var listaAtual = 0;
var lista = null;

function setOpacity(obj, valor){
	if (navigator.userAgent.indexOf("MSIE") >= 0){
		obj.style.filter = "alpha(opacity=" + (valor * 100) + ")";
	}else{
		obj.style.opacity = valor;
		obj.style.MozOpacity = valor;
	}
}

function getOpacity(obj){
	if (obj.style.opacity){
		return parseFloat(obj.style.opacity);
	}else if(obj.style.MozOpacity){
		return parseFloat(obj.style.MozOpacity);
	}else if(navigator.userAgent.indexOf("MSIE") >= 0){
		if (obj.style.filter != ""){
			return parseInt(obj.style.filter.replace("alpha(opacity=", ""))/100;
		}
	}
	// Caso não retorne nada acima, é pq a opacidade não foi definida
	return 1;
}
function fadeIn(obj, esp, dif, fim){
	if (!obj.__fade) obj.__fade = "in";
	if (obj.__fade != "in") return;
	if (getOpacity(obj) > 0){
		var nOp = getOpacity(obj) - dif;
		if (nOp < 0) nOp = 0;
		setOpacity(obj, nOp);
		setTimeout(function(){fadeIn(obj, esp, dif, fim)}, esp);
	}else{
		obj.__fade = false;
		if (fim != null) setTimeout(fim,0);
	}
}
function fadeOut(obj, esp, dif, fim){
	if (!obj.__fade) obj.__fade = "out";
	if (obj.__fade != "out") return;
	if (parseFloat(getOpacity(obj)) < 1){
		var nOp = getOpacity(obj) + dif;
		if (nOp > 1) nOp = 1;
		setOpacity(obj, nOp);
		setTimeout(function(){fadeOut(obj, esp, dif, fim)}, esp);
	}else{
		obj.__fade = false;
		if (fim != null) setTimeout(fim,0);
	}
}

function desabilitaBtns(){
	var ant = document.getElementById("exibe-proj-ant");
	var prox = document.getElementById("exibe-proj-prox");
	
	if (listaAtual == 0){
		if (ant.className.indexOf(" disabled") == -1) ant.className += " disabled";
		//else alert("Início da lista");
	}else if (ant.className.indexOf(" disabled") != -1){
		ant.className = ant.className.replace(" disabled", "");
	}
	
	if (listaAtual >= lista.length - 1){
		if (prox.className.indexOf(" disabled") == -1) prox.className += " disabled";
		//else alert("Fim da lista");
	}else if (prox.className.indexOf(" disabled") != -1){
		prox.className = prox.className.replace(" disabled", "");
	}
}

function alteraPara(i){
	var fim = function(){
		lista[i].style.display = 'block';
		lista[listaAtual].style.display = 'none';
		listaAtual = i;
		setOpacity(lista[i].getElementsByTagName("img")[0], 0);
		fadeOut(lista[i].getElementsByTagName("img")[0], 80, 0.2, null);
	}
	setOpacity(lista[listaAtual].getElementsByTagName("img")[0], 1);
	fadeIn(lista[listaAtual].getElementsByTagName("img")[0], 80, 0.2, fim);
}
function criaPaginacao(){
var pf = document.getElementById("portifolio-exibe");
var pg = '<ul class="pag">';
pg += '<li><a href="#" class="anterior" id="exibe-proj-ant">Anterior</a></li>';
pg += '<li><a href="#" class="proximo" id="exibe-proj-prox">Pr&oacute;ximo</a></li>';
pf.innerHTML += pg + '</ul>';
}
window.onload = function(){
	criaPaginacao();
	lista = document.getElementById("portifolio-exibe").getElementsByTagName("ul")[0].getElementsByTagName("li");
	for(var i = 1; i < lista.length; i++){
		lista[i].style.display = "none";
	}
	
	document.getElementById("exibe-proj-prox").onclick = function(){
		if (listaAtual + 1 <= lista.length - 1){
			//lista[listaAtual].style.display = "none";
			//lista[++listaAtual].style.display = "block";
			alteraPara(listaAtual + 1);
		}else{
			//lista[listaAtual].style.display = "none";
			//lista[(listaAtual = 0)].style.display = "block";
			alteraPara(0);
		}
		desabilitaBtns();
		return false;
	}
	document.getElementById("exibe-proj-ant").onclick = function(){
		if (listaAtual - 1 >= 0){
			//lista[listaAtual].style.display = "none";
			//lista[--listaAtual].style.display = "block";
			alteraPara(listaAtual - 1);
		}else{
			//lista[listaAtual].style.display = "none";
			//lista[(listaAtual = lista.length - 1)].style.display = "block";			
			alteraPara(lista.length - 1);
		}
		desabilitaBtns();
		return false;
	}
	desabilitaBtns();
}