#!/usr/bin/python

# Calculate the Julian day at this moment

import sys	# for system connections
import re       # for regex
from time import gmtime, strftime  # for utc

# Coordinated universal time

def utcnow():
  t = gmtime()
  year = t.tm_year
  month = t.tm_mon
  day = t.tm_mday
  hour = t.tm_hour
  minute = t.tm_min
  second = t.tm_sec
  yearday = t.tm_yday
  ut = second/3600. + minute/60. + hour
  return(ut)
  

# Julian day
# Code from aa.usno.navy.mil/faq/docs/JD_Formula.php
# Valid for CE March 1901 through 2099

def jd(year, month, day, utc):
  k = int(year)
  m = int(month)
  i = int(day)
  j1 = float(367*k)
  j2 = -1.*float( int( ( 7*(k + int((m+9)/12) ) )/4 ) )
  j3 = float(int(275*m/9))
  j4 = 1721013.5 + (utc/24.)
  julian = j1 + j2 + j3 +j4
  return(julian)
         

# Map a time in hours to the range 0 to 24         
         
def map24(hour):

  if hour < 0.0:
    n = int(hour/24.0) - 1
    h24 = hour - n*24.0
    return(h24)
  elif hour > 24.0:
    n = (int) (hour / 24.0) 
    h24 = hour - n*24.0
    return(h24)
  else:
    return(hour)  


# Julian day now
# Use system time and compute the Julian day at this moment
# Code from aa.usno.navy.mil/faq/docs/JD_Formula.php
# Valid for CE March 1901 through 2099

def jdnow():
  t = gmtime()
  year = t.tm_year
  month = t.tm_mon
  day = t.tm_mday
  hour = t.tm_hour
  minute = t.tm_min
  second = t.tm_sec
  yearday = t.tm_yday
  utc = second/3600. + minute/60. + hour
  k = int(year)
  m = int(month)
  i = int(day)
  j1 = float(367*k)
  j2 = -1.*float( int( ( 7*(k + int((m+9)/12) ) )/4 ) )
  j3 = float(i + int(275*m/9))
  j4 = 1721013.5 + (utc/24.)
  julian = j1 + j2 + j3 +j4
  return(julian)

# Julian day today
# Use system time and compute the Julian day number for today at 0h UTC
# Code from aa.usno.navy.mil/faq/docs/JD_Formula.php
# Valid for CE March 1901 through 2099

def jdtoday():
  t = gmtime()
  year = t.tm_year
  month = t.tm_mon
  day = t.tm_mday
  utc = 0.
  k = int(year)
  m = int(month)
  i = int(day)
  j1 = float(367*k)
  j2 = -1.*float( int( ( 7*(k + int((m+9)/12) ) )/4 ) )
  j3 = float(i + int(275*m/9))
  j4 = 1721013.5 + (utc/24.)
  julian = j1 + j2 + j3 +j4
  return(julian)

if len(sys.argv) != 1:
  print " "
  print "Usage: jd.py "
  print " "
  sys.exit("Calculate the Julian day at this moment\n")
    
print "JD Today: %2.6f" % (jdtoday())
print "JD Now:   %2.6f" % (jdnow())
print "UTC Now:  %2.6f" % (utcnow())