/*******************************************************************************
    * Copyright 2015 Internet2
    * 
    * 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
    * 
    *   http://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 edu.internet2.middleware.changelogconsumer.googleapps.cache;
  
  import com.google.api.services.admin.directory.model.Group;
  import com.google.api.services.admin.directory.model.User;
  import edu.internet2.middleware.subject.Subject;
  import org.joda.time.DateTime;
  
  import java.util.Hashtable;
  import java.util.List;
  import java.util.Set;
  
  /**
   * CacheObject supports Google User, Google Group, Grouper Subject, and Grouper Group objects.
   *
   * * @author John Gasper, Unicon
   */
  public class Cache<T> {
      private Hashtable<String, T> cache = new Hashtable<String, T>();
      private DateTime cachePopulatedTime;
      private int cacheValidity = 30;
  
      public T get(String id) {
          return cache.get(id);
      }
  
      public void clear() {
          cache.clear();
          cachePopulatedTime = null;
      }
  
      public void put(T item) {
          cache.put(getId(item), item);
      }
  
      public void remove (String id) {
          if (cache.containsKey(id)) {
              cache.remove(id);
          }
      }
  
      public void seed(int size) {
          cache = new Hashtable<String, T>(size);
      }
  
      public void seed(List<T> items) {
          cache = new Hashtable<String, T>(items.size() + 100);
  
          if (items == null) {
              seed(100);
          } else {
              for (T item : items) {
                  cache.put(getId(item), item);
              }
  
              cachePopulatedTime = new DateTime();
          }
      }
  
      public int size() {
          return cache == null ? 0 : cache.size();
      }
  
      private String getId(T item) {
          if (item.getClass().equals(User.class)) {
              return ((User) item).getPrimaryEmail();
          } else if (item.getClass().equals(Group.class)) {
              return ((Group) item).getEmail();
          } else if (item.getClass().equals(Subject.class)) {
              return ((Subject) item).getSourceId() + "__" + ((Subject) item).getId();
          } else if (item.getClass().equals(edu.internet2.middleware.grouper.Group.class)) {
              return ((edu.internet2.middleware.grouper.Group) item).getName();
          } else {
              return item.toString();
          }
      }
  
      public void setCacheValidity(int minutes){
          cacheValidity = minutes;
      }
  
      public DateTime getExpiration() {
          return cachePopulatedTime != null ? cachePopulatedTime.plusMinutes(cacheValidity) : null;
      }
  
     public boolean isExpired() {
         return cachePopulatedTime == null || getExpiration().isBeforeNow();
     }
 
     public Set<String> getKeySet() {
         return cache.keySet();
     }
 }