/*
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (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.mozilla.org/MPL/>.
 * 
 * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
 * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
 * language governing rights and limitations under the License.
 * 
 * The Original Code is the Venice Web Communities System.
 * 
 * The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
 * for Silverwrist Design Studios.  Portions created by Eric J. Bowersox are
 * Copyright (C) 2001 Eric J. Bowersox/Silverwrist Design Studios.  All Rights Reserved.
 * 
 * Contributor(s): 
 */
package com.silverwrist.venice.servlets;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.silverwrist.venice.ValidationException;
import com.silverwrist.venice.core.*;
import com.silverwrist.venice.db.PostLinkDecoder;
import com.silverwrist.venice.servlets.format.*;

public class PostShortcut extends VeniceServlet
{
  /*--------------------------------------------------------------------------------
   * Overrides from class HttpServlet
   *--------------------------------------------------------------------------------
   */

  public String getServletInfo()
  {
    String rc = "PostShortcut servlet - Decodes a post link and redirects to it\n"
              + "Part of the Venice Web Communities System\n";
    return rc;

  } // end getServletInfo

  public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
  {
    UserContext user = getUserContext(request);
    RenderData rdat = createRenderData(request,response);
    String raw_link = request.getPathInfo().substring(1);
    PostLinkDecoder decoder;

    try
    { // attempt to decode the path link information
      decoder = new PostLinkDecoder(raw_link);
      if (decoder.getSIG()==null)  // it must include the SIG
	throw new ValidationException("ambiguous post link (no SIG)");

    } // end try
    catch (ValidationException e)
    { // display an error message for validation
      String page_title = "Invalid Post Link";
      ContentRender content = new ErrorBox(page_title,"Invalid post link \"" + raw_link + "\": "
					   + e.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;
      
    } // end catch

    SIGContext sig;
    try
    { // get the SIG represented by that alias
      sig = user.getSIGContext(decoder.getSIG());

    } // end try
    catch (DataException e)
    { // can't find the SIG - we're screwed
      String page_title = "Invalid Post Link";
      ContentRender content = new ErrorBox(page_title,"Invalid post link \"" + raw_link
					   + "\": cannot find SIG: " + e.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;
      
    } // end catch

    if (decoder.getConference()==null)
    { // it's a SIG link only - redirect to the SIG's default page
      rdat.redirectTo("sig/" + decoder.getSIG());
      return;

    } // end if

    ConferenceContext conf;
    try
    { // get the conference represented by that alias
      conf = sig.getConferenceContext(decoder.getConference());

    } // end try
    catch (DataException e)
    { // can't find the conference - we're screwed
      String page_title = "Invalid Post Link";
      ContentRender content = new ErrorBox(page_title,"Invalid post link \"" + raw_link
					   + "\": cannot find conference: " + e.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;
      
    } // end catch
    catch (AccessError ae)
    { // we can't get to the conference...
      String page_title = "Access Error";
      ContentRender content = new ErrorBox(page_title,ae.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;

    } // end catch

    // compute an elementary "locator"
    String locator = "sig=" + String.valueOf(sig.getSIGID()) + "&conf=" + String.valueOf(conf.getConfID());

    if (decoder.getTopic()==-1)
    { // just a conference link - go to the top-level display
      rdat.redirectTo("confdisp?" + locator);
      return;

    } // end if

    TopicContext topic;
    try
    { // get the topic number specified within that topic
      topic = conf.getTopic(decoder.getTopic());

    } // end try
    catch (DataException e)
    { // we can't find the topic - we're screwed
      String page_title = "Invalid Post Link";
      ContentRender content = new ErrorBox(page_title,"Invalid post link \"" + raw_link
					   + "\": cannot find topic: " + e.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;
      
    } // end catch
    catch (AccessError ae)
    { // we can't get to the topic...
      String page_title = "Access Error";
      ContentRender content = new ErrorBox(page_title,ae.getMessage(),null);
      new BaseJSPData(page_title,"top",content).transfer(getServletContext(),rdat);
      return;

    } // end catch

    // add the topic to our locator
    locator += "&top=" + String.valueOf(decoder.getTopic());

    if (decoder.getFirstPost()==-1) // we're just referencing the topic
      rdat.redirectTo("confdisp?" + locator + "&rnm=1");
    else  // we're referencing a post range within the topic
      rdat.redirectTo("confdisp?" + locator + "&p1=" + String.valueOf(decoder.getFirstPost()) + "&p2="
		      + String.valueOf(decoder.getLastPost()));

  } // end doGet

} // end class PostShortcut