very beginning of a series of calls, or at the very end.
 *
 * @param delay
 * A zero-or-greater delay in milliseconds. For event callbacks, values around
 * 100 or 250 (or even higher) are most useful.
 *
 * @param callback
 * A function to be executed after delay milliseconds. The `this` context and
 * all arguments are passed through, as-is, to `callback` when the
 * debounced-function is executed.
 *
 * @param options
 * An object to configure options.
 *
 * @param options.atBegin
 * If atBegin is false or unspecified, callback will only be executed `delay`
 * milliseconds after the last debounced-function call. If atBegin is true,
 * callback will be executed only at the first debounced-function call. (After
 * the throttled-function has not been called for `delay` milliseconds, the
 * internal counter is reset).
 *
 * @return
 * A new, debounced function.
 */
export function debounce<T extends (...args: any[]) => any>(
    delay: number,
    callback: T,
    options?: DebounceOptions,
): debounce<T>;