/* MarcGrabanski.com */
/* Pop-Up Calendar Built from Scratch by Marc Grabanski */
/* Enhanced by Keith Wood (kbwood@iprimus.com.au). */
/* Under the Creative Commons Licience http://creativecommons.org/licenses/by/3.0/
    Share or Remix it but please Attribute the authors. */
var popUpCal = {
    selectedDay: new Date().getDate(),
    selectedMonth: new Date().getMonth(), // 0-11
    selectedYear: new Date().getFullYear(), // 4-digit year
    closeText: 'Close', // Display text for close link
    prevText: '<Prev', // Display text for previous month link
    nextText: 'Next>', // Display text for next month link
    currentText: 'Today', // Display text for current month link
    appendText: '', // Display text following the input box, e.g. showing the format
    buttonText: '...', // Text for trigger button
    buttonImage: '', // URL for trigger button image
    dayNames: new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'), // Names of days starting at Sunday
    monthNames: new Array('January','February','March','April','May','June','July','August','September','October','November','December'), // Names of months
    dateFormat: 'DMY/', // First three are day, month, year in the required order, fourth is the separator, e.g. US would be 'MDY/'
    yearRange: '-10:+10', // Range of years to display in drop-down, either relative to current year (-nn:+nn) or absolute (nnnn:nnnn)
    firstDay: 0, // The first day of the week, Sun = 0, Mon = 1, ...
    minDate: null, // The earliest selectable date, or null for no limit
    maxDate: null, // The latest selectable date, or null for no limit
    speed: 'medium', // Speed of display/closure
    autoPopUp: true, // True for popup on focus, false for trigger button

    init: function() {
        this.popUpShowing = false;
        $('<div id="calendar_div"></div>').appendTo('body');
        this.showFunction = function() { // pop-up calendar when triggered
            input = this;
            if (input.nodeName.toLowerCase() != 'input') { // find from button trigger
                input = $("../input", input)[0];
            }
            popUpCal.input = $(input);
            popUpCal.hideCalendar();
            popUpCal.setDateFromField();
            popUpCal.setPos(input, $('#calendar_div'));
            popUpCal.showCalendar();
            input.focus();
        };
        this.keyDownFunction = function(e) {
            if (popUpCal.popUpShowing) {
                if (e.keyCode == 9) { // hide on tab out
                    popUpCal.hideCalendar();
                }
                else if (e.keyCode == 27) { // hide on escape
                    popUpCal.hideCalendar(popUpCal.speed);
                }
                else if (e.keyCode == 33) { // previous month/year on page up/+ ctrl
                    popUpCal.adjustDate(-1, (e.ctrlKey ? 'Y' : 'M'));
                }
                else if (e.keyCode == 34) { // next month/year on page down/+ ctrl
                    popUpCal.adjustDate(+1, (e.ctrlKey ? 'Y' : 'M'));
                }
                else if (e.keyCode == 36 && e.ctrlKey) { // current on ctrl+home
                    $('#calendar_current').click();
                }
                else if (e.keyCode == 37 && e.ctrlKey) { // -1 day on ctrl+left
                    popUpCal.adjustDate(-1, 'D');
                }
                else if (e.keyCode == 38 && e.ctrlKey) { // -1 week on ctrl+up
                    popUpCal.adjustDate(-7, 'D');
                }
                else if (e.keyCode == 39 && e.ctrlKey) { // +1 day on ctrl+right
                    popUpCal.adjustDate(+1, 'D');
                }
                else if (e.keyCode == 40 && e.ctrlKey) { // +1 week on ctrl+down
                    popUpCal.adjustDate(+7, 'D');
                }
                else if (e.keyCode == 13) { // select the value on enter
                    popUpCal.selectDate();
                }
            }
            else if (e.keyCode == 36 && e.ctrlKey) { // display the calendar on ctrl+home
                popUpCal.showCalendar();
            }
        };
        this.keyPressFunction = function(e) {
            chr = String.fromCharCode(e.charCode == undefined ? e.keyCode : e.charCode);
            if (chr > ' ' && chr != popUpCal.dateFormat.charAt(3) && (chr < '0' || chr > '9')) { // only allow numbers and separator
                return false;
            }
        };
    }, // end init

    connectCalendar: function(target) {
        var $input = $(target);
        $input.after('<span class="calendar_append">' + this.appendText + '</span>');
        if (this.autoPopUp) { // pop-up calendar when in the marked fields
            $input.focus(this.showFunction);
        }
        else { // pop-up calendar when button clicked
            $input.wrap('<span class="calendar_wrap"></span>').
                after('<button class="calendar_trigger" type="button">' +
                (this.buttonImage != '' ? '<img src="' + this.buttonImage + '" alt="' + this.buttonText + '"/>' :
                this.buttonText) + '</button>');
            $('button.calendar_trigger', $input.parent('span')).click(this.showFunction);
        }
        $input.keydown(this.keyDownFunction).keypress(this.keyPressFunction);
    },

    showCalendar: function() {
        // build the calendar HTML
        html = '<a id="calendar_close">' + this.closeText + '</a>' +
            '<div id="calendar_links"><a id="calendar_prev">' + this.prevText + '</a>' +
            '<a id="calendar_current">' + this.currentText + '</a>' +
            '<a id="calendar_next">' + this.nextText + '</a></div>' +
            '<div id="calendar_header"><select id="calendar_newMonth">';
        inMinYear = (this.minDate != null && this.minDate.getFullYear() == this.selectedYear);
        inMaxYear = (this.maxDate != null && this.maxDate.getFullYear() == this.selectedYear);
        for (var month = 0; month < 12; month++) {
            if (!((inMinYear && month < this.minDate.getMonth()) ||
                    (inMaxYear && month > this.maxDate.getMonth()))) {
                html += '<option value="' + month + '"' +
                    (month == this.selectedMonth ? ' selected="selected"' : '') +
                    '>' + this.getMonthName(month) + '</option>';
            }
        }
        html += '</select> <select id="calendar_newYear">';
        // determine range of years to display
        years = this.yearRange.split(':');
        if (years.length != 2) {
            year = this.selectedYear - 10;
            endYear = this.selectedYear + 10;
        }
        else if (years[0].charAt(0) == '+' || years[0].charAt(0) == '-') {
            year = this.selectedYear + parseInt(years[0]);
            endYear = this.selectedYear + parseInt(years[1]);
        }
        else {
            year = parseInt(years[0]);
            endYear = parseInt(years[1]);
        }
        if (this.minDate != null) {
            year = Math.max(year, this.minDate.getFullYear());
        }
        if (this.maxDate != null) {
            endYear = Math.min(endYear, this.maxDate.getFullYear());
        }
        for (; year <= endYear; year++) {
            html += '<option value="' + year + '"' +
                (year == this.selectedYear ? ' selected="selected"' : '') +
                '>' + year + '</option>';
        }
        html += '</select></div>' +
            '<table id="calendar" cellpadding="0" cellspacing="0"><thead>' +
            '<tr class="calendar_titleRow">';
        for (var dow = 0; dow < this.dayNames.length; dow++) {
            html += '<td>' + this.dayNames[(dow + this.firstDay) % 7].charAt(0) + '</td>';
        }
        html += '</tr></thead><tbody>';
        daysInMonth = this.getDaysInMonth(this.selectedYear, this.selectedMonth);
        this.selectedDay = Math.min(this.selectedDay, daysInMonth);
        noPrintDays = (this.getFirstDayOfMonth(this.selectedYear, this.selectedMonth) - this.firstDay + 7) % 7;
        printDate = 1;
        numRows = Math.ceil((noPrintDays + daysInMonth) / 7); // calculate the number of rows to generate
        today = new Date();
        inMinMonth = (this.minDate != null && this.minDate.getFullYear() == this.selectedYear &&
            this.minDate.getMonth() == this.selectedMonth);
        inMaxMonth = (this.maxDate != null && this.maxDate.getFullYear() == this.selectedYear &&
            this.maxDate.getMonth() == this.selectedMonth);
        for (var row = 0; row < numRows; row++) { // create calendar rows
            html += '<tr class="calendar_daysRow">';
            for (var dow = 0; dow < 7; dow++) { // create calendar days
                unselectable = ((inMinMonth && printDate < this.minDate.getDate()) ||
                            (inMaxMonth && printDate > this.maxDate.getDate()));
                html += '<td class="calendar_daysCell' +
                    ((dow + this.firstDay + 6) % 7 >= 5 ? ' calendar_weekEndCell' : '') + // highlight weekends too
                    (printDate == this.selectedDay && noPrintDays == 0 ?
                    ' calendar_daysCellOver' : '') + // highlight selected day
                    (unselectable ? ' calendar_unselectable' : '') + '"'; // highlight unselectable days
                if ((printDate == this.currentDay) && (this.selectedMonth == this.currentMonth) &&
                        (this.selectedYear == this.currentYear) && (noPrintDays == 0)) {
                    html += ' id="calendar_currentDay"'; // highlight current day
                }
                else if ((printDate == today.getDate()) && (this.selectedMonth == today.getMonth()) &&
                        (this.selectedYear == today.getFullYear()) && (noPrintDays == 0)) {
                    html += ' id="calendar_today"'; // highlight today (if different)
                }
                html += '>';
                if (noPrintDays == 0) {
                    if (unselectable) {
                        html += (printDate <= daysInMonth ? printDate : '&nbsp;');
                    }
                    else {
                        html += (printDate <= daysInMonth ? '<a>' + printDate + '</a>' : '&nbsp;');
                    }
                    printDate++;
                }
                else {
                    html += '&nbsp;';
                }
                html += '</td>';
                if (noPrintDays > 0) noPrintDays--;
            }
            html += '</tr>';
        }
        html += '</tbody></table><!--[if lte IE 6.5]><iframe id="calendar_cover"></iframe><![endif]-->';
        // add calendar to element to calendar Div
        $('#calendar_div').empty().append(html).show(this.speed);
        this.popUpShowing = true;
        this.setupDayLinks();
        // close button link
        $('#calendar_close').click(function() {
            popUpCal.hideCalendar(popUpCal.speed);
        });
        // setup navigation links
        $('#calendar_prev').click(function() {
            popUpCal.adjustDate(-1, 'M');
        });
        $('#calendar_next').click(function() {
            popUpCal.adjustDate(+1, 'M');
        });
        $('#calendar_current').click(function() {
            this.currentDay = new Date().getDate();
            popUpCal.selectedDay = new Date().getDate();
            popUpCal.selectedMonth = new Date().getMonth();
            popUpCal.selectedYear = new Date().getFullYear();
            popUpCal.showCalendar();
        });
        $('#calendar_newMonth').change(function() {
            popUpCal.selectedMonth = this.options[this.selectedIndex].value - 0;
            popUpCal.adjustDate();
        });
        $('#calendar_newYear').change(function() {
            popUpCal.selectedYear = this.options[this.selectedIndex].value - 0;
            popUpCal.adjustDate();
        });
    }, // end showCalendar

    setupDayLinks: function() {
        // set up link events on calendar table
        $('#calendar td[a]').hover(
            function() {
                $(this).addClass('calendar_daysCellOver');
            }, function() {
                $(this).removeClass('calendar_daysCellOver');
        });
        $('#calendar a').click(function() {
            popUpCal.selectedDay = $(this).html();
            popUpCal.selectDate();
        });
    },

    hideCalendar: function(speed) {
        if (this.popUpShowing) {
            $('#calendar_div').hide(speed);
            this.popUpShowing = false;
        }
    },

    selectDate: function() {
        this.hideCalendar(this.speed);
        setVal = this.formatDate(this.selectedDay, this.selectedMonth, this.selectedYear);
        this.input.val(setVal);
    },

    /* Functions Dealing with Dates */
    formatDate: function(day, month, year) {
        month++; // adjust javascript month
        if (month <10) month = '0' + month; // add a zero if less than 10
        if (day < 10) day = '0' + day; // add a zero if less than 10
        var dateString = '';
        for (var i = 0; i < 3; i++) {
            dateString += this.dateFormat.charAt(3) + (this.dateFormat.charAt(i) == 'D' ? day :
                (this.dateFormat.charAt(i) == 'M' ? month :
                (this.dateFormat.charAt(i) == 'Y' ? year : '?')));
        }
        return dateString.substring(1);
    },

    setDateFromField: function() {
        currentDate = this.input.val().split(this.dateFormat.charAt(3));
        if (currentDate.length == 3) {
            this.currentDay = parseInt(this.trimNumber(currentDate[this.dateFormat.indexOf('D')]));
            this.currentMonth = parseInt(this.trimNumber(currentDate[this.dateFormat.indexOf('M')])) - 1;
            this.currentYear = parseInt(this.trimNumber(currentDate[this.dateFormat.indexOf('Y')]));
        } else {
            this.currentDay = new Date().getDate();
            this.currentMonth = new Date().getMonth();
            this.currentYear = new Date().getFullYear();
        }
        this.selectedDay = this.currentDay;
        this.selectedMonth = this.currentMonth;
        this.selectedYear = this.currentYear;
        this.adjustDate(0, 'D', true);
    },

    trimNumber: function(value) {
        if (value == '')
            return '';
        while (value.charAt(0) == '0') {
            value = value.substring(1);
        }
        return value;
    },

    adjustDate: function(offset, period, dontShow) {
        // adjust the data as requested
        if (period == 'D') {
            this.selectedDay = this.selectedDay + offset;
        }
        else if (period == 'M') {
            this.selectedMonth = this.selectedMonth + offset;
        }
        else if (period == 'Y') {
            this.selectedYear = this.selectedYear + offset;
        }
        date = new Date(this.selectedYear, this.selectedMonth, this.selectedDay);
        // ensure it is within the bounds set
        if (this.minDate != null) {
            date = (date > this.minDate ? date : this.minDate);
        }
        if (this.maxDate != null) {
            date = (date < this.maxDate ? date : this.maxDate);
        }
        this.selectedDay = date.getDate();
        this.selectedMonth = date.getMonth();
        this.selectedYear = date.getFullYear();
        if (!dontShow) {
            this.showCalendar();
        }
    },

    getMonthName: function(month) {
        return this.monthNames[month];
    },

    getDayName: function(day) {
        return this.dayNames[day];
    },

    getDaysInMonth: function(year, month) {
        return 32 - new Date(year, month, 32).getDate();
    },

    getFirstDayOfMonth: function(year, month) {
        return new Date(year, month, 1).getDay();
    },

    /* Position Functions */
    setPos: function(targetObj, moveObj) {
        var coords = this.findPos(targetObj);
        moveObj.css('position', 'absolute');
        moveObj.css('left', coords[0] + 'px');
        moveObj.css('top', (coords[1] + targetObj.offsetHeight) + 'px');
    },

    findPos: function(obj) {
    var curleft = curtop = 0;
    if (obj.offsetParent) {
        curleft = obj.offsetLeft;
        curtop = obj.offsetTop;
            while (obj = obj.offsetParent) {
                var origcurleft = curleft;
                curleft += obj.offsetLeft;
                if (curleft < 0) {
                    curleft = origcurleft;
                }
                curtop += obj.offsetTop;
            }
    }
    return [curleft,curtop];
    }
};

$.fn.calendar = function(a) {
    // attach the calendar to each nominated input element
    this.each(function() {
        if (this.nodeName.toLowerCase() == 'input') {
            popUpCal.connectCalendar(this);
        }
    });
    return this;
};

// Initialise the calendar
$(document).ready(function() {
   popUpCal.init();
});