/*
 * Copyright 2012-2016 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
 *
 *      http://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.devtools.remote.client;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.util.Assert;

/**
 * {@link Runnable} that waits to triggers live reload until the remote server has
 * restarted.
 *
 * @author Phillip Webb
 */
class DelayedLiveReloadTrigger implements Runnable {

	private static final long SHUTDOWN_TIME = 1000;

	private static final long SLEEP_TIME = 500;

	private static final long TIMEOUT = 30000;

	private static final Log logger = LogFactory.getLog(DelayedLiveReloadTrigger.class);

	private final OptionalLiveReloadServer liveReloadServer;

	private final ClientHttpRequestFactory requestFactory;

	private final URI uri;

	private long shutdownTime = SHUTDOWN_TIME;

	private long sleepTime = SLEEP_TIME;

	private long timeout = TIMEOUT;

	DelayedLiveReloadTrigger(OptionalLiveReloadServer liveReloadServer,
			ClientHttpRequestFactory requestFactory, String url) {
		Assert.notNull(liveReloadServer, "LiveReloadServer must not be null");
		Assert.notNull(requestFactory, "RequestFactory must not be null");
		Assert.hasLength(url, "URL must not be empty");
		this.liveReloadServer = liveReloadServer;
		this.requestFactory = requestFactory;
		try {
			this.uri = new URI(url);
		}
		catch (URISyntaxException ex) {
			throw new IllegalArgumentException(ex);
		}
	}

	protected void setTimings(long shutdown, long sleep, long timeout) {
		this.shutdownTime = shutdown;
		this.sleepTime = sleep;
		this.timeout = timeout;
	}

	@Override
	public void run() {
		try {
			Thread.sleep(this.shutdownTime);
			long start = System.currentTimeMillis();
			while (!isUp()) {
				long runTime = System.currentTimeMillis() - start;
				if (runTime > this.timeout) {
					return;
				}
				Thread.sleep(this.sleepTime);
			}
			logger.info("Remote server has changed, triggering LiveReload");
			this.liveReloadServer.triggerReload();
		}
		catch (InterruptedException ex) {
			Thread.currentThread().interrupt();
		}
	}

	private boolean isUp() {
		try {
			ClientHttpRequest request = createRequest();
			ClientHttpResponse response = request.execute();
			return response.getStatusCode() == HttpStatus.OK;
		}
		catch (Exception ex) {
			return false;
		}
	}

	private ClientHttpRequest createRequest() throws IOException {
		return this.requestFactory.createRequest(this.uri, HttpMethod.GET);
	}

}
