// Assumptions
//   3 form select fields with id= "month", "day", and "year"
//
//

function updateDays()
{
	var i;
	var monthDays = [31,29,31,30,31,30,31,31,30,31,30,31];
	var monthSelect = document.getElementById("month");
	var daySelect = document.getElementById("day");
	var mIndex = monthSelect.selectedIndex-1;
	var days = monthDays[mIndex];
	
	daySelect.length = days+1;
	for (i=1; i <= days; i++)
	{
		daySelect.options[i].text = i;
		daySelect.options[i].value = i;
	}
}

function getFullYear(d)
{
	var y = d.getYear();
	if (y < 1000) y += 1900;
	return y;
}

function setYears()
{
	var i, j;
	var yearsBack = 60;
	var today = new Date();
	var thisYear = getFullYear(today);
	var firstYear = thisYear - yearsBack; //go back 60 years - should be enough
	var yearSelect = document.getElementById("year");
	
	yearSelect.length = yearsBack+2;
	j = thisYear;
	for ( i=1; i <= yearsBack+2; i++ )
	{
		yearSelect.options[i].text = j;
		yearSelect.options[i].value = j;
		j--;
	}
}


function isOldEnough(minYears)
{
	var today = new Date();
	
	var monthSelect = document.getElementById("month");
	var daySelect = document.getElementById("day");
	var yearSelect = document.getElementById("year");
	
	if (yearSelect.selectedIndex != 0 || monthSelect.selectedIndex != 0 && daySelect.selectedIndex != 0)
	{
		var birthYear = yearSelect.options[yearSelect.selectedIndex].value;
		var birthMonth = monthSelect.selectedIndex-1;
		var birthDay = daySelect.selectedIndex
	
		var years = getFullYear(today) - birthYear;
		var months = today.getMonth() - birthMonth;
		var days = today.getDate() - birthDay;
	
		if (days < 0) months--;
		if (months < 0) years--;
		if (years >= minYears) 
			return true;
	}
	return false;
}

function dropCookiePass(name)
{
	var expiresDate = new Date();
	expiresDate.setFullYear( getFullYear(expiresDate) + 1 ); // expires in a year
	document.cookie = name + "=true;expires=" + expiresDate.toString();
}

function dropCookieRestrict(name, expiresDate)
{
	document.cookie = name + "=false;expires=" + expiresDate.toString();
}

function cookieStore(name,  expiresDate)
{
	document.cookie = name + "=false;expires=" + expiresDate.toString();
}

function cookieExists(name)
{
	var allcookies = document.cookie;
	var pos = allcookies.indexOf(name);
	if (pos == -1)
		return false;
	else
		return true;
}	

function isRestricted(name)
{
	var allcookies = document.cookie;
	var key=name+"=";
	var start = allcookies.indexOf(key);
	var end;
	if (start != -1)
	{
		start += key.length;
		end = allcookies.indexOf(';', start);
		if (end == -1) end = allcookies.length;
		var cookieval = allcookies.substring(start, end);
		if (cookieval=="false")
			return true;
	}
	return false;
}	

function getExpirationDate(age)
{
	var today = new Date();
	
	var monthSelect = document.getElementById("month");
	var daySelect = document.getElementById("day");
	var yearSelect = document.getElementById("year");

	var birthYear = yearSelect.options[yearSelect.selectedIndex].value;
	var birthMonth = monthSelect.selectedIndex-1;
	var birthDay = daySelect.selectedIndex
	
	var years = getFullYear(today) - birthYear;
	var months = today.getMonth() - birthMonth;
	var days = today.getDate() - birthDay;
	
	if (days < 0) months--;
	if (months < 0) years--;
	
	var ofAgeDate = new Date()
	ofAgeDate.setDate(birthDay);
	ofAgeDate.setMonth(birthMonth);
	ofAgeDate.setFullYear(parseInt(birthYear) + (age - years));
	ofAgeDate.setHours(0);
	ofAgeDate.setMinutes(0);
	ofAgeDate.setSeconds(0);
	
	return ofAgeDate;
}


function isOfAge(age,name,denyPage)
{
	if (!isOldEnough(age))
	{
		dropCookieRestrict(name, getExpirationDate(age));
		location.href = denyPage;
		return false;
	}
	else
	{
		dropCookiePass(name);
		return true;
	}
}

function allFieldsSelected()
{
	var monthSelect = document.getElementById("month");
	var daySelect = document.getElementById("day");
	var yearSelect = document.getElementById("year");
	
	if (yearSelect.selectedIndex != 0 || monthSelect.selectedIndex != 0 && daySelect.selectedIndex != 0)
		return true;
	else
		return false;
}

// site specific age gate cookie check

var tag = "psiops";
function checkAge()
{
	if ( allFieldsSelected() )
	{
		return isOfAge(17,tag,"restricted.html");
	}
	alert ("All birth date fields must be selected");
	return false;
}

var url = document.URL.toString();
if (url.indexOf("site.php") != -1)
{
	if (cookieExists(tag))
	{
		if (isRestricted(tag))
		{
				location.href = 'restricted.html';
		}
	}
	else
	{
			location.href = 'index.html'; // go to age gate page
	}
}
else // index.html, or default url // if (url.indexOf("index.html") != -1)
{
	if (cookieExists(tag))
	{
		if (isRestricted(tag))
		{
				location.href = 'restricted.html';
		}
		else
		{
				location.href = 'site.php';
		}
	}
}