package com.ctrip.framework.apollo.biz.service;

 import com.google.common.base.Strings;

 import com.ctrip.framework.apollo.biz.entity.ServerConfig;

 import com.ctrip.framework.apollo.biz.repository.ServerConfigRepository;

 import com.ctrip.framework.apollo.core.ConfigConsts;

 import com.ctrip.framework.foundation.Foundation;

 import org.springframework.beans.factory.annotation.Autowired;

 import org.springframework.stereotype.Service;

 /**

  * @author Jason Song(song_s@ctrip.com)

  */

 @Service

 public class ServerConfigService {

   @Autowired

   private ServerConfigRepository serverConfigRepository;

   public String getValue(String key) {

     ServerConfig serverConfig = null;

     //1. Load from cluster config

     if (!Strings.isNullOrEmpty(System.getProperty(ConfigConsts.APOLLO_CLUSTER_KEY))) {

       serverConfig =

           serverConfigRepository.findTopByKeyAndCluster(key, System.getProperty(ConfigConsts.APOLLO_CLUSTER_KEY));

     }

     //2. Fall back to data center config

     if (serverConfig == null && !Strings.isNullOrEmpty(getDataCenter())) {

       serverConfig = serverConfigRepository.findTopByKeyAndCluster(key, getDataCenter());

     }

     //3. Fall back to default cluster config

     if (serverConfig == null) {

       serverConfig =

           serverConfigRepository.findTopByKeyAndCluster(key, ConfigConsts.CLUSTER_NAME_DEFAULT);

     }

     return serverConfig == null ? null : serverConfig.getValue();

   }

   public String getValue(String key, String defaultValue) {

     String value = getValue(key);

     return value == null ? defaultValue : value;

   }

   String getDataCenter() {

     return Foundation.server().getDataCenter();

   }

 }