s3_direct_upload with preview and delete

gistfile1.txt

add: (e, data) ->
        file = data.files[0]
        r = new FileReader()
        r.onload = (e) ->
          file.result = e.target.result
        r.readAsDataURL(file)
        file.unique_id = Math.random().toString(36).substr(2,16)

        unless settings.before_add and not settings.before_add(file)
          current_files.push data
          if $('#template-upload').length > 0
            data.context = $($.trim(tmpl("template-upload", file)))
            node = $(data.context).appendTo(settings.progress_bar_target || $uploadForm)
            $(data.context).find(".delete").click (e) ->
              e.preventDefault()
              for i in [0...forms_for_submit.length] by 1
                if this.parentElement.id == forms_for_submit[i].context[0].id
                  forms_for_submit.splice(i,1)
                  current_files.splice(i,1)
                  break
              this.parentElement.remove()
            $(data.context).find(".preview").on "click mouseover", (e) ->
              $(".upload.active").removeClass('active')
              for i in [0...forms_for_submit.length] by 1
                if $(this).closest(".upload")[0].id == forms_for_submit[i].context[0].id
                  $(".fileinput-preview img").attr("src", forms_for_submit[i].files[0].result)
                  $(this).closest(".upload").addClass('active')
                  break
          else if !settings.allow_multiple_files
            data.context = settings.progress_bar_target
          if settings.click_submit_target
            if settings.allow_multiple_files
              forms_for_submit.push data
            else
              forms_for_submit = [data]
          else
            data.submit()