/*
 * Copyright 2012-2022 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.boot.web.context;

import org.springframework.boot.web.server.WebServer;
import org.springframework.context.SmartLifecycle;

/**
 * {@link SmartLifecycle} to trigger {@link WebServer} graceful shutdown.
 *
 * @author Andy Wilkinson
 * @since 2.5.0
 */
public final class WebServerGracefulShutdownLifecycle implements SmartLifecycle {

	/**
	 * {@link SmartLifecycle#getPhase() SmartLifecycle phase} in which graceful shutdown
	 * of the web server is performed.
	 */
	public static final int SMART_LIFECYCLE_PHASE = SmartLifecycle.DEFAULT_PHASE - 1024;

	private final WebServer webServer;

	private volatile boolean running;

	/**
	 * Creates a new {@code WebServerGracefulShutdownLifecycle} that will gracefully shut
	 * down the given {@code webServer}.
	 * @param webServer web server to shut down gracefully
	 */
	public WebServerGracefulShutdownLifecycle(WebServer webServer) {
		this.webServer = webServer;
	}

	@Override
	public void start() {
		this.running = true;
	}

	@Override
	public void stop() {
		throw new UnsupportedOperationException("Stop must not be invoked directly");
	}

	@Override
	public void stop(Runnable callback) {
		this.running = false;
		this.webServer.shutDownGracefully((result) -> callback.run());
	}

	@Override
	public boolean isRunning() {
		return this.running;
	}

	@Override
	public int getPhase() {
		return SMART_LIFECYCLE_PHASE;
	}

}
