$(document).ready(function() {
  var thumbs = $("#thumbs .thumbnail");
  if (!thumbs.length) return;
  var num = thumbs.length;
  var idx = -1;

  function zoom(elem) {
    elem.focus();
    idx = parseInt(elem.id.match(/\d+$/), 10) - 1;

    thumbs.removeClass("active");
    $("#bigimg img").get(0).src = elem.href;
    $(elem).addClass("active");

    $("#prevnext button").attr("disabled", true).removeClass("active");
    if (idx > 0) $("#prevnext .prev").attr("disabled", false).addClass("active");
    if (idx < num - 1) $("#prevnext .next").attr("disabled", false).addClass("active");
  }

  thumbs
    .blur(function() { $(this).removeClass("focus") })
    .focus(function() { $(this).addClass("focus") })
    .click(function() { zoom(this); return false });

  $("#prevnext .prev").attr("disabled", true).removeClass("active").click(function() {
    zoom(thumbs.get(idx - 1));
  });
  $("#prevnext .next").addClass("active").click(function() {
    zoom(thumbs.get(idx + 1));
  });

  if (document.location.hash) {
    zoom(thumbs.get(parseInt(document.location.hash.substr(2), 10) - 1));
  } else {
    zoom(thumbs.get(0));
  }

});