#!/usr/bin/perl
use warnings;
use strict;

my $filename = shift;
my $date     = pop;

print qq(Processing "$filename"...\n);
(my $outfile = "$date.txt") =~ s/ /-/;

open my $IN, '<', $filename or die "$filename: $!\n";

# Count the lines.
1 while <$IN>;
my $line_count = $.;
seek $IN, $. = 0, 0;

open my $OUT, '>', $outfile or die "$outfile: $!\n";

my %stations;
@stations{ @ARGV } = ();

while (<$IN>) {
   chomp;
   my $pcntg = int 100 * ($. / $line_count );
   print STDERR "$pcntg %\r";
   my ($file_date, $file_station) = (split /,/)[0, 5];
   $file_station =~ s/ //g;
   if ($file_date eq $date and exists $stations{$file_station}) {
       print $OUT "$_\n";
       print "Record written to $outfile...\n";

       delete $stations{$file_station};
       last unless %stations;

   }
}

print "\nFinished\n";
close $OUT;