import Async, { CustomSignalClass, Signal } from "typescene-async";
/** Specialized custom event used by Drag to keep track of the operation */
export interface CustomDragEvent extends CustomEvent {
    /** Detail object provided to Drag.start to initiate drag operation */
    detail: any;
}
/** Represents a drag operation (created by static .start(...) method) */
export declare class Drag extends Async.ObservableObject {
    /** Current drag operation, if any (use while handling drag events, e.g. get/set .detail with custom data, or observe coordinates) */
    static current: Drag | null;
    /** Start tracking mouse movement after given mousedown event, sets and returns Drag.current to new instance of Drag with given detail object; Drop targets may listen for drag events (over/out/drop), and use information from the detail object to respond */
    static start(mousedownEvent: {
        target: EventTarget | HTMLElement;
        clientX: number;
        clientY: number;
    }, detail?: any): Drag;
    /** Initialize the operation and start tracking mouse movement, sends drag start event to given target DOM element; starts sending drag over and drag out events as well */
    private constructor(target, x, y, detail?);
    /** Application-defined data for this operation (observable), to be set by drag start event handler */
    detail: any;
    /** Current screen X coordinate (read-only observable, constrained) */
    readonly x: number;
    /** Current screen Y coordinate (read-only observable, constrained) */
    readonly y: number;
    /** Promise for drop target HTML element, created when dragging, resolved after dropping, rejected when drag operation is cancelled. */
    dropTarget: Async.Promise<HTMLElement>;
    /** Resolves to true when mouse actually moves, useful e.g. for calling pickUp */
    moved: Async.Promise<boolean>;
    /** Signal emitted when the drag operation completes successfully */
    readonly Drop: CustomSignalClass<{}, Signal<{}>>;
    /** Signal emitted when the drag operation is cancelled */
    readonly Cancel: CustomSignalClass<{}, Signal<{}>>;
    /** Constrain effective drag coordinates on (original) X and/or Y axis, and/or contrain to stay within given element on screen (calling this method twice does not constrain further, but the constraints are replaced) */
    constrain(constrainX?: boolean, constrainY?: boolean, element?: HTMLElement): void;
    /** Make given element follow the mouse cursor while dragging; the element needs to be positioned absolute or fixed */
    pickUp(element: HTMLElement, removeWhenDone?: boolean): void;
    /** Stop the current drag operation */
    cancel(): void;
    /** Accept the current drop target (i.e. perform the drop, primarily called automatically by mouseup handler but can be called manually); sends drop event to drop target element */
    drop(): void;
    /** Update mouse cursor screen coordinates (primarily called by mousemove handler); returns true if an element was scrolled - meaning update should be called again after a short time */
    update(x: number, y: number): boolean;
    private _x;
    private _y;
    private _origTarget;
    private _currentTarget;
    private _moved_resolve;
    private _dropTarget_resolve;
    private _dropTarget_reject;
    private _getTarget;
    private _setCoords;
}
export default Drag;