// Definitions
posx = new Array();
posy = new Array();
speedx = Math.random() * maxstepx;
speedy = new Array();
active = new Array();
actives = snowflakes;

maxwidth = window.innerWidth;
maxheight = window.innerHeight;
if (!maxwidth) {
	maxwidth = document.documentElement.clientWidth;
	maxheight = document.documentElement.clientHeight;
}
if (!maxwidth) {
	maxwidth = document.body.clientWidth;
	maxheight = document.body.clientHeight;
}

flakesize = 40; // biggest flake

// Create some position + movement data
for (i = 0; i < snowflakes; i++) {
	// starting position
	posy[i] = Math.random() * maxheight;
	posx[i] = maxwidth / snowflakes * i;
	// movement
	speedy[i] = 2 + Math.random() * (maxstepy - 2);
	active[i] = true;
}


window.onload=function(){
	currentTime = new Date();
	endtime = currentTime.getTime() + maxtime;
	snow(endtime);
}

function snow(endtime) {
	currentTime = new Date();
	for (i = 0; i < snowflakes; i++) {
		if (active[i] === true) {
			posy[i] = posy[i] + speedy[i];
			posx[i] = posx[i] + speedx;
			// wind effect
			if (Math.random() > 0.99) {
				if (speedx < 2 && speedx > -2) {
					speedx = - maxstepx +  Math.random() * maxstepx * 2;
				}
			}
			// wind effect diminishes with time
			if (speedx > 0) {
				if (Math.random() > 0.9) {
					speedx = speedx / 1.2;
				}
			}
			else if (speedx < 0) {
				if (Math.random() > 0.9) {
					speedx = speedx / 1.1;
				}
			}
			// move flakes when they reach a limit
			if (posy[i] > maxheight ) {
				posx[i] = Math.random() * maxwidth;
				posy[i] = - Math.random() * maxheight / 2;
				if (currentTime.getTime() > endtime) {
					active[i] = false;
					posy[i] = -100;
					actives--;
				}
			}
			if (posx[i] > maxwidth + flakesize) {
				posx[i] = -flakesize ;
				//posy[i] = maxheight - Math.random() * maxheight;
			}
			else if (posx[i] < - flakesize ) {
				posx[i] = maxwidth + flakesize;
				//posy[i] = maxheight - Math.random() * maxheight;
			}
			document.getElementById(i).style.top=posy[i] + "px";
			document.getElementById(i).style.left=posx[i] + "px";
		}
	}
	// TODO: don't repeat if time  is over + no flakes are left
	if (actives > 0) {
		window.setTimeout("snow(endtime)", timeout);
	}
}