#!/usr/local/bin/perl -w
#
#  CreateObsDateFile
#
#  This script stores useful versions of the
#  observation date in a file for access by 
#  other scripts.
#
#  1995/08/07 Created by W. Prescott
#  1995/08/11 Modified by N.E. King to 
#             use input date of the form yyyymmdd,
#             include JPL date,
#             add date strings for /attic directory names,
#             fix bug in calculation of day+1, at end of month,
#             re-write month-boundary calculations,
#             change daym2 to daym1 in both name and function,
#             rename input string (was date, now datelong),
#             re-do comments.
#  1995/08/12 Modified by N.E. King to
#             check input argument string for length & char type,
#             check input year/month/day,
#             check for leap year,
#             handle special cases of Jan 1 and Dec 31,
#             add comments.
#  1995/08/14 whp  Added output for day - 2.
#  1995/12/1-3 whp  Converted to use cal2sec and perl.
#  1996/11/14 whp  Decimal year calculation ignored leap year
#                  Added accounting for leap year and modified
#                  DecYr so that it refers to 12 noon.
#  1997/01/13 whp  Added -f to rm to suppress error message.


#  All variables are written to the file "SaveObsDate"
#  They can be extracted with the command
#
#  set XXX =  `grep YYY SaveObsDate | awk '{print $2}'`
#    or 
#  setenv XXX `grep YYY SaveObsDate | awk '{print $2}'`
#    or 
#  open (Hdl,"SaveObsDate");
#  @UUU = grep /YYY/,<Hdl>;
#  @VVV = split /[ \n\t]+/,$UUU[0];
#  $XXX = $VVV[1];
#  
#  where XXX is the destination name and 
#  YYY is the variable name at the bottom of the script. 
#  (without the "$").
#
#  XXX and YYY may need not be the same

   unshift (@INC,"/goa/local/gp_dir");
   require gp_utils;
   &gp_utils::setEnviron;

#  Process command line
#  --------------------
   if ($#ARGV == -1) {
      print "\n";
      print "Usage: CreateObsDateFile yyyymmdd\n";
      print "\n";
      exit 1;
   }

#  Check and parse input argument
#  ------------------------------
   $datelong = $ARGV[0];
   $datelong = &gp_utils::untaint($datelong);
   if (length($datelong) != 8) {
      print "CreateObsDateFile:",
            "Argument does not have 8 characters.\n";
      print "Usage: CreateObsDateFile yyyymmdd\n";
      print "                   Script stops.\n";
      exit 1;
   }

   ($numcheck=$datelong) =~  tr/0-9//d;
   if ($numcheck ne "") {
      print "CreateObsDateFile:",
            "Argument contains non-numeric characters.\n";
      print "Usage: CreateObsDateFile yyyymmdd\n";
      print "                   Script stops.\n";
      exit 2;
   }

#  Pick apart input date
#  ---------------------
   $dateshort =  substr($datelong,2,6);
   $yymm = substr($datelong,2,4);
   $yrobs = substr($datelong,2,2);
   $longyr = substr($datelong,0,4);
   $moobs = substr($datelong,4,2);
   $dayobs = substr($datelong,6,2);
   $hour = "00";
   $minute = "00";


#  Set J2000 date
#  --------------
   system ("cal2sec $longyr $moobs $dayobs $hour $minute > temp1.seconds");
   open (HDL,"temp1.seconds");
   $sec = <HDL>;
   $sec = &gp_utils::untaint($sec);
   $sec = sprintf ("%16.5f",$sec);
   close (HDL);
   $secdm1 = $sec - 86400;
   $secdm2 = $secdm1 - 86400;
   $secdp1 = $sec + 86400;
   system ("sec2cal $sec > temp2.seconds");
   system ("sec2cal $secdm1 >> temp2.seconds");
   system (`sec2cal $secdm2 >> temp2.seconds`);
   system (`sec2cal $secdp1 >> temp2.seconds`);
   system (`/bin/csh -bf /goa/bin/sec2doy $sec >> temp2.seconds`);
   system (`sec2gpsws $sec >> temp2.seconds`);
   open (HDL,"temp2.seconds");
   $CheckDate = <HDL>;
   $Datedm1 = <HDL>;
   $Datedm2 = <HDL>;
   $Datedp1 = <HDL>;
   $Datedoy = <HDL>;
   $Dategpsweeksec = <HDL>;
   close (HDL);
#   system ("rm temp?.seconds");

#  Check that date is valid
#  ------------------------
   ($CDyyyy,$CDmm,$CDdd) = split(' ',$CheckDate,5);
   if (length($CDmm) == 1) {$CDmm = "0$CDmm";}
   if (length($CDdd) == 1) {$CDdd = "0$CDdd";}
   if ($datelong ne "$CDyyyy$CDmm$CDdd") {
      print "CreateObsDateFile: Input date invalid.",
            "$datelong ?=? $CDyyyy$CDmm$CDdd\n";
      print "                   Script stops.\n";
      exit 3;
   }

#  Define month names
#  ------------------
   @months =  ("jan", "feb", "mar", "apr", "may", "jun",
               "jul", "aug", "sep", "oct", "nov", "dec");

#  Set JPL date, hour, minute, and hypenated date strings
#  ------------------------------------------------------
   $monthobs = $months[$moobs-1];
   $datejpl = $yrobs.$monthobs.$dayobs;

   $ymdobs = "$longyr-$moobs-$dayobs";
   $dmyobs = "$dayobs-$monthobs-$longyr";

#  Convert yymmmdd (ie:93sep16) to julian day of year
#  --------------------------------------------------
   @fields = split(' ',$Datedoy);
   $doy = $fields[1];
   while (length($doy) < 3) {$doy="0$doy";}

#  Decimal year
#  ------------
   $NoDaysYear = 365;
   if ($longyr%4 == 0 && $longyr%400 != 0) {$NoDaysYear = 366;}
   $decyr = $longyr + ($doy-0.5)/$NoDaysYear;
   $decyr = sprintf ("%9.4f",$decyr);

#  Month name of day +/- 1
#  -----------------------------------------------------------------------
   if ($moobs == "01") {
      $mom1 = "12";
      $mop1 = "02";
   }
   else {
      $mom1 = $moobs-1;
      if (length($mom1) == 1) {$mom1 = "0$mom1";}
   }

   if ($moobs == "12") {
      $mom1 = "11";
      $mop1 = "01";
   }
   else {
      $mop1 = $moobs+1;
      if (length($mop1) == 1) {$mop1 = "0$mop1";}
   }

#  Calculate values for obs date-1
#  -------------------------------
   ($lgyrdm1,$modm1,$daym1) = split(' ',$Datedm1,5);
   $shyrdm1 = substr($lgyrdm1,2,2);
   if (length($modm1) == 1) {$modm1 = "0$modm1";}
   if (length($daym1) == 1) {$daym1 = "0$daym1";}
   $monthdm1 = $months[$modm1-1];

#  Calculate values for obs date-2
#  -------------------------------
   ($lgyrdm2,$modm2,$daym2) = split(' ',$Datedm2,5);
   if (length($modm2) == 1) {$modm2 = "0$modm2";}
   if (length($daym2) == 1) {$daym2 = "0$daym2";}
   $monthdm2 = $months[$modm2-1];


#  Calculate values for obs date+1
#  -------------------------------
   ($lgyrdp1,$modp1,$dayp1) = split(' ',$Datedp1,5);
   $shyrdp1 = substr($lgyrdp1,2,2);
   if (length($modp1) == 1) {$modp1 = "0$modp1";}
   if (length($dayp1) == 1) {$dayp1 = "0$dayp1";}
   $monthdp1 = $months[$modp1-1];


   $dmym2  = $daym2."-".$monthdm2."-".$lgyrdm2;
   $dmym1  = $daym1."-".$monthdm1."-".$lgyrdm1;
   $dmyp1  = $dayp1."-".$monthdp1."-".$lgyrdp1;


#  GPS week and day-of-week calculations
#  -------------------------------------
   ($gpsweekobs,$dayofweekobs) = split(' ',$Dategpsweeksec,4);
   $dayofweekobs /= 86400;

   $dayofweekm1 = $dayofweekobs-1;
   $gpsweekdm1 = $gpsweekobs;
   $dayofweekp1 = $dayofweekobs+1;
   $gpsweekdp1 = $gpsweekobs;

   if ($dayofweekm1 < 0) {
      --$gpsweekdm1;
      $dayofweekm1 = 6;
   }
   if ($dayofweekp1 > 6) {
      ++$gpsweekdp1;
      $dayofweekp1 = 0;
   }

#  Save for future reruns
#  ------------------------------------------------
   system ("rm -f SaveObsDate");

   open (HDL,">SaveObsDate");

   print (HDL "datelong     $datelong\n");
#        yyyymmdd

   print (HDL "dateshort    $dateshort\n");
#        yymmdd

   print (HDL "datejpl      $datejpl\n");
#        yyMMMdd, where MMM is alpha month

   print (HDL "yrobs        $yrobs\n");
#        yy

   print (HDL "shyrdm1      $shyrdm1\n");
#        yy for preceding day

   print (HDL "shyrdp1      $shyrdp1\n");
#        yy for succeeding day

   print (HDL "longyr       $longyr\n");
#        yyyy

   print (HDL "lgyrdm1      $lgyrdm1\n");
#        yyyy for preceding day

   print (HDL "lgyrdp1      $lgyrdp1\n");
#        yyyy for succeeding day

   print (HDL "yymm         $yymm\n");
#        yymm, for use in /attic pathnames

   print (HDL "moobs        $moobs\n");
#        mm

   print (HDL "modm1        $modm1\n");
#        mm for previous day

   print (HDL "modp1        $modp1\n");
#        mm for succeeding day

   print (HDL "mom1         $mom1\n");
#        moobs-1, with leading zero if necessary

   print (HDL "mop1         $mop1\n");
#        moobs+1, with leading zero if necessary

   print (HDL "monthobs     $monthobs\n");
#        month of observation, alpha form

   print (HDL "monthdm2     $monthdm2\n");
#        month of pre-previous day, alpha form

   print (HDL "monthdm1     $monthdm1\n");
#        month of previous day, alpha form

   print (HDL "monthdp1     $monthdp1\n");
#        month of next day, alpha form

   print (HDL "dayobs       $dayobs\n");
#        dd

   print (HDL "daym2        $daym2\n");
#        dd-2, going into previous month if necessary

   print (HDL "daym1        $daym1\n");
#        dd-1, going into previous month if necessary

   print (HDL "dayp1        $dayp1\n");
#        dd+1, going into next month if necessary

   print (HDL "hour         $hour\n");
#        hour = 0

   print (HDL "minute       $minute\n");
#        minute = 0

   print (HDL "ymdobs       $ymdobs\n");
#        yyyy-mm-dd

   print (HDL "dmyobs       $dmyobs\n");
#        dd-MMM-yyyy, where MMM is alpha month
 
   print (HDL "dmym2        $dmym2\n");
#        date of pre-previous day, in dd-MMM-yyyy format

   print (HDL "dmym1        $dmym1\n");
#        date of previous day, in dd-MMM-yyyy format

   print (HDL "dmyp1        $dmyp1\n");
#        date of next day, in dd-MMM-yyyy format

   print (HDL "doy          $doy\n");
#        Julian day

   print (HDL "decyr        $decyr\n");
#        Decimal year

   print (HDL "sec          $sec\n");
#        J2000

   print (HDL "gpsweekobs   $gpsweekobs\n");
#        GPS week

   print (HDL "dayofweekobs $dayofweekobs\n");
#        day of GPS week (0-6 for Sun-Sat)

   print (HDL "gpsweekdm1   $gpsweekdm1\n");
#        GPS week of previous day

   print (HDL "dayofweekm1  $dayofweekm1\n");
#        day of GPS week, for previous day

   print (HDL "gpsweekdp1   $gpsweekdp1\n");
#        GPS week of next day

   print (HDL "dayofweekp1  $dayofweekp1\n");
#        day of GPS week, for next day

close (HDL);
   exit;