var nrWalls = 4;
function get_new_wall_html(n) {
	var txt = 'Length = <input type="text" name="wL_'+n+'" id="wL_'+n+'" value="15" size="3"/>  &nbsp; ' +
		'Height = <input type="text" name="wH_'+n+'" id="wH_'+n+'" value="9" size="3"/>  <br>';
	return txt;
}
function add_new_wall()
{
	nrWalls++;
	$('wallDimN').innerHTML += get_new_wall_html(nrWalls);
	return false;
}
function calculate()
{
	//now the big big momma
	var total = 0;
	var wt = 0, ct = 0, dt = 0, tt = 0;
	
	if($('isWalls').checked) {
		//add the walls surface
		//check for dims: wallDimRoom and wallDimWalls
		if($('wallDimRoom').checked) {
			// add the total room surface
			wt = 2 * parseInt($('rH').value) * ( parseInt($('rW').value) + parseInt($('rL').value) );
		}
		if($('wallDimWalls').checked) {
			for(i = 1; i <= nrWalls; i++) wt += $('wL_'+i).value * $('wH_'+i).value;
		}
	}
	if($('isCeilings').checked) {
		ct = $('cL').value * $('cW').value;
	}
	if($('isDoors').checked) {
		dt = $('nD').value * 22; 
	}
	if($('isTrim').checked) {
		tt += $('bbL').value * $('bbW').value / 12;
		tt += $('wtL').value * $('wtW').value / 12;
		tt += $('dtL').value * $('dtW').value / 12;
		tt += $('cmL').value * $('cmW').value / 12;
	}
	total = wt + ct + dt + tt;
	//alert("Grand Total="+total+" Walls="+wt+" Ceilings="+ct+" Doors="+dt+" Trims="+tt);
	$('wg').innerHTML = getGallons(wt);
	$('cg').innerHTML = getGallons(ct);
	$('dg').innerHTML = getGallons(dt);
	$('tg').innerHTML = getGallons(tt);
	$('ttg').innerHTML = getGallons(total);
}

function getGallons(sqft)
{
	var g = Math.floor(sqft / 360.0);
	var q = Math.ceil((sqft - g * 360) / 90.0 );
	if(q<0)	q=0;
	if(q==4) { q=0; g++; }
	var sg = '', sq = '';
	if(g > 0) sg += '<b>'+g+"</b> gallons";
	if(q > 0) sq = "<b>"+q+"</b> quarts";
	if(g > 0 && q > 0) return sg + " and " + sq;
	if(g > 0) return sg;
	if(q > 0) return sq;
	return '-'
}

function output()
{
   var txt='Amount of paint needed:<br>'+
	'for walls <b>'+dg+'</b> gallons and or  ------- quarts'+
	'for ceiling  ---------   gallons and or  ------- quarts'+
	'for doors      ---------  gallons and or  ------- quarts'+
	'for  trim      ---------  gallons and or  ------- quarts ';
}

function $(id)
{
	return document.getElementById(id);
}

function v(id)
{
	return document.getElementById(id).value;
}