package com.ctrip.apollo.internals;

 import com.google.common.base.Function;

 import com.google.common.collect.Maps;

 import com.ctrip.apollo.model.ConfigChange;

 import com.ctrip.apollo.model.ConfigChangeEvent;

 import com.ctrip.apollo.util.ExceptionUtil;

 import com.dianping.cat.Cat;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import java.util.List;

 import java.util.Map;

 import java.util.Properties;

 /**

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

  */

 public class SimpleConfig extends AbstractConfig implements RepositoryChangeListener {

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

   private final String m_namespace;

   private final ConfigRepository m_configRepository;

   private volatile Properties m_configProperties;

   /**

    * Constructor.

    *

    * @param namespace        the namespace for this config instance

    * @param configRepository the config repository for this config instance

    */

   public SimpleConfig(String namespace, ConfigRepository configRepository) {

     m_namespace = namespace;

     m_configRepository = configRepository;

     this.initialize();

   }

   private void initialize() {

     try {

       m_configProperties = m_configRepository.getConfig();

     } catch (Throwable ex) {

       Cat.logError(ex);

       logger.warn("Init Apollo Simple Config failed - namespace: {}, reason: {}", m_namespace,

           ExceptionUtil.getDetailMessage(ex));

     } finally {

       //register the change listener no matter config repository is working or not

       //so that whenever config repository is recovered, config could get changed

       m_configRepository.addChangeListener(this);

     }

   }

   @Override

   public String getProperty(String key, String defaultValue) {

     if (m_configProperties == null) {

       logger.error("Config initialization failed, always return default value!");

       return defaultValue;

     }

     return this.m_configProperties.getProperty(key, defaultValue);

   }

   @Override

   public synchronized void onRepositoryChange(String namespace, Properties newProperties) {

     if (newProperties.equals(m_configProperties)) {

       return;

     }

     Properties newConfigProperties = new Properties();

     newConfigProperties.putAll(newProperties);

     List<ConfigChange>

         changes =

         calcPropertyChanges(namespace, m_configProperties, newConfigProperties);

     Map<String, ConfigChange> changeMap = Maps.uniqueIndex(changes,

         new Function<ConfigChange, String>() {

           @Override

           public String apply(ConfigChange input) {

             return input.getPropertyName();

           }

         });

     m_configProperties = newConfigProperties;

     this.fireConfigChange(new ConfigChangeEvent(m_namespace, changeMap));

     Cat.logEvent("Apollo.Client.ConfigChanges", m_namespace);

   }

 }