// *****************************************************************************
// Copyright (C) 2022 Ericsson 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 WITH Classpath-exception-2.0
// *****************************************************************************

import { FrontendApplicationConfig } from '@theia/application-package';
import { FrontendApplicationState, StopReason } from '../common/frontend-application-state';
import { BrowserWindow, BrowserWindowConstructorOptions } from '../../electron-shared/electron';
import { inject, injectable, postConstruct } from '../../shared/inversify';
import { ElectronMainApplicationGlobals } from './electron-main-constants';
import { DisposableCollection, Emitter, Event } from '../common';
import { createDisposableListener } from './event-utils';
import { URI } from '../common/uri';
import { FileUri } from '../node/file-uri';
import { TheiaRendererAPI } from './electron-api-main';

/**
 * Theia tracks the maximized state of Electron Browser Windows.
 */
export interface TheiaBrowserWindowOptions extends BrowserWindowConstructorOptions {
    isMaximized?: boolean;
    isFullScreen?: boolean;
    /**
     * Represents the complete screen layout for all available displays.
     * This field is used to determine if the layout was updated since the electron window was last opened,
     * in which case we want to invalidate the stored options and use the default options instead.
     */
    screenLayout?: string;
}

export const TheiaBrowserWindowOptions = Symbol('TheiaBrowserWindowOptions');

export const WindowApplicationConfig = Symbol('WindowApplicationConfig');
export type WindowApplicationConfig = FrontendApplicationConfig;

@injectable()
export class TheiaElectronWindow {
    @inject(TheiaBrowserWindowOptions) protected readonly options: TheiaBrowserWindowOptions;
    @inject(WindowApplicationConfig) protected readonly config: WindowApplicationConfig;
    @inject(ElectronMainApplicationGlobals) protected readonly globals: ElectronMainApplicationGlobals;

    protected onDidCloseEmitter = new Emitter<void>();

    get onDidClose(): Event<void> {
        return this.onDidCloseEmitter.event;
    }

    protected readonly toDispose = new DisposableCollection(this.onDidCloseEmitter);

    protected _window: BrowserWindow;
    get window(): BrowserWindow {
        return this._window;
    }

    protected closeIsConfirmed = false;
    protected applicationState: FrontendApplicationState = 'init';

    @postConstruct()
    protected init(): void {
        this._window = new BrowserWindow(this.options);
        this._window.setMenuBarVisibility(false);
        this.attachReadyToShow();
        this.restoreMaximizedState();
        this.attachCloseListeners();
        this.trackApplicationState();
        this.attachReloadListener();
    }

    /**
     * Only show the window when the content is ready.
     */
    protected attachReadyToShow(): void {
        this._window.once('ready-to-show', () => this._window.show());
    }

    protected attachCloseListeners(): void {
        createDisposableListener<Electron.Event>(this._window, 'closed', () => {
            this.onDidCloseEmitter.fire();
            this.dispose();
        }, this.toDispose);
        createDisposableListener<Electron.Event>(this._window, 'close', async event => {
            // User has already indicated that it is OK to close this window, or the window is being closed before it's ready.
            if (this.closeIsConfirmed || this.applicationState !== 'ready') {
                return;
            }
            event.preventDefault();
            this.handleStopRequest(() => this.doCloseWindow(), StopReason.Close);
        }, this.toDispose);
    }

    protected doCloseWindow(): void {
        this.closeIsConfirmed = true;
        this._window.close();
    }

    close(reason: StopReason = StopReason.Close): Promise<boolean> {
        return this.handleStopRequest(() => this.doCloseWindow(), reason);
    }

    protected reload(): void {
        this.handleStopRequest(() => {
            this.applicationState = 'init';
            this._window.reload();
        }, StopReason.Reload);
    }

    protected async handleStopRequest(onSafeCallback: () => unknown, reason: StopReason): Promise<boolean> {
        // Only confirm close to windows that have loaded our frontend.
        // Both the windows's URL and the FS path of the `index.html` should be converted to the "same" format to be able to compare them. (#11226)
        // Notes:
        //  - Windows: file:///C:/path/to/somewhere vs file:///c%3A/path/to/somewhere
        //  - macOS: file:///Applications/App%20Name.app/Contents vs /Applications/App Name.app/Contents
        // This URL string comes from electron, we can expect that this is properly encoded URL. For example, a space is `%20`
        const currentUrl = new URI(this.window.webContents.getURL()).toString();
        // THEIA_FRONTEND_HTML_PATH is an FS path, we have to covert to an encoded URI string.
        const frontendUri = FileUri.create(this.globals.THEIA_FRONTEND_HTML_PATH).toString();
        const safeToClose = !currentUrl.includes(frontendUri) || await this.checkSafeToStop(reason);
        if (safeToClose) {
            try {
                await onSafeCallback();
                return true;
            } catch (e) {
                console.warn(`Request ${StopReason[reason]} failed.`, e);
            }
        }
        return false;
    }

    protected checkSafeToStop(reason: StopReason): Promise<boolean> {
        return TheiaRendererAPI.requestClose(this.window.webContents, reason);
    }

    protected restoreMaximizedState(): void {
        if (this.options.isMaximized) {
            this._window.maximize();
        } else {
            this._window.unmaximize();
        }
    }

    protected trackApplicationState(): void {
        this.toDispose.push(TheiaRendererAPI.onApplicationStateChanged(this.window.webContents, state => {
            this.applicationState = state;
        }));
    }

    protected attachReloadListener(): void {
        this.toDispose.push(TheiaRendererAPI.onRequestReload(this.window.webContents, () => this.reload()));
    }

    dispose(): void {
        this.toDispose.dispose();
    }
}

export interface TheiaElectronWindowFactory {
    (options: TheiaBrowserWindowOptions, config: FrontendApplicationConfig): TheiaElectronWindow;
}

export const TheiaElectronWindowFactory = Symbol('TheiaElectronWindowFactory');