# The LearningOnline Network with CAPA
# (Publication Handler
#
# $Id: loncoursedata.pm,v 1.5 2002/07/25 19:31:32 minaeibi 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/
#
###

=pod

=head1 NAME

loncoursedata

=head1 SYNOPSIS

Set of functions that download and process student information.

=head1 PACKAGES USED

 Apache::Constants qw(:common :http)
 Apache::lonnet()
 HTML::TokeParser
 GDBM_File

=cut

package Apache::loncoursedata;

use strict;
use Apache::Constants qw(:common :http);
use Apache::lonnet();
use HTML::TokeParser;
use GDBM_File;

=pod

=head1 DOWNLOAD INFORMATION

This section contains all the files that get data from other servers 
and/or itself.  There is one function that has a call to get remote
information but isn't included here which is ProcessTopLevelMap.  The
usage was small enough to be ignored, but that portion may be moved
here in the future.

=cut

# ----- DOWNLOAD INFORMATION -------------------------------------------

=pod

=item &DownloadClasslist()

Collects lastname, generation, middlename, firstname, PID, and section for each
student from their environment database.  The list of students is built from
collecting a classlist for the course that is to be displayed.

=over 4

Input: $courseID, $c

$courseID:  The id of the course

$c: The connection class that can determine if the browser has aborted.  It
is used to short circuit this function so that it doesn't continue to 
get information when there is no need.

Output: \%classlist

\%classlist: A pointer to a hash containing the following data:

-A list of student name:domain (as keys) (known below as $name)

-A hash pointer for each student containing lastname, generation, firstname,
middlename, and PID : Key is $name.'studentInformation'

-A hash pointer to each students section data : Key is $name.section

=back

=cut

sub DownloadClasslist {
    my ($courseID, $lastDownloadTime, $c)=@_;
    my ($courseDomain,$courseNumber)=split(/\_/,$courseID);
    my %classlist;

#    my $modifiedTime = &GetFileTimestamp($courseDomain, $courseNumber,
#                                     'classlist.db', 
#                                     $Apache::lonnet::perlvar{'lonUsersDir'});

#    if($lastDownloadTime ne 'Not downloaded' &&
#       $lastDownloadTime >= $modifiedTime && $modifiedTime >= 0) {
#        $classlist{'lastDownloadTime'}=time;
#        $classlist{'UpToDate'} = 'true';
#        return \%classlist;
#    }

    %classlist=&Apache::lonnet::dump('classlist',$courseDomain, $courseNumber);
    my ($checkForError)=keys (%classlist);
    if($checkForError =~ /^(con_lost|error|no_such_host)/i) {
        return \%classlist;
    }

    foreach my $name (keys(%classlist)) {
        if($c->aborted()) {
            $classlist{'error'}='aborted';
            return \%classlist;
        }

        my ($studentName,$studentDomain) = split(/\:/,$name);
        # Download student environment data, specifically the full name and id.
        my %studentInformation=&Apache::lonnet::get('environment',
                                                    ['lastname','generation',
                                                     'firstname','middlename',
                                                     'id'],
                                                    $studentDomain,
                                                    $studentName);
        $classlist{$name.':studentInformation'}=\%studentInformation;

        if($c->aborted()) {
            $classlist{'error'}='aborted';
            return \%classlist;
        }

        #Section
        my %section=&Apache::lonnet::dump('roles',$studentDomain,$studentName);
        $classlist{$name.':sections'}=\%section;
    }

    $classlist{'UpToDate'} = 'false';
    $classlist{'lastDownloadTime'}=time;

    return \%classlist;
}

=pod

=item &DownloadCourseInformation()

Dump of all the course information for a single student.  There is no
pruning of data, it is all stored in a hash and returned.  It also
checks the timestamp of the students course database file and only downloads
if it has been modified since the last download.

=over 4

Input: $name, $courseID

$name: student name:domain

$courseID:  The id of the course

Output: \%courseData

\%courseData:  A hash pointer to the raw data from the student's course
database.

=back

=cut

sub DownloadCourseInformation {
    my ($namedata,$courseID,$lastDownloadTime)=@_;
    my %courseData;
    my ($name,$domain) = split(/\:/,$namedata);

#    my $modifiedTime = &GetFileTimestamp($domain, $name,
#                                      $courseID.'.db', 
#                                      $Apache::lonnet::perlvar{'lonUsersDir'});
#    if($lastDownloadTime >= $modifiedTime) {
#        $courseData{'lastDownloadTime'}=time;
#        $courseData{'UpToDate'} = 'true';
#        return \%courseData;
#    }

    # Download course data
    %courseData=&Apache::lonnet::dump($courseID, $domain, $name);
    $courseData{'UpToDate'} = 'false';
    $courseData{'lastDownloadTime'}=time;
    return \%courseData;
}

# ----- END DOWNLOAD INFORMATION ---------------------------------------

=pod

=head1 PROCESSING FUNCTIONS

These functions process all the data for all the students.  Also, they
are the only functions that access the cache database for writing.  Thus
they are the only functions that cache data.  The downloading and caching
were separated to reduce problems with stopping downloading then can't
tie hash to database later.

=cut

# ----- PROCESSING FUNCTIONS ---------------------------------------

=pod

=item &ProcessTopResourceMap()

Trace through the "big hash" created in rat/lonuserstate.pm::loadmap.  
Basically, this function organizes a subset of the data and stores it in
cached data.  The data stored is the problems, sequences, sequence titles,
parts of problems, and their ordering.  Column width information is also 
partially handled here on a per sequence basis.

=over 4

Input: $cache, $c

$cache:  A pointer to a hash to store the information

$c:  The connection class used to determine if an abort has been sent to the 
browser

Output: A string that contains an error message or "OK" if everything went 
smoothly.

=back

=cut

sub ProcessTopResourceMap {
    my ($cache,$c)=@_;
    my %hash;
    my $fn=$ENV{'request.course.fn'};
    if(-e "$fn.db") {
	my $tieTries=0;
	while($tieTries < 3) {
            if($c->aborted()) {
                return;
            }
	    if(tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) {
		last;
	    }
	    $tieTries++;
	    sleep 1;
	}
	if($tieTries >= 3) {
            return 'Coursemap undefined.';
        }
    } else {
        return 'Can not open Coursemap.';
    }

    # Initialize state machine.  Set information pointing to top level map.
    my (@sequences, @currentResource, @finishResource);
    my ($currentSequence, $currentResourceID, $lastResourceID);

    $currentResourceID=$hash{'ids_/res/'.$ENV{'request.course.uri'}};
    push(@currentResource, $currentResourceID);
    $lastResourceID=-1;
    $currentSequence=-1;
    my $topLevelSequenceNumber = $currentSequence;

    while(1) {
        if($c->aborted()) {
            last;
        }
	# HANDLE NEW SEQUENCE!
	#if page || sequence
	if(defined($hash{'map_pc_'.$hash{'src_'.$currentResourceID}})) {
	    push(@sequences, $currentSequence);
	    push(@currentResource, $currentResourceID);
	    push(@finishResource, $lastResourceID);

	    $currentSequence=$hash{'map_pc_'.$hash{'src_'.$currentResourceID}};

            # Mark sequence as containing problems.  If it doesn't, then
            # it will be removed when processing for this sequence is
            # complete.  This allows the problems in a sequence
            # to be outputed before problems in the subsequences
            if(!defined($cache->{'orderedSequences'})) {
                $cache->{'orderedSequences'}=$currentSequence;
            } else {
                $cache->{'orderedSequences'}.=':'.$currentSequence;
            }

	    $lastResourceID=$hash{'map_finish_'.
				  $hash{'src_'.$currentResourceID}};
	    $currentResourceID=$hash{'map_start_'.
				     $hash{'src_'.$currentResourceID}};

	    if(!($currentResourceID) || !($lastResourceID)) {
		$currentSequence=pop(@sequences);
		$currentResourceID=pop(@currentResource);
		$lastResourceID=pop(@finishResource);
		if($currentSequence eq $topLevelSequenceNumber) {
		    last;
		}
	    }
	}

	# Handle gradable resources: exams, problems, etc
	$currentResourceID=~/(\d+)\.(\d+)/;
        my $partA=$1;
        my $partB=$2;
	if($hash{'src_'.$currentResourceID}=~
	   /\.(problem|exam|quiz|assess|survey|form)$/ &&
	   $partA eq $currentSequence) {
	    my $Problem = &Apache::lonnet::symbclean(
			  &Apache::lonnet::declutter($hash{'map_id_'.$partA}).
			  '___'.$partB.'___'.
			  &Apache::lonnet::declutter($hash{'src_'.
							 $currentResourceID}));

	    $cache->{$currentResourceID.':problem'}=$Problem;
	    if(!defined($cache->{$currentSequence.':problems'})) {
		$cache->{$currentSequence.':problems'}=$currentResourceID;
	    } else {
		$cache->{$currentSequence.':problems'}.=
		    ':'.$currentResourceID;
	    }

	    my $meta=$hash{'src_'.$currentResourceID};
#            $cache->{$currentResourceID.':title'}=
#                &Apache::lonnet::metdata($meta,'title');
            $cache->{$currentResourceID.':title'}=
                $hash{'title_'.$currentResourceID};

            # Get Parts for problem
	    foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
		if($_=~/^stores\_(\d+)\_tries$/) {
		    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
                    if(!defined($cache->{$currentSequence.':'.
                                          $currentResourceID.':parts'})) {
                        $cache->{$currentSequence.':'.$currentResourceID.
                                   ':parts'}=$Part;
                    } else {
                        $cache->{$currentSequence.':'.$currentResourceID.
                                   ':parts'}.=':'.$Part;
                    }
                    foreach (split(/\,/,
                             &Apache::lonnet::metadata($meta,'packages'))) {
                        if($_=~/^optionresponse\_($Part)\_(\w+)$/) {
                            if(defined($cache->{'OptionResponses'})) {
                                $cache->{'OptionResponses'}.= ':::'.
                                    $hash{'src_'.$currentResourceID}.'::'.
                                    $hash{'title_'.$currentResourceID}.'::'.
                                    $Part.'::'.$Problem;
                            } else {
                                $cache->{'OptionResponses'}=
                                    $hash{'src_'.$currentResourceID}.'::'.
                                    $hash{'title_'.$currentResourceID}.'::'.
                                    $Part.'::'.$Problem;
                            }
                        }
                    }
                }
	    }
	}

	# if resource == finish resource, then it is the end of a sequence/page
	if($currentResourceID eq $lastResourceID) {
	    # pop off last resource of sequence
	    $currentResourceID=pop(@currentResource);
	    $lastResourceID=pop(@finishResource);

	    if(defined($cache->{$currentSequence.':problems'})) {
		# Capture sequence information here
		$cache->{$currentSequence.':title'}=
		    $hash{'title_'.$currentResourceID};
                $cache->{$currentSequence.':source'}=
                    $hash{'src_'.$currentResourceID};

                my $totalProblems=0;
                foreach my $currentProblem (split(/\:/,
                                               $cache->{$currentSequence.
                                               ':problems'})) {
                    foreach (split(/\:/,$cache->{$currentSequence.':'.
                                                   $currentProblem.
                                                   ':parts'})) {
                        $totalProblems++;
                    }
                }
		my @titleLength=split(//,$cache->{$currentSequence.
                                                    ':title'});
                # $extra is 3 for problems correct and 3 for space
                # between problems correct and problem output
                my $extra = 6;
		if(($totalProblems + $extra) > (scalar @titleLength)) {
		    $cache->{$currentSequence.':columnWidth'}=
                        $totalProblems + $extra;
		} else {
		    $cache->{$currentSequence.':columnWidth'}=
                        (scalar @titleLength);
		}
	    } else {
                # Remove sequence from list, if it contains no problems to
                # display.
                $cache->{'orderedSequences'}=~s/$currentSequence//;
                $cache->{'orderedSequences'}=~s/::/:/g;
                $cache->{'orderedSequences'}=~s/^:|:$//g;
            }

	    $currentSequence=pop(@sequences);
	    if($currentSequence eq $topLevelSequenceNumber) {
		last;
	    }
	}

	# MOVE!!!
	# move to next resource
	unless(defined($hash{'to_'.$currentResourceID})) {
	    # big problem, need to handle.  Next is probably wrong
	    last;
	}
	my @nextResources=();
	foreach (split(/\,/,$hash{'to_'.$currentResourceID})) {
	    push(@nextResources, $hash{'goesto_'.$_});
	}
	push(@currentResource, @nextResources);
	# Set the next resource to be processed
	$currentResourceID=pop(@currentResource);
    }

    unless (untie(%hash)) {
        &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                                 "Could not untie coursemap $fn (browse)".
                                 ".</font>"); 
    }

    return 'OK';
}

=pod

=item &ProcessClasslist()

Taking the class list dumped from &DownloadClasslist(), all the 
students and their non-class information is processed using the 
&ProcessStudentInformation() function.  A date stamp is also recorded for
when the data was processed.

Takes data downloaded for a student and breaks it up into managable pieces and 
stored in cache data.  The username, domain, class related date, PID, 
full name, and section are all processed here.


=over 4

Input: $cache, $classlist, $courseID, $ChartDB, $c

$cache: A hash pointer to store the data

$classlist:  The hash of data collected about a student from 
&DownloadClasslist().  The hash contains a list of students, a pointer 
to a hash of student information for each student, and each student's section 
number.

$courseID:  The course ID

$ChartDB:  The name of the cache database file.

$c:  The connection class used to determine if an abort has been sent to the 
browser

Output: @names

@names:  An array of students whose information has been processed, and are to 
be considered in an arbitrary order.

=back

=cut

sub ProcessClasslist {
    my ($cache,$classlist,$courseID,$c)=@_;
    my @names=();

    $cache->{'ClasslistTimeStamp'}=$classlist->{'lastDownloadTime'};
    if($classlist->{'UpToDate'} eq 'true') {
        return split(/:::/,$cache->{'NamesOfStudents'});;
    }

    foreach my $name (keys(%$classlist)) {
        if($name =~ /\:section/ || $name =~ /\:studentInformation/ ||
           $name eq '' || $name eq 'UpToDate' || $name eq 'lastDownloadTime') {
            next;
        }
        if($c->aborted()) {
            return ();
        }
        push(@names,$name);
        my $studentInformation = $classlist->{$name.':studentInformation'},
        my $sectionData = $classlist->{$name.':sections'},
        my $date = $classlist->{$name},
        my ($studentName,$studentDomain) = split(/\:/,$name);

        $cache->{$name.':username'}=$studentName;
        $cache->{$name.':domain'}=$studentDomain;
        if(!defined($cache->{$name.':lastDownloadTime'})) {
            $cache->{$name.':lastDownloadTime'}='Not downloaded';
        }

        my ($checkForError)=keys(%$studentInformation);
        if($checkForError =~ /^(con_lost|error|no_such_host)/i) {
            $cache->{$name.':error'}=
                'Could not download student environment data.';
            $cache->{$name.':fullname'}='';
            $cache->{$name.':id'}='';
        } else {
            $cache->{$name.':fullname'}=&ProcessFullName(
                                          $studentInformation->{'lastname'},
                                          $studentInformation->{'generation'},
                                          $studentInformation->{'firstname'},
                                          $studentInformation->{'middlename'});
            $cache->{$name.':id'}=$studentInformation->{'id'};
        }

        my ($end, $start)=split(':',$date);
        $courseID=~s/\_/\//g;
        $courseID=~s/^(\w)/\/$1/;

        my $sec='';
        foreach my $key (keys (%$sectionData)) {
            my $value = $sectionData->{$key};
            if ($key=~/^$courseID(?:\/)*(\w+)*\_st$/) {
                my $tempsection=$1;
                if($key eq $courseID.'_st') {
                    $tempsection='';
                }
                my ($dummy,$roleend,$rolestart)=split(/\_/,$value);
                if($roleend eq $end && $rolestart eq $start) {
                    $sec = $tempsection;
                    last;
                }
            }
        }

        my $status='Expired';
        if(((!$end) || time < $end) && ((!$start) || (time > $start))) {
            $status='Active';
        }
        $cache->{$name.':Status'}=$status;
        $cache->{$name.':section'}=$sec;
    }

    $cache->{'ClasslistTimestamp'}=time;
    $cache->{'NamesOfStudents'}=join(':::',@names);

    return @names;
}

=pod

=item &ProcessStudentData()

Takes the course data downloaded for a student in 
&DownloadCourseInformation() and breaks it up into key value pairs
to be stored in the cached data.  The keys are comprised of the 
$username:$domain:$keyFromCourseDatabase.  The student username:domain is
stored away signifying that the student's information has been downloaded and 
can be reused from cached data.

=over 4

Input: $cache, $courseData, $name

$cache: A hash pointer to store data

$courseData:  A hash pointer that points to the course data downloaded for a 
student.

$name:  username:domain

Output: None

*NOTE:  There is no output, but an error message is stored away in the cache 
data.  This is checked in &FormatStudentData().  The key username:domain:error 
will only exist if an error occured.  The error is an error from 
&DownloadCourseInformation().

=back

=cut

sub ProcessStudentData {
    my ($cache,$courseData,$name)=@_;

    if($courseData->{'UpToDate'} eq 'true') {
        $cache->{$name.':lastDownloadTime'}=$courseData->{'lastDownloadTime'};
        return;
    }

    my @courseKeys = keys(%$courseData);

    foreach (@courseKeys) {
        if(/^(con_lost|error|no_such_host)/i) {
            $cache->{$name.':error'}='Could not download course data.';
            return;
        }
    }

    $cache->{$name.':lastDownloadTime'}=$courseData->{'lastDownloadTime'};
    foreach (@courseKeys) {
        $cache->{$name.':'.$_}=$courseData->{$_};
    }

    return;
}

sub LoadDiscussion {
    my ( $courseID)=@_;
    my %Discuss=();
    my %contrib=&Apache::lonnet::dump(
                $courseID,
                $ENV{'course.'.$courseID.'.domain'},
                $ENV{'course.'.$courseID.'.num'});
				 
    #my %contrib=&DownloadCourseInformation($name, $courseID, 0);

    foreach my $temp(keys %contrib) {
	if ($temp=~/^version/) {
	    my $ver=$contrib{$temp};
	    my ($dummy,$prb)=split(':',$temp);
	    for (my $idx=1; $idx<=$ver; $idx++ ) {
		my $name=$contrib{"$idx:$prb:sendername"};
		$Discuss{"$name:$prb"}=$idx;	
	    }
	}
    }       

    return \%Discuss;
}

# ----- END PROCESSING FUNCTIONS ---------------------------------------

=pod

=head1 HELPER FUNCTIONS

These are just a couple of functions do various odd and end 
jobs.

=cut

# ----- HELPER FUNCTIONS -----------------------------------------------

=pod

=item &ProcessFullName()

Takes lastname, generation, firstname, and middlename (or some partial
set of this data) and returns the full name version as a string.  Format
is Lastname generation, firstname middlename or a subset of this.

=cut

sub ProcessFullName {
    my ($lastname, $generation, $firstname, $middlename)=@_;
    my $Str = '';

    if($lastname ne '') {
	$Str .= $lastname.' ';
	if($generation ne '') {
	    $Str .= $generation;
	} else {
	    chop($Str);
	}
	$Str .= ', ';
	if($firstname ne '') {
	    $Str .= $firstname.' ';
	}
	if($middlename ne '') {
	    $Str .= $middlename;
	} else {
	    chop($Str);
	    if($firstname eq '') {
		chop($Str);
	    }
	}
    } else {
	if($firstname ne '') {
	    $Str .= $firstname.' ';
	}
	if($middlename ne '') {
	    $Str .= $middlename.' ';
	}
	if($generation ne '') {
	    $Str .= $generation;
	} else {
	    chop($Str);
	}
    }

    return $Str;
}

=pod

=item &TestCacheData()

Determine if the cache database can be accessed with a tie.  It waits up to
ten seconds before returning failure.  This function exists to help with
the problems with stopping the data download.  When an abort occurs and the
user quickly presses a form button and httpd child is created.  This
child needs to wait for the other to finish (hopefully within ten seconds).

=over 4

Input: $ChartDB

$ChartDB: The name of the cache database to be opened

Output: -1, 0, 1

-1: Couldn't tie database
 0: Use cached data
 1: New cache database created, use that.

=back

=cut

sub TestCacheData {
    my ($ChartDB,$isRecalculate,$totalDelay)=@_;
    my $isCached=-1;
    my %testData;
    my $tieTries=0;

    if(!defined($totalDelay)) {
        $totalDelay = 10;
    }

    if ((-e "$ChartDB") && (!$isRecalculate)) {
	$isCached = 1;
    } else {
	$isCached = 0;
    }

    while($tieTries < $totalDelay) {
        my $result=0;
        if($isCached) {
            $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_READER,0640);
        } else {
            $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_NEWDB,0640);
        }
        if($result) {
            last;
        }
        $tieTries++;
        sleep 1;
    }
    if($tieTries >= $totalDelay) {
        return -1;
    }

    untie(%testData);

    return $isCached;
}

sub GetFileTimestamp {
    my ($studentDomain,$studentName,$filename,$root)=@_;
    $studentDomain=~s/\W//g;
    $studentName=~s/\W//g;
    my $subdir=$studentName.'__';
    $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
    my $proname="$studentDomain/$subdir/$studentName";
    $proname .= '/'.$filename;
    my @dir = &Apache::lonnet::dirlist($proname, $studentDomain, $studentName,
                                       $root);
    my $fileStat = $dir[0];
    my @stats = split('&', $fileStat);
    if(@stats) {
        return $stats[9];
    } else {
        return -1;
    }
}

# ----- END HELPER FUNCTIONS --------------------------------------------

1;
__END__