/**
 * Rotates the background color
 */
// Declare the namespace
var Rotator = {};

// Seconds to hold before switching
Rotator.delay=5;
// Colors to rotate through, 
// The starting color set in HTML or CSS should be at the end of this list 
Rotator.colors=[
            "FF66CC",
            "33CCFF",
            "00CC99",
            "FFFF33",
            "99FF33",
            "CC00CC",
            "FF6666",
            "CCFF00"
            ];

//*** Internal variables ***// 
Rotator.current;

Rotator.init = function() {
	this.current=this.colors.length-1;
	setInterval("Rotator.rotate()", this.delay*1000 );
};

Rotator.rotate = function(){
	var oldColor=this.colors[this.current];
	this.current=(this.current<this.colors.length-1)?this.current+1:0;
	var newColor=this.colors[this.current];
	
	//Rotator.switchColor(newColor);
	Rotator.fade("home_page","background",oldColor,newColor,20,25);
};

Rotator.switchColor = function(color){
	document.getElementById("home_page").style.backgroundColor="#"+color;
};

/**
 * Based on http://www.scriptiny.com/2008/05/javascript-color-fading-script/
 */
Rotator.fade = function(id,element,start,end,steps,speed) {
	  var startrgb,endrgb,er,eg,eb,step,rint,gint,bint,step;
	  var target = document.getElementById(id);
	  steps = steps || 20;
	  speed = speed || 20;
	  clearInterval(target.timer);
	  endrgb = Rotator.colorConv(end);
	  er = endrgb[0];
	  eg = endrgb[1];
	  eb = endrgb[2];
	  if(!target.r) {
	    startrgb = Rotator.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() { Rotator.animateColor(id,element,steps,er,eg,eb,rint,gint,bint) }, speed);
	};

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

	


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