// *****************************************************************************
// Copyright (C) 2022 STMicroelectronics, Ericsson, ARM, EclipseSource and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0.
//
// This Source Code may also be made available under the following Secondary
// Licenses when the conditions for such availability set forth in the Eclipse
// Public License v. 2.0 are satisfied: GNU General Public License, version 2
// with the GNU Classpath Exception which is available at
// https://www.gnu.org/software/classpath/license.html.
//
// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
// *****************************************************************************

import { Event } from '../../common';
import { ApplicationShell } from '../shell';
import { TheiaDockPanel } from '../shell/theia-dock-panel';
import { ExtractableWidget, TabBar, Widget } from '../widgets';

export abstract class SecondaryWindowRootWidget extends Widget {
    secondaryWindow: Window | SecondaryWindow;
    defaultRestoreArea?: ApplicationShell.Area;
    abstract widgets: ReadonlyArray<Widget>;
    abstract addWidget(widget: Widget, disposeCallback: () => void, options?: TheiaDockPanel.AddOptions): void;
    getTabBar?(widget: Widget): TabBar<Widget> | undefined;
}

export interface SecondaryWindow extends Window {
    rootWidget: SecondaryWindowRootWidget | undefined;
}

export function isSecondaryWindow(window: unknown): window is SecondaryWindow {
    if (!window) {
        return false;
    }
    return typeof window === 'object' && 'rootWidget' in window;
}

export const SecondaryWindowService = Symbol('SecondaryWindowService');

/**
 * Service for opening new secondary windows to contain widgets extracted from the application shell.
 *
 * @experimental The functionality provided by this service and its implementation is still under development. Use with caution.
 */
export interface SecondaryWindowService {
    /**
     * Creates a new secondary window for a widget to be extracted from the application shell.
     * The created window is closed automatically when the current theia instance is closed.
     *
     * @param onClose optional callback that is invoked when the secondary window is closed
     * @returns the created window or `undefined` if it could not be created
     */
    createSecondaryWindow(widget: ExtractableWidget, shell: ApplicationShell): SecondaryWindow | Window | undefined;
    readonly onWindowOpened: Event<Window>;
    /**
     * Emitted once a secondary window's final document has finished loading. Listeners can safely
     * modify the window's document, unlike with {@link onWindowOpened}: at that point the window
     * still shows the initial `about:blank` document, and anything added to it is discarded when
     * the final document replaces it.
     */
    readonly onWindowLoaded: Event<Window>;
    readonly onWindowClosed: Event<Window>;
    readonly beforeWidgetRestore: Event<[Widget, Window]>;

    /** Handles focussing the given secondary window in the browser and on Electron. */
    focus(win: Window): void;
    getWindows(): Window[];
}
