// 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

var Calendar = new Class({

  options: {
    blocked: [], // blocked dates 
    classes: [], // ['calendar', 'prev', 'next', 'month', 'year', 'today', 'invalid', 'valid', 'inactive', 'active', 'hover', 'hilite','today']
    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
  },

  // 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', 'today'];

    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);

    //for some reason ie6 is nor reporting as ie6 so set it as a hack here
    //window.ie6 = false;
    
    // 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: 9000 }
      }).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);
        }
        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)).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(1000, 0, 1); // jan 1, 1000
    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);
  },


  // 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
      if (!td.hasClass('todaysDateLink')) {
        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 = [];
    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 (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 && (day >= 1 && day <= last)) { 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);
    }

    // add the last row for todays date link
    var trToday = new Element('tr').injectInside(tbody);
    var tdToday = new Element('td').injectInside(trToday);
    tdToday.colSpan = 7;
    tdToday.addClass('todaysDateLink');

    var txtToday = new Element('span').injectInside(tdToday);
    txtToday.addClass('lnk');
    txtToday.appendText('Today\'s date');

    var day = d.getDate();

    tdToday.addEvents({
      'click': function(tdToday, day, cal) {
        var calDate = new Date(cal.val);
        if (!cal.val || (new Date(calDate.getFullYear(), calDate.getMonth(), calDate.getDate()) != new Date(d.getFullYear(), d.getMonth(), d.getDate()))) {
          cal.month = d.getMonth();
          cal.year = d.getFullYear();
          this.clicked(tdToday, day, cal);
        }
      } .pass([tdToday, day, cal], this)
    });
  },

  // 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);