(function($) {
  $.fn.thumbPopup = function(options)
  {
    //Combine the passed in options with the default settings
    settings = jQuery.extend({
      popupId: "thumbPopup",
      popupCSS: {'border': '2px solid #cccccc', 'background': '#FFFFFF'},
      imgSmallFlag: "_t",
      imgLargeFlag: "_l",
      cursorTopOffset: -370,
      cursorLeftOffset: -120,
      loadingHtml: "<span style='padding: 5px;'>Loading</span>"
    }, options);

    //Create our popup element
    popup =
    $("<div />")
    .css(settings.popupCSS)
    .attr("id", settings.popupId)
    .css("position", "absolute")
    .appendTo("body").hide();

    //Attach hover events that manage the popup
    $(this)
    .hover(setPopup)
    .mousemove(updatePopupPosition)
    .mouseout(hidePopup);


    function setPopup(event)
    {
      var fullImgURL = $(this).attr("src").replace(settings.imgSmallFlag, settings.imgLargeFlag);

      $(this).data("hovered", true);

      //Load full image in popup
      $("<img width='300px;'/>")
      .bind("load", {thumbImage: this}, function(event)
      {
        //Only display the larger image if the thumbnail is still being hovered
        if ($(event.data.thumbImage).data("hovered") == true) {
          $(popup).empty().append(this);
          updatePopupPosition(event);
          $(popup).show(300);
        }
        $(event.data.thumbImage).data("cached", true);
      })
      .attr("src", fullImgURL);

      //If no image has been loaded yet then place a loading message
      if ($(this).data("cached") != true) {
        $(popup).append($(settings.loadingHtml));
        $(popup).show(300);
      }

      updatePopupPosition(event);
    }

    function updatePopupPosition(event)
    {
      var windowSize = getWindowSize();
      var popupSize = getPopupSize();
      if (windowSize.width + windowSize.scrollLeft < event.pageX + popupSize.width + settings.cursorLeftOffset){
        $(popup).css("left", event.pageX - popupSize.width - settings.cursorLeftOffset);
      } else {
        $(popup).css("left", event.pageX + settings.cursorLeftOffset);
      }
      if (windowSize.height + windowSize.scrollTop < event.pageY + popupSize.height + settings.cursorTopOffset){
        $(popup).css("top", event.pageY - popupSize.height - settings.cursorTopOffset);
      } else {
        $(popup).css("top", event.pageY + settings.cursorTopOffset);
      }
    }

    function hidePopup(event)
    {
      $(this).data("hovered", false);
      $(popup).empty().hide();
    }

    function getWindowSize() {
      return {
        scrollLeft: $(window).scrollLeft(),
        scrollTop: $(window).scrollTop(),
        width: $(window).width(),
        height: $(window).height()
      };
    }

    function getPopupSize() {
      return {
        width: $(popup).width(),
        height: $(popup).height()
      };
    }

    //Return original selection for chaining
    return this;
  };
})(jQuery);