/**
 * DefaultHint
 * @version $Id$;
 * @author Nazar Lazorko <LazorkoN@gmail.com>
 * @uses jQuery
 *
 * Example of using DefaultHint in QSF2:
 * @see jQuery.fn.defaultHint#defaults
 * <code>
 * $('#form_contact-form').defaultHint({
 *     useWrapper: true
 * });
 * $().defaultHint({
 *     elements: [
 *         {selector: '#name', hint: '', trquired: true},
 *         {selector: '#emailOrPhone'}
 *     ]
 * });
 * $params = array(
 *      'elements' => array(
 *          array('selector' => '#name', 'hint' => 'Name:', 'required' => true),
 *          array('selector' => '#emailOrPhone')
 *      )
 * );
 * $this->_doc->addScript('js/defaultHint.js', array(), 'defaultHint');
 * $this->_doc->addInitFunction ('$().defaultHint', array($params));
 * </code>
 *
 */

(function ($, undefined) {

    var elementSelector = 'input[type="text"], input[type="password"], select, textarea';
    
    var defaults = {
        elements:           undefined,              // [{selector: '', hint: '', required: false}, ...]
        requiredClass:      'required',             // class of labels marked as required
        autoIndent:         true,
        asteriskTag:        'span',
        asteriskClass:      'asterisk',             // class of asterisk element
        asteriskText:       '*',
        useWrapper:         false,                  // wrap element with relative hints into div
        wrapperTag:         'div',
        wrapperIdSuffix:    '-wrapper',
        wrapperClass:       'defaultHint_wrapper',
        hintTag:            'div',
        hintIdSuffix:       '-hint',
        hintClass:          'defaultHint_element',
        activeElementClass: undefined,              // class that applied to active element
        activeParentClass:  undefined               // class that applied to active element parent
    };

    var isUndefined = function (mixed) {
        return ('undefined' === typeof mixed);
    };

    var checkCallContext = function () {
        if (!(this instanceof $)) {
            throw new Error('DefaultHint: Helper must be called from jQuery context');
        }
    };

    var isSupported = function ($element) {
        return ($element instanceof $) ? $element.is(elementSelector) : false;
    };

    var getElementLabel = function ($element) {
        return $($element.prop('form')).find('label[for="' + $element.attr('id') + '"]');
    };

    var helper = function (helperName, helperArgs) {
        checkCallContext.call(this);
        if ($.isFunction(helpers[helperName])) {
            return helpers[helperName].apply(this, helperArgs);
        }
        throw new Error('DefaultHint: Helper "' + helperName + '" not found');
    };

    var listeners = {
        hintClick: function (e) {
            $(this).data('$element.defaultHint').focus();
        },

        hintMouseDown: function (e) {
            var $element = $(this).data('$element.defaultHint');
            setTimeout(function () { $element.focus(); }, 1);
        },

        elementFocus: function (e) {
            var $this = $(this), $hint = $this.data('$hint.defaultHint'), _o = $this.data('options.defaultHint');
            if ($hint) {
                $hint.css('display', 'none');
            }
            if (_o.activeElementClass) {
                $this.addClass(_o.activeElementClass);
            }
            if (_o.activeParentClass) {
                $this.parent().addClass(_o.activeParentClass);
            }
        },

        elementBlur: function (e) {
            var $this = $(this), $hint = $this.data('$hint.defaultHint'), _o = $this.data('options.defaultHint');
            if ('' === $this.val() && $hint) {
                $hint.css('display', 'block');
            }
            if (_o.activeElementClass) {
                $this.removeClass(_o.activeElementClass);
            }
            if (_o.activeParentClass && this.parentNode) {
                $this.parent().removeClass(_o.activeParentClass);
            }
        }
    };

    var helpers = {
        hint: function ($element, hint, required) {
            checkCallContext.call(this);
            var label, $hint, $wrapper, tag = $element.prop('tagName'), _o = this.options;
            if (isUndefined(hint)) {
                label = getElementLabel($element);
                hint = label.text();
            }
            if (hint == '') {
                return false;
            }
            if (isUndefined(required)) {
                label = label || getElementLabel($element);
                required = label.hasClass(_o.requiredClass);
            }
            if (($hint = helper.call(this, ''+tag.toLowerCase() + 'Hint', [$element, hint, required]))) {
                $element.data('options.defaultHint', _o)
                    .bind('focus', listeners.elementFocus)
                    .bind('blur', listeners.elementBlur);
                if (_o.useWrapper) {
                    $wrapper = helper.call(this, 'wrapper', [$element, $hint]);
                }
            }
            return $hint;
        },

        wrapper: function ($element, $hint) {
            checkCallContext.call(this);
            var _o = this.options, $wrapper, id;
            // do not wrap special hints (like 'option')
            if (_o.hintTag === $hint.prop('tagName').toLowerCase()) {
                $wrapper = $(document.createElement(_o.wrapperTag)).addClass(_o.wrapperClass);
                if ((id = $element.attr('id'))) {
                    $wrapper.attr('id', $element.attr('id') + _o.wrapperIdSuffix);
                }
                $element.after($wrapper);
                $wrapper.append($element).append($hint);
                if (_o.autoIndent) {
                    $wrapper.css({
                        position: 'relative'
                    });

                    var css = {
                        position: 'absolute',
                        top: 0,
                        left: 2,
                        overflow: 'hidden'
                    };
                    for (var name in {paddingTop: '', paddingLeft: '', width: '', height: ''}) {
                        var value = $element.css(name);
                        if (!isNaN(parseFloat(value)) && parseFloat(value) > 0) {
                            css[name] = value;
                        }
                    }
                    $hint.css(css);
                }
                return $wrapper;
            }
            return undefined;
        },

        inputHint: function ($element, hint, required) {
            checkCallContext.call(this);
            var _o = this.options,
                $hint = $(document.createElement(_o.hintTag)).addClass(this.options.hintClass),
                elementId = $element.attr('id');
            if (elementId) {
                $hint.attr('id', elementId + _o.hintIdSuffix);
            }
            if (required) {
                $(document.createElement(_o.asteriskTag)).addClass(_o.asteriskClass)
                    .text(_o.asteriskText).appendTo($hint);
            }
            $hint.append(hint).data('options.defaultHint', _o).data('$element.defaultHint', $element)
                .bind('click', listeners.hintClick).bind('mousedown', listeners.hintMouseDown);
            if (document.activeElement == $element.get(0) || $element.val() !== '') {
                $hint.css('display', 'none');
            }
            $element.data('$hint.defaultHint', $hint).after($hint);
            return $hint;
        },

        textareaHint: function ($element, hint, required) {
            return helper.call(this, 'inputHint', [$element, hint, required]);
        },

        selectHint: function ($element, hint, required) {
            checkCallContext.call(this);
            var $first = $element.children(':first'), $hint;
            $hint = $(document.createElement('option')).prop('text', hint).prop('label', hint).val('');
            if ($first.size()) {
                if ('' === $first.val()) {
                    $first.prop('label', hint).prop('text', hint);
                } else {
                    $first.before($hint);
                    if ($first.val() == $element.val()) {
                        $element.prop('selectedIndex', 0);
                    }
                }
            } else {
                $element.append($hint);
            }
            return $hint;
        }
    };

    var setHint = function ($element, hint, required) {
        checkCallContext.call(this);
        if (isSupported($element) && isUndefined($element.data('$hint.defaultHint'))) {
            helper.call(this, 'hint', [$element, hint, required]);
        }
    };

    $.fn.defaultHint = function (options) {
        var _o = $.extend({}, defaults, options);
        this.options = _o;
        if ($.isArray(_o.elements)) {
            for (var i = 0, len = _o.elements.length; i < len; i++) {
                setHint.call(this, $(_o.elements[i].selector), _o.elements[i].hint, _o.elements[i].required);
            }
        } else {
            var that = this;
            this.find(elementSelector).each(function (index, element) {
                setHint.call(that, $(element));
            });
        }
        return this;
    };
})(jQuery);