package com.ctrip.framework.apollo.internals;

 import com.google.common.base.Objects;

 import com.google.common.collect.Lists;

 import com.google.common.collect.Sets;

 import com.ctrip.framework.apollo.Config;

 import com.ctrip.framework.apollo.ConfigChangeListener;

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

 import com.ctrip.framework.apollo.enums.PropertyChangeType;

 import com.ctrip.framework.apollo.model.ConfigChange;

 import com.ctrip.framework.apollo.model.ConfigChangeEvent;

 import com.dianping.cat.Cat;

 import com.dianping.cat.message.Message;

 import com.dianping.cat.message.Transaction;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import java.util.List;

 import java.util.Properties;

 import java.util.Set;

 import java.util.concurrent.ExecutorService;

 import java.util.concurrent.Executors;

 /**

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

  */

 public abstract class AbstractConfig implements Config {

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

   private static ExecutorService m_executorService;

   private List<ConfigChangeListener> m_listeners = Lists.newCopyOnWriteArrayList();

   static {

     m_executorService = Executors.newCachedThreadPool(ApolloThreadFactory

         .create("Config", true));

   }

   @Override

   public void addChangeListener(ConfigChangeListener listener) {

     if (!m_listeners.contains(listener)) {

       m_listeners.add(listener);

     }

   }

   @Override

   public Integer getIntProperty(String key, Integer defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Integer.parseInt(value);

   }

   @Override

   public Long getLongProperty(String key, Long defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Long.parseLong(value);

   }

   @Override

   public Short getShortProperty(String key, Short defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Short.parseShort(value);

   }

   @Override

   public Float getFloatProperty(String key, Float defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Float.parseFloat(value);

   }

   @Override

   public Double getDoubleProperty(String key, Double defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Double.parseDouble(value);

   }

   @Override

   public Byte getByteProperty(String key, Byte defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Byte.parseByte(value);

   }

   @Override

   public Boolean getBooleanProperty(String key, Boolean defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : Boolean.parseBoolean(value);

   }

   @Override

   public String[] getArrayProperty(String key, String delimiter, String[] defaultValue) {

     String value = getProperty(key, null);

     return value == null ? defaultValue : value.split(delimiter);

   }

   protected void fireConfigChange(final ConfigChangeEvent changeEvent) {

     for (final ConfigChangeListener listener : m_listeners) {

       m_executorService.submit(new Runnable() {

         @Override

         public void run() {

           String listenerName = listener.getClass().getName();

           Transaction transaction = Cat.newTransaction("Apollo.ConfigChangeListener", listenerName);

           try {

             listener.onChange(changeEvent);

             transaction.setStatus(Message.SUCCESS);

           } catch (Throwable ex) {

             transaction.setStatus(ex);

             Cat.logError(ex);

             logger.error("Failed to invoke config change listener {}", listenerName, ex);

           } finally {

             transaction.complete();

           }

         }

       });

     }

   }

   List<ConfigChange> calcPropertyChanges(String namespace, Properties previous,

                                          Properties current) {

     if (previous == null) {

       previous = new Properties();

     }

     if (current == null) {

       current = new Properties();

     }

     Set<String> previousKeys = previous.stringPropertyNames();

     Set<String> currentKeys = current.stringPropertyNames();

     Set<String> commonKeys = Sets.intersection(previousKeys, currentKeys);

     Set<String> newKeys = Sets.difference(currentKeys, commonKeys);

     Set<String> removedKeys = Sets.difference(previousKeys, commonKeys);

     List<ConfigChange> changes = Lists.newArrayList();

     for (String newKey : newKeys) {

       changes.add(new ConfigChange(namespace, newKey, null, current.getProperty(newKey),

           PropertyChangeType.ADDED));

     }

     for (String removedKey : removedKeys) {

       changes.add(new ConfigChange(namespace, removedKey, previous.getProperty(removedKey), null,

           PropertyChangeType.DELETED));

     }

     for (String commonKey : commonKeys) {

       String previousValue = previous.getProperty(commonKey);

       String currentValue = current.getProperty(commonKey);

       if (Objects.equal(previousValue, currentValue)) {

         continue;

       }

       changes.add(new ConfigChange(namespace, commonKey, previousValue, currentValue,

           PropertyChangeType.MODIFIED));

     }

     return changes;

   }

 }