/*---------------------------------------------------------------------------------------------

* Copyright (c) Microsoft Corporation. All rights reserved.

* Licensed under the MIT License. See License.txt in the project root for license information.

*--------------------------------------------------------------------------------------------*/

import { Event } from 'vs/base/common/event';

import { DisposableStore, Disposable } from 'vs/base/common/lifecycle';

import { CancelablePromise, createCancelablePromise } from 'vs/base/common/async';

import { IElectronService } from 'vs/platform/electron/node/electron';

export class ActiveWindowManager extends Disposable {

private readonly disposables = this._register(new DisposableStore());

private firstActiveWindowIdPromise: CancelablePromise<number | undefined> | undefined;

private activeWindowId: number | undefined;

constructor(@IElectronService electronService: IElectronService) {

super();

// remember last active window id upon events

const onActiveWindowChange = Event.latch(Event.any(electronService.onWindowOpen, electronService.onWindowFocus));

onActiveWindowChange(this.setActiveWindow, this, this.disposables);

// resolve current active window

this.firstActiveWindowIdPromise = createCancelablePromise(() => electronService.getActiveWindowId());

(async () => {

try {

const windowId = await this.firstActiveWindowIdPromise;

this.activeWindowId = (typeof this.activeWindowId === 'number') ? this.activeWindowId : windowId;

} finally {

this.firstActiveWindowIdPromise = undefined;

}

})();

}

private setActiveWindow(windowId: number | undefined) {

if (this.firstActiveWindowIdPromise) {

this.firstActiveWindowIdPromise.cancel();

this.firstActiveWindowIdPromise = undefined;

}

this.activeWindowId = windowId;

}

async getActiveClientId(): Promise<string | undefined> {

const id = this.firstActiveWindowIdPromise ? (await this.firstActiveWindowIdPromise) : this.activeWindowId;

return `window:${id}`;

}

}