/*
 * 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 ($) {
    var postionLabelForBase = function(base) {
        var fieldPosition = base.$field.position();
        var fieldPaddingTop = parseInt(base.$field.css("padding-top"));
        var fieldPaddingLeft = parseInt(base.$field.css("padding-left"));
        base.$label.css({
            'left': fieldPosition.left + fieldPaddingLeft,
            'top': fieldPosition.top + fieldPaddingTop
        });
    };

    $.InFieldLabels = function (label, field, options) {
        var base = this;
        base.$label = $(label);
        base.$field = $(field);
        base.$label.data("InFieldLabels", base);
        base.showing = true;
        base.init = function () {
            base.options = $.extend({}, $.InFieldLabels.defaultOptions, options);
            base.$label.css('position', 'absolute');

            postionLabelForBase(base);
            base.$label.addClass(base.options.labelClass);
            
            $(window).resize(function(e) {
                postionLabelForBase(base);
            });

            if (base.$field.val() != "") {
                base.$label.hide();
                base.showing = false;
            };
            base.$field.focus(function () {
                base.fadeOnFocus();
            }).blur(function () {
                base.checkForEmpty(true);
            }).bind('keydown.infieldlabel', function (e) {
                base.hideOnChange(e);
            }).change(function (e) {
                base.checkForEmpty();
            }).bind('onPropertyChange', function () {
                base.checkForEmpty();
            });
        };
        base.fadeOnFocus = function () {
            if (base.showing) {
                base.setOpacity(base.options.fadeOpacity);
            };
        };
        base.setOpacity = function (opacity) {
            base.$label.stop().animate({
                opacity: opacity
            }, base.options.fadeDuration);
            base.showing = (opacity > 0.0);
        };
        base.checkForEmpty = function (blur) {
            if (base.$field.val() == "") {
                base.prepForShow();
                base.setOpacity(blur ? 1.0 : base.options.fadeOpacity);
            } else {
                base.setOpacity(0.0);
            };
        };
        base.prepForShow = function (e) {
            if (!base.showing) {
                base.$label.css({
                    opacity: 0.0
                }).show();
                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;
            };
            base.$field.unbind('keydown.infieldlabel');
        };
        base.init();
    };

    $.InFieldLabels.defaultOptions = {
        fadeOpacity: 0.5,
        fadeDuration: 300,
        labelClass: 'infield'
    };

    $.fn.inFieldLabels = function (options) {
        return this.each(function () {
            var for_attr = $(this).attr('for');
            if (!for_attr) return;
            var $field = $("input#" + for_attr + "[type='text']," + "input#" + for_attr + "[type='password']," + "textarea#" + for_attr);
            if ($field.length == 0) return;
            (new $.InFieldLabels(this, $field[0], options));
        });
    };
})(jQuery);