import { type Point2d } from '../../mod.ts';
import { DnDEvent } from './events.ts';
import type { DragAndDropObserverContext, DragAndDropObserverOptions, DragAndDropPluginManager, DragAndDropState } from './types.ts';
/**
 * Drag-and-drop behavior observer.
 * Allows to implement drag-and-drop by providing event handlers.
 * Don't affects element' style or any other properties, just listens some events.
 * @internal
 */
export declare class DragAndDropObserver {
    protected readonly options: DragAndDropObserverOptions;
    protected state: DragAndDropState;
    protected plugins: DragAndDropPluginManager;
    protected sharedEvent?: DnDEvent<Event>;
    protected observation?: {
        readonly element: HTMLElement;
        readonly unobserve: VoidFunction;
    };
    constructor(options?: DragAndDropObserverOptions);
    /**
     * Connects instance to given element.
     * An observer can only observe one element at a time.
     * @param element Element.
     * @returns Unobserve function.
     * @throws When trying to observe second element.
     */
    observe(element: HTMLElement): VoidFunction;
    /**
     * Handles `pointerdown` event.
     * @param event Pointer event.
     * @param ctx Context.
     */
    protected handlePointerDown(event: PointerEvent, ctx: DragAndDropObserverContext): void;
    /**
     * Handles `pointermove` event.
     * @param event Pointer event.
     * @param ctx Context.
     */
    protected handlePointerMove(event: PointerEvent, ctx: DragAndDropObserverContext): void;
    /**
     * Handles `pointerup` and `pointercancel` events.
     * @param event Pointer event.
     * @param ctx Context.
     */
    protected handlePointerRelease(event: PointerEvent, ctx: DragAndDropObserverContext): void;
    /**
     * Dispatches `grab` event.
     * @param element Element.
     * @param nativeEvent  Native event.
     * @param clientPosition Client position from event.
     */
    protected dispatchGrab(element: HTMLElement, nativeEvent: PointerEvent, clientPosition: Point2d): void;
    /**
     * Returns DnDEvent from payload.
     * @param target Element.
     * @param state State.
     * @param nativeEvent Native event.
     * @param clientPosition Client position.
     * @returns Event.
     */
    protected getEvent<E extends Event>(target: HTMLElement, state: DragAndDropState, nativeEvent: E, clientPosition: Point2d): DnDEvent<E>;
}