/**
 * Input field validation for the send to a friend page
 */
function sendToFriendCheck(form){
	var valid = true;
	var errorText = "The following fields are missing and are required:\n\n";
	var email;
	var email2;
	// Validate all text fields
	var fields = form.getElementsByTagName("input");
	for (i=0; i<fields.length; i++) {
		var field = fields[i];
		if (field.type == "text") {
			if (field.name == "to") {
				email = field;
			} else if (field.name == "from") {
				email2 = field;
			}
			if (!field.value) {
				errorText += "\t* " + field.name + "\n";
				valid = false;
			}
		}
	}
	// Validate email
	if (valid) {
		valid = emailCheck(email.value);
	}
	if (valid) {
		valid = emailCheck(email2.value);
	}
	// Display errors if any
	if(!valid && errorText.length > 52){
		alert(errorText);
	}
	return valid;
}

/**
 * Input field validation for the partners page
 */
function partnerCheck(form){
	var valid = true;
	var errorText = "The following fields are missing and are required:\n\n";
	var email;
	// Validate all text fields
	var fields = form.getElementsByTagName("input");
	for (i=0; i<fields.length; i++) {
		var field = fields[i];
		if (field.type == "text") {
			if (field.name == "Email") {
				email = field;
			}
			if (field.name == "YourSite") {
				if(!field.value || field.value == "http://") {
					errorText += "\t* " + field.name + "\n";
					valid = false;
				}
			} else {
				if (!field.value) {
					errorText += "\t* " + field.name + "\n";
					valid = false;
				}
			}
		}
	}
	// Validate textareas
	fields = form.getElementsByTagName("textarea");
	for (i=0; i<fields.length; i++) {
		var field = fields[i];
		if(!field.value) {
			errorText += "\t* " + field.name + "\n";
			valid = false;
		}	
	}
	// Validate email
	if (valid) {
		valid = emailCheck(email.value);
	}
	// Display errors if any
	if(!valid){
		alert(errorText);
	}
	return valid;
}

/**
 *	Utility function to validate correct email address format
 */
function emailCheck (emailStr) {
	var checkTLD=1;
	var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
	var emailPat=/^(.+)@(.+)$/;
	var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
	var validChars="\[^\\s" + specialChars + "\]";
	var quotedUser="(\"[^\"]*\")";
	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
	var atom=validChars + '+';
	var word="(" + atom + "|" + quotedUser + ")";
	var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
	var matchArray=emailStr.match(emailPat);

	if (matchArray==null) {
		alert("Email address seems incorrect (check @ and .'s)");
		return false;
	}

	var user=matchArray[1];
	var domain=matchArray[2];

	for (i=0; i<user.length; i++) {
		if (user.charCodeAt(i)>127) {
			alert("Ths username contains invalid characters.");
			return false;
		}
	}

	for (i=0; i<domain.length; i++) {
		if (domain.charCodeAt(i)>127) {
			alert("Ths domain name contains invalid characters.");
			return false;
	   }
	}

	if (user.match(userPat)==null) {
		alert("The username doesn't seem to be valid.");
		return false;
	}

	var IPArray=domain.match(ipDomainPat);

	if (IPArray!=null) {
		for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) {
				alert("Destination IP address is invalid!");
				return false;
	   	}
		}
		return true;
	}

	var atomPat=new RegExp("^" + atom + "$");
	var domArr=domain.split(".");
	var len=domArr.length;

	for (i=0;i<len;i++) {
		if (domArr[i].search(atomPat)==-1) {
			alert("The domain name does not seem to be valid.");
			return false;
	   }
	}

	if (checkTLD && domArr[domArr.length-1].length!=2 && domArr[domArr.length-1].search(knownDomsPat)==-1) {
		alert("The email address must end in a well-known domain or two letter " + "country.");
		return false;
	}

	if (len<2) {
		alert("This email address is missing a hostname!");
		return false;
	}

	return true;
}