/*
 * Created on 15.12.2003
 *
 * (c) Stabsstelle IKT-Strategie des Bundes
 */
package at.gv.egovernment.moa.spss.slinterface;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Properties;

import org.apache.log4j.Logger;

/**
 * @author Gregor Karlinger (mailto:gregor.karlinger@cio.gv.at) 
 */
public class URLRewriter
{
  private static Logger logger_ = Logger.getLogger(Constants.LH_LISTENERS_);

  Properties initProps_;
  
  /**
   * Class that manges the rewriting of URLs for the result pages. Necessary as workaround for the deploy-
   * ment in the Federal Chancellory.
   */
  public URLRewriter(Properties initProps)
  {
    initProps_ = initProps;
  }
  
  /**
   * Rewrites the specified URL. 
   * 
   * @param url A URL relative to the context path of the serlet.
   * 
   * @param sessionId The session id which will be considered in the rewritten URL.
   * 
   * @return A URL fitting for the proxy component running at the Federal Chancellory.
   */
  public String rewrite(String url, String sessionId)
  {
    String proxyURLStr = initProps_.getProperty(Constants.IP_REW_PROXYRUL_);
    String slInterfaceURLParamName = initProps_.getProperty(Constants.IP_REW_SLI_URLPARAMNAME_);
    String slInterfaceURLStr = initProps_.getProperty(Constants.IP_REW_SLIRUL_);
    
    if (proxyURLStr == null || 
      slInterfaceURLParamName == null || 
      slInterfaceURLStr == null ||
      "".equals(proxyURLStr.trim()) ||
      "".equals(slInterfaceURLParamName.trim()) ||
      "".equals(slInterfaceURLStr.trim()))
    {
      logger_.warn("Some params for URL rewriting are not available; rewriting disabled:" +
        " proxyURL: \"" + proxyURLStr + "\"," +
        " slInterfaceURLParamName: \"" + slInterfaceURLParamName + "\"," +
        " slInterfaceURL: \"" + slInterfaceURLStr + "\"");
      return url;  
    }
    
    URL slInterfaceURL = null;
    try
    {
      slInterfaceURL = new URL(slInterfaceURLStr + url);
    }
    catch (MalformedURLException e)
    {
      logger_.warn("Parameter \"slInterfaceURL\" is not a valid URL: \"" + slInterfaceURLStr + "\"");
      return url;
    }
    URL proxyURL = null;
    try
    {
      proxyURL = new URL(proxyURLStr);
    }
    catch (MalformedURLException e)
    {
      logger_.warn("Parameter \"proxyURL\" is not a valid URL: \"" + proxyURLStr + "\"");
      return url;
    }

    String sessionIdParam = (sessionId != null) ? (";" + "jsessionid=" + sessionId) : "";
    String returnValue = 
      proxyURL.getProtocol() +
      "://" +
      proxyURL.getHost() +
      ((proxyURL.getPort() != -1) ? (":" + proxyURL.getPort()) : "") + 
      proxyURL.getPath() +
      ((proxyURL.getQuery() != null) ? "?" + proxyURL.getQuery() + "&" : "?") +
      slInterfaceURLParamName + "=" +
      slInterfaceURL.getProtocol() +
      "://" +
      slInterfaceURL.getHost() +
      ((slInterfaceURL.getPort() != -1) ? (":" + slInterfaceURL.getPort()) : "") +
      slInterfaceURL.getPath() + 
      sessionIdParam +
      ((slInterfaceURL.getQuery() != null) ? "?" + escapeQueryPart(slInterfaceURL.getQuery()) : ""); 
      
    logger_.debug("Rewritten URL: " + returnValue);
    return returnValue;
  }
  
  private String escapeQueryPart(String query)
  {
    StringBuffer querySB = new StringBuffer();
    for (int i = 0; i < query.length(); i++)
    {
      if (query.charAt(i) == '&')
      {
        querySB.append("%26");
      }
      else
      {
        querySB.append(query.charAt(i));
      } 
    }
    return querySB.toString();
  }
}