//
// JavaScript Event Calendar
//
// Version: 1.0
// Date: November 15, 1998
// For information: http://members.aol.com/kevinilsen  or kilsen@m-vation.com
//

// Configurable values are set to defaults here; can override them before calling Calendar( ) from the HTML page

var SpecialDay=0;       // 1=Sunday, 2=Monday, . . . 7=Saturday
var FontSize=5;
var ColorBackground="ffffcc";
var ColorSpecialDay = "green";
var ColorToday = "blue";
var ColorEvent = "red";

// Initialize the range of the calendar to Jan - Dec of the current year.  Calls to DefineEvent( ) will change this
// as needed; it is also possible to explicitly override the range before calling Calendar( ) from the HTML page.

var today = new Date();
var FirstMonth=GetFullYear(today) * 100 + 1;
var LastMonth=FirstMonth + 11;

// Events[] is a SPARSE array; Call DefineEvent( ) to populate it
var Events = new Array;

// Each event is defined by calling the DefineEvent( ) routine with the following parameters:
//
//   DefineEvent(EventDate, EventDescription, EventLink, Image, Width, Height)
//        EventDate is a numeric value in the format YYYYMMDD
//        EvenDescription is a string that can include embedded HTML tags (e.g., <BR>, <strong>, etc.)
//        EventLink is the URL of the target page if a hyperlink is desired from this event entry
//        Image is the URL of the image if you want to display an image with this event
//        Width is the width of the image in pixels
//        Height is the height of the image in pixels

function DefineEvent(EventDate, EventDescription, EventLink, Image, Width, Height) {
        var tmp;

        // Build the HTML string for this event: image (optional), link (optional), and description
        tmp = "";
        if (Image != "")
                tmp = tmp + '<img src="' + Image + '"  width="' + Width + '" height="' + Height + '" align="left" valign="top">';
        if (EventLink != "")
                tmp = tmp + '<a href="' + EventLink + '">';
        tmp = tmp + EventDescription;
        if (EventLink != "") tmp = tmp + '</a>';

        // If an event already exists for this date, append the new event to it.
        if (Events[EventDate])
                Events[EventDate] += "<BR>" + tmp;
        else
                Events[EventDate] = tmp;

        // Adjust the minimum and maximum month & year to include this date
        tmp = Math.floor(EventDate / 100);
        if (tmp < FirstMonth) FirstMonth = tmp;
        if (tmp > LastMonth) LastMonth = tmp;
}

// Utility function to populate an array with values
function arr() {
        for (var n=0;n<arr.arguments.length;n++) {
                this[n+1] = arr.arguments[n];
        }
}

// Create the array of month names (used in various places)
var months = new arr("January","February","March","April","May","June","July","August","September","October","November","December");

// Calendar( ) is the only routine that needs to be called to display the calendar

function Calendar( ) {
        var curdy, curmo, yr, mo, dy, dayofweek, yearmonth, bgn, lastday, jump;
        var weekdays = new arr("Sun","Mon","Tue","Wed","Thu","Fri","Sat");
        var thispage = window.location.pathname;

        // Save current day and month for comparison
        curdy = today.getDate();
        curmo = today.getMonth()+1;

        // Default to current month and year
        mo = curmo;
        yr = GetFullYear(today);
        yearmonth = (yr * 100) + mo;

        // If querystring parameter is present, get the month/year ("calendar.htm?YYYYMM")
        if (location.search.length > 1) {
                yearmonth = parseInt(location.search.substring(1,location.search.length));
                if ((""+yearmonth).length == 6) {
                        mo = yearmonth % 100;
                        yr = (yearmonth - mo) / 100;
                }
        }

        // Constrain to the range of months with events
        if (yearmonth < FirstMonth) {
                mo = FirstMonth % 100;
                yr = (FirstMonth - mo) / 100;
                yearmonth = FirstMonth;
        }
        if (yearmonth > LastMonth) {
                mo = LastMonth % 100;
                yr = (LastMonth - mo) / 100;
                yearmonth = LastMonth;
        }

        // Create a datae object for the first day of the desired month
        bgn = new Date(months[mo] + " 1," + yr);
        // Get the day-of-week of the first day, and the # days in the month
        dayofweek = bgn.getDay();
        lastday = NumDaysIn(mo,yr);
        document.write("<TABLE BORDER=2 BGCOLOR="+ColorBackground+"><TR><TD ALIGN=CENTER COLSPAN=7><FONT FACE=ARIAL SIZE="+FontSize+"><B>"+months[mo]+" "+yr+"</B></FONT></TD></TR><TR>");
        for (var i=1;i<=7;i++){
                document.write("<TD ALIGN=CENTER WIDTH=70><FONT FACE=ARIAL SIZE=1>"+weekdays[i]+"</FONT></TD>");
        }
        document.write("</TR><TR>");
        dy = 1;
        // Special handling for the first week of the month
        for (var i=1;i<=7;i++) {
                // If the day is less than the day of the
                // week determined to be the first day
                // of the month, print a space in
                // this cell of the table.
                if (i <= dayofweek){
                        document.write("<TD ALIGN=CENTER><FONT FACE=ARIAL SIZE="+FontSize+">&nbsp;</FONT></TD>");
                }
                // Otherwise, write date and the event,
                // if any, in this cell of the table.
                else {
                        ShowDate(yr,mo,dy,i,curmo,curdy);
                        dy++;
                }
        }
        document.write("</TR><TR>");
        // Rest of the weeks . . .
        while (dy <= lastday) {
                for (var i=1;i<=7;i++) {
                        // If the day is greater than the last
                        // day of the month, print a space in
                        // this cell of the table.
                        if (dy > lastday) {
                                document.write("<TD ALIGN=CENTER>&nbsp;</TD>");
                        }
                        // Otherwise, write date and the event,
                        // if any, in this cell of the table.
                        else {
                                ShowDate(yr,mo,dy,i,curmo,curdy);
                                dy++;
                        }
                }
                document.write("</TR><TR>");
        }

        jump = "";
        if (yearmonth > FirstMonth)
                jump += '<a href="' + thispage + '?'+PrevYearMonth(yearmonth)+'">&lt;-- View '+months[PrevMonth(mo)]+'</a>';
        if ((yearmonth > FirstMonth) && (yearmonth < LastMonth))
                jump += " &nbsp; | &nbsp; ";
        if (yearmonth < LastMonth)
                jump += '<a href="' + thispage + '?'+NextYearMonth(yearmonth)+'">View '+months[NextMonth(mo)]+' --&gt;</a>';
        document.write("</TR><TR><TD colspan=7 align=center>"+jump+"</TD></TR>");
        document.write("<TR><TD colspan=7 align=center valign=middle><FORM>Jump to month:&nbsp;&nbsp;");
        BuildSelectionList(yearmonth, thispage);
        document.write("</FORM></TD></TR></TABLE>");
}

// Display a date in the appropriate color, with events (if there are any)

function ShowDate(yr, mo, dy, dayofweek, currentmonth, currentday) {
        var ind, HighlightEvent, tmp;

        document.write("<TD width=70 ALIGN=CENTER VALIGN=TOP><P ALIGN=RIGHT><FONT FACE=ARIAL SIZE="+FontSize);
        HighlightEvent = true;
        if (dayofweek == SpecialDay) {
                document.write(" COLOR=" + ColorSpecialDay);
                HighlightEvent = false;
        }
        if ((mo == currentmonth) && (dy == currentday)) {
                document.write(" COLOR=" + ColorToday);
                HighlightEvent = false;
        }
        ind = (((yr * 100) + mo) * 100) + dy;
        if (Events[ind]) {
                tmp = Events[ind];
                if (HighlightEvent) {
                         document.write(" COLOR=" + ColorEvent);
                }
        } else tmp="&nbsp;<BR>&nbsp;";
        document.write("><B>"+dy+"</B></ALIGN></FONT></P><FONT FACE=ARIAL SIZE=1>"+tmp+"</TD>");
}


// Remaining routines are utilities used above

function NumDaysIn(mo,yr) {
        if (mo==4 || mo==6 || mo==9 || mo==11) return 30;
        else if ((mo==2) && LeapYear(yr)) return 29;
        else if (mo==2) return 28;
        else return 31;
}

function LeapYear(yr) {
        if (((yr % 4 == 0) && yr % 100 != 0) || yr % 400 == 0) return true;
        else return false;
}

// fixes a Netscape 2 and 3 bug
function GetFullYear(d) { // d is a date object
        var yr;

        yr = d.getYear();
        if (yr < 1000)
        yr +=1900;
        return yr;
}

function PrevMonth(mth) {
        if (mth == 1) return 12;
        else return (mth-1);
}

function NextMonth(mth) {
        if (mth == 12) return 1;
        else return (mth+1);
}

function PrevYearMonth(yrmth) {
        if ((yrmth % 100) == 1) return ((yrmth-100)+11);
        else return (yrmth-1);
}

function NextYearMonth(yrmth) {
        if ((yrmth % 100) == 12) return ((yrmth-11)+100);
        else return (yrmth+1);
}

function JumpTo(calendar, thispage) {
        var sel, yrmo;

        sel = calendar.selectedIndex;
        yrmo = calendar.form.jumpmonth[sel].value;
        document.location = thispage + "?" + yrmo;
}

function BuildSelectionList(current,thispage) {
        var mo, yr, yearmonth;

        yearmonth = FirstMonth;
        document.write("<select name=\"jumpmonth\" size=1 onchange=\"JumpTo(this,'" + thispage + "')\">");
        while (yearmonth <= LastMonth) {
                mo = yearmonth % 100;
                yr = (yearmonth - mo) / 100;
                document.write("<option value=");
                document.write(yearmonth);
                if (yearmonth == current) document.write(" selected");
                document.write(">");
                document.write(months[mo]+" "+yr);
                yearmonth = NextYearMonth(yearmonth);
        }
        document.write("</select>");
}