var fishData = new Object()
fishData.startDistanceH = new Array(100,0,0)
fishData.maxDistanceH = new Array(100,160,160)
fishData.moveDirectionH = new Array('L','R','R')
fishData.startDistanceV = new Array(45,0,0)
fishData.maxDistanceV = new Array(45,50,70)
fishData.moveDirectionV = new Array('U','D','D')
fishL = new Array()
fishR = new Array()

for(var i = 0; fishData.startDistanceH.length > i; i++) {
	fishL[i] = new Image()
	fishL[i].src = 'img/fish' + (i + 1) + '.L.gif'
	fishR[i] = new Image()
	fishR[i].src = 'img/fish' + (i + 1) + '.R.gif'
}

function moveFishes() {
	var f = document.getElementsByName('fish')
	for(var i = 0; f.length > i; i++) {
		f[i].distanceH += f[i].directionH == 'L' ? -1 : 1
		if(f[i].distanceH == 0) {
			f[i].directionH =  'R'
			f[i].src = f[i].src.replace(/L.gif/gi, 'R.gif')
		}
		if(f[i].distanceH == f[i].maxDistanceH) {
			f[i].directionH =  'L'
			f[i].src = f[i].src.replace(/R.gif/gi, 'L.gif')
		}
		f[i].distanceV += f[i].directionV == 'D' && f[i].maxDistanceV > f[i].distanceV ? 1 : (f[i].directionV == 'U' && f[i].distanceV > 0 ? -1 : 0)
		f[i].directionV = f[i].distanceV == f[i].maxDistanceV && rnd() > 98 ? 'U' : f[i].distanceV == 0 && rnd() > 98 ? 'D' :  f[i].directionV
		f[i].style.marginTop = f[i].distanceV
		f[i].style.marginLeft = f[i].distanceH
	}
}

function initFishes() {
	var f = document.getElementsByName('fish')
	for(var i = 0; f.length > i; i++) {
		f[i].distanceH = fishData.startDistanceH[i]
		f[i].maxDistanceH = fishData.maxDistanceH[i]
		f[i].directionH = fishData.moveDirectionH[i]
		f[i].style.marginLeft = f[i].distanceH
		f[i].distanceV = fishData.startDistanceV[i]
		f[i].maxDistanceV = fishData.maxDistanceV[i]
		f[i].directionV = fishData.moveDirectionV[i]
		f[i].style.marginTop = f[i].distanceV
		f[i].src = 'img/fish' + (i + 1) + '.' + f[i].directionH + '.gif'
		f[i].style.display = 'inline'
	}
	window.setInterval("moveFishes()", 40)
}

function rnd() {
	return(Math.ceil(Math.random()*100))
}

function modulo(cislo, modulo) {
	return((cislo/modulo) == Math.floor(cislo/modulo))
}