// main function to process the fade request //

function colorFadeByReference(domReference,element,start,end,reverse,steps,speed) {
  var startrgb,endrgb,er,eg,eb,step,rint,gint,bint,step;
  var target = domReference;
  steps = steps || 20;
  speed = speed || 20;  
  clearInterval(target.timer);
  endrgb = colorConv(end);
  er = endrgb[0];
  eg = endrgb[1];
  eb = endrgb[2];
  if(!target.r) {
    startrgb = colorConv(start);
    r = startrgb[0];
    g = startrgb[1];
    b = startrgb[2];
    target.r = r;
    target.g = g;
    target.b = b;
  }
  rint = Math.round(Math.abs(target.r-er)/steps);
  gint = Math.round(Math.abs(target.g-eg)/steps);
  bint = Math.round(Math.abs(target.b-eb)/steps);
  if(rint == 0) { rint = 1 }
  if(gint == 0) { gint = 1 }
  if(bint == 0) { bint = 1 }
  target.step = 1;
  target.timer = setInterval( function() { animateColorByReference(domReference,element,steps,er,eg,eb,rint,gint,bint,reverse)}, speed);
}
function colorFade(id,element,start,end,reverse,steps,speed) {
	colorFadeByReference(document.getElementById(id),element,start,end,reverse,steps,speed);
}

function animateColorByReference(domReference,element,steps,er,eg,eb,rint,gint,bint,reverse) {
	  var target = domReference;
	  var color;
	  if(target.step <= steps) {
	    var r = target.r;
	    var g = target.g;
	    var b = target.b;
	    if(r >= er) {
	      r = r - rint;
	    } else {
	      r = parseInt(r) + parseInt(rint);
	    }
	    if(g >= eg) {
	      g = g - gint;
	    } else {
	      g = parseInt(g) + parseInt(gint);
	    }
	    if(b >= eb) {
	      b = b - bint;
	    } else {
	      b = parseInt(b) + parseInt(bint);
	    }
	    color = 'rgb(' + r + ',' + g + ',' + b + ')';
	    if(element == 'background') {
	      target.style.backgroundColor = color;
	    } else if(element == 'border') {
	      target.style.borderColor = color;
	    } else {
	      target.style.color = color;
	    }
	    target.r = r;
	    target.g = g;
	    target.b = b;
	    target.step = target.step + 1;
	  } else {
		  if(reverse){
			  colorFadeByReference(domReference,element,'003c6b','FFFFFF',false,steps);		  
		 }
		  else{
		    clearInterval(target.timer);
		    color = 'rgb(' + er + ',' + eg + ',' + eb + ')';
		    if(element == 'background') {
		      target.style.backgroundColor = color;
		    } else if(element == 'border') {
		      target.style.borderColor = color;
		    } else {
		      target.style.color = color;
		    }
		  }
	  }
}

// incrementally close the gap between the two colors //
function animateColor(id,element,steps,er,eg,eb,rint,gint,bint,reverse) {
	animateColorByReference(document.getElementById(id),element,steps,er,eg,eb,rint,gint,bint,reverse);
}

// convert the color to rgb from hex //
function colorConv(color) {
  var rgb = [parseInt(color.substring(0,2),16), 
    parseInt(color.substring(2,4),16), 
    parseInt(color.substring(4,6),16)];
  return rgb;
}