var uploadHandlerManager = function(spec)
{
   var name = spec.inputName;
   var file_size_limit = spec.fileSizeLimit;
   var btn_background_selector = spec.buttonElementSelector || 'div.file-upload-wrapper';
//   var status_ele_selector = "#"+name+"-status";
   var status_ele_selector = "#"+name.replace('_','-')+"-status";
   var filename_input_name = name+'_filename'; // pdf_upload_name

   var showError = function(msg)
   {
      var error_obj = {};
      error_obj[filename_input_name] = msg;
      show_errors(error_obj);
   };

   var uploadButtonImage = function()
   {
      var orig = null;
      var btn_background_ele = $(btn_background_selector);
      log2console('btn_background_selector', btn_background_selector);
      log2console('btn_background_ele', btn_background_ele);

      var setBackground = function(st){btn_background_ele.css('background',st)};
      //  restoring the background in IE doesn't work
      if ($.browser.msie)
         return(
         {
            setWaitState: function(){},
            setNormalState: function(){}
         });
      
      return(
         {
            setWaitState: function() {
               log2console('about to setWaitState');
               if(orig == null)
                  orig = btn_background_ele.css('background');
               setBackground('url(images/choose_file_wait_btn.gif) no-repeat');
            },
            setNormalState: function(){
               setBackground(orig);
            }
         });
   }();

   return({
      onErrorHandler : function(event, queueID, fileObj, errorObj)
      {
         var msg = '';
         if (errorObj.type ==="File Size")
         {
            msg = "Your uploaded file size ("+bytesToKB(fileObj.size)+"KB) exceeds the maximum size allowed of "+bytesToKB(file_size_limit)+"KB";
         }
         else
         {
            //log2console(errorObj);
            msg = "Sorry, your file wasn't uploaded.";
         }
         showError(msg);
         uploadButtonImage.setNormalState();
      },
      onSelectOnce : function(event, queueID, fileObj)
      {
         uploadButtonImage.setWaitState();
         showError(" ");
         $(status_ele_selector).html(" ");
      },
      onCompleteHandler : function(event, queueID, fileObj, response, data)
      {
         uploadButtonImage.setNormalState();
         log2console('response', response);
         var resobj = $.parseJSON(response)
         //eval( "resobj={}&&"+response);

         showError("");
         $("input[name="+name+"_filename]").val(fileObj.name).hide().attr('disabled', false);
//         var status_ele_selector = "#"+name+"-status";
         var status_ele_selector = "#"+name.replace('_','-')+"-status";
          if (resobj.err!=undefined)
          {
              $(status_ele_selector).html("");
              showError(resobj.err);
              return true;
          }
         $("input[name="+name+"_guid]").val(resobj.url);
         var fileSizeInKB = bytesToKB(fileObj.size);
         $(status_ele_selector).html("Uploaded <b>"+fileObj.name+"</b> ("+fileSizeInKB+" KB)");
         return true;
      }

   });
   
};

var bytesToKB = function(bytes)
{
   if (typeof bytes == 'string')
      bytes = parseInt(bytes);
   return Math.round((bytes / 1024 * 100000) / 100000);
}