// 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 Å ego

var Calendar = new Class({   

   options: {
      blocked: [], // blocked dates 
      classes: ['calendar', 'prev'], // ['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: 1, // 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
      kstLang: "en", // add kst
      kstType: 1 // add kst
   },

   // 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'];

      // start:  add kst
      if(this.options.kstType==2) {
         this.kstEventDates = [];
         var kstEl = $('selectedDays1').getProperty('value');
         if(kstEl!="") {
            this.kstEventDates = kstEl.split(',');
         }
      }
      //end: add kst

      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).injectInside(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 }
         }).injectInside(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, 200); // mod: kst > add ', 200'
            }
            else { // hide
               this.fireEvent('onHideStart', this.element, 200); // mod: kst > add ', 200'
            }
         }.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, 200); // mod: kst > add ', 200'
            }
            else { // shown
               this.fireEvent('onShowComplete', this.element, 200); // mod: kst > add ', 200'
            }
         }.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)).injectAfter(cal.el);

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

         $extend(cal, this.bounds(cal)); // abs bounds of calendar

         $extend(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
      var start = new Date(2009, 0, 1); // jan 1, 1000 // mod kst: 1000 > 2009
      var end = new Date(2999, 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 ($type(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 ($type(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 ($type(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) {
         var month = new Element('span').addClass(this.classes.month).injectInside(caption);
         
         if (navigation.prev.month) { prev.clone().addEvent('click', function(cal) { this.navigate(cal, 'm', -1); }.pass(cal, this)).injectInside(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)).injectInside(month); }

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

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

      $extend(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();      

               $extend(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);
   },
   
   kstClicked: function(td, day, cal) {
   
      cal.val = new Date(cal.year, cal.month, day);
      
      var el = this.format(cal.val, cal.el.format);
      if(this.kstEventDates.contains(el)) {
         this.kstEventDates.remove(el);
         td.removeClass(this.classes.inactive);
         td.addClass(this.classes.valid);
      }else{
         this.kstEventDates.push(el);
         td.addClass(this.classes.inactive);
      }
      $("view-days").innerHTML = this.kstEventDates;
      $("selectedDays1").setProperty('value', this.kstEventDates);
   },   
   

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

   clicked: function(td, day, cal) {
      cal.val = (this.value(cal) == day) ? null : new Date(cal.year, cal.month, day); // 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').injectInside(this.calendar); // a wrapper div to help correct browser css problems with the caption element

      var table = new Element('table').injectInside(div).adopt(this.caption(cal));
            
      // 2. day names      
      var thead = new Element('thead').injectInside(table);

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

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

      // start: add kst 
      if(this.options.kstType==2) {
         var kstEventDates_copy = this.kstEventDates.map(function(item) {
            var day = null;
            var dateArray = item.split('-');
            dateArray[1]=dateArray[1]-1;
            //if (cal.val) {
               if (cal.year == dateArray[2] && cal.month == dateArray[1]) { day = dateArray[0].toInt();}
            //}
            return day;
         },this);
      }
      // end: add kst

      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();
      var today = new Date(d.getFullYear(), d.getMonth(), d.getDate()).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').injectInside(tbody); } // each week is it's own table row

         var td = new Element('td').injectInside(tr);
                  
         var day = i - offset;
         var date = new Date(cal.year, cal.month, day);
         
         var cls = '';
         
         if ((this.options.kstType==1 && day === active) ) { cls = this.classes.active; } // active // mod kst
         else if (inactive.contains(day) || (this.options.kstType==2 && kstEventDates_copy.contains(day))) { cls = this.classes.inactive; } // inactive // mod kst
         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')); // mod kst
            // start: add kst
            if (this.options.kstLang == "pl") {
               td.setProperty('title', this.format(date, 'l, j F Y')); // mod kst
            }else{
               td.setProperty('title', this.format(date, 'l, jS \of F Y')); // mod kst
            }
            // end: add kst
            
            td.addEvents({
               'click': function(td, day, cal) { 
                  if(this.options.kstType==2) { // mod kst > add if
                     this.kstClicked(td, day, cal);
                  }else{
                     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 ($type(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
         el.readOnly = true;
         el.addEvent('focus', function(cal) { this.toggle(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 ($type(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
                        this.navigate(cal, 'y', 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) {
                        this.navigate(cal, 'y', n);   
                     }
      
                     i = (i < 0) ? 11 : 0;
                  }
                  
                  cal.month = i;
               }      
               break;

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

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

      $extend(cal, this.values(cal));

      if ($type(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 ($type(val) == 'number') { arr[i] = val; }
         }); 
      }, this);

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

      var val = null;

      if (arr.every(function(i) { return $type(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).injectInside(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).injectInside(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) {
      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) { 
            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' }); 
         }

         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;
                  break;

               // day cases
               case 'd':
               case 'j':
                  dates[2] = i.toInt();
                  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 ($type(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 ($type(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);
   }
});

Calendar.implement(new Events, new Options);