package webraveler.vurl;

import java.util.*;

import webraveler.http.HTTPRequest;
import webraveler.http.HTTPResponse;
import webraveler.ravel.Raveler;
import webraveler.ravel.RavelerException;
import webraveler.ravel.RavelerUser;
/**
 * Some of the basic operations that many VURLs will want to use.
 * You can provide these operations by extending this class.
 *
 * @author Samuel A. Rebelsky
 * @version 1.0
 */
public abstract class GenericVURL
	implements VURL 
{
// +--------+------------------------------------------------------------
// | Fields |
// +--------+

	Hashtable specialChars;
	
// +--------------+------------------------------------------------------
// | Constructors |
// +--------------+

	/**
	 * Constructs a GenericVURL.
	 */
	public GenericVURL() {
		this.specialChars = new Hashtable();
		this.setupSpecialChars();
	} // PluginChangePref()


// +---------+-----------------------------------------------------------
// | Methods |
// +---------+

	/**
	 * Generate a standard page response.
	 *
	 * @param htmlContents
	 *   The contents of that page.
	 */
	protected HTTPResponse standardPage(String htmlContents)
	{
		return new HTTPResponse("HTTP/1.0",200,"OK",htmlContents.getBytes(),new Hashtable());	
	} // standardPage(String)

	/**
	 * Generate a redirect page.
	 */
	protected HTTPResponse redirectPage(String uri)
	{
		HTTPResponse red = new HTTPResponse("HTTP/1.1",307,"TEMPORARY REDIRECT",uri.getBytes(),new Hashtable());
		red.setHeader("Location", uri);
		red.correctContentLength();
		return red;
	} // redirectPage(String)

	/** 
	 * Converts the encoded special characters in the query string to their original form
	 *
	 * @param value a string to be decoded
	 * @return a String with the decoded value
	 */
	protected String handleSpecialChars(String value) {
		int percentIndex=0;
		while ((percentIndex= value.indexOf('%',percentIndex)) != -1) {
			String encod = value.substring(percentIndex,percentIndex+3);
			if (specialChars.containsKey(encod)) {
				String unencod = (String) specialChars.get(encod);
				value = value.substring(0,percentIndex)+unencod+value.substring(percentIndex+3,value.length());
			} //if
			percentIndex++;
		} //while
		/* Change all + to spaces */
		value = value.replace('+',' ');
		return value;
	} //handleSpecialChars(String)
	
// +-----------------+---------------------------------------------------
// | Private Methods |
// +-----------------+

	/**
	 * Sets up the hash table of special characters and their equivalent encoding
	 */
	private void setupSpecialChars() {
		/* Put the special characters and their encoding in hash */
		specialChars.put("%22"," ");
		specialChars.put("%5B","[");
		specialChars.put("%5D","]");
		specialChars.put("%7B","{");
		specialChars.put("%7D","}");
		specialChars.put("%26","&");
		specialChars.put("%3C","<");
		specialChars.put("%3E",">");
		specialChars.put("%2B","+");
		specialChars.put("%5C","\\");
		specialChars.put("%2F","/");
		specialChars.put("%28","(");
		specialChars.put("%29",")");
		specialChars.put("%3F","?");
		specialChars.put("%24","$");
		specialChars.put("%5E","^");
		specialChars.put("%25","%");
		specialChars.put("%3A",":");
		specialChars.put("%3D","=");
		specialChars.put("%21","!");
		specialChars.put("%40","@");
		specialChars.put("%23","#");
		specialChars.put("%3B",";");
		specialChars.put("%27","'");
		specialChars.put("%22","\"");
		specialChars.put("%2C",",");
		specialChars.put("%7E","~");
	}

} // class GenericVURL