/* http://keith-wood.name/maxlength.html
Textarea Max Length for jQuery v1.0.0.
Written by Keith Wood (kwood{at}iinet.com.au) May 2009.
Dual licensed under the GPL (http://dev.jquery.com/browser/trunk/jquery/GPL-LICENSE.txt) and 
MIT (http://dev.jquery.com/browser/trunk/jquery/MIT-LICENSE.txt) licenses. 
Please attribute the author if you use it. */

(function($) { // Hide scope, no $ conflict

	var PROP_NAME = 'maxlength';

	/* Max length manager. */
	function MaxLength() {
		this._defaults = {
			max: 200, // Maximum length
			showFeedback: true, // True to show user feedback
			feedbackText: '{r} characters remaining ({m} maximum)'
			// Display text for feedback message, use {r} for remaining characters,
			// {c} for characters entered, {m} for maximum
		};
	}

	$.extend(MaxLength.prototype, {
		/* Class name added to elements to indicate already configured with max length. */
		markerClassName: 'hasMaxLength',

		/* Class name for the feedback section. */
		_feedbackClass: 'maxlength-feedback',

		/* Override the default settings for all max length instances.
		@param  settings  (object) the new settings to use as defaults
		@return  (MaxLength) this object */
		setDefaults: function(settings) {
			$.extend(this._defaults, settings || {});
			return this;
		},

		/* Attach the max length functionality to a textarea.
		@param  target    (element) the control to affect
		@param  settings  (object) the custom options for this instance */
		_attachMaxLength: function(target, settings) {
			target = $(target);
			if (target.hasClass(this.markerClassName)) {
				return;
			}
			target.addClass(this.markerClassName).
			bind('keypress.maxlength', function(event) {
				var ch = String.fromCharCode(
					event.charCode == undefined ? event.keyCode : event.charCode);
				return (ch == '\u0000' || $(this).val().length < inst.settings.max);
			}).
			bind('keyup.maxlength', function() { $.maxlength._checkLength($(this)); });
			var inst = { settings: $.extend({}, this._defaults) };
			$.data(target[0], PROP_NAME, inst);
			this._changeMaxLength(target, settings);
		},

		/* Reconfigure the settings for a max length control.
		@param  target    (element) the control to affect
		@param  settings  (object) the new options for this instance or
		(string) an individual property name
		@param  value     (any) the individual property value (omit if settings is an object) */
		_changeMaxLength: function(target, settings, value) {
			target = $(target);
			if (!target.hasClass(this.markerClassName)) {
				return;
			}
			settings = settings || {};
			if (typeof settings == 'string') {
				var name = settings;
				settings = {};
				settings[name] = value;
			}
			var inst = $.data(target[0], PROP_NAME);
			$.extend(inst.settings, settings);
			var rem = target.nextAll('.' + this._feedbackClass);
			if (inst.settings.showFeedback && rem.length == 0) {
				target.after('<span class="' + this._feedbackClass + '"></span>');
			}
			if (!inst.settings.showFeedback && rem.length > 0) {
				rem.remove();
			}
			this._checkLength(target);
		},

		/* Check the length of the text and notify accordingly.
		@param  textarea  (jQuery) the control to check */
		_checkLength: function(textarea) {
			var inst = $.data(textarea[0], PROP_NAME);
			var value = textarea.val();
			if (value.length > inst.settings.max) {
				value = value.substring(0, inst.settings.max);
				textarea.val(value);
			}
			if (inst.settings.showFeedback) {
				textarea.nextAll('.' + this._feedbackClass).
				text(inst.settings.feedbackText.replace(/\{c\}/, value.length).
					replace(/\{m\}/, inst.settings.max).
					replace(/\{r\}/, inst.settings.max - value.length));
			}
		},

		/* Remove the max length functionality from a control.
		@param  target  (element) the control to affect */
		_destroyMaxLength: function(target) {
			target = $(target);
			if (!target.hasClass(this.markerClassName)) {
				return;
			}
			target.removeClass(this.markerClassName).
			unbind('.maxlength').
			nextAll('.' + this._feedbackClass).remove();
			$.removeData(target[0], PROP_NAME);
		}
	});

	/* Attach the max length functionality to a jQuery selection.
	@param  command  (string) the command to run (optional, default 'attach')
	@param  options  (object) the new settings to use for these instances (optional)
	@return  (jQuery) for chaining further calls */
	$.fn.maxlength = function(options) {
		var otherArgs = Array.prototype.slice.call(arguments, 1);
		return this.each(function() {
			if (typeof options == 'string') {
				$.maxlength['_' + options + 'MaxLength'].
				apply($.maxlength, [this].concat(otherArgs));
			}
			else {
				$.maxlength._attachMaxLength(this, options || {});
			}
		});
	};

	/* Initialise the max length functionality. */
	$.maxlength = new MaxLength(); // singleton instance

})(jQuery);