/**
* @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* @module engine/view/observer/focusobserver
*/
import { DomEventObserver } from "./domeventobserver.js";
import { type ViewDocumentDomEventData } from "./domeventdata.js";
import { type EditingView } from "../view.js";
/**
* {@link module:engine/view/document~ViewDocument#event:focus Focus}
* and {@link module:engine/view/document~ViewDocument#event:blur blur} events observer.
* Focus observer handle also {@link module:engine/view/rooteditableelement~ViewRootEditableElement#isFocused isFocused} property of the
* {@link module:engine/view/rooteditableelement~ViewRootEditableElement root elements}.
*
* Note that this observer is attached by the {@link module:engine/view/view~EditingView} and is available by default.
*/
export declare class FocusObserver extends DomEventObserver<"focus" | "blur"> {
	/**
	* Identifier of the timeout currently used by focus listener to delay rendering execution.
	*/
	private _renderTimeoutId;
	/**
	* Set to `true` if the document is in the process of setting the focus.
	*
	* The flag is used to indicate that setting the focus is in progress.
	*/
	private _isFocusChanging;
	/**
	* @inheritDoc
	*/
	readonly domEventType: readonly ["focus", "blur"];
	/**
	* @inheritDoc
	*/
	constructor(view: EditingView);
	/**
	* Finishes setting the document focus state.
	*/
	flush(): void;
	/**
	* @inheritDoc
	*/
	onDomEvent(domEvent: FocusEvent): void;
	/**
	* @inheritDoc
	*/
	override destroy(): void;
	/**
	* The `focus` event handler.
	*/
	private _handleFocus;
	/**
	* The `blur` event handler.
	*/
	private _handleBlur;
	/**
	* Clears timeout.
	*/
	private _clearTimeout;
}
/**
* Fired when one of the editables gets focus.
*
* Introduced by {@link module:engine/view/observer/focusobserver~FocusObserver}.
*
* Note that because {@link module:engine/view/observer/focusobserver~FocusObserver} is attached by the
* {@link module:engine/view/view~EditingView} this event is available by default.
*
* @see module:engine/view/observer/focusobserver~FocusObserver
* @eventName module:engine/view/document~ViewDocument#focus
* @param data Event data.
*/
export type ViewDocumentFocusEvent = {
	name: "focus";
	args: [data: ViewDocumentDomEventData<FocusEvent>];
};
/**
* Fired when one of the editables loses focus.
*
* Introduced by {@link module:engine/view/observer/focusobserver~FocusObserver}.
*
* Note that because {@link module:engine/view/observer/focusobserver~FocusObserver} is attached by the
* {@link module:engine/view/view~EditingView} this event is available by default.
*
* @see module:engine/view/observer/focusobserver~FocusObserver
* @eventName module:engine/view/document~ViewDocument#blur
* @param data Event data.
*/
export type ViewDocumentBlurEvent = {
	name: "blur";
	args: [data: ViewDocumentDomEventData<FocusEvent>];
};