// Calendar: a Javascript class for Mootools that adds accessible and unobtrusive date pickers to your form elements <http://electricprism.com/aeron/calendar>
// Calendar RC4, Copyright (c) 2007 Aeron Glemann <http://electricprism.com/aeron>, MIT Style License.
// Mootools 1.2 compatibility by Davorin Šego

Function.implement({
    create: function (options) {
        var self = this;
        options = options || {};
        return function (event) {
            var args = options.arguments;
            args = (args != null) ? jQuery.makeArray(args) : Array.slice(arguments, (options.event) ? 1 : 0);
            if (options.event) args = [event || window.event].append(args);
            var returns = function () {
                return self.apply(options.bind || null, args);
            };
            if (options.delay) return setTimeout(returns, options.delay);
            if (options.periodical) return setInterval(returns, options.periodical);
            if (options.attempt) return Function.attempt(returns);
            return returns();
        };
    }
});

var NewCalendar = new Class({

    Implements: Options,

    options: {
        blocked: [], // blocked dates
        classes: [], // ['calendar', 'prev', 'next', 'month', 'year', 'today', 'invalid', 'valid', 'inactive', 'active', 'hover', 'hilite']
        days: ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'], // days of the week starting at sunday
        direction: 0, // -1 past, 0 past + future, 1 future
        draggable: true,
        months: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
        navigation: 1, // 0 = no nav; 1 = single nav for month; 2 = dual nav for month and year
        offset: 0, // first day of the week: 0 = sunday, 1 = monday, etc..
        onHideStart: Class.empty,
        onHideComplete: Class.empty,
        onShowStart: Class.empty,
        onShowComplete: Class.empty,
        pad: 1, // padding between multiple calendars
        tweak: {x: 0, y: 0}, // tweak calendar positioning
        range: {min: 1971, max: 2150},
        readonly: 1
    },

    // initialize: calendar constructor
    // @param obj (obj) a js object containing the form elements and format strings { id: 'format', id: 'format' etc }
    // @param props (obj) optional properties

    initialize: function (obj, options) {
        // basic error checking
        if (!obj) {
            return false;
        }

        this.setOptions(options);

        // create our classes array
        var keys = ['calendar', 'prev', 'next', 'month', 'year', 'today', 'invalid', 'valid', 'inactive', 'active', 'hover', 'hilite'];

        var values = keys.map(function (key, i) {
            if (this.options.classes[i]) {
                if (this.options.classes[i].length) {
                    key = this.options.classes[i];
                }
            }
            return key;
        }, this);

        this.classes = values.associate(keys);

        // create cal element with css styles required for proper cal functioning
        this.calendar = new Element('div', {
            'styles': {left: '-1000px', opacity: 0, position: 'absolute', top: '-1000px', zIndex: 1000}
        }).addClass(this.classes.calendar).inject(document.body);

        // iex 6 needs a transparent iframe underneath the calendar in order to not allow select elements to render through
        if (window.ie6) {
            this.iframe = new Element('iframe', {
                'styles': {left: '-1000px', position: 'absolute', top: '-1000px', zIndex: 999}
            }).inject(document.body);
            this.iframe.style.filter = 'progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)';
        }

        // initialize fade method
        this.fx = new Fx.Tween(this.calendar, {
            onStart: function () {
                if (this.calendar.getStyle('opacity') == 0) { // show
                    if (window.ie6) {
                        this.iframe.setStyle('display', 'block');
                    }
                    this.calendar.setStyle('display', 'block');
                    this.fireEvent('onShowStart', this.element);
                }
                else { // hide
                    this.fireEvent('onHideStart', this.element);
                }
            }.bind(this),
            onComplete: function () {
                if (this.calendar.getStyle('opacity') == 0) { // hidden
                    this.calendar.setStyle('display', 'none');
                    if (window.ie6) {
                        this.iframe.setStyle('display', 'none');
                    }
                    this.fireEvent('onHideComplete', this.element);
                }
                else { // shown
                    this.fireEvent('onShowComplete', this.element);
                }
            }.bind(this)
        });

        // initialize drag method
        if (window.Drag && this.options.draggable) {
            this.drag = new Drag.Move(this.calendar, {
                onDrag: function () {
                    if (window.ie6) {
                        this.iframe.setStyles({left: this.calendar.style.left, top: this.calendar.style.top});
                    }
                }.bind(this)
            });
        }

        // create calendars array
        this.calendars = [];

        var id = 0;
        var d = new Date(); // today

        d.setDate(d.getDate() + this.options.direction.toInt()); // correct today for directional offset

        for (var i in obj) {
            var cal = {
                button: new Element('button', {'type': 'button'}),
                el: $(i),
                els: [],
                id: id++,
                month: d.getMonth(),
                visible: false,
                year: d.getFullYear()
            };

            // fix for bad element (naughty, naughty element!)
            if (!this.element(i, obj[i], cal)) {
                continue;
            }

            cal.el.addClass(this.classes.calendar);

            // create cal button
            cal.button.addClass(this.classes.calendar).addEvent('click', function (cal) {
                this.toggle(cal);
            }.pass(cal, this)).inject(cal.el, "after");

            // read in default value
            cal.val = this.read(cal);

            Object.append(cal, this.bounds(cal)); // abs bounds of calendar

            Object.append(cal, this.values(cal)); // valid days, months, years

            this.rebuild(cal);

            this.calendars.push(cal); // add to cals array
        }
    },


    // blocked: returns an array of blocked days for the month / year
    // @param cal (obj)
    // @returns blocked days (array)

    blocked: function (cal) {
        var blocked = [];
        var offset = new Date(cal.year, cal.month, 1).getDay(); // day of the week (offset)
        var last = new Date(cal.year, cal.month + 1, 0).getDate(); // last day of this month

        this.options.blocked.each(function (date) {
            var values = date.split(' ');

            // preparation
            for (var i = 0; i <= 3; i++) {
                if (!values[i]) {
                    values[i] = (i == 3) ? '' : '*';
                } // make sure blocked date contains values for at least d, m and y
                values[i] = values[i].contains(',') ? values[i].split(',') : new Array(values[i]); // split multiple values
                var count = values[i].length - 1;
                for (var j = count; j >= 0; j--) {
                    if (values[i][j].contains('-')) { // a range
                        var val = values[i][j].split('-');
                        for (var k = val[0]; k <= val[1]; k++) {
                            if (!values[i].contains(k)) {
                                values[i].push(k + '');
                            }
                        }
                        values[i].splice(j, 1);
                    }
                }
            }

            // execution
            if (values[2].contains(cal.year + '') || values[2].contains('*')) {
                if (values[1].contains(cal.month + 1 + '') || values[1].contains('*')) {
                    values[0].each(function (val) { // if blocked value indicates this month / year
                        if (val > 0) {
                            blocked.push(val.toInt());
                        } // add date to blocked array
                    });

                    if (values[3]) { // optional value for day of week
                        for (var i = 0; i < last; i++) {
                            var day = (i + offset) % 7;

                            if (values[3].contains(day + '')) {
                                blocked.push(i + 1); // add every date that corresponds to the blocked day of the week to the blocked array
                            }
                        }
                    }
                }
            }
        }, this);

        return blocked;
    },


    // bounds: returns the start / end bounds of the calendar
    // @param cal (obj)
    // @returns obj

    bounds: function (cal) {
        // 1. first we assume the calendar has no bounds (or a thousand years in either direction)

        // by default the calendar will accept a millennium in either direction
        // gwe tweak
        var start = new Date(this.options.range.min, 0, 1); // jan 1, 1000
        var end = new Date(this.options.range.max, 11, 31); // dec 31, 2999

        // 2. but if the cal is one directional we adjust accordingly
        var date = new Date().getDate() + this.options.direction.toInt();

        if (this.options.direction > 0) {
            start = new Date();
            start.setDate(date + this.options.pad * cal.id);
        }

        if (this.options.direction < 0) {
            end = new Date();
            end.setDate(date - this.options.pad * (this.calendars.length - cal.id - 1));
        }

        // 3. then we can further filter the limits by using the pre-existing values in the selects
        cal.els.each(function (el) {
            if (el.get('tag') == 'select') {
                if (el.format.test('(y|Y)')) { // search for a year select
                    var years = [];

                    el.getChildren().each(function (option) { // get options
                        var values = this.unformat(option.value, el.format);

                        if (!years.contains(values[0])) {
                            years.push(values[0]);
                        } // add to years array
                    }, this);

                    years.sort(this.sort);

                    if (years[0] > start.getFullYear()) {
                        d = new Date(years[0], start.getMonth() + 1, 0); // last day of new month

                        if (start.getDate() > d.getDate()) {
                            start.setDate(d.getDate());
                        }

                        start.setYear(years[0]);
                    }

                    if (years.getLast() < end.getFullYear()) {
                        d = new Date(years.getLast(), end.getMonth() + 1, 0); // last day of new month

                        if (end.getDate() > d.getDate()) {
                            end.setDate(d.getDate());
                        }

                        end.setYear(years.getLast());
                    }
                }

                if (el.format.test('(F|m|M|n)')) { // search for a month select
                    var months_start = [];
                    var months_end = [];

                    el.getChildren().each(function (option) { // get options
                        var values = this.unformat(option.value, el.format);

                        if (typeOf(values[0]) != 'number' || values[0] == years[0]) { // if it's a year / month combo for curr year, or simply a month select
                            if (!months_start.contains(values[1])) {
                                months_start.push(values[1]);
                            } // add to months array
                        }

                        if (typeOf(values[0]) != 'number' || values[0] == years.getLast()) { // if it's a year / month combo for curr year, or simply a month select
                            if (!months_end.contains(values[1])) {
                                months_end.push(values[1]);
                            } // add to months array
                        }
                    }, this);

                    months_start.sort(this.sort);
                    months_end.sort(this.sort);

                    if (months_start[0] > start.getMonth()) {
                        d = new Date(start.getFullYear(), months_start[0] + 1, 0); // last day of new month

                        if (start.getDate() > d.getDate()) {
                            start.setDate(d.getDate());
                        }

                        start.setMonth(months_start[0]);
                    }

                    if (months_end.getLast() < end.getMonth()) {
                        d = new Date(start.getFullYear(), months_end.getLast() + 1, 0); // last day of new month

                        if (end.getDate() > d.getDate()) {
                            end.setDate(d.getDate());
                        }

                        end.setMonth(months_end.getLast());
                    }
                }
            }
        }, this);

        return {'start': start, 'end': end};
    },


    // caption: returns the caption element with header and navigation
    // @param cal (obj)
    // @returns caption (element)

    caption: function (cal) {
        // start by assuming navigation is allowed
        var navigation = {
            prev: {'month': true, 'year': true},
            next: {'month': true, 'year': true}
        };

        // if we're in an out of bounds year
        if (cal.year == cal.start.getFullYear()) {
            navigation.prev.year = false;
            if (cal.month == cal.start.getMonth() && this.options.navigation == 1) {
                navigation.prev.month = false;
            }
        }
        if (cal.year == cal.end.getFullYear()) {
            navigation.next.year = false;
            if (cal.month == cal.end.getMonth() && this.options.navigation == 1) {
                navigation.next.month = false;
            }
        }

        // special case of improved navigation but months array with only 1 month we can disable all month navigation
        if (typeOf(cal.months) == 'array') {
            if (cal.months.length == 1 && this.options.navigation == 2) {
                navigation.prev.month = navigation.next.month = false;
            }
        }

        var caption = new Element('caption');

        var prev = new Element('a').addClass(this.classes.prev).appendText('\x3c'); // <
        var next = new Element('a').addClass(this.classes.next).appendText('\x3e'); // >

        if (this.options.navigation == 2) {
            caption.addClass('dualnav'); // gwe tweak
            var month = new Element('span').addClass(this.classes.month).inject(caption);

            if (navigation.prev.month) {
                prev.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'm', -1);
                }.pass(cal, this)).inject(month);
            }

            month.adopt(new Element('span').appendText(this.options.months[cal.month]));

            if (navigation.next.month) {
                next.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'm', 1);
                }.pass(cal, this)).inject(month);
            }

            var year = new Element('span').addClass(this.classes.year).inject(caption);

            if (navigation.prev.year) {
                prev.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'y', -1);
                }.pass(cal, this)).inject(year);
            }

            year.adopt(new Element('span').appendText(cal.year));

            if (navigation.next.year) {
                next.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'y', 1);
                }.pass(cal, this)).inject(year);
            }
        }
        else { // 1 or 0
            if (navigation.prev.month && this.options.navigation) {
                prev.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'm', -1);
                }.pass(cal, this)).inject(caption);
            }

            caption.adopt(new Element('span').addClass(this.classes.month).appendText(this.options.months[cal.month]));

            caption.adopt(new Element('span').addClass(this.classes.year).appendText(cal.year));

            if (navigation.next.month && this.options.navigation) {
                next.clone().addEvent('click', function (cal) {
                    this.navigate(cal, 'm', 1);
                }.pass(cal, this)).inject(caption);
            }

        }

        return caption;
    },


    // changed: run when a select value is changed
    // @param cal (obj)

    changed: function (cal) {
        cal.val = this.read(cal); // update calendar val from inputs

        Object.append(cal, this.values(cal)); // update bounds - based on curr month

        this.rebuild(cal); // rebuild days select

        if (!cal.val) {
            return;
        } // in case the same date was clicked the cal has no set date we should exit

        if (cal.val.getDate() < cal.days[0]) {
            cal.val.setDate(cal.days[0]);
        }
        if (cal.val.getDate() > cal.days.getLast()) {
            cal.val.setDate(cal.days.getLast());
        }

        cal.els.each(function (el) {	// then we can set the value to the field
            el.value = this.format(cal.val, el.format);
        }, this);

        this.check(cal); // checks other cals

        this.calendars.each(function (kal) { // update cal graphic if visible
            if (kal.visible) {
                this.display(kal);
            }
        }, this);
    },


    // check: checks other calendars to make sure no overlapping values
    // @param cal (obj)

    check: function (cal) {
        this.calendars.each(function (kal, i) {
            if (kal.val) { // if calendar has value set
                var change = false;

                if (i < cal.id) { // preceding calendar
                    var bound = new Date(Date.parse(cal.val));

                    bound.setDate(bound.getDate() - (this.options.pad * (cal.id - i)));

                    if (bound < kal.val) {
                        change = true;
                    }
                }
                if (i > cal.id) { // following calendar
                    var bound = new Date(Date.parse(cal.val));

                    bound.setDate(bound.getDate() + (this.options.pad * (i - cal.id)));

                    if (bound > kal.val) {
                        change = true;
                    }
                }

                if (change) {
                    if (kal.start > bound) {
                        bound = kal.start;
                    }
                    if (kal.end < bound) {
                        bound = kal.end;
                    }

                    kal.month = bound.getMonth();
                    kal.year = bound.getFullYear();

                    Object.append(kal, this.values(kal));

                    // TODO - IN THE CASE OF SELECT MOVE TO NEAREST VALID VALUE
                    // IN THE CASE OF INPUT DISABLE

                    // if new date is not valid better unset cal value
                    // otherwise it would mean incrementally checking to find the nearest valid date which could be months / years away
                    kal.val = kal.days.contains(bound.getDate()) ? bound : null;

                    this.write(kal);

                    if (kal.visible) {
                        this.display(kal);
                    } // update cal graphic if visible
                }
            }
            else {
                kal.month = cal.month;
                kal.year = cal.year;
            }
        }, this);
    },


    // clicked: run when a valid day is clicked in the calendar
    // @param cal (obj)

    clicked: function (td, day, cal) {
        // Use 6am to help avoid clock change issues
        cal.val = (this.value(cal) == day) ? null : new Date(cal.year, cal.month, day, 6); // set new value - if same then disable

        this.write(cal);

        // ok - in the special case that it's all selects and there's always a date no matter what (at least as far as the form is concerned)
        // we can't let the calendar undo a date selection - it's just not possible!!
        if (!cal.val) {
            cal.val = this.read(cal);
        }

        if (cal.val) {
            this.check(cal); // checks other cals
            this.toggle(cal); // hide cal
        }
        else { // remove active class and replace with valid
            td.addClass(this.classes.valid);
            td.removeClass(this.classes.active);
        }
    },


    // display: create calendar element
    // @param cal (obj)

    display: function (cal) {
        // 1. header and navigation
        this.calendar.empty(); // init div

        this.calendar.className = this.classes.calendar + ' ' + this.options.months[cal.month].toLowerCase();

        var div = new Element('div').inject(this.calendar); // a wrapper div to help correct browser css problems with the caption element

        var table = new Element('table').inject(div).adopt(this.caption(cal));

        // 2. day names
        var thead = new Element('thead').inject(table);

        var tr = new Element('tr').inject(thead);

        for (var i = 0; i <= 6; i++) {
            var th = this.options.days[(i + this.options.offset) % 7];
            var thclass = 'dashday' + (i + this.options.offset) % 7;
            tr.adopt(new Element('th', {'title': th, 'class': thclass}).appendText(th.substr(0, 1)));
        }

        // 3. day numbers
        var tbody = new Element('tbody').inject(table);
        var tr = new Element('tr').inject(tbody);

        var d = new Date(cal.year, cal.month, 1);
        var offset = ((d.getDay() - this.options.offset) + 7) % 7; // day of the week (offset)
        var last = new Date(cal.year, cal.month + 1, 0).getDate(); // last day of this month
        var prev = new Date(cal.year, cal.month, 0).getDate(); // last day of previous month
        var active = this.value(cal); // active date (if set and within curr month)
        var valid = cal.days; // valid days for curr month
        var inactive = []; // active dates set by other calendars
        var hilited = [];
        this.calendars.each(function (kal, i) {
            if (kal != cal && kal.val) {
                if (cal.year == kal.val.getFullYear() && cal.month == kal.val.getMonth()) {
                    inactive.push(kal.val.getDate());
                }

                if (cal.val) {
                    for (var day = 1; day <= last; day++) {
                        d.setDate(day);

                        if ((i < cal.id && d > kal.val && d < cal.val) || (i > cal.id && d > cal.val && d < kal.val)) {
                            if (!hilited.contains(day)) {
                                hilited.push(day);
                            }
                        }
                    }
                }
            }
        }, this);
        var d = new Date();
        // Use 6am to help avoid clock change issues
        var today = new Date(d.getFullYear(), d.getMonth(), d.getDate(), 6).getTime(); // today obv

        for (var i = 1; i < 43; i++) { // 1 to 42 (6 x 7 or 6 weeks)
            if ((i - 1) % 7 == 0) {
                tr = new Element('tr').inject(tbody);
            } // each week is it's own table row

            var td = new Element('td').inject(tr);

            var day = i - offset;
            // Use 6am to help avoid clock change issues
            var date = new Date(cal.year, cal.month, day, 6);

            td.setProperty('class', 'dashday' + ((i - 1) % 7 + this.options.offset) % 7);

            var cls = '';

            if (day === active) {
                cls = this.classes.active;
            } // active
            else if (inactive.contains(day)) {
                cls = this.classes.inactive;
            } // inactive
            else if (valid.contains(day)) {
                cls = this.classes.valid;
            } // valid
            else if (day >= 1 && day <= last) {
                cls = this.classes.invalid;
            } // invalid

            if (date.getTime() == today) {
                cls = cls + ' ' + this.classes.today;
            } // adds class for today

            if (hilited.contains(day)) {
                cls = cls + ' ' + this.classes.hilite;
            } // adds class if hilited

            td.addClass(cls);

            if (valid.contains(day)) { // if it's a valid - clickable - day we add interaction
                td.setProperty('title', this.format(date, 'D M jS Y'));

                td.addEvents({
                    'click': function (td, day, cal) {
                        this.clicked(td, day, cal);
                    }.pass([td, day, cal], this),
                    'mouseover': function (td, cls) {
                        td.addClass(cls);
                    }.pass([td, this.classes.hover]),
                    'mouseout': function (td, cls) {
                        td.removeClass(cls);
                    }.pass([td, this.classes.hover])
                });
            }

            // pad calendar with last days of prev month and first days of next month
            if (day < 1) {
                day = prev + day;
            }
            else if (day > last) {
                day = day - last;
            }

            td.appendText(day);
        }
    },


    // element: helper function
    // @param el (string) element id
    // @param f (string) format string
    // @param cal (obj)

    element: function (el, f, cal) {
        if (typeOf(f) == 'object') { // in the case of multiple inputs per calendar
            for (var i in f) {
                if (!this.element(i, f[i], cal)) {
                    return false;
                }
            }

            return true;
        }

        el = $(el);

        if (!el) {
            return false;
        }

        el.format = f;

        if (el.get('tag') == 'select') { // select elements allow the user to manually set the date via select option
            el.addEvent('change', function (cal) {
                this.changed(cal);
            }.pass(cal, this));
        }
        else { // input (type text) elements restrict the user to only setting the date via the calendar
            if (this.options.readonly) {
                el.readOnly = true;
                el.addEvent('focus', function (cal) {
                    this.toggle(cal);
                }.pass(cal, this));
            }
            else {
                el.addEvent('change', function (cal) {
                    this.changed(cal);
                }.pass(cal, this));
            }
        }

        cal.els.push(el);

        return true;
    },


    // format: formats a date object according to passed in instructions
    // @param date (obj)
    // @param f (string) any combination of punctuation / separators and d, j, D, l, S, m, n, F, M, y, Y
    // @returns string

    format: function (date, format) {
        var str = '';

        if (date) {
            var j = date.getDate(); // 1 - 31
            var w = date.getDay(); // 0 - 6
            var l = this.options.days[w]; // Sunday - Saturday
            var n = date.getMonth() + 1; // 1 - 12
            var f = this.options.months[n - 1]; // January - December
            var y = date.getFullYear() + ''; // 19xx - 20xx

            for (var i = 0, len = format.length; i < len; i++) {
                var cha = format.charAt(i); // format char

                switch (cha) {
                    // year cases
                    case 'y': // xx - xx
                        y = y.substr(2);
                    case 'Y': // 19xx - 20xx
                        str += y;
                        break;

                    // month cases
                    case 'm': // 01 - 12
                        if (n < 10) {
                            n = '0' + n;
                        }
                    case 'n': // 1 - 12
                        str += n;
                        break;

                    case 'M': // Jan - Dec
                        f = f.substr(0, 3);
                    case 'F': // January - December
                        str += f;
                        break;

                    // day cases
                    case 'd': // 01 - 31
                        if (j < 10) {
                            j = '0' + j;
                        }
                    case 'j': // 1 - 31
                        str += j;
                        break;

                    case 'D': // Sun - Sat
                        l = l.substr(0, 3);
                    case 'l': // Sunday - Saturday
                        str += l;
                        break;

                    case 'N': // 1 - 7
                        w += 1;
                    case 'w': // 0 - 6
                        str += w;
                        break;

                    case 'S': // st, nd, rd or th (works well with j)
                        if (j % 10 == 1 && j != '11') {
                            str += 'st';
                        }
                        else if (j % 10 == 2 && j != '12') {
                            str += 'nd';
                        }
                        else if (j % 10 == 3 && j != '13') {
                            str += 'rd';
                        }
                        else {
                            str += 'th';
                        }
                        break;

                    default:
                        str += cha;
                }
            }
        }

        return str; //  return format with values replaced
    },


    // navigate: calendar navigation
    // @param cal (obj)
    // @param type (str) m or y for month or year
    // @param n (int) + or - for next or prev

    navigate: function (cal, type, n) {
        switch (type) {
            case 'm': // month
                if (typeOf(cal.months) == 'array') {
                    var i = cal.months.indexOf(cal.month) + n; // index of current month
                    if (i < 0 || i == cal.months.length) { // out of range
                        if (this.options.navigation >= 1) { // if type 1 nav we'll need to increment the year
                            if (typeOf(cal.years) == 'array') {
                                var i = cal.years.indexOf(cal.year) + n;

                                cal.year = cal.years[i];
                            }
                            else {
                                cal.year += n;
                            }
                        }

                        i = (i < 0) ? cal.months.length - 1 : 0;
                    }
                    cal.month = cal.months[i];
                }
                else {
                    var i = cal.month + n;

                    if (i < 0 || i == 12) {
                        if (this.options.navigation >= 1) {
                            if (typeOf(cal.years) == 'array') {
                                var i = cal.years.indexOf(cal.year) + n;

                                cal.year = cal.years[i];
                            }
                            else {
                                cal.year += n;
                            }
                        }

                        i = (i < 0) ? 11 : 0;
                    }

                    cal.month = i;
                }
                break;

            case 'y': // year
                if (typeOf(cal.years) == 'array') {
                    var i = cal.years.indexOf(cal.year) + n;

                    cal.year = cal.years[i];
                }
                else {
                    cal.year += n;
                }
                break;
        }

        Object.append(cal, this.values(cal));

        if (typeOf(cal.months) == 'array') { // if the calendar has a months select
            var i = cal.months.indexOf(cal.month); // and make sure the curr months exists for the new year

            if (i < 0) {
                cal.month = cal.months[0];
            } // otherwise we'll reset the month
        }

        this.display(cal);
    },


    // read: compiles cal value based on array of inputs passed in
    // @param cal (obj)
    // @returns date (obj) or (null)

    read: function (cal) {
        var arr = [null, null, null];

        cal.els.each(function (el) {
            // returns an array which may contain empty values
            var values = this.unformat(el.value, el.format);

            values.each(function (val, i) {
                if (typeOf(val) == 'number') {
                    arr[i] = val;
                }
            });
        }, this);

        // we can update the cals month and year values
        if (typeOf(arr[0]) == 'number') {
            cal.year = arr[0];
        }
        if (typeOf(arr[1]) == 'number') {
            cal.month = arr[1];
        }

        var val = null;

        if (arr.every(function (i) {
            return typeOf(i) == 'number';
        })) { // if valid date
            var last = new Date(arr[0], arr[1] + 1, 0).getDate(); // last day of month

            if (arr[2] > last) {
                arr[2] = last;
            } // make sure we stay within the month (ex in case default day of select is 31 and month is feb)

            val = new Date(arr[0], arr[1], arr[2]);
        }

        return (cal.val == val) ? null : val; // if new date matches old return null (same date clicked twice = disable)
    },


    // rebuild: rebuilds days + months selects
    // @param cal (obj)

    rebuild: function (cal) {
        cal.els.each(function (el) {
            /*
            if (el.get('tag') == 'select' && el.format.test('^(F|m|M|n)$')) { // special case for months-only select
            if (!cal.options) { cal.options = el.clone(); } // clone a copy of months select

            var val = (cal.val) ? cal.val.getMonth() : el.value.toInt();

            el.empty(); // initialize select

            cal.months.each(function(month) {
            // create an option element
            var option = new Element('option', {
            'selected': (val == month),
            'value': this.format(new Date(1, month, 1), el.format);
            }).appendText(day).inject(el);
            }, this);
            }
            */

            if (el.get('tag') == 'select' && el.format.test('^(d|j)$')) { // special case for days-only select
                var d = this.value(cal);

                if (!d) {
                    d = el.value.toInt();
                } // if the calendar doesn't have a set value, try to use value from select

                el.empty(); // initialize select

                cal.days.each(function (day) {
                    // create an option element
                    var option = new Element('option', {
                        'selected': (d == day),
                        'value': ((el.format == 'd' && day < 10) ? '0' + day : day)
                    }).appendText(day).inject(el);
                }, this);
            }
        }, this);
    },


    // sort: helper function for numerical sorting

    sort: function (a, b) {
        return a - b;
    },


    // toggle: show / hide calendar
    // @param cal (obj)

    toggle: function (cal) {
        if (this.fn) $(document).removeEvent('mousedown', this.fn); // always remove the current mousedown script first

        if (cal.visible) { // simply hide curr cal
            cal.visible = false;
            cal.button.removeClass(this.classes.active); // active

            this.fx.start('opacity', 1, 0);
        }
        else { // otherwise show (may have to hide others)
            // hide cal on out-of-bounds click
            this.fn = function (e, cal) {
                if (!e.target) {
                    var e = new Event(e);
                }

                var el = e.target;

                var stop = false;

                while (el != document.body && el.nodeType == 1) {
                    if (el == this.calendar) {
                        stop = true;
                    }
                    this.calendars.each(function (kal) {
                        if (kal.button == el || kal.els.contains(el)) {
                            stop = true;
                        }
                    });

                    if (stop) {
                        e.stop();
                        return false;
                    }
                    else {
                        el = el.parentNode;
                    }
                }

                this.toggle(cal);
            }.create({'arguments': cal, 'bind': this, 'event': true});

            $(document).addEvent('mousedown', this.fn);

            this.calendars.each(function (kal) {
                if (kal == cal) {
                    kal.visible = true;
                    kal.button.addClass(this.classes.active); // css c-icon-active
                }
                else {
                    kal.visible = false;
                    kal.button.removeClass(this.classes.active); // css c-icon-active
                }
            }, this);

            var size = window.getScrollSize();

            var coord = cal.button.getCoordinates();

            var x = coord.right + this.options.tweak.x;
            var y = coord.top + this.options.tweak.y;

            // make sure the calendar doesn't open off screen
            if (!this.calendar.coord) {
                this.calendar.coord = this.calendar.getCoordinates();
            }

            if (x + this.calendar.coord.width > size.x) {
                x -= (x + this.calendar.coord.width - size.x);
            }
            if (y + this.calendar.coord.height > size.y) {
                y -= (y + this.calendar.coord.height - size.y);
            }

            this.calendar.setStyles({left: x + 'px', top: y + 'px'});

            if (window.ie6) {
                this.iframe.setStyles({
                    height: this.calendar.coord.height + 'px',
                    left: x + 'px',
                    top: y + 'px',
                    width: this.calendar.coord.width + 'px'
                });
            }

            // read in default value
            cal.val = this.read(cal);

            this.display(cal);

            this.fx.start('opacity', 0, 1);
        }
    },


    // unformat: takes a value from an input and parses the d, m and y elements
    // @param val (string)
    // @param f (string) any combination of punctuation / separators and d, j, D, l, S, m, n, F, M, y, Y
    // @returns array

    unformat: function (val, f) {
        f = f.escapeRegExp();

        var re = {
            d: '([0-9]{2})',
            j: '([0-9]{1,2})',
            D: '(' + this.options.days.map(function (day) {
                return day.substr(0, 3);
            }).join('|') + ')',
            l: '(' + this.options.days.join('|') + ')',
            S: '(st|nd|rd|th)',
            F: '(' + this.options.months.join('|') + ')',
            m: '([0-9]{2})',
            M: '(' + this.options.months.map(function (month) {
                return month.substr(0, 3);
            }).join('|') + ')',
            n: '([0-9]{1,2})',
            Y: '([0-9]{4})',
            y: '([0-9]{2})'
        };

        var arr = []; // array of indexes

        var g = '';

        // convert our format string to regexp
        for (var i = 0; i < f.length; i++) {
            var c = f.charAt(i);

            if (re[c]) {
                arr.push(c);

                g += re[c];
            }
            else {
                g += c;
            }
        }

        // match against date
        var matches = val.match('^' + g + '$');

        var dates = new Array(3);

        if (matches) {
            matches = matches.slice(1); // remove first match which is the date

            arr.each(function (c, i) {
                i = matches[i];

                switch (c) {
                    // year cases
                    case 'y':
                        i = '19' + i; // 2 digit year assumes 19th century (same as JS)
                    case 'Y':
                        dates[0] = i.toInt();
                        break;

                    // month cases
                    case 'F':
                        i = i.substr(0, 3);
                    case 'M':
                        i = this.options.months.map(function (month) {
                            return month.substr(0, 3);
                        }).indexOf(i) + 1;
                    case 'm':
                    case 'n':
                        dates[1] = i.toInt() - 1;
                        // Fix illegal inputs (gwe)
                        dates[1] = Math.min(Math.max(dates[1], 0), 11);
                        break;

                    // day cases
                    case 'd':
                    case 'j':
                        dates[2] = i.toInt();
                        // Fix illegal inputs (gwe)
                        dates[2] = Math.min(Math.max(dates[2], 0), 31);
                        break;
                }
            }, this);
        }

        return dates;
    },


    // value: returns day value of calendar if set
    // @param cal (obj)
    // @returns day (int) or null

    value: function (cal) {
        var day = null;

        if (cal.val) {
            if (cal.year == cal.val.getFullYear() && cal.month == cal.val.getMonth()) {
                day = cal.val.getDate();
            }
        }

        return day;
    },


    // values: returns the years, months (for curr year) and days (for curr month and year) for the calendar
    // @param cal (obj)
    // @returns obj

    values: function (cal) {
        var years, months, days;

        cal.els.each(function (el) {
            if (el.get('tag') == 'select') {
                if (el.format.test('(y|Y)')) { // search for a year select
                    years = [];

                    el.getChildren().each(function (option) { // get options
                        var values = this.unformat(option.value, el.format);

                        if (!years.contains(values[0])) {
                            years.push(values[0]);
                        } // add to years array
                    }, this);

                    years.sort(this.sort);
                }

                if (el.format.test('(F|m|M|n)')) { // search for a month select
                    months = []; // 0 - 11 should be

                    el.getChildren().each(function (option) { // get options
                        var values = this.unformat(option.value, el.format);

                        if (typeOf(values[0]) != 'number' || values[0] == cal.year) { // if it's a year / month combo for curr year, or simply a month select
                            if (!months.contains(values[1])) {
                                months.push(values[1]);
                            } // add to months array
                        }
                    }, this);

                    months.sort(this.sort);
                }

                if (el.format.test('(d|j)') && !el.format.test('^(d|j)$')) { // search for a day select, but NOT a days only select
                    days = []; // 1 - 31

                    el.getChildren().each(function (option) { // get options
                        var values = this.unformat(option.value, el.format);

                        // in the special case of days we dont want the value if its a days only select
                        // otherwise that will screw up the options rebuilding
                        // we will take the values if they are exact dates though
                        if (values[0] == cal.year && values[1] == cal.month) {
                            if (!days.contains(values[2])) {
                                days.push(values[2]);
                            } // add to days array
                        }
                    }, this);
                }
            }
        }, this);

        // we start with what would be the first and last days were there no restrictions
        var first = 1;
        var last = new Date(cal.year, cal.month + 1, 0).getDate(); // last day of the month

        // if we're in an out of bounds year
        if (cal.year == cal.start.getFullYear()) {
            // in the special case of improved navigation but no months array, we'll need to construct one
            if (months == null && this.options.navigation == 2) {
                months = [];

                for (var i = 0; i < 12; i++) {
                    if (i >= cal.start.getMonth()) {
                        months.push(i);
                    }
                }
            }

            // if we're in an out of bounds month
            if (cal.month == cal.start.getMonth()) {
                first = cal.start.getDate(); // first day equals day of bound
            }
        }
        if (cal.year == cal.end.getFullYear()) {
            // in the special case of improved navigation but no months array, we'll need to construct one
            if (months == null && this.options.navigation == 2) {
                months = [];

                for (var i = 0; i < 12; i++) {
                    if (i <= cal.end.getMonth()) {
                        months.push(i);
                    }
                }
            }

            if (cal.month == cal.end.getMonth()) {
                last = cal.end.getDate(); // last day equals day of bound
            }
        }

        // let's get our invalid days
        var blocked = this.blocked(cal);

        // finally we can prepare all the valid days in a neat little array
        if (typeOf(days) == 'array') { // somewhere there was a days select
            days = days.filter(function (day) {
                if (day >= first && day <= last && !blocked.contains(day)) {
                    return day;
                }
            });
        }
        else { // no days select we'll need to construct a valid days array
            days = [];

            for (var i = first; i <= last; i++) {
                if (!blocked.contains(i)) {
                    days.push(i);
                }
            }
        }

        days.sort(this.sort); // sorting our days will give us first and last of month

        return {'days': days, 'months': months, 'years': years};
    },


    // write: sets calendars value to form elements
    // @param cal (obj)

    write: function (cal) {
        this.rebuild(cal);	 // in the case of options, we'll need to make sure we have the correct number of days available

        cal.els.each(function (el) {	// then we can set the value to the field
            el.value = this.format(cal.val, el.format);
        }, this);
    }
});

NewCalendar.implement(new Events, new Options);