/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
/* tslint:disable:array-type member-access variable-name typedef
 only-arrow-functions directive-class-suffix component-class-suffix
 component-selector*/
import {Injectable, Optional, SkipSelf} from '@angular/core';


/**
 * The OverlayContainer is the container in which all overlays will load.
 * It should be provided in the root component to ensure it is properly shared.
 */
@Injectable()
export class OverlayContainer {
  protected _containerElement: HTMLElement;

  private _themeClass: string;

  /**
   * Base theme to be applied to all overlay-based components.
   */
  get themeClass(): string {
	return this._themeClass;
  }
  set themeClass(value: string) {
	if (this._containerElement) {
		this._containerElement.classList.remove(this._themeClass);

		if (value) {
		this._containerElement.classList.add(value);
		}
	}

	this._themeClass = value;
  }

  /**
   * This method returns the overlay container element.  It will lazily
   * create the element the first time  it is called to facilitate using
   * the container in non-browser environments.
   * @returns the container element
   */
  getContainerElement(): HTMLElement {
	if (!this._containerElement) {
		this._createContainer();
	}
	return this._containerElement;
  }

  /**
   * Create the overlay container element, which is simply a div
   * with the 'cdk-overlay-container' class on the document body.
   */
  protected _createContainer(): void {
	const container = document.createElement('div');
	container.classList.add('nz-overlay-container');

	if (this._themeClass) {
		container.classList.add(this._themeClass);
	}

	document.body.appendChild(container);
	this._containerElement = container;
  }
}

export function OVERLAY_CONTAINER_PROVIDER_FACTORY(
	parentContainer: OverlayContainer) {
  return parentContainer || new OverlayContainer();
}

export const OVERLAY_CONTAINER_PROVIDER = {
  // If there is already an OverlayContainer available, use that. Otherwise,
  // provide a new one.
  provide: OverlayContainer,
  deps: [[new Optional(), new SkipSelf(), OverlayContainer]],
  useFactory: OVERLAY_CONTAINER_PROVIDER_FACTORY
};