/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { constants as FSConstants, promises as FSPromises } from 'fs';
import { createInterface as readLines } from 'readline';
import * as Platform from 'vs/base/common/platform';

type ReleaseInfo = {
	id: string;
	id_like?: string;
	version_id?: string;
};

export async function getOSReleaseInfo(errorLogger: (error: any) => void): Promise<ReleaseInfo | undefined> {
	if (Platform.isMacintosh || Platform.isWindows) {
		return;
	}

	// Extract release information on linux based systems
	// using the identifiers specified in
	// https://www.freedesktop.org/software/systemd/man/os-release.html
	let handle: FSPromises.FileHandle | undefined;
	for (const filePath of ['/etc/os-release', '/usr/lib/os-release', '/etc/lsb-release']) {
		try {
			handle = await FSPromises.open(filePath, FSConstants.R_OK);
			break;
		} catch (err) { }
	}

	if (!handle) {
		errorLogger('Unable to retrieve release information from known identifier paths.');
		return;
	}

	try {
		const osReleaseKeys = new Set([
			'ID',
			'DISTRIB_ID',
			'ID_LIKE',
			'VERSION_ID',
			'DISTRIB_RELEASE',
		]);
		const releaseInfo: ReleaseInfo = {
			id: 'unknown'
		};

		for await (const line of readLines({ input: handle.createReadStream(), crlfDelay: Infinity })) {
			if (!line.includes('=')) {
				continue;
			}
			const key = line.split('=')[0].toUpperCase().trim();
			if (osReleaseKeys.has(key)) {
				const value = line.split('=')[1].replace(/"/g, '').toLowerCase().trim();
				if (key === 'ID' || key === 'DISTRIB_ID') {
					releaseInfo.id = value;
				} else if (key === 'ID_LIKE') {
					releaseInfo.id_like = value;
				} else if (key === 'VERSION_ID' || key === 'DISTRIB_RELEASE') {
					releaseInfo.version_id = value;
				}
			}
		}

		return releaseInfo;
	} catch (err) {
		errorLogger(err);
	}

	return;
}
