/* 
 * Auto Expanding Text Area (1.2.2)
 * by Chrys Bader (www.chrysbader.com)
 * chrysb@gmail.com
 *
 * Special thanks to:
 * Jake Chapa - jake@hybridstudio.com
 * John Resig - jeresig@gmail.com
 *
 * Copyright (c) 2008 Chrys Bader (www.chrysbader.com)
 * Licensed under the GPL (GPL-LICENSE.txt) license. 
 *
 *
 * NOTE: This script requires jQuery to work.  Download jQuery at www.jquery.com
 *
 */
 
(function(jQuery) {
      
  var self = null;
 
  jQuery.fn.autogrow = function(o)
  { 
    return this.each(function() {
      new jQuery.autogrow(this, o);
    });
  };
  

    /**
     * The autogrow object.
     *
     * @constructor
     * @name jQuery.autogrow
     * @param Object e The textarea to create the autogrow for.
     * @param Hash o A set of key/value pairs to set as configuration properties.
     * @cat Plugins/autogrow
     */
  
  jQuery.autogrow = function (e, o)
  {
    this.options        = o || {};
    this.dummy          = null;
    this.interval       = null;
    this.line_height      = this.options.lineHeight || parseInt(jQuery(e).css('line-height'));
    this.min_height       = this.options.minHeight || parseInt(jQuery(e).css('min-height'));
    this.max_height       = this.options.maxHeight || parseInt(jQuery(e).css('max-height'));;
    this.textarea       = jQuery(e);

    if (isNaN(this.line_height)) {
      this.line_height = 14;
    }
      
    
    // Only one textarea activated at a time, the one being used
    this.init();
  };
  
  jQuery.autogrow.fn = jQuery.autogrow.prototype = {
    autogrow: '1.2.2'
  };
  
  jQuery.autogrow.fn.extend = jQuery.autogrow.extend = jQuery.extend;
  
  jQuery.autogrow.fn.extend({
             
    init: function() {      
      var self = this;      
      this.textarea.css({overflow: 'hidden', display: 'block'});
      this.textarea.bind('focus', function() { self.startExpand() } ).bind('blur', function() { self.stopExpand() });
      this.checkExpand(); 
    },
             
    startExpand: function() {       
      var self = this;
      this.interval = window.setInterval(function() {self.checkExpand()}, 400);
    },
    
    stopExpand: function() {
      clearInterval(this.interval); 
    },
    
    checkExpand: function() {
      if (this.dummy == null)
      {
        this.dummy = jQuery('<div></div>');
        this.dummy.css({
                        'font-size'  : this.textarea.css('font-size'),
                        'font-family': this.textarea.css('font-family'),
                        'width'      : this.textarea.css('width'),
                        'padding'    : this.textarea.css('padding'),
                        'line-height': this.line_height + 'px',
                        'overflow-x' : 'hidden',
                        'position'   : 'absolute',
                        'top'        : 0,
                        'left'     : -9999
                        }).appendTo('body');
      }
      
      // Strip HTML tags
      var html = this.textarea.val().replace(/(<|>)/g, '');
      
      // IE is different, as per usual
      if ($.browser.msie)
      {
        html = html.replace(/\n/g, '<BR>new');
      }
      else
      {
        html = html.replace(/\n/g, '<br>new');
      }
      
      if (this.dummy.html() != html)
      {
        this.dummy.html(html);  
        
        if (this.max_height > 0 && (this.dummy.height() + this.line_height > this.max_height))
        {
          this.textarea.css('overflow-y', 'auto');  
        }
        else
        {
          this.textarea.css('overflow-y', 'hidden');
          if (this.textarea.height() < (this.dummy.height() + this.line_height) || (this.dummy.height() < this.textarea.height()))
          { 
            if (this.dummy.height() + this.line_height > parseInt(this.min_height)) {
              this.textarea.animate({height: (this.dummy.height() + this.line_height) + 'px'}, 100);  
            }
          }
        }
      }
    }
             
   });
})(jQuery);