/*
 * In-Field Label jQuery Plugin
 * http://fuelyourcoding.com/scripts/infield.html
 *
 * Copyright (c) 2009 Doug Neiner
 * Dual licensed under the MIT and GPL licenses.
 * Uses the same license as jQuery, see:
 * http://docs.jquery.com/License
 *
 * @version 0.1
 */
(function($) {

	$.InFieldLabels = function(label, field, options) {
		// To avoid scope issues, use 'base' instead of 'this'
		// to reference this class from internal events and functions.
		var base = this;

		// Access to jQuery and DOM versions of each element
		base.$label = $(label);
		base.label = label;

		base.$field = $(field);
		base.field = field;

		base.$label.data("InFieldLabels", base);
		base.showing = true;

		base.init = function() {
			// Merge supplied options with default options
			base.options = $.extend({}, $.InFieldLabels.defaultOptions, options);

			// Check if the field is already filled in
			if (base.$field.val() != "") {
				base.$label.hide();
				base.showing = false;
			};



			base.$field.focus(function() {
				base.fadeOnFocus();
			}).blur(function() {
				base.checkForEmpty(true);
			}).bind('keydown.infieldlabel', function(e) {
				// Use of a namespace (.infieldlabel) allows us to
				// unbind just this method later
				base.hideOnChange(e);
			}).change(function(e) {
				base.checkForEmpty();
			}).bind('onPropertyChange', function() {
				base.checkForEmpty();
			});
		};

		// If the label is currently showing
		// then fade it down to the amount
		// specified in the settings
		base.fadeOnFocus = function() {
			if (base.showing) {
				base.setOpacity(base.options.fadeOpacity);
			};
		};

		base.setOpacity = function(opacity) {
			base.$label.stop().animate({ opacity: opacity }, base.options.fadeDuration);
			base.showing = (opacity > 0.0);
		};

		// Checks for empty as a fail safe
		// set blur to true when passing from
		// the blur event
		base.checkForEmpty = function(blur) {
			if (base.$field.val() == "") {
				base.prepForShow();
				base.setOpacity(blur ? 1.0 : base.options.fadeOpacity);
			} else {
				base.setOpacity(0.0);
			};
		};

		base.prepForShow = function(e) {
			if (!base.showing) {
				// Prepare for a animate in...
				base.$label.css({ opacity: 0.0 }).show();

				// Reattach the keydown event
				base.$field.bind('keydown.infieldlabel', function(e) {
					base.hideOnChange(e);
				});
			};
		};

		base.hideOnChange = function(e) {
			if (
				(e.keyCode == 16) || // Skip Shift
				(e.keyCode == 9) // Skip Tab
			  ) return;

			if (base.showing) {
				base.$label.hide();
				base.showing = false;
			};

			// Remove keydown event to save on CPU processing
			base.$field.unbind('keydown.infieldlabel');
		};

		// Run the initialization method
		base.init();
	};

	$.InFieldLabels.defaultOptions = {
		fadeOpacity: 0.5, // Once a field has focus, how transparent should the label be
		fadeDuration: 300 // How long should it take to animate from 1.0 opacity to the fadeOpacity
	};


	$.fn.inFieldLabels = function(options) {
		return this.each(function() {
			// Find input or textarea based on for= attribute
			// The for attribute on the label must contain the ID
			// of the input or textarea element
			var for_attr;
			if (this.nodeName == 'LABEL' && $(this).hasClass("labelText"))
				for_attr = $(this).attr('id');
			else if (this.nodeName == 'LABEL')
				for_attr = $(this).attr('for');
			if (!for_attr) return; // Nothing to attach, since the for field wasn't used


			// Find the referenced input or textarea element
			var $field;
			if (this.nodeName == 'LABEL' && $(this).hasClass("labelText"))
				$field = $(this).next("input[type='text'], input[type='password'], textarea");
			else if (this.nodeName == 'LABEL') {
				$field = $(this).parent().next().children('input');
			}
			//			 $(
			//				"input#" + for_attr + "[type='text']," + 
			//				"input#" + for_attr + "[type='password']," + 
			//				"textarea#" + for_attr
			//				);
			//				
			if ($field.length == 0) return; // Again, nothing to attach

			// Only create object for input[text], input[password], or textarea
			(new $.InFieldLabels(this, $field[0], options));
		});
	};

})(jQuery);