/*  _____ _
 * |_   _| |_  _ _ ___ ___ _ __  __ _
 *   | | | ' \| '_/ -_) -_) '  \/ _` |_
 *   |_| |_||_|_| \___\___|_|_|_\__,_(_)
 *
 * Threema for Android
 * Copyright (c) 2019-2020 Threema GmbH
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

package ch.threema.app.utils;

import android.content.Context;

import org.apache.commons.io.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.IOException;
import java.util.UUID;

public class DeviceIdUtil {
	private static final Logger logger = LoggerFactory.getLogger(DeviceIdUtil.class);

	private static final String DEVICE_ID_FILENAME = "device_id";

	public static String getDeviceId(Context context) {
		String deviceId = null;
		File deviceIdFile = new File(context.getFilesDir(), DEVICE_ID_FILENAME);
		if (deviceIdFile.exists()) {
			try {
				deviceId = FileUtils.readFileToString(deviceIdFile);
			} catch (IOException e) {
				logger.error("Exception", e);
			}
		}

		if (deviceId == null) {
			deviceId = UUID.randomUUID().toString();
			try {
				FileUtils.writeStringToFile(deviceIdFile, deviceId);
			} catch (IOException e) {
				logger.error("Exception", e);
			}
		}

		return deviceId;
	}
}
