// Basic Calendar Calculation Functions
// Written by Joseph F. Buchanan - 2/11/2000
//  translated from Pacsal, Hypercard to JavaScript

function Leapy(yy) {  // Written by Joseph F. Buchanan - 2/11/2000
// Given the year, will return 1 if it is a leap year otherwise a zero.
// The year must be full 4 digits.
var lp=0
 if ((yy % 4) == 0) {
    if ((yy % 100) == 0) {
      if ((yy % 400) == 0) {
        lp = 1
      } else {
        lp = 0
      }
     }else {
      lp = 1
    }
  }
  return lp
} // end of Leapy

function JulDay (yy,mm,dd) {  // Written by Joseph F. Buchanan - 2/11/2000
  // Given the year, month and day, will return the day of the year
  // 1 - 366 (julian day). The year must be full 4 digits.
  // month is 0-11
  var jd = dd-30+Math.floor((((mm+1)*275) / 9))
  if (mm > 1) { jd = jd-2+Leapy(yy) }
  return jd
} // end of JulDay

function DOW (yy,mm,dd) {  // Written by Joseph F. Buchanan - 2/11/2000
  // Given the year, month and day will return the number of the day
  // of the week (0-6). The year must be full 4 digits.
  // month is 0-11
  var df = yy-1600
  var daze = df+1+Math.floor(((df-1) / 4))-Math.floor(((df-1) / 100))+Math.floor(((df-1) / 400))
  var dayow = (daze % 7)
  dayow = ((dayow+JulDay(yy,mm,dd)+5) % 7)
  return dayow
} // end of DOW

function MDays (yy,mm) {  // Written by Joseph F. Buchanan - 2/11/2000
  // Given the year and month, will return the number of days of that
  // month. The year must be full 4 digits. Month is 0-11
  var mm1 = mm+1
  if (yy == 11) {
    return 31
  } else {
    return JulDay(yy,mm1,1)-JulDay(yy,mm,1)
  }
} // end of MDays

function weekOfMonth (theDay) {  // Written by Joseph F. Buchanan - 2/11/2000
  n = theDay.getDate()
  return Math.floor((n+6) / 7)
} // end of weekOfMonth

function easterCalc(yyyy) {  // Written by Joseph F. Buchanan - 2/11/2000
  // Given the year, will return the day for Easter Sunday in the form
  // yyyymmdd. The year must be full 4 digits.
  var ii = (yyyy % 19) // yyyy modulo 19 // hard coded Paschal calendaring
  var em = new Array(3,3,2,3,2,3,3,2,3,3,2,3,3,2,3,2,3,3,2)
  var ed = new Array(14,3,23,11,31,18,8,28,16,5,25,13,2,22,10,30,17,7,27)
  var mm = em[ii]
  var dd = ed[ii]
  var dayow = DOW(yyyy,mm,dd)
  dd = dd+7-dayow
  if (dd > 31) {
    dd = dd-31
    mm = mm + 1
  }
var easterDay = new Date()
easterDay.setYear(yyyy)
easterDay.setMonth(mm)
easterDay.setDate(dd)
 return easterDay
} // end of easterCalc

function todayText() {
  var output = new Date()
  return (output.getMonth()+1) + "/" + (output.getDate()) + "/" + (output.getYear()+1900)
}

function monthName(n) {
  var MonthNames = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December")
  it = MonthNames[n]
  return it
}

function wkDayName(n) {
  var WeekdayNames = new Array("Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday")
  return WeekdayNames[n]
}

function makeCalendar (yy,mm,dd,howMany) {  // Written by Joseph F. Buchanan - 2/11/2000 revised 2/24/2003
  // yy is 4 digit year, mm is month 0-11, howMany is number of months
  // dd is either 0 or the day to be hilighted (on the first month)
 var mLine, nSpaces, doweek, dSpot, LNum, i, n, x
 var weekLine = " S  M  T  W  T  F  S"
  var blankLine = "                    "
  var gapspace = "   "
 var MonWidth = weekLine.length
  var mfirst = 1
  if (howMany == NaN) { howMany = 1 }
  var textBlock = new Array("", "", "", "", "", "", "", "", "", "")
  var textLines = 0 // ignore element 0 of the array
  for (n = 1; n<= howMany; n++) { // outer for loop - number of months across
    if (n>1) {
    for (i = 1; i<=textLines; i++) {
        textBlock[i] += gapspace
      }
    }
    mLine = monthName(mm) + " " + yy
    nSpaces = Math.floor((MonWidth - (mLine.length) + 1) / 2)
    mLine = blankLine.substr(0,nSpaces) + mLine
    mLine += blankLine
    textBlock[1] += mLine.substr(0,MonWidth)
    textBlock[2] += weekLine
    doweek = DOW(yy,mm,1) + 1 // it comes as 0 thru 6
    dSpot = doweek
    LNum = 3
    if (doweek>1) {
      nSpaces = (doweek-1)*3
      textBlock[LNum] += blankLine.substr(0,nSpaces)
    }
    if (textLines<3) {textLines=3}
    for (i=1; i<=MDays(yy,mm); i++) { // get all days of the month
     if (mfirst && i==dd) { textBlock[LNum] += "<b><font color=red>" }
     if (i<10) {
        textBlock[LNum] += " " + i
      } else {
        textBlock[LNum] += i
      }
     if (mfirst && i==dd) {
       textBlock[LNum] += "</font></b>"
       mfirst = 0
       }
      if (dSpot<7) { textBlock[LNum] += " " }
        dSpot += 1
      if ( i<MDays(yy,mm)) {
        if (dSpot>7) {
          dSpot = 1
          LNum += 1
         if ((n>1) && (LNum>textLines)) {
           for (x=1; x<=(n-1); x++) {
             textBlock[LNum] += blankLine + gapspace
           }
          }
        }
      }
    } // days of month for loop
    if (dSpot<8) {
      nSpaces = (8-dSpot)*3 - 1
      textBlock[LNum] += blankLine.substr(1,nSpaces)
    }
    if (LNum<textLines) {
      for (i=(LNum+1); i<=textLines; i++) {
       textBlock[i] += blankLine.substr(0,MonWidth)
     }
    }
    if (LNum>textLines) {textLines = LNum}
    mm += 1
    if (mm>11) {
      mm = 0
      yy += 1
    }
  } // months for loop
  var finishText = ""
  for (n=1; n<=textLines; n++) {
    finishText += textBlock[n] + "\n"
  }
  return finishText
} // end of Make Calendar