# The LearningOnline Network with CAPA
# Handler to retrieve an old version of a file
#
# $Id: lonretrieve.pm,v 1.22 2003/05/19 21:53:03 albertel Exp $
#
# 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/
#
#
# (Publication Handler
# 
# (TeX Content Handler
#
# YEAR=2000
# 05/29/00,05/30,10/11 Gerd Kortemeyer)
#
# 11/28,11/29,11/30,12/01,12/02,12/04,12/23 Gerd Kortemeyer
# YEAR=2001
# 03/23 Guy Albertelli
# 03/24,03/29 Gerd Kortemeyer)
#
# 03/31,04/03,05/02,05/09,06/23,08/20 Gerd Kortemeyer
#
###

package Apache::lonretrieve;

use strict;
use Apache::File;
use File::Copy;
use Apache::Constants qw(:common :http :methods);
use Apache::loncacc;
use Apache::loncommon();

# ------------------------------------ Interface for selecting previous version
sub phaseone {
    my ($r,$fn,$uname,$udom)=@_;
    my $docroot=$r->dir_config('lonDocRoot');

    my $urldir='/res/'.$udom.'/'.$uname.$fn;
    $urldir=~s/\/[^\/]+$/\//;

    my $resfn=$docroot.'/res/'.$udom.'/'.$uname.$fn;
    my $resdir=$resfn;
    $resdir=~s/\/[^\/]+$/\//;

    $fn=~/\/([^\/]+)\.(\w+)$/;
    my $main=$1;
    my $suffix=$2;

    if (-e $resfn) {  
    $r->print('<form action=/adm/retrieve method=post>'.
	      '<input type=hidden name=filename value="/~'.$uname.$fn.'">'.
              '<input type=hidden name=phase value=two>'.
              '<table border=2><tr><th>Select</th><th>Version</th>'.
              '<th>Became this version on ...</th>'.
              '<th>Metadata</th></tr>');
    my $filename;
    opendir(DIR,$resdir);
    while ($filename=readdir(DIR)) {
        if ($filename=~/^\Q$main\E\.(\d+)\.\Q$suffix\E$/) {
	   my $version=$1;
           my ($rdev,$rino,$rmode,$rnlink,
                $ruid,$rgid,$rrdev,$rsize,
                $ratime,$rmtime,$rctime,
                $rblksize,$rblocks)=stat($resdir.'/'.$filename);
           $r->print('<tr><td><input type=radio name=version value="'.
                     $version.'"></td><th>'.$version.'</th><td>'.
                     localtime($rmtime).'</td><td>'.
                     '<a href="'.$urldir.$filename.'.meta" target=cat>'.
                     'Metadata Version '.$version.'</a>');
           if (&Apache::loncommon::fileembstyle($suffix) eq 'ssi') {
               $r->print(
                    '&nbsp;&nbsp;<a target=cat href="/adm/diff?filename=/~'.
                        $uname.$fn.
                        '&versiontwo=priv&versiontwo='.$version.
                        '">Diffs with Version '.$version.'</a>');
           }
           $r->print('</a></td></tr>');
        }
    }
    closedir(DIR);
    my ($rdev,$rino,$rmode,$rnlink,
        $ruid,$rgid,$rrdev,$rsize,
        $ratime,$rmtime,$rctime,
        $rblksize,$rblocks)=stat($resfn);
    $r->print('<tr><td><input type=radio name=version value="new"></td>'.
              '<th>Current</th><td>'.localtime($rmtime).
           '</td><td><a href="'.$urldir.$main.'.'.$suffix.'.meta" target=cat>'.
              'Metadata current version</a>');           
           if (&Apache::loncommon::fileembstyle($suffix) eq 'ssi') {
               $r->print(
                    '&nbsp;&nbsp;<a target=cat href="/adm/diff?filename=/~'.
                        $uname.$fn.
                        '&versiontwo=priv'.
                        '">Diffs with current Version</a>');
           }
           $r->print('</td></tr></table><p>'.
           '<font size=+1 color=red>Retrieval of an old version will '.
           'overwrite the file currently in construction space</font><p>'.
           '<input type=submit value="Retrieve version"></form>');
} else {
    $r->print('<h3>No previous versions published.</h3>');
}
}

# ---------------------------------- Interface for presenting specified version
sub phasetwo {
    my ($r,$fn,$uname,$udom)=@_;
    if ($ENV{'form.version'}) {
        my $version=$ENV{'form.version'};
	if ($version eq 'new') {
	    $r->print('<h3>Retrieving current (most recent) version</h3>');
        } else {
            $r->print('<h3>Retrieving old version '.$version.'</h3>');
        }
        my $logfile;
        my $ctarget='/home/'.$uname.'/public_html'.$fn;
        my $vfn=$fn;
        if ($version ne 'new') {
	    $vfn=~s/\.(\w+)$/\.$version\.$1/;
        }
        my $csource=$r->dir_config('lonDocRoot').'/res/'.$udom.'/'.$uname.$vfn;
        unless ($logfile=Apache::File->new('>>'.$ctarget.'.log')) {
	  $r->print(
         '<font color=red>No write permission to user directory, FAIL</font>');
        }
        print $logfile 
"\n\n================= Retrieve ".localtime()." ================\n".
"Version: $version\nSource: $csource\nTarget: $ctarget\n";
        $r->print('<p>Copying file: ');
        if (copy($csource,$ctarget)) {
	    $r->print('ok<p>');
            print $logfile "Copied sucessfully.\n\n";
        } else {
            my $error=$!;
	    $r->print('fail, '.$error.'<p>');
            print $logfile "Copy failed: $error\n\n";
        }
        $r->print('<font size=+2><a href="/priv/'.$uname.$fn.
                  '">Back to '.$fn.'</a></font>'); 
    } else {
       $r->print(
   '<font size=+1 color=red>Please pick a version to retrieve</font><p>');
       &phaseone($r,$fn,$uname,$udom);
    }
}

# ---------------------------------------------------------------- Main Handler
sub handler {

  my $r=shift;

  my $fn;


# Get query string for limited number of parameters

  &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
					  ['filename']);

  if ($ENV{'form.filename'}) {
      $fn=$ENV{'form.filename'};
      $fn=~s/^http\:\/\/[^\/]+//;
  } else {
     $r->log_reason($ENV{'user.name'}.' at '.$ENV{'user.domain'}.
         ' unspecified filename for retrieval', $r->filename); 
     return HTTP_NOT_FOUND;
  }

  unless ($fn) { 
     $r->log_reason($ENV{'user.name'}.' at '.$ENV{'user.domain'}.
         ' trying to retrieve non-existing file', $r->filename); 
     return HTTP_NOT_FOUND;
  } 

# ----------------------------------------------------------- Start page output
  my $uname;
  my $udom;

  ($uname,$udom)=
    &Apache::loncacc::constructaccess($fn,$r->dir_config('lonDefDomain'));
  unless (($uname) && ($udom)) {
     $r->log_reason($uname.' at '.$udom.
         ' trying to publish file '.$ENV{'form.filename'}.
         ' ('.$fn.') - not authorized', 
         $r->filename); 
     return HTTP_NOT_ACCEPTABLE;
  }

  $fn=~s/\/\~(\w+)//;

  $r->content_type('text/html');
  $r->send_http_header;

  $r->print('<html><head><title>LON-CAPA Construction Space</title></head>');

  $r->print(&Apache::loncommon::bodytag('Retrieve Published Resources'));

  
  $r->print('<h1>Retrieve previous versions of <tt>'.$fn.'</tt></h1>');
  
  if (($uname ne $ENV{'user.name'}) || ($udom ne $ENV{'user.domain'})) {
          $r->print('<h3><font color=red>Co-Author: '.$uname.' at '.$udom.
               '</font></h3>');
  }


  if ($ENV{'form.phase'} eq 'two') {
      &phasetwo($r,$fn,$uname,$udom);
  } else {
      &phaseone($r,$fn,$uname,$udom);
  }

  $r->print('</body></html>');
  return OK;  
}

1;
__END__

=head1 NAME

Apache::lonretrieve - retrieves an old version of a file

=head1 SYNOPSIS

Invoked by /etc/httpd/conf/srm.conf:

 <Location /adm/retrieve>
 PerlAccessHandler       Apache::lonacc
 SetHandler perl-script
 PerlHandler Apache::lonretrieve
 ErrorDocument     403 /adm/login
 ErrorDocument     404 /adm/notfound.html
 ErrorDocument     406 /adm/unauthorized.html
 ErrorDocument	  500 /adm/errorhandler
 </Location>

=head1 INTRODUCTION

This module retrieves an old published version of a file.

This is part of the LearningOnline Network with CAPA project
described at http://www.lon-capa.org.

=head1 HANDLER SUBROUTINE

This routine is called by Apache and mod_perl.

=over 4

=item *

Get query string for limited number of parameters

=item *

Start page output

=item *

print phase relevant output

=item *

(phase one is to select version; phase two retrieves version)

=back

=head1 OTHER SUBROUTINES

=over 4

=item *

phaseone() : Interface for selecting previous version.

=item *

phasetwo() : Interface for presenting specified version.

=back

=cut