/*
@author: remy sharp / http://remysharp.com
@params:
feedback - the selector for the element that gives the user feedback. Note that this will be relative to the form the plugin is run against.
hardLimit - whether to stop the user being able to keep adding characters. Defaults to true.
useInput - whether to look for a hidden input named 'maxlength' instead of the maxlength attribute. Defaults to false.
words - limit by characters or words, set this to true to limit by words. Defaults to false.
@version: 1.2
*/

(function($)
{
	$.fn.maxlength = function(settings)
	{
		if (typeof settings == 'string')
			settings = { feedback: settings };
		
		settings = $.extend({}, $.fn.maxlength.defaults, settings);

		function length(el)
		{
			var parts = el.value;
			if (settings.words)
				parts = el.value.length ? parts.split(/\s+/) : { length: 0 };
			return parts.length;
		}

		return this.each(function()
		{
			var field = this,
        	$field = $(field),
        	$form = $(field.form),
        	limit = settings.useInput ? $form.find('input[name=maxlength]').val() : $field.attr('maxlength'),
        	$charsLeft = $form.find(settings.feedback);

			function limitCheck(event)
			{
				var len = length(this),
        	    exceeded = len >= limit,
        		code = event.keyCode;

				if (!exceeded)
					return;

				switch (code)
				{
					case 8:  // allow delete
					case 9:
					case 17:
					case 36: // and cursor keys
					case 35:
					case 37:
					case 38:
					case 39:
					case 40:
					case 46:
					case 65:
						return;

					default:
						return settings.words && code != 32 && code != 13 && len == limit;
				}
			}


			var updateCount = function()
			{
				var len = length(field),
            	diff = limit - len;

				$charsLeft.html(diff || "0");

				// truncation code
				if (settings.hardLimit && diff < 0)
				{
					field.value = settings.words ?
					// split by white space, capturing it in the result, then glue them back
            		field.value.split(/(\s+)/, (limit * 2) - 1).join('') :
            		field.value.substr(0, limit);

					updateCount();
				}
			};

			$field.keyup(updateCount).change(updateCount);
			if (settings.hardLimit)
			{
				$field.keydown(limitCheck);
			}

			updateCount();
		});
	};

	$.fn.maxlength.defaults = {
		useInput: false,
		hardLimit: true,
		feedback: '.charsLeft',
		words: false
	};
})(jQuery);