#!/usr/bin/perl

# The LearningOnline Network with CAPA
# thumbnail.gif - a CGI script that ships out the thumbnail
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA 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.
#
# LON-CAPA 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 LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
###

# Example usage: /cgi-bin/thumbnail.gif?url=...


use strict;

sub filelocation {
  my ($dir,$file) = @_;
  my $location;
  $file=~ s/^\s*(\S+)\s*$/$1/; ## strip off leading and trailing spaces
  if ($file=~m:^/~:) { # is a contruction space reference
    $location = $file;
    $location =~ s:/~(.*?)/(.*):/home/$1/public_html/$2:;
  } else {
    $file=~s/\/home\/httpd\/html//;
    $file=~s:^/*res::;
    if ( !( $file =~ m:^/:) ) {
      $location = $dir. '/'.$file;
    } else {
      $location = '/home/httpd/html/res'.$file;
    }
  }
  $location=~s://+:/:g; # remove duplicate /
  while ($location=~m:/\.\./:) {$location=~ s:/[^/]+/\.\./:/:g;} #remove dir/..
  return $location;
}

my %env;

$|=1;   # Autoflush after each print/write
foreach (split(/&/,$ENV{'QUERY_STRING'})) {
    my ($name, $value) = split(/=/,$_);
    $value =~ tr/+/ /;
    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
    if ($name eq 'url') {
	$env{'form.'.$name}=$value;
    }
}


my $ofn=&filelocation('',$env{'form.url'});
my $fn=$ofn.'.thumbnail';

my $exists=1;
my $generate=0;

if (-e $ofn) {
   my ($dev,$ino,$mode,$nlink,
       $uid,$gid,$rdev,$size,
       $atime,$omtime,$ctime,
       $blksize,$blocks)=stat($ofn);
   if (-e $fn) {
       my ($dev,$ino,$mode,$nlink,
           $uid,$gid,$rdev,$size,
           $atime,$mtime,$ctime,
           $blksize,$blocks)=stat($fn);
       if ($omtime>$mtime) { $generate=1; }
   } else {
       $generate=1;
   }
} else {
    $exists=0;
}

# FIXME: generate thumbnail instead
if ($generate) { $exists=0; }


unless ($exists) {
   $fn='/home/httpd/html/res/adm/pages/nothumb.gif';
}

# Tell the server we are sending a gif graphic
print <<END;
Content-type: image/gif

END

open (IN,$fn);
binmode(STDOUT);
print join('',<IN>); # output image
$|=1; # be sure to flush before closing
close IN;