#!/usr/local/bin/webwork-perl

####################################################################
# Copyright @ 1995-1999 University of Rochester
# All Rights Reserved
####################################################################

use lib '.'; use webworkInit; # WeBWorKInitLine

use CGI qw(:standard);
use Global;
use Auth;
use strict;
use GDBM_File;

# begin Timing code
use Benchmark;
my $beginTime = new Benchmark;
# end Timing code

&CGI::ReadParse;
my %inputs =%main::in;

# get information from CGI inputs  (see also below for additional information)

my $Course 			= $inputs{'course'};
my $User 			= $inputs{'user'};
my $Session_key 	= $inputs{'key'};


# verify that information has been received
unless($Course && $User && $Session_key) {
    &wwerror("$0","The script did not receive the proper input data.","","");
}


# establish environment for this script

&Global::getCourseEnvironment($inputs{'course'});

my $cgiURL   				= getWebworkCgiURL;
my $scriptDirectory   		= getWebworkScriptDirectory;
require "${scriptDirectory}$Global::FILE_pl";
require "${scriptDirectory}$Global::HTMLglue_pl";

# log access
&Global::log_info('', query_string);


my $permissionsFile = &Global::getCoursePermissionsFile($inputs{'course'});
my $permissions = &get_permissions($inputs{'user'}, $permissionsFile);
my $keyFile = &Global::getCourseKeyFile($inputs{'course'});


#verify session key
&verify_key($inputs{'user'}, $inputs{'key'}, $keyFile, $inputs{'course'});

# verify permissions are correct
if ($permissions != $Global::instructor_permissions ) {
    print "permissions = $permissions instructor_permissions = $Global::instructor_permissions\n";
    print &html_NO_PERMISSION;
    exit(0);
}
# Directory paths

my $databaseDirectory = getCourseDatabaseDirectory();
my $databaseFile = $Global::database;

            ## exit unless the course uses gdbm for the webwork database
unless ($Global::DBtie_file eq 'gdbm_tie.pl') {
    wwerror("Wrong database type", "Compress works only for gdbm databases.  No changes
    have been made to your non gdbm database");
}    



my $mode = &GDBM_WRCREAT();
my $permission = $Global::standard_tie_permission;
my ($db, %hash, $tries);
my $TieMaxTries =30;	# try to tie() 30 times, then fail
my $TieSleepInterval =2; # sleep 2 sec after failed tie()

&tie_hash();
$db->reorganize();
untie($db);
chmod($permission,"${databaseDirectory}${databaseFile}") or
          warn("$0 error", " Can't do chmod($permission, ${databaseDirectory}${databaseFile})");
chown(-1,$Global::numericalGroupID,"${databaseDirectory}${databaseFile}") or
          warn("$0 error", " Can't do chown(-1,$Global::numericalGroupID,${databaseDirectory}${databaseFile})");          


&compressSuccess();
exit;
 
sub tie_hash {
    for ($tries = 0; $tries < $TieMaxTries; $tries++) {
        return 1 if ($db = tie(%hash, "GDBM_File", "${databaseDirectory}${databaseFile}", $mode, $permission));
        sleep($TieSleepInterval);
    }
    &wwerror("Key database error", "Can't tie ${databaseDirectory}${databaseFile}: $!");
}    
   

sub compressSuccess {
  
  print"content-type:\n\n<H2>Success, ${databaseDirectory}${databaseFile} compressed. </H2>\n";
  print "The WeBWorK database file ${databaseDirectory}${databaseFile} has been compressed";
    
  print "<FORM METHOD=POST ACTION=\"${cgiURL}profLogin.pl\"><P>";
  print &sessionKeyInputs(\%inputs);
print <<"ENDOFHTML";
<INPUT TYPE=SUBMIT VALUE="Return to Prof Page">
</FORM>
ENDOFHTML
  print &htmlBOTTOM("profCompress_GDBM_webwork-database.pl", \%inputs);
}