/**
    *    Copyright 2011 meltmedia
    *
    *    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 org.xchain.framework.scanner;
  
  import java.io.IOException;
  import java.net.URL;
  import java.net.MalformedURLException;
  import java.util.jar.JarFile;
  import java.util.jar.JarEntry;
  import java.util.jar.JarInputStream;
  import java.util.Map;
  import java.util.TreeMap;
  
  /**
   * <p>This protocol scanner scans the protocol "jar:" and returns the root node of the scan.  The root node of the scan
   * can be used to discover other nodes in the jar.</p>
   *
   * @author Christian Trimble
   */
  public class ZipProtocolScanner
    implements ProtocolScanner
  {
    /**
     * <p>Scans the entries in a Weblogic Zip URL and adds all of the entries of that jar into the tree rooted at rootNode.  Missing
     * directory nodes will be added.</p>
     *
     * @param rootNode the root node of the scan.
     * @param jarUrl the url of the jar with entries to be added to the scan node.
     */
    public void scan( ScanNode rootNode, URL zipUrl )
      throws IOException
    {
      // get the file url for this zip url.
      URL fileUrl = zipUrlToFileUrl(zipUrl);
  
      JarInputStream in = null;
      try {
        in = new JarInputStream(fileUrl.openStream());
        JarEntry entry = null;
        while( (entry = in.getNextJarEntry()) != null ) {
          insertEntryNodes( rootNode, entry );
        }
      }
      catch( Exception e ) {
  
      }
      finally {
        if( in != null ) {
          try { in.close(); } catch( Exception e ) {}
        }
      }
    }
  
    /**
     * <p>Converts a url for the root of a zip file (ends with !/) and returns the file for that jar.</p>
     */
    URL zipUrlToFileUrl( URL zipRootUrl )
      throws MalformedURLException
    {
      return new URL("file:"+zipRootUrl.getPath().replaceAll("\\!/\\Z", ""));
    }
  
    /**
     * <p>Adds an entry to the root node for a JarEntry.  This method is declared to be protected, so that test cases an interact with it.
     * In general, this method should be treaded as private.</p>
     *
     * @param rootNode the root node of the scan.
     * @param entry the jar entry to place under the root node.
     */
    void insertEntryNodes( ScanNode rootNode, JarEntry entry )
    {
      String name = entry.getName();
      // TODO: verify that this works on windows.
      String[] parts = name.split("\\/");
      int depth = 0;
      ScanNode parentNode = rootNode;
  
      // create any missing directory nodes.
      for( int i = 0; i < parts.length - 1; i++ ) {
        ScanNode currNode = parentNode.getChildMap().get(parts[i]);
        if( currNode == null ) {
          currNode = new ScanNode();
          currNode.setResourceName("".equals(parentNode.getResourceName())?parts[i]:parentNode.getResourceName()+"/"+parts[i]);
          currNode.setName(parts[i]);
          currNode.setDirectory(true);
          currNode.setFile(false);
         parentNode.getChildMap().put(parts[i], currNode);
       }
       else {
         currNode.setDirectory(true);
       }
       parentNode = currNode;
     }
 
     // ASSERT: parentNode is now the parent node of this entry.
 
     // create the entry node if it is not already in the scan tree.
     ScanNode currNode = parentNode.getChildMap().get(parts[parts.length-1]);
     if( currNode == null ) {
       currNode = new ScanNode();
       currNode.setResourceName("".equals(parentNode.getResourceName())?parts[parts.length-1]:parentNode.getResourceName()+"/"+parts[parts.length-1]);
       currNode.setName(parts[parts.length-1]);
       currNode.setDirectory(entry.isDirectory()?true:false);
       currNode.setFile(entry.isDirectory()?false:true);
       parentNode.getChildMap().put(parts[parts.length-1], currNode);
     }
     else {
       if( entry.isDirectory() ) {
         currNode.setDirectory(true);
       }
       else {
         currNode.setFile(true);
       }
     }
   }
 }