// Check that the number of characters in a string is between a max and a min
function isValidLength(string, min, max) 
{
	if (string.length < min || string.length > max) 
		return false;
	else 
		return true;
}

// RSS feed validation
function isValidUrl (url) {
  var regexp = "^((http|https)\://)([a-zA-Z0-9]+)(\.[a-zA-Z0-9]+)+(\:[0-9]+)?([\/a-zA-Z0-9\.\,\;\?\'\\\+&%\$#\=~_\-]+)*$";
  var match = url.match (regexp);
  return (match != null);
}

// Remove leading and trailing whitespace from a string
function trimWhitespace(string) 
{
	var newString  = '';
	var substring  = '';
	beginningFound = false;
   
	// copy characters over to a new string
	// retain whitespace characters if they are between other characters
	for (var i = 0; i < string.length; i++) 
	{
		// copy non-whitespace characters
		if (string.charAt(i) != ' ' && string.charCodeAt(i) != 9) 
		{
			// if the temporary string contains some whitespace characters, 
			// copy them first
			if (substring != '') 
			{
            	newString += substring;
            	substring = '';
			}
			newString += string.charAt(i);
			if (beginningFound == false) 
				beginningFound = true;
		}
		else if (beginningFound == true) 
		{
			substring += string.charAt(i);
		}
   }
   return newString;
}

function isValidIP(objIP) 
{
	var ip = objIP.value; 
	if (objIP.length == 0)
		return false;

	// Invalid Format, number of dots is not 3
	if (countChars(ip, ".") != 3) 
		return false; 

	var arrIP = ip.split(".");
	for (var i = 0; i < 4; i++)
	{
		if ((arrIP[i].length < 1) || (arrIP[i].length > 3))
		{
			// Invalid Format, multiple dots or more than 3 digits between dots
			return false;
		}
				
		if (!isInteger(arrIP[i]))
		{
			// non-integers present in the value
			return false;
		}
				
		arrIP[i] = parseInt(arrIP[i]);
				
		if (i == 0)
		{
			// start IP value
			if ((arrIP[i] == 0) || (arrIP[i] > 223) || (arrIP[i] == 127))
			{
				return false;
			}
		}
		else
		{
			// the 2nd, 3rd and 4th IP values between the dots
			// these must not be more than 255
			if (arrIP[i] > 255)
			{
				return false;
			}
		}
	}
			
	objIP.value = arrIP.join(".");
			
	return true;
}

function countChars(s,c)
{
	var spos = 0;
	var fpos =0;
	var count = 0;
		
	// checking for the null character	
	if (c == "")
	{
		return count;
	}	
	while((fpos = s.indexOf(c, spos)) >= 0)
	{
		count++;
		spos = fpos + 1;
	}
			
	return count;
}

function isInteger(s)
{
	var c;
	// checking for null string 
	if (s.length==0)  
	{
		return false;
 	}
		 
 	for (var i=0;i < s.length;i++)
	{
		c = s.substring(i,i+1);
		if (c < "0" || c > "9")
		{ 
			return false;
		}
	} 
	return true;
}

function validateField(e) 
{
	var p = e.getAttribute("pattern");

	var re;
	switch (p.toLowerCase()) 
	{
		case "txt" :
		case "textonly" : 		// Text only allowed
			re = /^[a-z ]*$/i;
			break;
		case "num" :
		case "number" :			// Only numbers (allow decimal)
			re = /^[\d\.]*$/;
			break;
		case "int" :
		case "integer" :		// Integers only
			re = /^\d*$/;
			break;
		case "phonenumber" :	// Phone number characters
			re = /^[\d \-\(\)\+]*$/;
			break;
		case "date" :
			re = /^(()|(\d{1,2}(\/|-)\d{1,2}(\/|-)\d{2,4}))$/;
			break;
		case "idate" :
			re = /^(()|(\d{2,4}(\/|-)\d{1,2}(\/|-)\d{1,2}))$/;
			break;
		case "email" : 
			re = /^.+@[^\.].*\.[a-z]{2,}$/;
			break;
		case "alnum" :
		case "alphanumeric" :
			re = /^[\w]*$/i;
			break;
		case "ipaddress" :		// IP Address rule
			return isValidIP(e);
		case "addr" :
		case "hostaddress" :	// Address rule
			re = /^[\w- \.,#]*$/i;
			break;
		case "name" :
			re = /^[a-z,0-9,\-\. ]*$/i;
			break;
		case "uname" :
		case "username" :		// User name 
			re = /^[\w- \-\@\_\.,#]*$/i;
			break;
		case "path" :
        		re = /^[a-z\-\.\d \/]*$/gi;
        		break;
		case "folder" :
        		re = /^[a-z\-\d]*$/gi;
        		break;
		case "database" :		// Database name 
			re = /^[a-z][a-z,0-9,\-\_]*$/i;
			break;
		case "notnull" :		// Requires *anything*
		default :
			re = /.+/;
			break;
	}
	
	if (re.test(e.value)) 
	{
		return true;
	}
	else 
	{
		return false;
	}
}

function setError(e, msg) 
{
	var name = e.getAttribute("err");
	if (name == null)
		return;

	var err = document.getElementById(name);
	if (err == null)
		return;

	if (msg == null)
	{
		if (err.innerHTML.length > 0)
			err.innerHTML = String.fromCharCode(160);
	}
	else
	{
		err.innerHTML = "<br/>" + msg + "<br/>";
	}
}

function validateForm(f) 
{
	errors = 0;
	err = document.getElementById("validationError");
	if (err)
	{
		err.innerHTML = "";
		err.className = "";
	}
		
	// Loop through every element in the form specified.
	for (i = 0; i < f.elements.length; i++)
	{
		fe = f.elements[i];

		if (fe.type.toLowerCase() == "text" || 
			fe.type.toLowerCase() == "textarea" || 
			fe.type.toLowerCase() == "password")
		{
			fe.style.background = "#ffffff";
			setError(fe, null);
			fe.value = trimWhitespace(fe.value)

			if (fe.getAttribute("required") && fe.value == '') 
			{
				fe.style.background = "#ffff99";
				setError(fe, "Required field.");
				errors++;
			}
         	else if (fe.getAttribute("maxlength") && 
				!isValidLength(fe.value, 0, fe.getAttribute("maxlength")))
			{
				fe.style.background = "#ffff99";
				setError(fe, "Field length exceeds maximum: " + 
					fe.getAttribute("maxlength"));
				errors++;
			}
         	else if (fe.getAttribute("minlength") && 
				!isValidLength(fe.value, fe.getAttribute("minlength"), 
				Number.MAX_VALUE))
			{
				fe.style.background = "#ffff99";
				setError(fe, "Field length does not meet the minimum: " + 
					fe.getAttribute("minlength"));
				errors++;
         	}
			else if ((fe.value != '') &&
				fe.getAttribute("pattern") && 
				!validateField(fe))
			{
				fe.style.background = "#ffff99";
				setError(fe, "Field violates pattern expected (" + 
					fe.getAttribute("pattern") + ")");
				errors++;
			}
		}
	}
	
	if (errors > 0) 
	{
		if (err)
		{
			err.className = "error";
			err.innerHTML = "<center>Please correct the highlighted fields.</center>";
		}
		else
		{
			alert("One or more fields are incomplete or have invalid content; the fields have been highlighted.");
		}

		return false;
	}

	return true;
}