/*
    Spinner provides a simple approach for adding and removing a preloader
    for your web applications. Usage is as simple as calling $('elem').spinner() and
    subsequently $('elem').spinner.remove(). You may create your own preloader
    at http://www.ajaxload.info. Please note that if you use a custom preloader,
    you must pass in the new height and width as options.
    
    Copyright (C) 2010 Corey Ballou
    Website: http://www.jqueryin.com
    Documentation: http://www.jqueryin.com/projects/spinner-jquery-preloader-plugin/

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
(function($) {
   $.fn.spinner = function(options) {
      var opts = $.extend({}, $.fn.spinner.defaults, options);

      return this.each(function() {
         var l = 0, t = 0, w = 0, h = 0, shim = 0, $s;
         var $this = $(this);

         // removal handling
         if (options == 'remove' || options == 'close') {
            var $s = $this.data('spinner');
            var o = $this.data('opts');
            if (typeof $s != 'undefined') {
               $s.remove();
               $this.removeData('spinner').removeData('opts');
               if (o.hide) $this.css('visibility', 'visible');
               o.onFinish.call(this);
               return;
            }
         }

         // retrieve element positioning
         var pos = $this.offset();
         w = $this.outerWidth();
         h = $this.outerHeight();

         // calculate vertical centering
         if (h > opts.height) shim = Math.round((h - opts.height) / 2);
         else if (h < opts.height) shim = 0 - Math.round((opts.height - h) / 2);
         t = pos.top + shim + 'px';

         // calculate horizontal positioning
         if (opts.position == 'right') {
            l = pos.left + w + 10 + 'px';
         } else if (opts.position == 'left') {
            l = pos.left - opts.width - 10 + 'px';
         } else {
            l = pos.left + Math.round(.5 * w) - Math.round(.5 * opts.width) + 'px';
         }

         // call start callback
         opts.onStart.call(this);

         // hide element?
         if (opts.hide) $this.css('visibility', 'hidden');

         // create the spinner and attach
         $s = $('<img src="' + opts.img + '" style="position: absolute; left: ' + l + '; top: ' + t + '; width: ' + opts.width + 'px; height: ' + opts.height + 'px; z-index: ' + opts.zIndex + ';" />').appendTo('body');

         // removal handling
         $this.data('spinner', $s).data('opts', opts);
      });
   };

   // default spinner options
   $.fn.spinner.defaults = {
      position: 'right'       // left, right, center
        , img: 'spinner.gif' // path to spinner img
        , height: 16            // height of spinner img
        , width: 16            // width of spinner img
        , zIndex: 1001          // z-index of spinner
        , hide: false         // whether to hide the elem
        , onStart: function() { } // start callback
        , onFinish: function() { } // end callback
   };
})(jQuery);