/*
 * jQuery autoResize (textarea auto-resizer)
 * @copyright James Padolsey http://james.padolsey.com
 * @version 1.04
 */

(function($){

    $.fn.autoResize = function(options) {
        if (!$(this).hasClass('resize-init')) {          

            // Just some abstracted details,
            // to make plugin users happy:
            var settings = $.extend({
                onResize : function(){},
                animate : true,
                animateDuration : 300,
                animateCallback : function(){},
                extraSpace : 20,
                limit: 1000,
                minHeight: 159
            }, options);

            // Only textarea's auto-resize:
            this.find('textarea').each(function(){

                // Get rid of scrollbars and disable WebKit resizing:
                var textarea = $(this).css({
                    resize:'none',
                    'overflow-y':'hidden'
                }),

                // Cache original height, for use later:
                origHeight = textarea.height(),

                // Need clone of textarea, hidden off screen:
                clone = (function(){

                    // Properties which may effect space taken up by chracters:
                    var props = ['height','width','lineHeight','textDecoration','letterSpacing'],
                    propOb = {};

                    // Create object of styles to apply:
                    $.each(props, function(i, prop){
                        propOb[prop] = textarea.css(prop);
                    });

                    // Clone the actual textarea removing unique properties
                    // and insert before original textarea:
                    return textarea.clone().removeAttr('id').removeAttr('name').css({
                        position: 'absolute',
                        top: 0,
                        left: -9999
                    }).css(propOb).attr('tabIndex','-1').insertBefore(textarea);

                })(),
                lastScrollTop = null,
                updateSize = function() {

                    // Prepare the clone:
                    clone.height(0).val($(this).val()).scrollTop(10000);

                    // Find the height of text:
                    var scrollTop = Math.max(clone.scrollTop(), origHeight) + settings.extraSpace,
                    toChange = $(this).add(clone);

                    // Don't do anything if scrollTip hasen't changed:
                    if (lastScrollTop === scrollTop) {
                        return;
                    }
                    lastScrollTop = scrollTop;

                    // Check for limit:
                    if ( scrollTop >= settings.limit ) {
                        $(this).css('overflow-y','');
                        return;
                    }
                    // Fire off callback:
                    settings.onResize.call(this);

                    // Justin's minHeight Fix
                    if (scrollTop <= settings.minHeight) {
                        scrollTop = settings.minHeight;
                    }

                    // Either animate or directly apply height:
                    settings.animate && textarea.css('display') === 'block' ?
                    toChange.stop().animate({
                        height:scrollTop
                    }, settings.animateDuration, settings.animateCallback)
                    : toChange.height(scrollTop);
                };

                // Bind namespaced handlers to appropriate events:
                textarea
                .unbind('.dynSiz')
                .bind('keyup.dynSiz', updateSize)
                .bind('keydown.dynSiz', updateSize)
                .bind('change.dynSiz', updateSize);

            });

            // Now Init
            $(this).addClass('resize-init');
        }

        // Chain:
        return this;

    };



})(jQuery);