// *****************************************************************************
// Copyright (C) 2019 TypeFox 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 { inject, injectable, optional } from 'inversify';
import { isOSX } from '../../common/os';
import { CommandContribution, CommandRegistry, Command } from '../../common/command';
import { BrowserKeyboardLayoutProvider, KeyboardLayoutData } from './browser-keyboard-layout-provider';
import { QuickPickValue, QuickInputService, QuickPickItemOrSeparator } from '../quick-input';
import { nls } from '../../common/nls';

export namespace KeyboardCommands {

    const KEYBOARD_CATEGORY = 'Keyboard';
    const KEYBOARD_CATEGORY_KEY = nls.getDefaultKey(KEYBOARD_CATEGORY);

    export const CHOOSE_KEYBOARD_LAYOUT = Command.toLocalizedCommand({
        id: 'core.keyboard.choose',
        category: KEYBOARD_CATEGORY,
        label: 'Choose Keyboard Layout',
    }, 'theia/core/keyboard/choose', KEYBOARD_CATEGORY_KEY);

}

@injectable()
export class BrowserKeyboardFrontendContribution implements CommandContribution {

    @inject(BrowserKeyboardLayoutProvider)
    protected readonly layoutProvider: BrowserKeyboardLayoutProvider;

    @inject(QuickInputService) @optional()
    protected readonly quickInputService: QuickInputService;

    registerCommands(commandRegistry: CommandRegistry): void {
        commandRegistry.registerCommand(KeyboardCommands.CHOOSE_KEYBOARD_LAYOUT, {
            execute: () => this.chooseLayout()
        });
    }

    protected async chooseLayout(): Promise<KeyboardLayoutData | undefined> {
        const current = this.layoutProvider.currentLayoutData;
        const autodetect: QuickPickValue<'autodetect'> = {
            label: nls.localizeByDefault('Auto Detect'),
            description: this.layoutProvider.currentLayoutSource !== 'user-choice' ? nls.localize('theia/core/keyboard/current', '(current: {0})', current.name) : undefined,
            detail: nls.localize('theia/core/keyboard/tryDetect', 'Try to detect the keyboard layout from browser information and pressed keys.'),
            value: 'autodetect'
        };
        const pcLayouts = this.layoutProvider.allLayoutData
            .filter(layout => layout.hardware === 'pc')
            .sort((a, b) => compare(a.name, b.name))
            .map(layout => this.toQuickPickValue(layout, current === layout));
        const macLayouts = this.layoutProvider.allLayoutData
            .filter(layout => layout.hardware === 'mac')
            .sort((a, b) => compare(a.name, b.name))
            .map(layout => this.toQuickPickValue(layout, current === layout));
        let layouts: Array<QuickPickValue<KeyboardLayoutData | 'autodetect'> | QuickPickItemOrSeparator>;
        const macKeyboards = nls.localize('theia/core/keyboard/mac', 'Mac Keyboards');
        const pcKeyboards = nls.localize('theia/core/keyboard/pc', 'PC Keyboards');
        if (isOSX) {
            layouts = [
                autodetect,
                { type: 'separator', label: macKeyboards }, ...macLayouts,
                { type: 'separator', label: pcKeyboards }, ...pcLayouts
            ];
        } else {
            layouts = [
                autodetect,
                { type: 'separator', label: pcKeyboards }, ...pcLayouts,
                { type: 'separator', label: macKeyboards }, ...macLayouts
            ];
        }
        const selectedItem = await this.quickInputService?.showQuickPick(layouts, { placeholder: nls.localize('theia/core/keyboard/chooseLayout', 'Choose a keyboard layout') });
        if (selectedItem && ('value' in selectedItem)) {
            return this.layoutProvider.setLayoutData(selectedItem.value);
        }
    }

    protected toQuickPickValue(layout: KeyboardLayoutData, isCurrent: boolean): QuickPickValue<KeyboardLayoutData> {
        return {
            label: layout.name,
            description:
                `${layout.hardware === 'mac' ? 'Mac' : 'PC'} (${layout.language})${isCurrent ? nls.localize('theia/core/keyboard/currentLayout', ' - current layout') : ''}`,
            value: layout
        };
    }
}

function compare(a: string, b: string): number {
    if (a < b) {
        return -1;
    }
    if (a > b) {
        return 1;
    }
    return 0;
}