/* -*- mode: JDE; c-basic-offset: 2; indent-tabs-mode: nil -*-
    *
    * $Id: SourceForge.java,v 1.4 2004/07/27 20:20:36 ljnelson Exp $
    *
    * Copyright (c) 2003 Laird Jarrett Nelson.
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense and/or sell 
   * copies of the Software, and to permit persons to whom the Software is 
   * furnished to do so, subject to the following conditions:
   * 
   * The above copyright notice and this permission notice shall be included in 
   * all copies or substantial portions of the Software.
   * 
   * THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   * The original copy of this license is available at
   * http://www.opensource.org/license/mit-license.html.
   */
  package sfutils;
  
  import java.io.IOException;
  
  import java.util.Collections;
  import java.util.Map;
  import java.util.WeakHashMap;
  
  import com.meterware.httpunit.GetMethodWebRequest;
  import com.meterware.httpunit.HttpUnitOptions;
  import com.meterware.httpunit.WebConversation;
  import com.meterware.httpunit.WebLink;
  import com.meterware.httpunit.WebResponse;
  
  import org.xml.sax.SAXException;
  
  /***
   * A utility class that provides access to small, core bits of information from
   * the <a href="http://sourceforge.net/">SourceForge</a> website.
   *
   * @author     <a href="mailto:ljnelson94@alumni.amherst.edu">Laird Nelson</a>
   * @version    $Revision: 1.4 $ $Date: 2004/07/27 20:20:36 $
   * @since      July 12, 2003
   */
  public final class SourceForge {
  
    /***
     * The leading portion of the URL required to access a <a
     * href="http://sourceforge.net/">SourceForge</a> project.
     */
    private static final String PROJECT_PREFIX = 
      "http://sourceforge.net/projects/";
  
    /***
     * A {@link Map} of project IDs indexed by project short names.  This field is
     * thread-safe.
     */
    private static final Map PROJECT_ID_MAP = 
      Collections.synchronizedMap(new WeakHashMap());
  
    /***
     * Static initializer; ensures that the {@link
     * HttpUnitOptions#setExceptionsThrownOnScriptError(boolean)} method is called
     * with <code>false</code> as its parameter to work around the fact that <a
     * href="http://sourceforge.net/">SourceForge</a> pages have JavaScript errors
     * in them.
     */
    static {
      HttpUnitOptions.setExceptionsThrownOnScriptError(false);
      HttpUnitOptions.setScriptingEnabled(false);
    }
  
    /***
     * Throws an {@link UnsupportedOperationException} when invoked.
     *
     * @exception  UnsupportedOperationException
     *               when invoked
     */
    private SourceForge() throws UnsupportedOperationException {
      super();
      throw new UnsupportedOperationException();
    }
  
    /***
     * Returns the <a href="http://sourceforge.net/">SourceForge</a> project
     * identifier given a project short name.  This method may return
     * <code>null</code>.
     *
     * @param      projectShortName
     *               the name of the project whose identifier should be returned;
     *               may be <code>null</code> in which case <code>null</code> will
     *               be returned
    * @return     the identifier corresponding to the <a
    *               href="http://sourceforge.net/">SourceForge</a> project with
    *               the supplied short name, or <code>null</code>
    * @exception  SourceForgeException
    *               if an error occurs
    */
   public static final String getProjectID(final String projectShortName) 
     throws SourceForgeException {
     if (projectShortName == null) {
       return null;
     }
     String projectID = (String)PROJECT_ID_MAP.get(projectShortName);
     if (projectID != null) {
       return projectID;
     }
     try {
       final WebConversation webConversation = new WebConversation();
       final WebResponse summaryPage = 
         webConversation.getResponse(new GetMethodWebRequest(PROJECT_PREFIX +
                                                             projectShortName));
       assert summaryPage != null;
       final WebLink viewMembersLink = summaryPage.getLinkWith("[View Members]");
       if (viewMembersLink == null) {
         // Maybe it was an invalid project?
         final String text = summaryPage.getText();
         assert text != null;
         if (text.indexOf("Invalid Project") >= 0) {
           throw new NoSuchProjectException(projectShortName);
         }
         // OK, uh, UI change?
         throw new SourceForgeUIChangeException();
       }
       final String linkText = viewMembersLink.getURLString();
       assert linkText != null;
       final int groupIDIndex = linkText.indexOf("?group_id=");
       if (groupIDIndex < 0) {
         throw new SourceForgeUIChangeException();
       }
       projectID = linkText.substring(groupIDIndex + "?group_id=".length());
       PROJECT_ID_MAP.put(projectShortName, projectID);
       return projectID;
     } catch (final IOException kaboom) {
       throw new SourceForgeException(kaboom);
     } catch (final SAXException kaboom) {
       throw new SourceForgeException(kaboom);
     }
   }
 
 }