//This variables are used to verify the validity of the characters written
//in the fields, will be scanned to find out wether a given character is
//valid or not within a specific field.
var alphabet  = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
var salphabet = "????????????";
var digits    = "0123456789";
var alphaChars         = alphabet + salphabet + " .&-!?():;";
var extendedAlphaChars = alphabet + salphabet + digits + " .#-/,;:&()";
var categoryChars	   = alphabet + salphabet + " -";
var activityChars	   = alphabet + salphabet + digits + " -.&,;;?!()%$'\"#@/\\";
var emailChars 		   = alphabet + digits + "-.@_";
var phoneChars		   = digits + " -()" + alphabet;
var accountChars       = alphabet + digits + "_";

function validatefield(fieldValue,fieldName,isRequired,
                       minimumLength,validateChars,validCharsArray)
{
   if(isRequired){
		if(fieldValue == "")
		{
			alert("You must write a value for the field " + fieldName);
			return false;
		}
	}

	if(minimumLength > 0 && fieldValue.length > 0)
	{
		if(fieldValue.length < minimumLength)
		{
			alert("The value of field " + fieldName + " should have at least " + minimumLength + " characters.");
			return false;
		}
	}

	if(validateChars)
	{
		for(var x = 0; x < fieldValue.length ; x++)
		{
			if(validCharsArray.lastIndexOf(fieldValue.charAt(x)) < 0)
			{
				if(confirm("The field " + fieldName + " has invalid characters.\n Would you like to see a list of valid characters for field " + fieldName + " ?"))
				{
					alert("The list of valid characters for field " + fieldName + " is:\n" + validCharsArray);
				}
				return false;
			}
		}
	}

	//This is a valid field according to the given parameters
	return true;
}

/* This function will be used with the automathon procedure for e-Mail validation */

function getColumn(character)
{
	if(alphabet.lastIndexOf(character) >= 0)
		return 0;
	if(digits.lastIndexOf(character) >= 0)
		return 1;
	if(character == ".")
		return 2;
	if(character == "_")
		return 3;
	if(character == "-")
		return 4;
	if(character == "@")
		return 5;
	if(character == "endl")
		return 6;

	return 7;
}

function verifyemail(theemail)
{
    //if the previous was true then do some parsing for any present e-mail addresses
	if(theemail != "")
	{
		//we will use an automathon to do the parsing, so let's define the state's table:
		var states = new Array(13);
		states[0]  = new Array(1,7,7,7,7,7,7,7);
		states[1]  = new Array(1,1,1,1,1,2,8,8);
		states[2]  = new Array(3,3,9,9,9,9,9,9);
		states[3]  = new Array(3,3,4,10,3,10,10,10);
		states[4]  = new Array(5,5,11,11,11,11,11,11);
		states[5]  = new Array(5,5,4,12,5,12,6,12);
		states[6]  = new Array(0,0,0,0,0,0,0,0);
		states[7]  = new Array(-1,-1,-1,-1,-1,-1,-1,-1);
		states[8]  = new Array(-2,-2,-2,-2,-2,-2,-2,-2);
		states[9]  = new Array(-3,-3,-3,-3,-3,-3,-3,-3);
		states[10] = new Array(-4,-4,-4,-4,-4,-4,-4,-4);
		states[11] = new Array(-5,-5,-5,-5,-5,-5,-5,-5);
		states[12] = new Array(-6,-6,-6,-6,-6,-6,-6,-6);

		var laststate = 0;
		for(var x=0;x <= theemail.length;)
		{
			if(x == theemail.length) //This means endl is reached
				laststate = states[laststate][getColumn("endl")];
			else //get the state in a normal fashion
				laststate = states[laststate][getColumn(theemail.charAt(x))];

			switch(laststate)
			{
				case 0:
					//This is the case everything is ok so just increase x to leave the for !!!
					x++;
					break;
				case 1:
				case 2:
				case 3:
				case 4:
				case 5:
				case 6:
					x++;
					break;
				case 7:
				case 8:
				case 9:
				case 10:
				case 11:
				case 12:
					alert("Invalid e-Mail");
					return false;
			}
		}

		return true;
	}
	else
	{
		alert("Invalid e-Mail");
		return false;
	}
}