// *****************************************************************************
// Copyright (C) 2018 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-only WITH Classpath-exception-2.0
// *****************************************************************************
import { injectable } from '@theia/core/shared/inversify';
import { MetricsContribution } from './metrics-contribution';
import { PROMETHEUS_REGEXP, toPrometheusValidName } from './prometheus';
import { backendGlobal } from '@theia/core/lib/node';

const metricsName = 'theia_extension_version';

@injectable()
export class ExtensionMetricsContribution implements MetricsContribution {
    private metrics: string = '';

    getMetrics(): string {
        return this.metrics;
    }

    startCollecting(): void {
        let latestMetrics = '';
        const installedExtensions = backendGlobal.extensionInfo;
        latestMetrics += `# HELP ${metricsName} Theia extension version info.\n`;
        latestMetrics += `# TYPE ${metricsName} gauge\n`;
        installedExtensions.forEach(extensionInfo => {
            let extensionName = extensionInfo.name;
            if (!PROMETHEUS_REGEXP.test(extensionName)) {
                extensionName = toPrometheusValidName(extensionName);
            }

            const metricsValue = metricsName + `{extension="${extensionName}",version="${extensionInfo.version}"} 1`;
            latestMetrics += metricsValue + '\n';
        });

        this.metrics = latestMetrics;
    }
}
