// *****************************************************************************
// Copyright (C) 2019 Red Hat, Inc. 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 debounce = require('@theia/core/shared/lodash.debounce');
import { injectable } from '@theia/core/shared/inversify';
import { MimeAssociation, MimeService } from '@theia/core/lib/browser/mime-service';
import { StandaloneServices } from '@theia/monaco-editor-core/esm/vs/editor/standalone/browser/standaloneServices';
import { ILanguageService } from '@theia/monaco-editor-core/esm/vs/editor/common/languages/language';
import * as monaco from '@theia/monaco-editor-core';
import { clearConfiguredLanguageAssociations, registerConfiguredLanguageAssociation } from '@theia/monaco-editor-core/esm/vs/editor/common/services/languagesAssociations';
import { LanguageService } from '@theia/monaco-editor-core/esm/vs/editor/common/services/languageService';

@injectable()
export class MonacoMimeService extends MimeService {

    protected associations: MimeAssociation[] = [];
    protected updatingAssociations = false;

    constructor() {
        super();
        StandaloneServices.get(ILanguageService).onDidChange(() => {
            if (this.updatingAssociations) {
                return;
            }
            this.updateAssociations();
        });
    }

    override setAssociations(associations: MimeAssociation[]): void {
        this.associations = associations;
        this.updateAssociations();
    }

    protected updateAssociations = debounce(() => {
        this.updatingAssociations = true;
        try {
            clearConfiguredLanguageAssociations();

            for (const association of this.associations) {
                const mimetype = this.getMimeForMode(association.id) || `text/x-${association.id}`;
                registerConfiguredLanguageAssociation({ id: association.id, mime: mimetype, filepattern: association.filepattern });
            }
            (StandaloneServices.get(ILanguageService) as LanguageService)['_onDidChange'].fire(undefined);
        } finally {
            this.updatingAssociations = false;
        }
    });

    protected getMimeForMode(langId: string): string | undefined {
        for (const language of monaco.languages.getLanguages()) {
            if (language.id === langId && language.mimetypes) {
                return language.mimetypes[0];
            }
        }

        return undefined;
    }
}