# The LearningOnline Network
# Switch Servers Handler
#
# $Id: switchserver.pm,v 1.20 2007/11/15 01:16:32 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/
#

package Apache::switchserver;

use strict;
use Apache::Constants qw(:common);
use Apache::lonnet;
use Apache::lonmenu;
use CGI::Cookie();
use Apache::lonlocal;

sub init_env {
    my ($r) = @_;
    
    if (-e $env{'user.environment'}) {
	return  $env{'user.environment'};
    }
    my $requrl=$r->uri;
    my $handle= &Apache::lonnet::check_for_valid_session($r);
    if ($handle ne '') {
	return undef;
    }
    my $lonidsdir=$r->dir_config('lonIDsDir');
    &Apache::lonnet::transfer_profile_to_env($lonidsdir,$handle);
    
    return $r->dir_config('lonIDsDir')."/$handle.id";
}

sub do_redirect {
    my ($r,$url,$only_body,$extra_text) = @_;
    $r->send_http_header;
    my $start_page = 
	&Apache::loncommon::start_page('Switching Server ...',undef,
				       {'redirect'       => [0.5,$url],
                                        'no_inline_link' => 1,
					'only_body'      => $only_body,});
    my $end_page   = &Apache::loncommon::end_page();
    $r->print($start_page.$extra_text.$end_page);
    return OK;

}

sub handler {
    my ($r) = @_;
    
    my $handle=&init_env($r);
    if (!defined($handle)) { return FORBIDDEN; }

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

    my $switch_to=&Apache::lonnet::hostname($env{'form.otherserver'});
    if (! $env{'form.otherserver'}) {
	$env{'form.otherserver'} =	
	    &Apache::lonnet::find_existing_session($env{'user.domain'},
						   $env{'user.name'});
	if (! $env{'form.otherserver'}) {
	    $env{'form.otherserver'} = 
		&Apache::lonnet::spareserver(30000,undef,1);
	}

	$switch_to=&Apache::lonnet::hostname($env{'form.otherserver'});
    }

    if (!defined($switch_to)) { return FORBIDDEN; }

    if ($env{'user.name'} eq 'public'
	&& $env{'user.domain'} eq 'public') {
	my $url = 'http://'.$switch_to.$r->uri;
	return &do_redirect($r,$url,1)
    }

    if ($env{'form.role'} && 
	!exists($env{'user.role.'.$env{'form.role'}})) { return FORBIDDEN; }

    #remove session env, and log event
    unlink($handle);
    my %temp=('switchserver' => time.':'.$env{'form.otherserver'},
	      $env{'form.role'});
    &Apache::lonnet::put('email_status',\%temp);
    &Apache::lonnet::log($env{'user.domain'},$env{'user.name'},
			 $env{'user.home'},
			 "Switch Server to $env{'form.otherserver'} with role $env{'form.role'} $ENV{'REMOTE_ADDR'}");

    &Apache::loncommon::content_type($r,'text/html');

    #expire the cookie
    my $c = new CGI::Cookie(-name    => 'lonID',
			    -value   => '',
			    -expires => '-10y',);
    $r->header_out('Set-cookie' => $c);

    if ($r->header_only) {
	$r->send_http_header;
	return OK;
    }
# -------------------------------------------------------- Menu script and info
	   
    my $windowinfo=
	&Apache::lonmenu::close().
	&Apache::lonnavmaps::close();
# ---------------------------------------------------------------- Get handover

    my %info=('ip'       => $ENV{'REMOTE_ADDR'},
	      'domain'   => $env{'user.domain'},
	      'username' => $env{'user.name'},
	      'role'     => $env{'form.role'},
	      'server'   => $r->dir_config('lonHostID'));
    if ($env{'request.sso.login'}) {
	$info{'sso.login'} = $env{'request.sso.login'};
    }
    if ($env{'request.sso.reloginserver'}) {
        $info{'sso.reloginserver'} = $env{'request.sso.reloginserver'};
    }
    my $token = &Apache::lonnet::tmpput(\%info,$env{'form.otherserver'});
    my $url ='http://'.$switch_to.'/adm/login?'.
	'domain='.$env{'user.domain'}.
	'&username='.$env{'user.name'}.
	'&token='.$token;
# --------------------------------------------------------------- Screen Output
    &Apache::lonnet::flushcourselogs();
    return &do_redirect($r,$url,0,$windowinfo);
}

1;
__END__