/*
 * Copyright 2010-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.data.gemfire.fork;

import java.io.File;
import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.data.gemfire.process.support.ProcessUtils;
import org.springframework.data.gemfire.test.support.FileSystemUtils;
import org.springframework.util.Assert;

/**
 * The ServerProcess class is a main Java class using Spring Data GemFire to configure and bootstrap
 * a GemFire Cache Server process.
 *
 * @author John Blum
 * @see org.springframework.context.ConfigurableApplicationContext
 * @see org.springframework.context.support.ClassPathXmlApplicationContext
 * @since 1.5.2
 */
public class ServerProcess {

	private static final Logger logger = LoggerFactory.getLogger(ServerProcess.class);

	public static void main(String[] args) throws Throwable {
		ConfigurableApplicationContext applicationContext = null;

		try {
			applicationContext = newApplicationContext(args);
			waitForShutdown();
		}
		catch (Throwable e) {
			logger.debug("", e);
			throw e;
		}
		finally {
			close(applicationContext);
		}
	}

	private static ConfigurableApplicationContext newApplicationContext(String[] configLocations) {
		Assert.notEmpty(configLocations, String.format("Usage: >java -cp ... %1$s %2$s",
			ServerProcess.class.getName(), "classpath:/to/applicationContext.xml"));

		ConfigurableApplicationContext applicationContext = new ClassPathXmlApplicationContext(configLocations);

		applicationContext.registerShutdownHook();

		return applicationContext;
	}

	private static boolean close(ConfigurableApplicationContext applicationContext) {
		if (applicationContext != null) {
			applicationContext.close();
			return !(applicationContext.isRunning() || applicationContext.isActive());
		}

		return true;
	}

	private static void waitForShutdown() throws IOException {
		ProcessUtils.writePid(new File(FileSystemUtils.WORKING_DIRECTORY, getServerProcessControlFilename()),
			ProcessUtils.currentPid());

		ProcessUtils.waitForStopSignal();
	}

	public static String getServerProcessControlFilename() {
		return ServerProcess.class.getSimpleName().toLowerCase().concat(".pid");
	}
}
