/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community 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.osedu.org/licenses/ECL-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 org.kuali.student.common.ui.server.gwt;

 import java.lang.ref.SoftReference;

 import java.util.Collections;

 import java.util.LinkedHashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.Map.Entry;

 import org.kuali.student.common.assembly.transform.IdTranslatorFilter;

 import org.kuali.student.common.exceptions.MissingParameterException;

 import org.kuali.student.common.search.dto.SearchParam;

 import org.kuali.student.common.search.dto.SearchRequest;

 import org.kuali.student.common.search.dto.SearchResult;

 import org.kuali.student.common.search.dto.SearchResultCell;

 import org.kuali.student.common.search.dto.SearchResultRow;

 import org.kuali.student.common.search.service.SearchDispatcher;

 import org.kuali.student.common.ui.client.service.SearchRpcService;

 import org.springframework.beans.factory.InitializingBean;

 import com.google.gwt.user.server.rpc.RemoteServiceServlet;

 public class SearchDispatchRpcGwtServlet extends RemoteServiceServlet implements SearchRpcService, InitializingBean {

     private static final long serialVersionUID = 1L;

     private IdTranslatorFilter idTranslatorFilter;

     private SearchDispatcher searchDispatcher;

     protected boolean cachingEnabled = false;

         protected int searchCacheMaxSize = 20;

         protected int searchCacheMaxAgeSeconds = 90;

         protected Map<String,MaxAgeSoftReference<SearchResult>> searchCache;

     public SearchDispatchRpcGwtServlet() {

         super();

     }

     /**

      * Delegates to the service responsible for the given search type key

      *

      * @param searchRequest

      * @return The searchResult from the delegated search or null

      * @throws MissingParameterException

      */

     @Override

     public SearchResult search(SearchRequest searchRequest) {

         SearchResult searchResult = searchDispatcher.dispatchSearch(searchRequest);

         List<SearchParam> params  = searchRequest.getParams();

         if(params != null && params.size() > 0){

             SearchParam firstParam = params.get(0);

             if(firstParam.getKey().equals("lu.queryParam.cluVersionIndId")){//FIXME can this special case be handled after this call?

                 doIdTranslation(searchResult);

             }

         }

         return searchResult;

     }

     @Override

     public SearchResult cachingSearch(SearchRequest searchRequest) {

             String cacheKey = searchRequest.toString();

             if(cachingEnabled){

                     //Get From Cache

                     MaxAgeSoftReference<SearchResult> ref = searchCache.get(cacheKey);

                     if ( ref != null ) {

                             SearchResult cachedSearchResult = ref.get();

                             if(cachedSearchResult!=null){

                                     return cachedSearchResult;

                             }

                     }

                 }

             //Perform the actual Search

             SearchResult searchResult = search(searchRequest);

             if(cachingEnabled){

                     //Store to cache

                     searchCache.put(cacheKey, new MaxAgeSoftReference<SearchResult>( searchCacheMaxAgeSeconds, searchResult) );

             }

         return searchResult;

     }

     private void doIdTranslation(SearchResult searchResult) {

         for (SearchResultRow searchResultRow : searchResult.getRows()) {

             for (SearchResultCell searchResultCell : searchResultRow.getCells()) {

                 String value = searchResultCell.getValue();

                 if (value != null && value.startsWith("kuali.atp")) {

                     String newValue = idTranslatorFilter.getTranslationForAtp(value);

                     if (newValue != null) {

                         searchResultCell.setValue(newValue);

                     }

                 }

             }

         }

     }

         @Override

         public void afterPropertiesSet() throws Exception {

                 if(cachingEnabled){

                         searchCache = Collections.synchronizedMap( new MaxSizeMap<String,MaxAgeSoftReference<SearchResult>>( searchCacheMaxSize ) );

                 }

         }

     public void setSearchDispatcher(SearchDispatcher searchDispatcher) {

         this.searchDispatcher = searchDispatcher;

     }

     public void setIdTranslatorFilter(IdTranslatorFilter idTranslatorFilter) {

         this.idTranslatorFilter = idTranslatorFilter;

     }

         public void setCachingEnabled(boolean cachingEnabled) {

                 this.cachingEnabled = cachingEnabled;

         }

         public void setSearchCacheMaxSize(int searchCacheMaxSize) {

                 this.searchCacheMaxSize = searchCacheMaxSize;

         }

         public void setSearchCacheMaxAgeSeconds(int searchCacheMaxAgeSeconds) {

                 this.searchCacheMaxAgeSeconds = searchCacheMaxAgeSeconds;

         }

         //Added as inner classes to avoid huge dependency on rice-impl

         /**

          * An extension to SoftReference that stores an expiration time for the 

          * value stored in the SoftReference. If no expiration time is passed in

          * the value will never be cached.  

          */

         public class MaxAgeSoftReference<T> extends SoftReference<T> {

                 private long expires;

                 public MaxAgeSoftReference(long expires, T referent) {

                         super(referent);

                         this.expires = System.currentTimeMillis() + expires * 1000;

                 }

                 public boolean isValid() {

                         return System.currentTimeMillis() < expires;

                 }

                 public T get() {                        

                         return isValid() ? super.get() : null;

                 }                

         }

         /**

          * This class acts like an LRU cache, automatically purging contents when it gets above a certain size. 

          * 

          * @author Kuali Rice Team (rice.collab@kuali.org)

          */

         public class MaxSizeMap<K,V> extends LinkedHashMap<K,V> {

                 private static final long serialVersionUID = -5354227348838839919L;

                 private int maxSize;

                 /**

                  * @param maxSize

                  */

                 public MaxSizeMap( int maxSize  ) {

                         this( maxSize, false );

                 }

                 /**

                  * @param maxSize

                  * @param accessOrder Whether to sort in the order accessed rather than the order inserted.

                  */

                 public MaxSizeMap( int maxSize, boolean accessOrder ) {

                         super( maxSize / 2, 0.75f, accessOrder );

                         this.maxSize = maxSize;

                 }

                 /**

                  * @see java.util.LinkedHashMap#removeEldestEntry(java.util.Map.Entry)

                  */

                 @Override

                 protected boolean removeEldestEntry(Entry<K,V> eldest) {

                         return size() > maxSize;

                 }

         }

 }