#!/usr/bin/perl -wT
# 
# Author          : C Matthew Curtin <cmcurtin@interhack.net>
# Created On      : <1998/10/22 00:14:30 cmcurtin>
# Last Modified By: $Author: cmcurtin $
# Last Modified On: $Date: 2003/07/23 15:31:57 $
# Update Count    :
# Status          : 
# 
# HISTORY 
# $Log: rotbanner.txt,v $
# Revision 1.2  2003/07/23 15:31:57  cmcurtin
# committing new content
#
# Revision 1.1  1998/10/29 12:43:48  cmcurtin
# Initial revision
#
# 

# dependencies
use CGI;
use CGI::Carp;
use strict;

my $cgi = new CGI;

# file dependencies
my $bannerdir = "/var/www/sam/images/poweredby";
my $relbannerdir = "http://" . $cgi->virtual_host() . "/images/poweredby";

# $bannerdir/.last has to exist and be writable by the http daemon uid
# LOG (see bottom) needs to be defined.  If the file exists, it must be
# writable, if not, the directory must be writable so LOG file can be created.

opendir(BANNERS, "$bannerdir") or croak "Cannot open $bannerdir: $!";
my @banners = grep(!/^\./, readdir(BANNERS)); # all non dot-files, i.e., .foo
closedir BANNERS;

my $last;

undef $/;

open(LAST, "< $bannerdir/.last") or croak "Cannot open $bannerdir/.last: $!";
$last = <LAST>;
chomp $last;
close LAST;

$last++;

$last = 0 if ($last >= scalar @banners);

# give redirect to the banner we want
#print "Location: " . $relbannerdir . "/" . $banners[$last] . "\n\n";
# or... actually spew the thing directly, which is probably a better idea.

my @stat = stat("$bannerdir/$banners[$last]");

my $type = "$banners[$last]";
$type =~ s/^.*\.([a-zA-Z]+)$/$1/;

if (lc($type) eq "jpg") {
  $type = "jpeg";
} elsif (lc($type) eq "jpeg") {
  $type = "jpeg";
} elsif (lc($type) eq "gif") {
  $type = "gif";
} else {
  croak "Don't know how to generate header for file type $type";
}

$/="\n";

open(BANNER, "< $bannerdir/$banners[$last]") 
  or croak "Cannot open $bannerdir/$banners[$last]: $!";

print "Pragma: No-cache\n";
print "Expires: Thu, 01 Dec 1994 16:00:00 GMT\n";
print "Content-type: image/$type\n";
print "Content-length: $stat[7]\n\n";

while(<BANNER>) {
  print;
}

close BANNER;

open(LAST, "> $bannerdir/.last") 
  or croak "Cannot write to $bannerdir/.last: $!";
print LAST $last;
close LAST;

open(LOG, ">> $bannerdir/.log") or croak ("Cannot open $bannerdir/.log: $!");
print LOG $banners[$last] . ":" . $cgi->referer() . ":" . 
  scalar localtime() . "\n";
close LOG;