/* 
 * 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)
 * Copyright (c) 2009 Miles Nordin <carton@Ivy.NET>
 * Licensed under GPL (gpl.txt)
 *
 *
 * 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);
		
		this.blur_callback		= this.options.blur_callback;
		this.focus_callback		= this.options.focus_callback;
		
		if (isNaN(this.line_height))
		{
			this.line_height = 0;
		}
		
		if (isNaN(this.min_height) || this.min_height == 0)
		{
			this.min_height == this.textarea.height();	
		}
		  
	
		
		// 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(0, true);
		},
						 
		startExpand: function() {				
		  	var self = this;
			// while focused, leave an extra line.  The cursor can never actually reach 
			// this extra line, but it makes the gesture for select-all much easier to perform
			// (or, _possible_ to perform, if the last line is overflow-x-hidden)
			this.checkExpand(this.line_height, true);
			this.interval = window.setInterval(function() {self.checkExpand(self.line_height, false)}, 400);
			if(this.focus_callback!=null) this.focus_callback(this.textarea);		
		},
		
		stopExpand: function() {
			clearInterval(this.interval);	
			this.checkExpand(0, true);
			if(this.blur_callback!=null) this.blur_callback(this.textarea);
		},
		
		checkExpand: function(extraspace, forcecheck) {
			extraspace = 0;
			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');
			}
			
			// textarea -> div
			// textarea rules are unique.  it's not the same as <pre> because it word-wraps, 
			// but it does not condense spaces like html.
			// dot at the end is to make sure we leave room for the cursor, if the cursor is on a blank line
			var html = this.textarea.val().toString().replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/^ /, '&nbsp;').replace(/  /g, ' &nbsp;') + ".";
			
			// IE is different, as per usual
			if ($.browser.msie)
			{
				html = html.replace(/\n/g, '<BR>');
			}
			else
			{
				html = html.replace(/\n/g, '<br>');
			}
			
			if (forcecheck || this.dummy.html() != html)
			{
				this.dummy.html(html);	
				
				if (this.max_height > 0 && (this.dummy.height() + extraspace + 1 > this.max_height))
				{
					this.textarea.css('overflow-y', 'auto');	
				}
				else
				{
					this.textarea.css('overflow-y', 'hidden');
					if (this.textarea.height() != this.dummy.height() + extraspace + 1)
					{	
						this.textarea.animate({height: (this.dummy.height() + extraspace + 1) + 'px'}, 100);	
					}
				}
			}
		}
						 
	 });
})(jQuery);