/*
	 * 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) || (e.keyCode == 9)) 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: 0.3, // 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 = $(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 = $(
				"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);