import { Message } from '@phosphor/messaging';
import { Widget } from '@phosphor/widgets';
import { DisposableCollection, Disposable } from './disposable';
import { Event, Emitter } from './event';
import PerfectScrollbar from 'perfect-scrollbar';
export declare type MaybePromise<T> = T | PromiseLike<T>;
export declare const DEFAULT_SCROLL_OPTIONS: PerfectScrollbar.Options;
/**
 * At a number of places in the code, we have effectively reimplemented Phosphor's Widget.attach and Widget.detach,
 * but omitted the checks that Phosphor expects to be performed for those operations. That is a bad idea, because it
 * means that we are telling widgets that they are attached or detached when not all the conditions that should apply
 * do apply. We should explicitly mark those locations so that we know where we should go fix them later.
 */
export declare namespace UnsafeWidgetUtilities {
    /**
     * Ordinarily, the following checks should be performed before detaching a widget:
     * It should not be the child of another widget
     * It should be attached and it should be a child of document.body
     */
    function detach(widget: Widget): void;
    /**
     * @param ref The child of the host element to insert the widget before.
     * Ordinarily the following checks should be performed:
     * The widget should have no parent
     * The widget should not be attached, and its node should not be a child of document.body
     * The host should be a child of document.body
     * We often violate the last condition.
     */
    function attach(widget: Widget, host: HTMLElement, ref?: HTMLElement | null): void;
}
export declare type EventListener<K extends keyof HTMLElementEventMap> = (this: HTMLElement, event: HTMLElementEventMap[K]) => any;
export interface EventListenerObject<K extends keyof HTMLElementEventMap> {
    handleEvent(evt: HTMLElementEventMap[K]): void;
}
export declare namespace EventListenerObject {
    function is<K extends keyof HTMLElementEventMap>(listener: any | undefined): listener is EventListenerObject<K>;
}
export declare type EventListenerOrEventListenerObject<K extends keyof HTMLElementEventMap> = EventListener<K> | EventListenerObject<K>;
export declare function addEventListener<K extends keyof HTMLElementEventMap>(element: HTMLElement, type: K, listener: EventListenerOrEventListenerObject<K>, useCapture?: boolean): Disposable;
export declare class BaseWidget extends Widget {
    protected readonly onScrollYReachEndEmitter: Emitter<void>;
    readonly onScrollYReachEnd: Event<void>;
    protected readonly onScrollUpEmitter: Emitter<void>;
    readonly onScrollUp: Event<void>;
    protected readonly onDidChangeVisibilityEmitter: Emitter<boolean>;
    readonly onDidChangeVisibility: Event<boolean>;
    protected readonly onDidDisposeEmitter: Emitter<void>;
    readonly onDidDispose: Event<void>;
    protected readonly toDispose: DisposableCollection;
    protected readonly toDisposeOnDetach: DisposableCollection;
    protected scrollBar: PerfectScrollbar;
    protected scrollOptions: PerfectScrollbar.Options;
    constructor();
    setScrollOptions(options: PerfectScrollbar.Options): void;
    private resizeHandler;
    private debouncedResizeHandler;
    dispose(): void;
    protected onCloseRequest(msg: Message): void;
    protected onBeforeAttach(msg: Message): void;
    protected onAfterDetach(msg: Message): void;
    protected onBeforeDetach(msg: Message): void;
    protected onAfterAttach(msg: Message): void;
    protected getScrollContainer(): MaybePromise<HTMLElement>;
    protected disableScrollBarFocus(scrollContainer: HTMLElement): void;
    protected onUpdateRequest(msg: Message): void;
    protected onResize(msg: Widget.ResizeMessage): void;
    protected addUpdateListener<K extends keyof HTMLElementEventMap>(element: HTMLElement, type: K, useCapture?: boolean): void;
    protected addEventListener<K extends keyof HTMLElementEventMap>(element: HTMLElement, type: K, listener: EventListenerOrEventListenerObject<K>, useCapture?: boolean): void;
    setFlag(flag: Widget.Flag): void;
    clearFlag(flag: Widget.Flag): void;
    updateScrollBar(): void;
}