Object.extend(Date.prototype, {

    monthnames: ['January','February','March','April','May','June','July','August','September','October','November','December'],

    daynames: ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'],

    succ: function(){

        var sd = new Date(this.getFullYear(),this.getMonth(),this.getDate()+1);

        sd.setHours(this.getHours(),this.getMinutes(),this.getSeconds(),this.getMilliseconds());

        return sd;

    },

    firstofmonth: function(){

        return new Date(this.getFullYear(),this.getMonth(),1);

    },

    lastofmonth: function(){

        return new Date(this.getFullYear(),this.getMonth()+1,0);

    },

	formatPadding: true,

    format: function(f){

        if (!this.valueOf()) { return ' '; }

        var d = this;

        var formats = {

            'yyyy' : d.getFullYear(),

            'mmmm': this.monthnames[d.getMonth()],

            'mmm':  this.monthnames[d.getMonth()].substr(0, 3),

            'mm':   this.formatPadding ? ((d.getMonth()).succ()).toPaddedString(2) : (d.getMonth()).succ(),

            'dddd': this.daynames[d.getDay()],

            'ddd':  this.daynames[d.getDay()].substr(0, 3),

            'dd':   d.getDate().toPaddedString(2),

            'hh':   h = d.getHours() % 12 ? h : 12,

            'nn':   d.getMinutes(),

            'ss':   d.getSeconds(),

            'a/p':  d.getHours() < 12 ? 'a' : 'p'

        };

        return f.gsub(/(yyyy|mmmm|mmm|mm|dddd|ddd|dd|hh|nn|ss|a\/p)/i,

            function(match) { return formats[match[0].toLowerCase()]; });

    }

});



var scal = {};

scal = Class.create();

scal.prototype = {

    initialize: function(element,update) {

        this.element = $(element);

        var type = Try.these(

            function(){ if(!Object.isUndefined(Effect)) { return 'Effect'; }},

            function(){ return 'Element'; }

        );  

        this.startdate = new Date();

        this.startdate.setHours(0,0,0,0);

        this.options = Object.extend({

		  oncalchange: Prototype.emptyFunction,

		  daypadding: false,

          titleformat: 'mmmm yyyy',

          updateformat: 'yyyy-mm-dd',

          closebutton: 'X',

          prevbutton: '&laquo;',

          nextbutton: '&raquo;',

          yearnext: '&raquo;&raquo;',

          yearprev: '&laquo;&laquo;',

          openeffect: type == 'Effect' ? Effect.Appear : Element.show,

          closeeffect: type == 'Effect' ? Effect.Fade : Element.hide,

          exactweeks: false,

          dayheadlength: 2,

          weekdaystart: 0,

          planner: false,

          tabular: false,

          year: this.startdate.getFullYear(),

          month: 0,

          day: 0

        }, arguments[2] || { });   

        --this.options.month;

        this.table = false;

        this.thead = false;

        if(this.options.month != -1 && Object.isNumber(this.options.month)) { this.startdate.setMonth(this.options.month); }

        if(this.options.day != 0 && Object.isNumber(this.options.day)) { this.startdate.setDate(this.options.day); }

        if(this.options.year != this.startdate.getFullYear() && Object.isNumber(this.options.month)) { this.startdate.setYear(this.options.year); }

        if(this.options.planner) { this.planner = this._setupPlanner(this.options.planner); }

        if(this.options.tabular) { 

            this.table = new Element('table',{'class': 'cal_table',border: 0,cellspacing: 0,cellpadding: 0});

            this.thead = new Element('thead');

            this.table.insert(this.thead);

            this.element.insert(this.table);

        }

        this.updateelement = update;

        this._setCurrentDate(this.startdate); 

        this.initDate = new Date(this.currentdate);

        this.controls = this._buildControls();

		this.title.setAttribute('title', this.initDate.format(this.options.titleformat));

        this._updateTitles();

        this[this.table ? 'thead' : 'element'].insert(this.controls);

        this.cal_wrapper = this._buildHead();

        this.cells = [];

        this._buildCal();

    },

/*------------------------------- INTERNAL -------------------------------*/    

    _emptyCells: function() {

        if(this.cells.size() > 0) { 

            this.cells.invoke('stopObserving'); 

            this.cells.invoke('remove');

            this.cells = [];

        }

    },

    _buildCal: function() {

        this._emptyCells();

        if(!(Object.isUndefined(this.cal_weeks_wrapper) || this.table)) { this.cal_weeks_wrapper.remove(); }

        this.cal_weeks_wrapper = this._buildWrapper();

        if(this.table) {

            this.table.select('tbody tr.weekbox:not(.weekboxname)').invoke('remove');

            this.table.select('tbody.cal_wrapper').invoke('remove');

            this.cal_weeks_wrapper.each(function(row){

                this.cal_wrapper.insert(row);

            }.bind(this));

        } else {

            this.cal_wrapper.insert(this.cal_weeks_wrapper);

        }

        this[this.table ? 'table' : 'element'].insert(this.cal_wrapper);

    },

    _click: function(event,cellIndex) {

        this.element.select('.dayselected').invoke('removeClassName', 'dayselected');

        (event.target.hasClassName('daybox') ? event.target : event.target.up()).addClassName('dayselected');

        this._setCurrentDate(this.dateRange[cellIndex]);

        this._updateExternal();

    },

    _updateExternal: function(){	

        if (Object.isFunction(this.updateelement)){

            this.updateelement(this.currentdate);

        } else {	

            var updateElement = $(this.updateelement);

            updateElement[updateElement.tagName == 'INPUT' ? 'setValue' : 'update'](this.currentdate.format(this.options.updateformat));

        }            

    },    

    _buildHead: function() {

        var cal_wrapper = new Element(this.table ? 'tbody' : 'div',{'class':'cal_wrapper'});

        var weekbox = new Element(this.table ? 'tr' : 'div',{'class':'weekbox weekboxname'});

        Date.prototype.daynames.sortBy(function(s,i){

            i+=this.options.weekdaystart;

            if(i>6){i-=7;}

            return i;

        }.bind(this)).each(function(day,i) {

        var cell = new Element(this.table ? 'td' : 'div',{'class':'cal_day_name_'+ i});

        cell.addClassName('daybox').addClassName('dayboxname').update(day.substr(0,this.options.dayheadlength));

        if(i == 6) { cell.addClassName('endweek'); }

        weekbox.insert(cell);

        }.bind(this));

        return cal_wrapper.insert(weekbox);

    },

    _buildWrapper: function() {

        var firstdaycal = new Date(this.firstofmonth.getFullYear(),this.firstofmonth.getMonth(),this.firstofmonth.getDate());

        var lastdaycal = new Date(this.lastofmonth.getFullYear(),this.lastofmonth.getMonth(),this.lastofmonth.getDate());

        firstdaycal.setDate(firstdaycal.getDate() - firstdaycal.getDay() + this.options.weekdaystart);

        var dateRange = $A($R(firstdaycal,lastdaycal));

        var cal_weeks_wrapper = this.table ? [] : new Element('div',{'class': 'calweekswrapper'});

        var wk;

        var row;

        var lastday;

        this.dateRange = [];

        this.indicators = []; // holds values to determine if continued checking for custom classes is needed

        var buildWeek = function(day) {

            row.insert(this._buildDay(wk, day));

            lastday = day;

        }.bind(this);       

        dateRange.eachSlice(7, function(slice,i) {

            wk = i;

            row = new Element(this.table ? 'tr' : 'div',{'class':'cal_week_' + wk}).addClassName('weekbox');

            while(slice.length < 7) { 

                slice.push(slice.last().succ());

            }

            slice.map(buildWeek);	

            cal_weeks_wrapper[this.table ? 'push' : 'insert'](row);

        }.bind(this));

        if(!this.options.exactweeks) {

            var toFinish = 42 - this.cells.size(); 

            var wkstoFinish = Math.ceil(toFinish / 7);

            if(wkstoFinish > 0) { toFinish = toFinish / wkstoFinish; }

            $R(1,wkstoFinish).each(function(w){

                wk += 1;

                row = new Element(this.table ? 'tr' : 'div',{'class':'cal_week_' + wk}).addClassName('weekbox'); 

                $R(1,toFinish).each(function(i) {

                    var d = lastday.succ();

                    row.insert(this._buildDay(wk, d));

                    cal_weeks_wrapper[this.table ? 'push' : 'insert'](row);

                    lastday = d;

                }.bind(this));

            }.bind(this));

        }	

        return cal_weeks_wrapper;

    },

    _compareDates: function(date1,date2,type){

        return (this.indicators.indexOf(type) >= 0) ? false : Object.isUndefined(['getMonth','getDate','getFullYear'].find(function(n){ return date1[n]() != date2[n](); }));

    },

    _buildDay: function(week,day){

        this.dateRange.push(day);

        var cellid = 'cal_day_' + week + '_' + day.getDay();

        var cell = new Element(this.table ? 'td' : 'div',{'class':cellid});

        var celldate = new Element('div',{'class':cellid+'_date'}).addClassName('dayboxdate').update(this.options.daypadding ? ((day.getDate()).toPaddedString(2)) : day.getDate());

        var cellvalue = new Element('div',{'class':cellid+'_value'}).addClassName('dayboxvalue');

        if(this.options.planner) { this._updatePlanner(day,cellvalue); }

        cell.insert(celldate).insert(cellvalue).addClassName('daybox').addClassName('daybox'+ day.format('dddd').toLowerCase());

        // if we are on the currently selected date, set the class to dayselected (i.e. highlight it).

        if(this._compareDates(day,this.currentdate,'dayselected')) {

            cell.addClassName('dayselected');

            this.indicators.push('dayselected');

        }

        if(this._compareDates(day,new Date(),'today')) {

            cell.addClassName('today');

            this.indicators.push('today');

        }

        if(day.getDay() == 6) { cell.addClassName('endweek'); }

        // if we are outside the current month set the day style to 'deactivated'

        var cs = day.getMonth() != this.currentdate.getMonth() ? ['dayoutmonth','dayinmonth'] : ['dayinmonth','dayoutmonth'];

        cell.addClassName(cs[0]);

        if(cell.hasClassName(cs[1])) { cell.removeClassName(cs[1]); }

        this.cells.push(cell);

        return cell.observe('click', this._click.bindAsEventListener(this, this.cells.size() - 1));

    },

    _updateTitles: function() {

        var yr = this.currentdate.getFullYear();

        var mnth = this.currentdate.getMonth();

        var titles = {

            calprevmonth: Date.prototype.monthnames[(mnth - 1) == -1 ? 11 : mnth - 1],

            calprevyear: yr - 1,

            calnextyear: yr + 1,

            calnextmonth: Date.prototype.monthnames[(mnth + 1) == 12 ? 0 : mnth + 1]

        };

        this.controls.select('.calcontrol').each(function(ctrl) {

           var title = titles[ctrl.className.split(' ')[0]];

           if(!Object.isUndefined(title)) { ctrl.setAttribute('title',title); }

        });

    },

    _buildControls: function() {

        var hParts = [

            {p: 'calclose', u: this.options.closebutton, f:  this.toggleCalendar.bindAsEventListener(this)},

            {p: 'calprevmonth', u: this.options.prevbutton, f: this._switchCal.bindAsEventListener(this,'monthdown')},

            {p: 'calprevyear', u: this.options.yearprev, f: this._switchCal.bindAsEventListener(this,'yeardown')},

            {p: 'calnextyear', u: this.options.yearnext, f: this._switchCal.bindAsEventListener(this,'yearup')},

            {p: 'calnextmonth', u: this.options.nextbutton, f: this._switchCal.bindAsEventListener(this,'monthup')},

            {p: 'caltitle', u: this.currentdate.format(this.options.titleformat), f: this._switchCal.bindAsEventListener(this,'init')}

        ];

        if(this.table) { hParts = [hParts[1],hParts[2],hParts[5],hParts[3],hParts[4],hParts[0]]; }

        var cal_header = new Element(this.table ? 'tr' : 'div',{'class':'calheader'});

        hParts.each(function(part) {

            var el = new Element(this.table ? 'td' : 'div',{'class': part.p});

            if(part.p == 'caltitle') {

                this.title = el;

                if(this.table) { el.writeAttribute({colspan: 2}); }

                el.update(part.u).observe('click',part.f);

            } else {

                el.addClassName('calcontrol');

                el[typeof(part.u) == 'object' ? 'insert' : 'update'](part.u).observe('click',part.f);

            }

            cal_header.insert(el);

        }.bind(this));

        return cal_header;

    },

    _switchCal: function(){

		if(arguments[1]) {

			var event = arguments[0];

			var direction = arguments[1];

			event.date = this.currentdate;

		} else {

			var direction = arguments[0];

		}			

		var params = {f: 'setTime', p: this.initDate.getTime()};

		if(direction != 'init') {

            var d = this.currentdate[direction.include('month') ? 'getMonth' : 'getFullYear']();

			params = {f: direction.include('month') ? 'setMonth' : 'setYear', p: direction.include('up') ? d + 1 : d - 1};

		}

		this.currentdate[params.f](params.p);

    	if(arguments[1]) { this.options.oncalchange(event); }

        this._update();

    }, 

    _update: function() {

        this._setCurrentDate(arguments[0] ? arguments[0] : this.currentdate);

        this.title.update(this.currentdate.format(this.options.titleformat));

        this._buildCal();

        this._updateTitles();

    },

    _setCurrentDate: function(date){

        this.currentdate = new Date(date.getFullYear(),date.getMonth(),date.getDate());

        this.firstofmonth = this.currentdate.firstofmonth();

        this.lastofmonth = this.currentdate.lastofmonth();

    },    

    _getCellIndexByDate: function(d) {

        var dj = d.toJSON();

        var cellIndex = 0;

        this.dateRange.each(function(dt,i) {

            if(dt.toJSON() == dj) {

                cellIndex = i;

                throw $break;

            }

        });

        return cellIndex;

    },

/*------------------------------- PUBLIC -------------------------------*/        

    destroy: function(){

        this._emptyCells();

        if(this.table) { 

            this.element.select('.cal_table').invoke('remove');

        } else {

            this.cal_weeks_wrapper.remove();

        }

		this.controls.descendants().invoke('stopObserving');

        [this.cal_wrapper,this.controls].invoke('remove');

    },

    setCurrentDate: function(direction){

        this[(direction instanceof Date) ? '_update' : '_switchCal'](direction);

        if(!arguments[1]) { this._updateExternal(); }

		return this.currentdate; 

    },

    toggleCalendar: function(){

        this.options[this.element.visible() ? 'closeeffect' : 'openeffect'](this.element);

    },

    getElementByDate: function(d) {

        return this.cells[this._getCellIndexByDate(d)];

    },

    getElementsByWeek: function(week) {

        return this.element.select('.weekbox:nth-of-type(' + (week + 1) + ') .daybox:not(.dayboxname)');

    },

    getSelectedElement: function() {

        return this.element.select('.dayselected')[0];

    },

    getTodaysElement: function() {

        return this.element.select('.today')[0];

    },

    getDateByElement: function(element) {

        return this.dateRange[this.cells.indexOf(element)];

    },

/*------------------------------- PLUG-IN PLACEHOLDERS -------------------------------*/            

    _setupPlanner: Prototype.emptyFunction,

    _updatePlanner: Prototype.emptyFunction,

/*------------------------------- DEPRECATED -------------------------------*/            

    openCalendar: function(){ 

        if(!this.isOpen()){ this.toggleCalendar(); }

    },

    closeCalendar: function(){ 
        if(this.isOpen()){ this.toggleCalendar(); }

    },

    isOpen: function(){ 

        return this.element.visible();

    }

};