#!/usr/bin/perl -w

use CGI qw(:standard);
use Time::localtime;
use Time::Local;

print header(-type => "image/gif",
	     -expires => "+1d");
print "GIF89a\x01\x00\x01\x00\x80\x00\x00\xff\xff\xff\x00\x00\x00\x21\xf9\x04\x01\x00\x00\x00\x00\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3b";

# update hit stats file

my $file = "data/counter.data";
my $now_stamp = time;
my $now = localtime($now_stamp);
my $early_today_stamp = timelocal(0, 0, 0, $now->mday, $now->mon, $now->year);

if ((!(-f $file)) ||
    (-M $file > (($now_stamp-$early_today_stamp)/(24*60*60)))) {
  my $year = $now->year+1900;
  my $month = $now->mon+1;
  my $day = $now->mday;
  if ($month < 10) {$month = "0$month";}
  if ($day < 10) {$day = "0$day";}
  AppendFile($file, "\n$month/$day/$year .");
} else {
  AppendFile($file, ".");
}

# update user stats file

local @browser_types;
local @browser_count;
local @host_types;
local @host_count;
$file = "data/user.data";
my $toappend = "";

ParseReferFile($file);

my $browser = $ENV{HTTP_USER_AGENT};
if ($browser ne "") {
  my $thisnum = -1;
  for (my $n=0; $n<=$#browser_types; $n++) {
    my $type = $browser_types[$n];
    if (lc($browser) eq lc($type)) {$thisnum = $n;}
  }
  if ($thisnum < 0) {
    $toappend .= "b\t$browser\n";
  } else {
    $toappend .= "+b$thisnum\n";
  }
}

my $host = $ENV{REMOTE_HOST};
if ($host ne "") {
  my $thisnum = -1;
  for (my $n=0; $n<=$#host_types; $n++) {
    my $type = $host_types[$n];
    if (lc($host) eq lc($type)) {$thisnum = $n;}
  }
  if ($thisnum < 0) {
    $toappend .= "h\t$host\n";
  } else {
    $toappend .= "+h$thisnum\n";
  }
}

if ($toappend ne "") {
  AppendFile($file, $toappend);
}

sub ParseReferFile {
  foreach my $line (split(/\n/, ReadFile($_[0]))) {
    if ($line =~ /^\+b(\d+)$/) {
      $browser_count[$1]++;
    } elsif ($line =~ /^\+b(\d+)\+(\d+)$/) {
      $browser_count[$1] += $2;
    } elsif ($line =~ /^b\t(.*)/) {
      push(@browser_types, $1);
      $browser_count[$#browser_types] = 1;

    } elsif ($line =~ /^\+h(\d+)$/) {
      $host_count[$1]++;
    } elsif ($line =~ /^\+h(\d+)\+(\d+)$/) {
      $host_count[$1] += $2;
    } elsif ($line =~ /^h\t(.*)/) {
      push(@host_types, $1);
      $host_count[$#host_types] = 1;
    }
  }
}

sub ReadFile {
# USAGE: $file_contents = ReadFile($file_name);

  unless (open(FILE,"< $_[0]")) {return 0;}
  my $readin = join "", <FILE>;
  close FILE;
  $readin =~ s/\r//g;
  return ($readin);
}

sub AppendFile {
# USAGE: AppendFile ($filename, $contents)
  my $data = $_[1];
  unless (open(FILE,">> $_[0]")) {return 0;}
  print FILE $data;
  close FILE;
  return 1;
}