#!/bin/csh -f
#
# UTdate
#
# returns the UT date for the night's observing.  Note that the UT date
# actually changes at 2 p.m. HST.  However, this will return TONIGHT's
# UT date if it is after 10 a.m. HST, anticipating that it is being 
# used by tonight's observer starting software earlier than 2 p.m. HST.
#

# UTC date changes at 2 p.m. HST.
# After UTC 18 hr (HST 8 a.m.) assume that the required UTC date is one
# larger than it currently is.  This is to handle directory construction
# done between 8 a.m. and 2 p.m., when the UTC date will be less than
# the UTC date of that (HST) night.

set UThr = `date -u | awk '{print $4}' | sed 's/:..*//' `

set day = `date -u | awk '{print $3}' `
set month = `date -u | awk '{print $2}' `
set yr = `date -u | awk '{print $6}' `

if ($UThr > 18) then

set day = `expr $day + 1`

switch ($month)
case "Jan":
    if ($day == "32") then
        set month = "feb"
        set day = 1
    endif
    breaksw

case "Feb":
    set leap = `expr 4 \* \( $yr / 4 \) - $yr`
    if ($day == "29" && $leap != "0") then
        set month = "mar"
        set day = 1
    else if ($day == "30" && $leap == "0") then
        set month = "mar"
        set day = 1
    endif
    breaksw
 
case "Mar":
    if ($day == "32") then
        set month = "apr"
        set day = 1
    endif
    breaksw
 
case "Apr":
    if ($day == "31") then
        set month = "may"
        set day = 1
    endif
    breaksw
 
case "May":
    if ($day == "32") then
        set month = "jun"
        set day = 1
    endif
    breaksw
 
case "Jun":
    if ($day == "31") then
        set month = "jul"
        set day = 1
    endif
    breaksw
 
case "Jul":
    if ($day == "32") then
        set month = "aug"
        set day = 1
    endif
    breaksw
 
case "Aug":
    if ($day == "32") then
        set month = "sep"
        set day = 1
    endif
    breaksw
 
case "Sep":
    if ($day == "31") then
        set month = "oct"
        set day = 1
    endif
    breaksw
 
case "Oct":
    if ($day == "32") then
        set month = "nov"
        set day = 1
    endif
    breaksw
 
case "Nov":
    if ($day == "31") then
        set month = "dec"
        set day = 1
    endif
    breaksw
 
case "Dec":
    if ($day == "32") then
        set month = "jan"
        set day = 1
        set yr = `echo $yr + 1 | expr`
    endif
    breaksw
 
endsw
endif

# Make sure day has two digits.

if ($day < 10) set day = "0$day"

# Remove capital letters from month.

set month = `echo $month | sed 'y/JFMASOND/jfmasond/'`

set UTdate = `echo $yr$month$day`
echo $UTdate