// 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({	

  Implements: Options,

	options: {
		blocked: [], // blocked dates 
		classes: [], // ['calendar', 'prev', 'next', 'month', 'year', 'today', 'invalid', 'valid', 'inactive', 'active', 'hover', 'hilite']
		direction: 0, // -1 past, 0 past + future, 1 future
		draggable: true,
		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);
                
                this.boundDockClick = this.docClick.bind(this);

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

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

		this.classes = values.associate(keys);

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

		// iex 6 needs a transparent iframe underneath the calendar in order to not allow select elements to render through
		if (Browser.Engine.trident4) {
			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 (Browser.Engine.trident4) { 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 (Browser.Engine.trident4) { 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

                // Fix for IE adding a 1px margin to the input fields (it causes the button to be misplaced)
                var cssFix = (Browser.Engine.trident) ? 'bottom:3px' : '';

		for (var i in obj) {
			var cal = { 
				button: new Element('button', { 'type': 'button', 'style': cssFix }),
				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(ev, cal) { ev.stop(); this.toggle(cal); }.bindWithEvent(this, cal)).injectAfter(cal.el);
			cal.button.addClass(this.classes.calendar).addEvent('click', this.elemClick.bind(this)).injectAfter(cal.el);
                        cal.button.cal = cal;

			// 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);
			var comma = new Element('span').appendText(', ').injectInside(caption);
			var year  = new Element('span').addClass(this.classes.year).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); }


			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').appendText(', '));
			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);
		this.fireEvent('onChange', this.element);
	},


	// 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.days = cal.days;
				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
			td.addClass(this.classes.valid);
			td.removeClass(this.classes.active);
		}		
		this.fireEvent('onChange', this.element);
	},
	

	// 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', { 'cellpadding': 0, 'cellspacing': 0 }).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) { 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', DateFormat.format(date));
				
				td.addEvents({
					'click': function(td, day, cal) { 
						this.clicked(td, day, cal); 
					}.pass([td, day, cal], this),
					'mouseover': function(td, cls) { 
						td.addClass(cls); 
					}.pass([td, this.classes.hover]),
					'mouseout': function(td, cls) { 
						td.removeClass(cls); 
					}.pass([td, this.classes.hover])
				});
			}

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

			td.appendText(day);
		}
	},


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