// *****************************************************************************
// Copyright (C) 2018 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 { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
import { TreeSource } from '@theia/core/lib/browser/source-tree';
import { DebugScope } from '../console/debug-console-items';
import { DebugViewModel } from './debug-view-model';
import debounce = require('p-debounce');

@injectable()
export class DebugVariablesSource extends TreeSource {

    @inject(DebugViewModel)
    protected readonly model: DebugViewModel;

    @postConstruct()
    protected init(): void {
        this.refresh();
        this.toDispose.push(this.model.onDidChange(() => this.refresh()));
        this.toDispose.push(this.model.onDidResolveLazyVariable(() => this.fireDidChange()));
    }

    protected readonly refresh = debounce(() => this.fireDidChange(), 400);

    async getElements(): Promise<IterableIterator<DebugScope>> {
        const { currentSession } = this.model;
        const scopes = currentSession ? await currentSession.getScopes() : [];
        return scopes[Symbol.iterator]();
    }

}