package org.owasp.webgoat.lessons;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpSession;

import org.apache.ecs.Element;
import org.apache.ecs.ElementContainer;
import org.apache.ecs.StringElement;
import org.apache.ecs.html.A;
import org.apache.ecs.html.B;
import org.apache.ecs.html.BR;
import org.apache.ecs.html.Form;
import org.apache.ecs.html.H1;
import org.apache.ecs.html.Input;
import org.owasp.webgoat.session.WebSession;
import org.owasp.webgoat.util.HtmlEncoder;


/***************************************************************************************************
 * 
 * 
 * This file is part of WebGoat, an Open Web Application Security Project utility. For details,
 * please see http://www.owasp.org/
 * 
 * This program is free software; you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with this program; if
 * not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 * 
 * Getting Source ==============
 * 
 * Source for this application is maintained at code.google.com, a repository for free software
 * projects.
 * 
 * For details, please see http://code.google.com/p/webgoat/
 * 
 * @author Contributed by <a href="http://www.partnet.com">PartNet.</a>
 * 
 */
public class CsrfPromptByPass extends CSRF
{
	protected static final String TRANSFER_FUND_AMOUNT_ATTRIBUTE = "transferFundAmount";
	protected static final String CANCEL_TRANSFER = "CANCEL";
	protected static final String CONFIRM_TRANFER = "CONFIRM";
	
	/**
	 * if TRANSFER_FUND_PARAMETER is a parameter, them doTransfer is invoked.  doTranser presents the 
	 * web content to confirm and then execute a simulated transfer of funds.  An initial request
	 * should have a dollar amount specified.  The amount will be stored and a confirmation form is presented.  
	 * The confirmation can be canceled or confirmed.  Confirming the transfer will mark this lesson as completed.
	 * 
	 * @param s
	 * @return Element will appropriate web content for a transfer of funds.
	 */
	protected Element doTransfer(WebSession s) {
		String transferFunds = HtmlEncoder.encode(s.getParser().getRawParameter(TRANSFER_FUNDS_PARAMETER, ""));
		ElementContainer ec = new ElementContainer();
		
		if (transferFunds.length() != 0) {
			
			HttpSession httpSession = s.getRequest().getSession();
			Integer transferAmount = (Integer) httpSession.getAttribute(TRANSFER_FUND_AMOUNT_ATTRIBUTE);
			
			if (transferFunds.equalsIgnoreCase(TRANSFER_FUNDS_PAGE)){
				
				//present transfer form
				ec.addElement(new H1("Electronic Transfer:"));
				String action = getLink();
				Form form = new Form(action, Form.POST);
				form.addElement( new Input(Input.text, TRANSFER_FUNDS_PARAMETER, "0"));
				//if this token is present we won't mark the lesson as completed
				form.addElement( new Input(Input.submit));
				ec.addElement(form);
				
			} else if (transferFunds.equalsIgnoreCase(CONFIRM_TRANFER) && transferAmount != null ){
				
				//transfer is confirmed
				ec.addElement(new H1("Electronic Transfer Complete"));
				ec.addElement(new StringElement("Amount Transfered: "+transferAmount));
				makeSuccess(s);
				
			} else if (transferFunds.equalsIgnoreCase(CANCEL_TRANSFER)){
				
				//clear any pending fund transfer
				s.getRequest().removeAttribute(TRANSFER_FUND_AMOUNT_ATTRIBUTE);
				
			} else if (transferFunds.length() > 0){
				
				//save the transfer amount in the session
				transferAmount = new Integer(transferFunds);
				httpSession.setAttribute(TRANSFER_FUND_AMOUNT_ATTRIBUTE, transferAmount);
				
				//prompt for confirmation
				
				ec.addElement(new H1("Electronic Transfer Confirmation:"));
				ec.addElement(new StringElement("Amount to transfer: "+transferAmount));
				ec.addElement(new BR());
				String action = getLink();
				Form form = new Form(action, Form.POST);
				form.addElement( new Input(Input.submit, TRANSFER_FUNDS_PARAMETER, CONFIRM_TRANFER));
				form.addElement( new Input(Input.submit, TRANSFER_FUNDS_PARAMETER, CANCEL_TRANSFER));
				ec.addElement(form);	
			}
		}
		// white space
		ec.addElement(new BR());
		ec.addElement(new BR());
		ec.addElement(new BR());
		return ec;
	}

	/**
	 * @param s current web session
	 * @return true if the page should be rendered as a Transfer of funds page or false for the normal message posting page.
	 */
	protected boolean isTransferFunds(WebSession s) {
		String transferFunds = s.getParser().getRawParameter(TRANSFER_FUNDS_PARAMETER, "");
		if (transferFunds.length() != 0){
			return true;
		}
		return false;
	}

	@Override
	protected Category getDefaultCategory()
	{
		return Category.XSS;
	}

	private final static Integer DEFAULT_RANKING = new Integer(122);

	@Override
	protected Integer getDefaultRanking()
	{

		return DEFAULT_RANKING;
	}

	@Override
	protected List<String> getHints(WebSession s)
	{
		List<String> hints = new ArrayList<String>();
		hints.add("Add 'transferFunds=400' to the URL and inspect the form that is returned");
		hints.add("Add java script to send the confirmation after requesting the transfer");
		hints.add("Insert two images or iframes, the second with no source.  Specify the onload attribute of the first to set the source of the second. ");
		hints.add("Include this URL in the message <pre>&lt;img src='" + getLink()
				+ "&transferFunds=5000' width=\"1\" height=\"1\" /&gt;</pre>");

		return hints;
	}

	/**
	 * Gets the title attribute of the MessageBoardScreen object
	 * 
	 * @return The title value
	 */
	public String getTitle()
	{
		return ("CSRF Prompt By-Pass");
	}

	public Element getCredits()
	{
		A partnet = new A("http://www.partnet.com");
		partnet.setPrettyPrint(false);
		partnet.addElement(new StringElement("PART"));
		partnet.addElement(new B().addElement(new StringElement("NET")).setPrettyPrint(false));
		partnet.setStyle("background-color:midnightblue;color:white");
		
		ElementContainer credits = new ElementContainer();
		credits.addElement(new StringElement("Contributed by "));
		credits.addElement(partnet);
		return credits;
	}
}