/* 
 * 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)
 * Dual licensed under the MIT (MIT-LICENSE.txt)
 * and GPL (GPL-LICENSE.txt) licenses.
 *
 *
 * 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(this.line_height == NaN)
          this.line_height = 0;
        
        // 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 (navigator.userAgent
                    .search(/MSIE/i) > -1)
            {
                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()))
                    {   
                        this.textarea.animate({height: (this.dummy.height() + this.line_height) + 'px'}, 100);  
                    }
                }
            }
        }
                         
     });
})(jQuery);
