var selectedViewNumber = 1;
var imageList;
var imgtoshow;
var firstViewable = 1;

$(document).ready(function() {
    if (imageList > 1) { $("#mainImage").hover(function() { arrowControl("show"); }, function() { arrowControl("hide"); }) }
    else if (imageList == 1) { $("#thumbshold").addClass("single-image"); }
    else { $("#thumbshold").addClass("no-images"); $(".image-alert").css("display", "block") }
    $("#vimage_next").click(function() { switchImage("forward", 1); });
    $("#vimage_prev").click(function() { if (firstViewable == 1) { switchImage("backward", 1); } return false; });
    $("#thumbs img").click(function() { switchFromThumb($(this)); });
    if (imageList > 3) {
        $("#thumbnext, #thumbprev").css("visibility", "visible");
        $("#thumbnext").click(function() { scrollThumbs("next"); });
        $("#thumbprev").click(function() { scrollThumbs("prev"); });
    }

});
function arrowControl(toDo) {
    if (toDo == "show") {
        $("#vimage_prev, #vimage_next").css("display", "block");
    if (selectedViewNumber == 1) {$("#vimage_prev").css("display", "none");}else if (selectedViewNumber == imageList) {$("#vimage_next").css("display", "none");}
} else { $("#vimage_prev, #vimage_next").css("display", "none"); }
}
function switchImage(toGo, notojump) {
    if (toGo == "forward") {
        imgtoshow = Number(selectedViewNumber) + Number(notojump);
    }else if(toGo == "backward"){ imgtoshow = Number(selectedViewNumber) - Number(notojump);
    }
    $("#big").attr("src", $("#big").attr("src").replace("_" + selectedViewNumber + "_c.jpg", "_" + imgtoshow + "_c.jpg"));
    selectedViewNumber = imgtoshow;
    arrowControl("show");
}
function switchFromThumb(imginfo) {
    var timgno = GetSelectedImgIndex(imginfo.attr("src")); //imginfo.attr("src").slice(-5, -4);
    $("#big").attr("src", $("#big").attr("src").replace("_" + selectedViewNumber + "_c.jpg", "_" + timgno + "_c.jpg"));
    selectedViewNumber = timgno;
}
function scrollThumbs(toGo) {
    $("#thumbnext, #thumbprev").removeClass("disabled");
    if (toGo == "next") {
        if ((Number(firstViewable) + Number('2')) == imageList) { $("#thumbnext").addClass("disabled"); return false; }
        if ((Number(firstViewable) + Number('3')) == imageList) { $("#thumbnext").addClass("disabled"); }
    toHide = Number(firstViewable);
    toShow = Number(firstViewable) + Number('3');
    firstViewable = Number(firstViewable) + Number('1'); 
    }else{
    if (firstViewable == 1) { $("#thumbprev").addClass("disabled"); return false; };
    if ((Number(firstViewable) - Number('1')) == 1) { $("#thumbprev").addClass("disabled"); };
    toHide = Number(firstViewable) + Number('2');
    toShow = Number(firstViewable) - Number('1');
    firstViewable = toShow;
    }
    $("#thumbs img:nth-child(" + toShow + ")").css("display", "block");
    $("#thumbs img:nth-child(" + toHide + ")").css("display", "none");
}

function GetSelectedImgIndex(url) {
    var matches = url.match(/_\d+_/g);
    return matches[matches.length - 1].slice(1,2);
}