//
// M A Y A N  C A L E N D A R
// Using FutureBasic 7.0.33, January 2025 R.W.
//
//=================================================================
// Convert Gregorian to real Julian Date (not JDE)
// 				 on entry Gregorian M = month, D = day, Y = YYYY
//         on exit Long JD = Julian Date
//=================================================================

local fn Greg2Julian (M as Int, D as Int, Y as Int) as Long
  Long JD
  JD= D-32075+1461*(Y+4800+(M-14)/12)/4+367*(M-2-(M-14)/12*12)/12-3*((Y+4900+(M-14)/12)/100)/4
End fn = JD

//==================================================================
// Convert Gregorian to Mayan Calendar
// 				 on entry Gregorian M = month, D = day, Y = YYYY
//					 On exit CFStringRef of Mayan calendar
//==================================================================
local fn Greg2Mayan (M as Int, D as Int, Y as Int) as CFStringRef

  CFStringRef tM(19),hM(18) //Tzolkin and Haad Months
  CFStringRef result
  Long longParts(5)
  Double remainder
  Double JulianDays				 //Julian Date
  Double LCD(4)             //long count days
  Double correlation				 //Day of creation GTM
  correlation = 584283			 //Julian date of Monday	3114 B.C. September 6, @noon
  CFStringRef longDate, roundDate, HaabDay, tmp
  Long tzolkinMonth, tzolkinDay
  Long haabMonth, haabDayNum
  Long lordNumber // Lord of the Nights, nine Deity, God 1 through God 9 (G1 - G9)
  Int i

  // Sacred Tzolk'in Months, 20 days

  tM(0) = @"Imix'": tM(1) = @"Ik'": tM(2) = @"Ak'bal": tM(3) = @"K'an"
  tM(4) = @"Chikchan": tM(5) = @"Kimi": tM(6) = @"Manik'": tM(7) = @"Lamat"
  tM(8) = @"Muluk": tM(9) = @"Ok": tM(10) = @"Chuwen": tM(11) = @"Eb"
  tM(12) = @"Ben": tM(13) = @"Hix": tM(14) = @"Men": tM(15) = @"K'ib'"
  tM(16) = @"Kaban": tM(17) = @"Etz'nab'": tM(18) = @"Kawak": tM(19) = @"Ajaw"

  // Civil Haab Months 20 days

  hM(0) = @"Pop": hM(1) = @"Wo'": hM(2) = @"Sip": hM(3) = @"Sotz'"
  hM(4) = @"Sek": hM(5) = @"Xul": hM(6) = @"Yaxk'in": hM(7) = @"Mol"
  hM(8) = @"Ch'en": hM(9) = @"Yax": hM(10) = @"Sak'": hM(11) = @"Keh"
  hM(12) = @"Mak": hM(13) = @"K'ank'in": hM(14) = @"Muwan": hM(15) = @"Pax"
  hM(16) = @"K'ayab": hM(17) = @"Kumk'u": hM(18) = @"Wayeb'"

  // Long count days

  LCD(0) = 144000: LCD(1) = 7200: 	LCD(2) = 360: LCD(3) = 20: LCD(4) = 1

  JulianDays = fn Greg2Julian (M, D, Y)
  remainder = JulianDays - correlation
  For i = 0 To 4
    longParts(i) = Fix(remainder / LCD(i))
    remainder = remainder - (longParts(i) * LCD(i))
  Next i

  longDate = @""
  For i = 0 To 4
    If i > 0 Then longDate = concat (longDate,@".")
    tmp = mid(str(longParts(i)),1)
    if len(tmp) < 2 then tmp = concat(@"0",tmp)
    longDate = concat(longDate, tmp)
  Next i

  tzolkinMonth = fix((julianDays + 16) Mod 20)
  tzolkinDay = fix(((julianDays + 5) Mod 13)) + 1

  haabMonth = fix(((julianDays + 65) Mod 365) / 20)
  haabDayNum = fix(((julianDays + 65) Mod 365) Mod 20)

  If haabDayNum = 0
    haabDay = @"Chum"
  Else
    haabDay = mid(Str(haabDayNum),1)
  End If

  lordNumber = Fix((julianDays - correlation) Mod 9)
  If lordNumber = 0 Then lordNumber = 9

  roundDate = @""
  roundDate = concat(roundDate, @" ", mid(str(tzolkinDay),1), @"\t", tM(tzolkinMonth), @" ",	haabDay, @" ", hM(haabMonth), @" G",	mid(str(lordNumber),1))
  result = concat(longDate, @" ", roundDate)
end fn = result

Window 1

CFStringRef mayanDate, GregDate
CFArrayRef comps
Int i,mm,dd,yy
CFStringRef testDate(7)
testDate(1) = @"2004-06-19": testDate(2) = @"2012-12-18": testDate(3) = @"2012-12-21": testDate(4) = @"2019-01-19"
testDate(5) = @"2019-03-27": testDate(6) = @"2020-02-29": testDate(7) = @"2020-03-01"

for i = 1 to 7
  GregDate = testDate(i)
  comps = fn StringComponentsSeparatedByString(GregDate, @"-" )
  dd = IntVal(comps[2])
  mm = IntVal(comps[1])
  yy = IntVal(comps[0])
  mayanDate = fn Greg2Mayan (mm,dd,yy)
  print GregDate;" - ";mayanDate
next i

handleEvents