#!/usr/local/bin/perl

# PERL program to correct name changes in tropical storms.  Uses
# the WMO header numbers, the dates, and the positions to sort things out.
#
# 1996-04-08 TRM Make sure each storm name has only one associated
#            depression.


#   Copyright (C) 1996 Thomas R. Metcalf
#
#   This software is provided "as is" and is subject to change without
#   notice.  No warranty of any kind is made with regard to this software,
#   including, but not limited to, the implied warranties of
#   merchantability and fitness for a particular purpose.  The author shall
#   not be liable for any errors or for direct, indirect, special,
#   incidental or consequential damages in connection with the furnishing,
#   performance, or use of this software:  use it at your own risk.
#
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of the GNU General Public
#    License as published by the Free Software Foundation; either
#    version 2 of the License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    General Public License for more details.
#
#    You should have received a copy of the GNU General Public
#    License along with this library; if not, write to the Free
#    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

$LastFile = "/data1/WWW/Tropical/Bin/LastNameChange";
$GifArchive = "/data1/WWW/Tropical/GifArchive";
$DataDir = "/data1/WWW/Tropical/Data";

$debug = 0;
$oneweek = 0.0191257;
$oneday = 0.00274;
$onehour = 0.000114;
$tconstraint = $oneday;
$piover2 = atan2(1,0);
$pi = $piover2*2;
$dtor = $piover2/90;

#setpriority(0,0,getpriority(0,0)+4);   # nice the process

($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime;
if ($year>=94) {$year+=1900;} else {$year+=2000;}
$now = $year + ($yday+1 + ($hour/24.0) + ($min/1440.))/366.0;

if (open(LASTFILE,"$LastFile")) { 
   while(<LASTFILE>) {
      chop;
      s/  / /g;
      @line = split(" ");
      if (($now-$line[2]) < ($oneweek*4)) {
         $changes{$line[0]} = $line[1]; 
         $cdate{$line[1]} = $line[2];
      }
   }
   close LASTFILE;
}
@namedstorms = keys(%cdate);
@depressions = keys(%changes);
open(LASTFILE,">$LastFile");

while (<>) {   # Read input file into an array and grab the headers/names
   s/\n//;                 # Get rid of carriage return.
   while (s/\s\s/ /g) {};  # Remove multiple white spaces.
   $#sp = 0;               # Delete the old sp variable.
   @sp = split;
   # wmo is an associative array.  The key is the WMO header and the values
   # is the best name of the storm.
   # wmo* holds the date/position of the _first_ incidence of a name.
   # wmo*2 holds the date/position of the _last_ incidence of a name.
   if ($sp[22] ne "" && $sp[22] ne "???" && $sp[20] ne "FOR" &&
       $sp[22] =~ /^WT/) {
      if ($wmo{$sp[22]} ne $sp[9]) {
         if ($wmo{$sp[22]} ne "") {
            if (!&ISDEPRESSION($sp[9])) {
               $wmo{$sp[22]} = $sp[9];
               $wmodate{$sp[22]} = $sp[21];
               $wmolatitude{$sp[22]} = $sp[5];
               $wmolongitude{$sp[22]} = $sp[7];
               if ($sp[6] eq "S") {$wmolatitude{$sp[22]} = -$wmolatitude{$sp[22]};}
               if ($sp[8] eq "W") {$wmolongitude{$sp[22]} = -$wmolongitude{$sp[22]};}
               $wmodate2{$sp[22]} = $sp[21];  # Get most recent date
               $wmolatitude2{$sp[22]} = $sp[5];
               $wmolongitude2{$sp[22]} = $sp[7];
               if ($sp[6] eq "S") {$wmolatitude2{$sp[22]} = -$wmolatitude2{$sp[22]};}
               if ($sp[8] eq "W") {$wmolongitude2{$sp[22]} = -$wmolongitude2{$sp[22]};}
            }
         } else {
            $wmo{$sp[22]} = $sp[9];
            $wmodate{$sp[22]} = $sp[21];
            $wmolatitude{$sp[22]} = $sp[5];
            $wmolongitude{$sp[22]} = $sp[7];
            if ($sp[6] eq "S") {$wmolatitude{$sp[22]} = -$wmolatitude{$sp[22]};}
            if ($sp[8] eq "W") {$wmolongitude{$sp[22]} = -$wmolongitude{$sp[22]};}
            $wmodate2{$sp[22]} = $sp[21];  # Get most recent date
            $wmolatitude2{$sp[22]} = $sp[5];
            $wmolongitude2{$sp[22]} = $sp[7];
            if ($sp[6] eq "S") {$wmolatitude2{$sp[22]} = -$wmolatitude2{$sp[22]};}
            if ($sp[8] eq "W") {$wmolongitude2{$sp[22]} = -$wmolongitude2{$sp[22]};}
         }
      } else {
         $wmodate2{$sp[22]} = $sp[21];  # Get most recent date
         $wmolatitude2{$sp[22]} = $sp[5];
         $wmolongitude2{$sp[22]} = $sp[7];
         if ($sp[6] eq "S") {$wmolatitude2{$sp[22]} = -$wmolatitude2{$sp[22]};}
         if ($sp[8] eq "W") {$wmolongitude2{$sp[22]} = -$wmolongitude2{$sp[22]};}
      }
   }
   $input[$.-1] = $_;
}

if ($debug) {
   foreach $key (keys(%wmo)) {
      print STDERR $key," ",$wmo{$key},"\n";
   }
}

# Loop through the input looking for name changes.
# If the depression is before the named storm, use wmo*.  If the depression
# is after the named storm, use wmo*2.

for ($i=0;$i<=$#input;++$i) {
   $#sp = 0;               # Delete the old sp variable.
   @sp = split(/\s/,$input[$i]);
   @sp1 = split(/\s/,$input[$i+1]);
   #  Look for identical entries (except for name).  Assumes input sorted by time.
   #if ($sp[9] ne $sp1[9] &&$sp[0] eq $sp1[0] && $sp[1] eq $sp1[1] && $sp[2] eq $sp1[2] &&
   #    $sp[3] eq $sp1[3] && $sp[5] eq $sp1[5] && $sp[6] eq $sp1[6] &&
   #    $sp[7] eq $sp1[7] && $sp[8] eq $sp1[8] && $sp[10] eq $sp1[10] &&
   #    $sp[12] eq $sp1[12] && $sp[14] eq $sp1[14] && $sp[16] eq $sp1[16] &&
   #    $sp[17] eq $sp1[17] && $sp[19] eq $sp1[19] && $sp[20] eq $sp1[20] &&
   #    $sp[21] eq $sp1[21] && $sp[22] eq $sp1[22]) {
   #   if (&ISDEPRESSION($sp[9]) && !&ISDEPRESSION($sp1[9])) {
   #      $changes{$sp[9]}=$sp1[9];
   #   } elsif (!&ISDEPRESSION($sp[9]) && &ISDEPRESSION($sp1[9])) {
   #      $changes{$sp1[9]}=$sp[9];
   #   }
   #}
   # Look for reasonable name changes.  Check WMO header, time, position, speed
   $wmoname = $wmo{$sp[22]};
   $advname = $sp[9];
   if ($sp[22] ne "" && $sp[22] ne "???" && $sp[22] =~ /^WT/) {
      if ($advname ne $wmoname && $sp[20] ne "FOR" &&
          &ISDEPRESSION($advname) && !&ISDEPRESSION($wmoname) &&
          grep(/^$wmoname$/,@namedstorms) == 0 &&
          grep(/^$advname$/,@depressions) == 0) {
         if ($debug) {
            $stone = $sp[9];
            $sttwo = $wmo{$sp[22]};
            print STDERR "Checking $stone $sttwo\n";
         }
         $timegap = $sp[21] - $wmodate{$sp[22]};  # time difference from first name
         $timegap2 = $sp[21] - $wmodate2{$sp[22]};  # time difference from last name
         # compute Great Circle distance between observations
         $latitude = $sp[5];
         $longitude = $sp[7];
         if ($sp[6] eq "S") {$latitude = -$latitude;}
         if ($sp[8] eq "W") {$longitude = -$longitude;}
         $distance = &GCDISTANCE($latitude,$longitude,$wmolatitude{$sp[22]},$wmolongitude{$sp[22]});
         $distance2 = &GCDISTANCE($latitude,$longitude,$wmolatitude2{$sp[22]},$wmolongitude2{$sp[22]});
         $speed = 0;
         $speed2 = 0;
         if ($timegap != 0) {$speed = $distance/($timegap/$onehour);}
         if ($timegap2 != 0) {$speed2 = $distance2/($timegap2/$onehour);}
         if ($speed < 0) {$speed = -$speed;}
         if ($speed2 < 0) {$speed2 = -$speed2;}
         if($timegap <= $onehour && $timegap2 <= $onehour) {
            if ($timegap>-$tconstraint && $distance <= 500 && $speed <= 50) {
               $changes{$sp[9]}=$wmo{$sp[22]};
            }
         } elsif ($timegap >= -$onehour && $timegap2 >= -$onehour) {
            if ($timegap2<$tconstraint && $distance2 <= 500 && $speed2 <= 50) {
               $changes{$sp[9]}=$wmo{$sp[22]};
            }
         } elsif ($timegap > $onehour && $timegap2 < -$onehour) {
            if (($distance <= 500 && $speed <= 50) || ($distance2 <= 500 && $speed2 <= 50)) {
               $changes{$sp[9]}=$wmo{$sp[22]};
            }
         }
      }
   }
}

if ($debug) {
   foreach $key (keys(%changes)) {
      print STDERR $key," --> ",$changes{$key},"\n";
   }
}

# Substitute corrected names and print

for ($i=0;$i<=$#input;++$i) {
   foreach $key (keys(%changes)) {
      $metakey = $key;
      $metakey =~ s/(\W)/\\\1/g;     # make any metacharacters literal
      if ($input[$i] =~ /$metakey/i) {$cdate{$changes{$key}}=$now;}
      $input[$i] =~ s/$metakey/$changes{$key}/i;
   }
   print $input[$i],"\n";
}

foreach $key (keys(%changes)) {
   if ($cdate{$changes{$key}} eq "") {$cdate{$changes{$key}}=$now;}
   print LASTFILE $key," ",$changes{$key}," ",$cdate{$changes{$key}},"\n";
}
close LASTFILE;

foreach $dep (keys(%changes)) {
   $storm = $changes{$dep};
   $changed = $GifArchive."/$dep.gif";
   $changedto = $GifArchive."/$storm.gif";
   if (-e $changed) {rename($changed,$changedto);}
   $changed = $DataDir."/$dep";
   $changedto = $DataDir."/$storm";
   if (-e $changed) {rename($changed,$changedto);}
   $changed = $DataDir."/$dep.html";
   $changedto = $DataDir."/storm.html";
   if (-e $changed) {rename($changed,$changedto);}
   $changed = $DataDir."/$dep.forecast";
   $changedto = $DataDir."/$storm.forecast";
   if (-e $changed) {rename($changed,$changedto);}
}


##################################

sub ISDEPRESSION {

# Check if a name looks like a tropical depression name

   local($newname) = @_;
   local($junk) = 0;
   local($HyphenNumNew) = 0;

   $HyphenNumNew = split(/\-/,$newname);   # How many hyphens in the new name?
   if ($HyphenNumNew > 2 ||
       $newname =~ /[^a-z0-9 -]/i ||
       $newname =~ /^\d+[A-Z]\-/i ||
       $newname =~ /^\d+\-/i ||
       $newname =~ /^one\-/i ||
       $newname =~ /^two\-/i ||
       $newname =~ /^three\-/i ||
       $newname =~ /^four\-/i ||
       $newname =~ /^five\-/i ||
       $newname =~ /^six\-/i ||
       $newname =~ /^seven\-/i ||
       $newname =~ /^eight\-/i ||
       $newname =~ /^nine\-/i ||
       $newname =~ /^ten\-/i ||
       $newname =~ /^eleven\-/i ||
       $newname =~ /^twelve\-/i ||
       $newname =~ /^thirteen\-/i ||
       $newname =~ /^fourteen\-/i ||
       $newname =~ /^fifteen\-/i ||
       $newname =~ /^sixteen\-/i ||
       $newname =~ /^seventeen\-/i ||
       $newname =~ /^eighteen\-/i ||
       $newname =~ /^nineteen\-/i ||
       $newname =~ /^twenty\-/i ||      # is there a dash after twenty etc.?
       $newname =~ /^thirty\-/i ||
       $newname =~ /^fourty\-/i ||
       $newname =~ /^forty\-/i ||
       $newname =~ /^fifty\-/i ||
       $newname =~ /^sixty\-/i ||
       $newname =~ /^seventy\-/i ||
       $newname =~ /^eighty\-/i ||
       $newname =~ /^ninety\-/i) {$junk=1;} else {$junk=0;}
   $junk;
}


sub ACOS {

# Compute the arc cosine
# Input: Cosine (forced to -1 <= cosine <= 1)
# Output: Angle in radians (0<angle<pi)

   local($cosine) = @_;
   local($argument);
   $argument = 1.0-$cosine**2;
   if ($argument<=0) {
      if ($cosine > 0) {0;} else {$pi;}
   } else {
      $piover2 - atan2($cosine/(sqrt($argument)),1);
   }
}


sub GCDISTANCE {

# Compute Great Circle distance between positions
# Input:  lat1, lon1, lat2, lon, all in decimal degrees
# Output: Distance in Nautical Miles

   local($latitude1,$longitude1,$latitude2,$longitude2) = @_;

   &ACOS(sin($latitude1*$dtor)*sin($latitude2*$dtor) + 
         cos($latitude1*$dtor)*cos($latitude2*$dtor) *
         cos(($longitude1-$longitude2)*$dtor))*60/$dtor;
}