/*
    * Copyright 2005-2008 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.opensource.org/licenses/ecl2.php
   * 
   * 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.rice.kew.plugin;
  
  import java.io.File;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  /**
   * Tracks modifications to a set of files and directories.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class ModificationTracker implements Modifiable {
  
  	protected final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(getClass());
  	
  	// Maintains a map of root directories that we are watching to sub directories  
      private final Map dirTree = new HashMap();
      
      public synchronized void addURL(URL url) {
          addURL(dirTree, url);
      }
              
      private void addURL(Map parentMap, URL url)  {
          Node node = new Node(url);
          if (!parentMap.keySet().contains(node)) {
              Map subDir = new HashMap();
              parentMap.put(node, subDir);
              if (node.getFile().isDirectory()) {
                  File[] files = node.getFile().listFiles();
                  for (int index = 0; index < files.length; index++) {
                      try {
                          addURL(subDir, files[index].toURL());
                      } catch (MalformedURLException e) {
                          // TODO fix up this error handling
                          throw new RuntimeException(e);
                      }
                  }
              }
          }
      }
      
      public boolean isModified() {
      	return isModified(dirTree);
      }
          
      private boolean isModified(Map dirTree) {
      	for (Iterator iterator = dirTree.keySet().iterator(); iterator.hasNext();) {
  			Node node = (Node) iterator.next();
  			if (node.isModified() || isModified((Map)dirTree.get(node))) {
  				return true;
  			}
  		}
      	return false;
      }
      
      private class Node implements Modifiable {
          private URL url;
          private File file;
          private long lastModified;
          public Node(URL url) {
              this.url = url;
              this.file = new File(url.getFile());
              this.lastModified = file.lastModified();
          }
          public URL getURL() {
              return url;
          }
          public File getFile() {
              return file;
          }
          public long getLastModified() {
              return lastModified;
          }
          public boolean isModified() {
              return lastModified != file.lastModified();
          }
          public boolean equals(Object object) {
              if (object instanceof Node) {
                  return ((Node)object).getURL().equals(getURL());
              }
             return false;
         }
         public int hashCode() {
             return url.hashCode();
         }
     }
 
 }