package com.ctrip.framework.apollo.internals;

 import com.google.common.base.Joiner;

 import com.google.common.base.Strings;

 import com.google.common.collect.Lists;

 import com.google.common.collect.Maps;

 import com.google.common.escape.Escaper;

 import com.google.common.net.UrlEscapers;

 import com.google.gson.reflect.TypeToken;

 import com.ctrip.framework.apollo.core.dto.ServiceDTO;

 import com.ctrip.framework.apollo.core.utils.ApolloThreadFactory;

 import com.ctrip.framework.apollo.exceptions.ApolloConfigException;

 import com.ctrip.framework.apollo.util.ConfigUtil;

 import com.ctrip.framework.apollo.util.http.HttpRequest;

 import com.ctrip.framework.apollo.util.http.HttpResponse;

 import com.ctrip.framework.apollo.util.http.HttpUtil;

 import com.dianping.cat.Cat;

 import com.dianping.cat.message.Message;

 import com.dianping.cat.message.Transaction;

 import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable;

 import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import org.unidal.lookup.annotation.Inject;

 import org.unidal.lookup.annotation.Named;

 import java.lang.reflect.Type;

 import java.util.List;

 import java.util.Map;

 import java.util.concurrent.Executors;

 import java.util.concurrent.ScheduledExecutorService;

 import java.util.concurrent.TimeUnit;

 import java.util.concurrent.atomic.AtomicReference;

 @Named(type = ConfigServiceLocator.class)

 public class ConfigServiceLocator implements Initializable {

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

   @Inject

   private HttpUtil m_httpUtil;

   @Inject

   private ConfigUtil m_configUtil;

   private AtomicReference<List<ServiceDTO>> m_configServices;

   private Type m_responseType;

   private ScheduledExecutorService m_executorService;

   private static final Joiner.MapJoiner MAP_JOINER = Joiner.on("&").withKeyValueSeparator("=");

   private static final Escaper queryParamEscaper = UrlEscapers.urlFormParameterEscaper();

   /**

    * Create a config service locator.

    */

   public ConfigServiceLocator() {

     List<ServiceDTO> initial = Lists.newArrayList();

     m_configServices = new AtomicReference<>(initial);

     m_responseType = new TypeToken<List<ServiceDTO>>() {

     }.getType();

     this.m_executorService = Executors.newScheduledThreadPool(1,

         ApolloThreadFactory.create("ConfigServiceLocator", true));

   }

   @Override

   public void initialize() throws InitializationException {

     this.tryUpdateConfigServices();

     this.schedulePeriodicRefresh();

   }

   /**

    * Get the config service info from remote meta server.

    *

    * @return the services dto

    */

   public List<ServiceDTO> getConfigServices() {

     if (m_configServices.get().isEmpty()) {

       updateConfigServices();

     }

     return m_configServices.get();

   }

   private boolean tryUpdateConfigServices() {

     try {

       updateConfigServices();

       return true;

     } catch (Throwable ex) {

       //ignore

     }

     return false;

   }

   private void schedulePeriodicRefresh() {

     this.m_executorService.scheduleAtFixedRate(

         new Runnable() {

           @Override

           public void run() {

             logger.debug("refresh config services");

             Cat.logEvent("Apollo.MetaService", "periodicRefresh");

             tryUpdateConfigServices();

           }

         }, m_configUtil.getRefreshInterval(), m_configUtil.getRefreshInterval(),

         m_configUtil.getRefreshIntervalTimeUnit());

   }

   private synchronized void updateConfigServices() {

     String url = assembleMetaServiceUrl();

     HttpRequest request = new HttpRequest(url);

     int maxRetries = 5;

     Throwable exception = null;

     for (int i = 0; i < maxRetries; i++) {

       Transaction transaction = Cat.newTransaction("Apollo.MetaService", "getConfigService");

       transaction.addData("Url", url);

       try {

         HttpResponse<List<ServiceDTO>> response = m_httpUtil.doGet(request, m_responseType);

         transaction.setStatus(Message.SUCCESS);

         List<ServiceDTO> services = response.getBody();

         if (services == null || services.isEmpty()) {

           logConfigServiceToCat("Empty response!");

           continue;

         }

         m_configServices.set(services);

         logConfigServicesToCat(services);

         return;

       } catch (Throwable ex) {

         Cat.logError(ex);

         transaction.setStatus(ex);

         exception = ex;

       } finally {

         transaction.complete();

       }

       try {

         TimeUnit.SECONDS.sleep(1);

       } catch (InterruptedException ex) {

         //ignore

       }

     }

     throw new ApolloConfigException(

         String.format("Get config services failed from %s", url), exception);

   }

   private String assembleMetaServiceUrl() {

     String domainName = m_configUtil.getMetaServerDomainName();

     String appId = m_configUtil.getAppId();

     String localIp = m_configUtil.getLocalIp();

     Map<String, String> queryParams = Maps.newHashMap();

     queryParams.put("appId", queryParamEscaper.escape(appId));

     if (!Strings.isNullOrEmpty(localIp)) {

       queryParams.put("ip", queryParamEscaper.escape(localIp));

     }

     return domainName + "/services/config?" + MAP_JOINER.join(queryParams);

   }

   private void logConfigServicesToCat(List<ServiceDTO> serviceDtos) {

     for (ServiceDTO serviceDto : serviceDtos) {

       logConfigServiceToCat(serviceDto.getHomepageUrl());

     }

   }

   private void logConfigServiceToCat(String serviceUrl) {

     Cat.logEvent("Apollo.Config.Services", serviceUrl);

   }

 }