content: /*
   * Copyright 2013-2023 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 com.alibaba.cloud.nacos.discovery;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
  import com.alibaba.cloud.nacos.NacosServiceManager;
  import com.alibaba.nacos.api.naming.NamingService;
  import com.alibaba.nacos.api.naming.listener.Event;
  import com.alibaba.nacos.api.naming.listener.EventListener;
  import com.alibaba.nacos.api.naming.listener.NamingEvent;
  import com.alibaba.nacos.api.naming.pojo.Instance;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.springframework.beans.factory.DisposableBean;
  import org.springframework.context.SmartLifecycle;
  
  /**
   * @author xiaojing
   * @author yuhuangbin
   * @author pengfei.lu
   * @author ruansheng
   */
  public class NacosWatch implements SmartLifecycle, DisposableBean {
  
  	private static final Logger log = LoggerFactory.getLogger(NacosWatch.class);
  
  	private final Map<String, EventListener> listenerMap = new ConcurrentHashMap<>(16);
  
  	private final AtomicBoolean running = new AtomicBoolean(false);
  
  	private final NacosServiceManager nacosServiceManager;
  
  	private final NacosDiscoveryProperties properties;
  
  	public NacosWatch(NacosServiceManager nacosServiceManager,
  			NacosDiscoveryProperties properties) {
  		this.nacosServiceManager = nacosServiceManager;
  		this.properties = properties;
  	}
  
  	@Override
  	public boolean isAutoStartup() {
  		return true;
  	}
  
  	@Override
  	public void stop(Runnable callback) {
  		this.stop();
  		callback.run();
  	}
  
  	@Override
  	public void start() {
  		if (this.running.compareAndSet(false, true)) {
  			EventListener eventListener = listenerMap.computeIfAbsent(buildKey(),
  					event -> new EventListener() {
  						@Override
  						public void onEvent(Event event) {
  							if (event instanceof NamingEvent namingEvent) {
  								List<Instance> instances = namingEvent.getInstances();
  								Optional<Instance> instanceOptional = selectCurrentInstance(
  										instances);
  								instanceOptional.ifPresent(currentInstance -> {
  									resetIfNeeded(currentInstance);
  								});
  							}
  						}
  					});
  
  			NamingService namingService = nacosServiceManager.getNamingService();
  			try {
  				namingService.subscribe(properties.getService(), properties.getGroup(),
  						Arrays.asList(properties.getClusterName()), eventListener);
  			}
  			catch (Exception e) {
  				log.error("namingService subscribe failed, properties:{}", properties, e);
  			}
  
  		}
  	}
  
  	private String buildKey() {
  		return String.join(":", properties.getService(), properties.getGroup());
  	}
  
  	private void resetIfNeeded(Instance instance) {
  		if (!properties.getMetadata().equals(instance.getMetadata())) {
  			properties.setMetadata(instance.getMetadata());
  		}
  	}
  
  	private Optional<Instance> selectCurrentInstance(List<Instance> instances) {
  		return instances.stream()
  				.filter(instance -> properties.getIp().equals(instance.getIp())
  						&& properties.getPort() == instance.getPort())
  				.findFirst();
  	}
  
  	@Override
  	public void stop() {
  		if (this.running.compareAndSet(true, false)) {
  
  			EventListener eventListener = listenerMap.get(buildKey());
  			try {
  				NamingService namingService = nacosServiceManager.getNamingService();
  				namingService.unsubscribe(properties.getService(), properties.getGroup(),
  						Arrays.asList(properties.getClusterName()), eventListener);
  			}
  			catch (Exception e) {
  				log.error("namingService unsubscribe failed, properties:{}", properties,
  						e);
  			}
  		}
  	}
  
  	@Override
  	public boolean isRunning() {
  		return this.running.get();
  	}
  
  	@Override
  	public int getPhase() {
  		return 0;
  	}
  
  	@Override
  	public void destroy() {
  		this.stop();
  	}
  }
  