/*
Check that a string is a valid email

Metode: emailCheck (ssn,answer)
Inputs:
	emailStr: string with email adress

Returns: 
	True hvis epost er korrekt, False hvis strengen ikke inneholder en gyldig epost adresse
	
Remarks:
	ingen
*/

function emailCheck (emailStr) {
	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) { return false; }

	var user=matchArray[1];
	var domain=matchArray[2];
	if (user.match(userPat)==null) { return false; }

	var IPArray=domain.match(ipDomainPat)
	if (IPArray!=null) {
		// this is an IP address
		for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) { return false; }
		}
		return true;
	}

	var domainArray=domain.match(domainPat)
	if (domainArray==null) { return false; }

	var atomPat=new RegExp(atom,"g");
	var domArr=domain.match(atomPat);
	var len=domArr.length;
	if (domArr[domArr.length-1].length<2 || domArr[domArr.length-1].length>3) { return false; }
	if (len<2) { return false; }
	
	return true;
}