'. &mt('Request another Worktime').'

# The LearningOnline Network with CAPA
# Handler for requesting to have slots added to a students record
#
# $Id: slotrequest.pm,v 1.2 2005/05/31 21:13:01 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::slotrequest;

use strict;
use Apache::Constants qw(:common :http :methods);
use Apache::loncommon();
use Apache::lonlocal;
use Apache::lonnet;

sub fail {
    my ($r,$code)=@_;
    if ($code eq 'not_valid') {
	$r->print('<p>'.&mt('Unable to understand what resource you wanted to sign up for.').'</p>'.$env{'form.symb'});

    }
    $r->print('<p><a href="/adm/flip?postdata=return:">'.
	      &mt('Return to last resource').'</a></p>');
    &end_page($r);
}

sub start_page {
    my ($r)=@_;
    my $html=&Apache::lonxml::xmlbegin();
    $r->print($html.'<head><title>'.
	      &mt('Request another Worktime').'</title></head>');
    $r->print(&Apache::loncommon::bodytag('Requesting another Worktime'));
}

sub end_page {
    my ($r)=@_;
    $r->print(&Apache::loncommon::endbodytag().'</html>');
}

=pod

 slot_reservations db
   - keys are 
    - slotname\0id -> value is an hashref of
                         name -> user@domain of holder
                         timestamp -> timestamp of reservation
                         symb -> symb of resource that it is reserved for

=cut

sub get_course {
    (undef,my $courseid)=&Apache::lonxml::whichuser();
    my $cdom=$env{'course.'.$courseid.'.domain'};
    my $cnum=$env{'course.'.$courseid.'.num'};
    return ($cnum,$cdom);
}

sub get_reservation_ids {
    my ($slot_name)=@_;
    
    my ($cnum,$cdom)=&get_course();

    my %consumed=&Apache::lonnet::dump('slot_reservations',$cdom,$cnum,
				       "^$slot_name\0");
    
    my ($tmp)=%consumed;
    if ($tmp=~/^error: 2 / ) {
	return 0;
    }
    return keys(%consumed);
}

sub space_available {
    my ($slot_name,$slot)=@_;
    my $max=$slot->{'maxspace'};

    if (!defined($max)) { return 1; }

    my $consumed=scalar(&get_reservation_ids($slot_name));
    if ($consumed < $max) {
	return 1
    }
    return 0;
}
 
sub make_reservation {
    my ($slot_name,$slot,$symb)=@_;
    my $max=$slot->{'maxspace'};

    if (!defined($max)) { return 1; }

    my (@ids)=&get_reservation_ids($slot_name);

    # FIXME we could end up having holes... 
    my $last=0;
    foreach my $id (@ids) {
	my $num=(split('\0',$id))[1];
	if ($num > $last) { $last=$num; }
    }
    
    my $wanted=$last+1;
    if ($wanted >= $max) {
	# full up
	return -1;
    }
    
    my %reservation=('name'      => $env{'user.name'}.'@'.$env{'user.domain'},
		     'timestamp' => time,
		     'symb'      => $symb);

    my ($cnum,$cdom)=&get_course();
    my $success=&Apache::lonnet::newput('slot_reservations',
					{"$slot_name\0$wanted" =>
					     \%reservation},
					$cdom,$cnum);
    if ($success eq 'ok') {
	return $wanted;
    }
    # someone else got it
    return -1;
}


sub show_choices {
    my ($r,$symb)=@_;

    my ($cnum,$cdom)=&get_course();
    my %slots=&Apache::lonnet::dump('slots',$cdom,$cnum);
    $r->print('<table border="1">');
    foreach my $slot (sort 
		      { return $slots{$a}->{'starttime'} <=> $slots{$b}->{'starttime'} }
		      (keys(%slots)))  {
	my $description=$slots{$slot}->{'description'};
	if (!defined($description)) {
	    $description=&mt('[_1] From [_2] to [_3]',$slot,
			     &Apache::lonlocal::locallocaltime($slots{$slot}->{'starttime'}),
			     &Apache::lonlocal::locallocaltime($slots{$slot}->{'endtime'}));
	}

	my $form=&mt('Unavailable');
	if (&space_available($slot,$slots{$slot})) {
	    $form=<<STUFF;
   <form>
     <input type="submit" name="Select" value="Select" />
     <!-- FIXME needs to send data -->
   </form>
STUFF
	}
	$r->print(<<STUFF);
<tr>
 <td>$form</td>
 <td>$description</td>
</tr>
STUFF
    }
    $r->print('</table>');
}

sub handler {
    my $r=shift;

    &start_page($r);
    my $symb=&Apache::lonnet::unescape($env{'form.symb'});
    my (undef,undef,$res)=&Apache::lonnet::decode_symb($symb);
    if ($res !~ /\.task$/) {
	&fail($r,'not_valid');
	return OK;
    }
    
    if ($env{'form.requestattempt'}) {
	&show_choices($r,$symb);
    }

    &end_page($r);
    return OK;
}