package org.owasp.webgoat.session;

import java.util.Enumeration;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.regex.Pattern;

import javax.servlet.ServletRequest;

import org.owasp.webgoat.util.HtmlEncoder;


/**
 *  Copyright (c) 2002-2004 Free Software Foundation developed under the custody of
 *  the Open Web Application Security Project (http://www.owasp.org) This
 *  software package org.owasp.webgoat.is published by OWASP under the GPL. You should read and
 *  accept the LICENSE before you use, modify and/or redistribute this software.
 *
 * @author Jeff Williams <a href="http://www.aspectsecurity.com">Aspect Security</a>
 */
public class ParameterParser
{
    private final static String ALLOWED_CHARACTERS = "$()-?.@!,:;=//+"; // Don't allow #& specifically
    private ServletRequest request;

    /**
     *  Constructs a new ParameterParser to handle the parameters of the given
     *  request.
     *
     *@param  request  the servlet request
     */
    public ParameterParser(ServletRequest request)
    {
        this.request = request;
    }

    /**
     *  Description of the Method
     *
     *@param  s  Description of the Parameter
     *@return    Description of the Return Value
     */
    private String clean(String s)
    {
        StringBuffer clean = new StringBuffer();

        for (int loop = 0; loop < s.length(); loop++)
        {
            char c = s.charAt(loop);

            if (Character.isLetterOrDigit(c) || Character.isWhitespace(c) || (ALLOWED_CHARACTERS.indexOf(c) != -1))
            {
                clean.append(c);
            }
            else
            {
                clean.append('.');
            }
        }

        return (clean.toString());
    }


    /**
     *  Gets the named parameter value as a boolean
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a boolean
     *@exception  ParameterNotFoundException  if the parameter was not found
     */
    public boolean getBooleanParameter(String name) throws ParameterNotFoundException
    {
        return new Boolean(getStringParameter(name)).booleanValue();
    }


    /**
     *  Gets the named parameter value as a boolean, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a boolean, or the default
     */
    public boolean getBooleanParameter(String name, boolean def)
    {
        try
        {
            return getBooleanParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the booleanSubParameter attribute of the ParameterParser object
     *
     *@param  first  Description of the Parameter
     *@param  next   Description of the Parameter
     *@param  def    Description of the Parameter
     *@return        The booleanSubParameter value
     */
    public boolean getBooleanSubParameter(String first, String next, boolean def)
    {
        try
        {
            return new Boolean(getSubParameter(first, next)).booleanValue();
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a byte
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a byte
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter value could not be
     *      converted to a byte
     */
    public byte getByteParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return Byte.parseByte(getStringParameter(name));
    }


    /**
     *  Gets the named parameter value as a byte, with a default. Returns the
     *  default value if the parameter is not found or cannot be converted to a
     *  byte.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a byte, or the default
     */
    public byte getByteParameter(String name, byte def)
    {
        try
        {
            return getByteParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a char
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a char
     *@exception  ParameterNotFoundException  if the parameter was not found or was
     *      the empty string
     */
    public char getCharParameter(String name) throws ParameterNotFoundException
    {
        String param = getStringParameter(name);

        if (param.length() == 0)
        {
            throw new ParameterNotFoundException(name + " is empty string");
        }
        else
        {
            return (param.charAt(0));
        }
    }


    /**
     *  Gets the named parameter value as a char, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a char, or the default
     */
    public char getCharParameter(String name, char def)
    {
        try
        {
            return getCharParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the classNameParameter attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@return       The classNameParameter value
     */
    public String getClassNameParameter(String name) throws ParameterNotFoundException
    {
 		String p = getStringParameter(name);
		StringTokenizer st = new StringTokenizer(p);

		return (st.nextToken().trim());
     }


    // FIXME: check for [a-zA-Z].([a-zA-Z])*

    /**
     *  Gets the classNameParameter attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@param  def   Description of the Parameter
     *@return       The classNameParameter value
     */
    public String getClassNameParameter(String name, String def)
    {
        try
        {
            return getClassNameParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a double
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a double
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter could not be
     *      converted to a double
     */
    public double getDoubleParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return new Double(getStringParameter(name)).doubleValue();
    }


    /**
     *  Gets the named parameter value as a double, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a double, or the default
     */
    public double getDoubleParameter(String name, double def)
    {
        try
        {
            return getDoubleParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a float
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a float
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter could not be
     *      converted to a float
     */
    public float getFloatParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return new Float(getStringParameter(name)).floatValue();
    }


    /**
     *  Gets the named parameter value as a float, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a float, or the default
     */
    public float getFloatParameter(String name, float def)
    {
        try
        {
            return getFloatParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as an IP String, with a default. Returns the
     *  default value if the parameter is not found or is the empty string.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a String, or the default
     */
    public String getIPParameter(String name, String def)
    {
        try
        {
            return getIPParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as an IP String
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a valid IP
     *      String or an Empty string if invalid
     *@exception  ParameterNotFoundException  if the parameter was not found or was
     *      the empty string
     */
    public String getIPParameter(String name) throws ParameterNotFoundException
    {
        boolean valid = true;
        String[] values = request.getParameterValues(name);
        String value;

        if (values == null)
        {
            throw new ParameterNotFoundException(name + " not found");
        }
        else if (values[0].length() == 0)
        {
            throw new ParameterNotFoundException(name + " was empty");
        }
        else
        {
            // trim illegal characters
            value = clean(values[0].trim());

            if (value.indexOf("&") > 0)
            {
                // truncate additional parameters that follow &
                value = value.substring(0, value.indexOf("&"));
            }

            // validate the IP  ex: 124.143.12.254
            int startIndex = 0;
            int endIndex = 0;
            int octetCount = 0;
            int octetValue;
            String octet;

            // if no .'s then it's not an IP
            if (value.indexOf(".") >= 0)
            {
                while ((valid == true) && (octetCount < 4))
                {
                    endIndex = value.indexOf(".", startIndex);

                    if (endIndex == -1)
                    {
                        endIndex = value.length();
                    }

                    octet = value.substring(startIndex, endIndex);
                    startIndex = endIndex + 1;

                    try
                    {
                        octetValue = Integer.parseInt(octet);

                        if ((octetValue <= 0) || (octetValue >= 256))
                        {
                            valid = false;
                        }
                    }
                    catch (Exception e)
                    {
                        valid = false;
                    }

                    octetCount++;
                }
            }
            else
            {
                // Not a valid IP
                valid = false;
            }

            // Check for any extra garbage. If the last octet was a large value
            // it would be trapped by the above range check.
            if (value.length() != endIndex)
            {
                valid = false;
            }

            return valid ? value : null;
        }
    }


    /**
     *  Gets the named parameter value as a int
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a int
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter could not be
     *      converted to a int
     */
    public int getIntParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return Integer.parseInt(getStringParameter(name));
    }


    /**
     *  Gets the named parameter value as a int, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a int, or the default
     */
    public int getIntParameter(String name, int def)
    {
        try
        {
            return getIntParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a long
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a long
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter could not be
     *      converted to a long
     */
    public long getLongParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return Long.parseLong(getStringParameter(name));
    }


    /**
     *  Gets the named parameter value as a long, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a long, or the default
     */
    public long getLongParameter(String name, long def)
    {
        try
        {
            return getLongParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Determines which of the required parameters were missing from the request.
     *  Returns null if all the parameters are present.
     *
     *@param  requestuired  Description of the Parameter
     *@return               an array of missing parameters, or null if none are
     *      missing
     */
    public String[] getMissingParameters(String[] requestuired)
    {
        Vector missing = new Vector();

        for (int i = 0; i < requestuired.length; i++)
        {
            String val = getStringParameter(requestuired[i], null);

            if (val == null)
            {
                missing.addElement(requestuired[i]);
            }
        }

        if (missing.size() == 0)
        {
            return null;
        }
        else
        {
            String[] ret = new String[missing.size()];
            missing.copyInto(ret);

            return ret;
        }
    }


    /**
     *  Gets the parameterNames attribute of the ParameterParser object
     *
     *@return    The parameterNames value
     */
    public Enumeration getParameterNames()
    {
        if (request == null)
        {
            return (null);
        }

        return request.getParameterNames();
    }


    /**
     *  Gets the parameterValues attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@return       The parameterValues value
     */
    public String[] getParameterValues(String name)
    {
        if (request == null)
        {
            return (null);
        }

        return request.getParameterValues(name);
    }


    /**
     *  Gets the rawParameter attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@param  def   Description of the Parameter
     *@return       The rawParameter value
     */
    public String getRawParameter(String name, String def)
    {
        try
        {
            return getRawParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the rawParameter attribute of the ParameterParser object
     *
     *@param  name                            Description of the Parameter
     *@return                                 The rawParameter value
     *@exception  ParameterNotFoundException  Description of the Exception
     */
    public String getRawParameter(String name) throws ParameterNotFoundException
    {
        String[] values = request.getParameterValues(name);

        if (values == null)
        {
            throw new ParameterNotFoundException(name + " not found");
        }
        else if (values[0].length() == 0)
        {
            throw new ParameterNotFoundException(name + " was empty");
        }

        return (values[0]);
    }


    /**
     *  Gets the named parameter value as a short
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a short
     *@exception  ParameterNotFoundException  if the parameter was not found
     *@exception  NumberFormatException       if the parameter could not be
     *      converted to a short
     */
    public short getShortParameter(String name) throws ParameterNotFoundException, NumberFormatException
    {
        return Short.parseShort(getStringParameter(name));
    }


    /**
     *  Gets the named parameter value as a short, with a default. Returns the
     *  default value if the parameter is not found.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a short, or the default
     */
    public short getShortParameter(String name, short def)
    {
        try
        {
            return getShortParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the named parameter value as a String
     *
     *@param  name                            the parameter name
     *@return                                 the parameter value as a String
     *@exception  ParameterNotFoundException  if the parameter was not found or was
     *      the empty string
     */
    public String getStringParameter(String name) throws ParameterNotFoundException
    {
        String[] values = request.getParameterValues(name);
        String value;

        if (values == null)
        {
            throw new ParameterNotFoundException(name + " not found");
        }
        else if (values[0].length() == 0)
        {
            throw new ParameterNotFoundException(name + " was empty");
        }
        else
        {
            // trim illegal characters
            value = clean(values[0].trim());

            if (value.indexOf("&") > 0)
            {
                // truncate additional parameters that follow &
                value = value.substring(0, value.indexOf("&"));
            }

            return value;
        }
    }


    /**
     *  Gets the named parameter value as a String, with a default. Returns the
     *  default value if the parameter is not found or is the empty string.
     *
     *@param  name  the parameter name
     *@param  def   the default parameter value
     *@return       the parameter value as a String, or the default
     */
    public String getStringParameter(String name, String def)
    {
        try
        {
            return getStringParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the subParameter attribute of the ParameterParser object
     *
     *@param  first  Description of the Parameter
     *@param  next   Description of the Parameter
     *@param  def    Description of the Parameter
     *@return        The subParameter value
     */
    public String getSubParameter(String first, String next, String def)
    {
        try
        {
            return getSubParameter(first, next);
        }
        catch (Exception e)
        {
            return def;
        }
    }


    /**
     *  Gets the parameter named 'next' following the parameter 'first'. Presumes
     *  the structure: first=firstvalue&next=nextValue
     *
     *@param  first                           Description of the Parameter
     *@param  next                            Description of the Parameter
     *@return                                 The subParameter value
     *@exception  ParameterNotFoundException  Description of the Exception
     */
    public String getSubParameter(String first, String next) throws ParameterNotFoundException
    {
        String[] values = request.getParameterValues(first);
        String value;

        if (values == null)
        {
            throw new ParameterNotFoundException(first + " not found");
        }
        else if (values[0].length() == 0)
        {
            throw new ParameterNotFoundException(first + " was empty");
        }
        else
        {
            value = clean(values[0].trim());

            int idx = value.indexOf("&") + 1;

            // index of first char of first sub-param name
            if (idx == 0)
            {
                throw new ParameterNotFoundException("No subparameter key");
            }

            value = value.substring(idx);

            //System.out.println("= = = = = =Parameter parser looking for " + next + " in " + value );
            int nextValueIndex = value.indexOf(next + "=");

            //System.out.println("= = = = = =Parameter parser nextValueIndex = " + nextValueIndex );
            if (nextValueIndex < 0)
            {
                throw new ParameterNotFoundException("No subparameter value");
            }

            nextValueIndex += (next.length() + 1);

            if (nextValueIndex >= 0)
            {
                value = value.substring(nextValueIndex);
            }
            else
            {
                throw new ParameterNotFoundException(next + " not found");
            }
        }

        if (value.indexOf("&") > 0)
        {
            // truncate additional parameters that follow &
            value = value.substring(0, value.indexOf("&"));
        }

        //System.out.println("=-=-=-=-=ParameterParser returning value " + value );
        return value;
    }


    /**
     *  Gets the wordParameter attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@return       The wordParameter value
     */
    public String getWordParameter(String name) throws ParameterNotFoundException
    {
 		String p = getStringParameter(name);
		StringTokenizer st = new StringTokenizer(p);

		return (st.nextToken().trim());
    }


    // FIXME: check for [a-zA-Z]

    /**
     *  Gets the wordParameter attribute of the ParameterParser object
     *
     *@param  name  Description of the Parameter
     *@param  def   Description of the Parameter
     *@return       The wordParameter value
     */
    public String getWordParameter(String name, String def)
    {
        try
        {
        	return getWordParameter(name);
        }
        catch (Exception e)
        {
            return def;
        }
    }

    /**
     * Gets the specified parameter from the request and validates it against the provided regular expression. 
     * If the regular expression check fails, the default value is returned instead. 
     *
     *@param  name  		The name of the parameter to retrieve from the request.
     *@param  def   		The default value of the parameter.
     *@param  regexpattern	The precompiled regular expression to be used to validate the parameter.
     *@return       The validated parameter value, or the default value if validation failed.
     */
    private String getRegexParameter(String name, String def, Pattern regexpattern) throws ValidationException
    {
    	try
    	{
    		return getRegexParameter(name, regexpattern);
    	}
    	catch (Exception e)
    	{
    		//System.out.println("Exception occured in defined pattern match");
    		//e.printStackTrace();
    		return def;
    	}	
    }

    /**
     * Gets the specified parameter from the request and validates it against the provided regular expression. 
     * If the regular expression check fails, the default value is returned instead. 
     *
     *@param  name  		The name of the parameter to retrieve from the request.
     *@param  def   		The default value of the parameter.
     *@param  regexpattern	The precompiled regular expression to be used to validate the parameter.
     *@return       The validated parameter value, or the default value if validation failed.
     */
    private String getRegexParameter(String name, Pattern regexpattern) 
    			throws ParameterNotFoundException, ValidationException
    {
		String param = getStringParameter( name );
		
		if ( regexpattern.matcher( param ).matches() )
		{
			return param;
		}
		else
		{
			//System.out.println(param + " didn't match defined pattern.");
			throw new ValidationException(name + " contained an invalid value");
		}
    }
    
    
    
    public String getStrictAlphaParameter(String name, int maxLength) 
    			throws ParameterNotFoundException, ValidationException
    {
		String alphaRegEx = "^[a-zA-Z\\s]{0," + maxLength + "}$";
		Pattern alphaPattern = Pattern.compile(alphaRegEx);
		
		return getRegexParameter(name, alphaPattern);
    }
    
    
    
    public String getStrictNumericParameter(String name, int maxLength)
    			throws ParameterNotFoundException, ValidationException
    {
		String numericRegEx = "^\\d{0," + maxLength + "}$";
		Pattern numericPattern = Pattern.compile(numericRegEx);
		
		return getRegexParameter(name, numericPattern);
    }
    
    
    
    private static final String SSNREGEX = "^\\d{3}-\\d{2}-\\d{4}$";
    private static final Pattern Ssnpattern = Pattern.compile(SSNREGEX);
    
    public String getSsnParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getRegexParameter(name, Ssnpattern);
    }
    
    
    // Validates format for major brands of credit card.
	//private static final String CCNREGEX = "^(?:(?<Visa>4\\d{3})|(?<Mastercard>5[1-5]\\d{2})|(?<Discover>6011)|(?<DinersClub>(?:3[68]\\d{2})|(?:30[0-5]\\d))|(?<AmericanExpress>3[47]\\d{2}))([ -]?)(?(DinersClub)(?:\\d{6}\\1\\d{4})|(?(AmericanExpress)(?:\\d{6}\\1\\d{5})|(?:\\d{4}\\1\\d{4}\\1\\d{4})))$";
    	private static final String CCNREGEX = "^\\d{16}$";
    private static final Pattern Ccnpattern = Pattern.compile(CCNREGEX);
    
    public String getCcnParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getRegexParameter(name, Ccnpattern);
    }
    
    
    private static final String ZIPREGEX = "^\\d{5}(-\\d{4})?$";
    private static final Pattern Zippattern = Pattern.compile( ZIPREGEX );
     
    public String getZipParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getZipParameter(name, null);
    }
    
    public String getZipParameter(String name, String def) throws ValidationException
    {
    		return getRegexParameter(name, def, Zippattern);
    }

    
    private static final String PHONEREGEX = "^\\(?[\\d]{3}\\)?[\\s-]?[\\d]{3}[\\s-]?[\\d]{4}$";
    // Or this more forgiving pattern:
    //private static final String PHONEREGEX = "^([\\-()+ 0-9x])+$";
    private static final Pattern phonepattern = Pattern.compile( PHONEREGEX );
    
    public String getPhoneParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getPhoneParameter(name, null);
    }
    
    public String getPhoneParameter(String name, String def) throws ValidationException
    {
    		return getRegexParameter(name, def, phonepattern);
    }
    
    
    private static final String EMAILREGEX = "^[\\w-]+(?:\\.[\\w-]+)*@(?:[\\w-]+\\.)+[a-zA-Z]{2,7}$";
    private static final Pattern emailpattern = Pattern.compile( EMAILREGEX );
    
    public String getEMailParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getEMailParameter(name, null);
    }
    
    public String getEMailParameter(String name, String def) throws ValidationException
    {
    		return getRegexParameter(name, def, emailpattern);
    }
    
    
    private static final String DATEREGEX =	"([\\/ .,:0-9a-zA-Z])+$";
    private static final Pattern datepattern = Pattern.compile( DATEREGEX );
    
    public String getDateParameter(String name) throws ParameterNotFoundException, ValidationException
    {
		return getDateParameter(name, null);
    }
    
    public String getDateParameter(String name, String def) throws ValidationException
    {
    		return getRegexParameter(name, def, datepattern);
    }
    
    
    private static final String URLREGEX = "^(((https?)://)([-()_.!~*';/?:@&=+$,A-Za-z0-9])+)([).!';/?:,][[:blank:]])?$";
    private static final Pattern URLpattern = Pattern.compile( URLREGEX );
    
    public String getURLParameter(String name) throws ParameterNotFoundException, ValidationException
    {
    		return getURLParameter(name, null);
    }
    
    public String getURLParameter(String name, String def) throws ValidationException
    {
    		return getRegexParameter(name, def, URLpattern);
    }
    
	
	protected static String htmlEncode(String s)
	{
		return HtmlEncoder.encode(s);
	}

    /**
     *  Description of the Method
     *
     *@return    Description of the Return Value
     */
    public String toString()
    {
        StringBuffer s = new StringBuffer("[");
        Enumeration e = getParameterNames();

        while (e.hasMoreElements())
        {
            String key = (String) e.nextElement();
            s.append(key + "=" + getParameterValues(key)[0]);

            // FIXME: Other values?
            if (e.hasMoreElements())
            {
                s.append(",");
            }
        }

        s.append("]");

        return (s.toString());
    }


    /**
     *  Description of the Method
     *
     *@param  request  Description of the Parameter
     */
    public void update(ServletRequest request)
    {
        this.request = request;
    }
}