# The LearningOnline Network with CAPA
# a pile of common routines
#
# $Id: loncommon.pm,v 1.24 2002/01/30 17:40:39 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/
#
# YEAR=2001
# 2/13-12/7 Guy Albertelli
# 12/11,12/12,12/17 Scott Harrison
# 12/21 Gerd Kortemeyer
# 12/21 Scott Harrison
# 12/25,12/28 Gerd Kortemeyer
# YEAR=2002
# 1/4 Gerd Kortemeyer

# Makes a table out of the previous attempts
# Inputs result_from_symbread, user, domain, course_id
# Reads in non-network-related .tab files

package Apache::loncommon;

use strict;
use Apache::lonnet();
use POSIX qw(strftime);
use Apache::Constants qw(:common);
use Apache::lonmsg();

my $readit;

# ----------------------------------------------- Filetypes/Languages/Copyright
my %language;
my %cprtag;
my %fe; my %fd;
my %fc;

# -------------------------------------------------------------- Thesaurus data
my @therelated;
my @theword;
my @thecount;
my %theindex;
my $thetotalcount;
my $thefuzzy=2;
my $thethreshold=0.1/$thefuzzy;
my $theavecount;

# ----------------------------------------------------------------------- BEGIN
BEGIN {

    unless ($readit) {
# ------------------------------------------------------------------- languages
    {
	my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonTabDir'}.
				 '/language.tab');
	if ($fh) {
	    while (<$fh>) {
		next if /^\#/;
		chomp;
		my ($key,$val)=(split(/\s+/,$_,2));
		$language{$key}=$val;
	    }
	}
    }
# ------------------------------------------------------------------ copyrights
    {
	my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonIncludes'}.
				  '/copyright.tab');
	if ($fh) {
	    while (<$fh>) {
		next if /^\#/;
		chomp;
		my ($key,$val)=(split(/\s+/,$_,2));
		$cprtag{$key}=$val;
	    }
	}
    }
# ------------------------------------------------------------- file categories
    {
	my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonTabDir'}.
				  '/filecategories.tab');
	if ($fh) {
	    while (<$fh>) {
		next if /^\#/;
		chomp;
		my ($key,$val)=(split(/\s+/,$_,2));
		push @{$fc{$key}},$val;
	    }
	}
    }
# ------------------------------------------------------------------ file types
    {
	my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonTabDir'}.
	       '/filetypes.tab');
	if ($fh) {
            while (<$fh>) {
		next if (/^\#/);
		chomp;
		my ($ending,$emb,$descr)=split(/\s+/,$_,3);
		if ($descr ne '') { 
		    $fe{$ending}=lc($emb);
		    $fd{$ending}=$descr;
		}
	    }
	}
    }
# -------------------------------------------------------------- Thesaurus data
    {
	my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonTabDir'}.
	       '/thesaurus.dat');
	if ($fh) {
            while (<$fh>) {
               my ($tword,$tindex,$tcount,$trelated)=split(/\@/,$_);
               $theindex{$tword}=$tindex;
               $theword[$tindex]=$tword;
               $thecount[$tindex]=$tcount;
               $thetotalcount+=$tcount;
               $therelated[$tindex]=$trelated;
	   }
        }
        $theavecount=$thetotalcount/$#thecount;
    }
    &Apache::lonnet::logthis(
              "<font color=yellow>INFO: Read file types and thesaurus</font>");
    $readit=1;
}

}
# ============================================================= END BEGIN BLOCK


# ---------------------------------------------------------- Is this a keyword?

sub keyword {
    my $newword=shift;
    $newword=~s/\W//g;
    $newword=~tr/A-Z/a-z/;
    my $tindex=$theindex{$newword};
    if ($tindex) {
        if ($thecount[$tindex]>$theavecount) {
           return 1;
        }
    }
    return 0;
}
# -------------------------------------------------------- Return related words

sub related {
    my $newword=shift;
    $newword=~s/\W//g;
    $newword=~tr/A-Z/a-z/;
    my $tindex=$theindex{$newword};
    if ($tindex) {
        my %found=();
        foreach (split(/\,/,$therelated[$tindex])) {
# - Related word found
            my ($ridx,$rcount)=split(/\:/,$_);
# - Direct relation index
            my $directrel=$rcount/$thecount[$tindex];
            if ($directrel>$thethreshold) {
               foreach (split(/\,/,$therelated[$ridx])) {
                  my ($rridx,$rrcount)=split(/\:/,$_);
                  if ($rridx==$tindex) {
# - Determine reverse relation index
                     my $revrel=$rrcount/$thecount[$ridx];
# - Calculate full index
                     $found{$ridx}=$directrel*$revrel;
                     if ($found{$ridx}>$thethreshold) {
                        foreach (split(/\,/,$therelated[$ridx])) {
                            my ($rrridx,$rrrcount)=split(/\:/,$_);
                            unless ($found{$rrridx}) {
                               my $revrevrel=$rrrcount/$thecount[$ridx];
                               if (
                          $directrel*$revrel*$revrevrel>$thethreshold
                               ) {
                                  $found{$rrridx}=
                                       $directrel*$revrel*$revrevrel;
                               }
                            }
                        }
                     }
                  }
               }
            }
        }
    }
    return ();
}

# ---------------------------------------------------------------- Language IDs
sub languageids {
    return sort(keys(%language));
}

# -------------------------------------------------------- Language Description
sub languagedescription {
    return $language{shift(@_)};
}

# --------------------------------------------------------------- Copyright IDs
sub copyrightids {
    return sort(keys(%cprtag));
}

# ------------------------------------------------------- Copyright Description
sub copyrightdescription {
    return $cprtag{shift(@_)};
}

# ------------------------------------------------------------- File Categories
sub filecategories {
    return sort(keys(%fc));
}

# -------------------------------------- File Types within a specified category
sub filecategorytypes {
    return @{$fc{lc(shift(@_))}};
}

# ------------------------------------------------------------------ File Types
sub fileextensions {
    return sort(keys(%fe));
}

# ------------------------------------------------------------- Embedding Style
sub fileembstyle {
    return $fe{lc(shift(@_))};
}

# ------------------------------------------------------------ Description Text
sub filedescription {
    return $fd{lc(shift(@_))};
}

# ------------------------------------------------------------ Description Text
sub filedescriptionex {
    my $ex=shift;
    return '.'.$ex.' '.$fd{lc($ex)};
}

sub get_previous_attempt {
  my ($symb,$username,$domain,$course)=@_;
  my $prevattempts='';
  if ($symb) {
    my (%returnhash)=
      &Apache::lonnet::restore($symb,$course,$domain,$username);
    if ($returnhash{'version'}) {
      my %lasthash=();
      my $version;
      for ($version=1;$version<=$returnhash{'version'};$version++) {
        foreach (sort(split(/\:/,$returnhash{$version.':keys'}))) {
	  $lasthash{$_}=$returnhash{$version.':'.$_};
        }
      }
      $prevattempts='<table border=2></tr><th>History</th>';
      foreach (sort(keys %lasthash)) {
        $prevattempts.='<th>'.$_.'</th>';
      }
      for ($version=1;$version<=$returnhash{'version'};$version++) {
        $prevattempts.='</tr><tr><th>Attempt '.$version.'</th>';
        foreach (sort(keys %lasthash)) {
	  my $value;
	  if ($_ =~ /timestamp/) {
	    $value=scalar(localtime($returnhash{$version.':'.$_}));
	  } else {
	    $value=$returnhash{$version.':'.$_};
	  }
	  $prevattempts.='<td>'.$value.'</td>';   
        }
      }
      $prevattempts.='</tr><tr><th>Current</th>';
      foreach (sort(keys %lasthash)) {
	my $value;
	if ($_ =~ /timestamp/) {
	  $value=scalar(localtime($lasthash{$_}));
	} else {
	  $value=$lasthash{$_};
	}
	$prevattempts.='<td>'.$value.'</td>';
      }
      $prevattempts.='</tr></table>';
    } else {
      $prevattempts='Nothing submitted - no attempts.';
    }
  } else {
    $prevattempts='No data.';
  }
}

sub get_student_view {
  my ($symb,$username,$domain,$courseid) = @_;
  my ($map,$id,$feedurl) = split(/___/,$symb);
  my (%old,%moreenv);
  my @elements=('symb','courseid','domain','username');
  foreach my $element (@elements) {
    $old{$element}=$ENV{'form.grade_'.$element};
    $moreenv{'form.grade_'.$element}=eval '$'.$element #'
  }
  &Apache::lonnet::appenv(%moreenv);
  my $userview=&Apache::lonnet::ssi('/res/'.$feedurl);
  &Apache::lonnet::delenv('form.grade_');
  foreach my $element (@elements) {
    $ENV{'form.grade_'.$element}=$old{$element};
  }
  $userview=~s/\<body[^\>]*\>//gi;
  $userview=~s/\<\/body\>//gi;
  $userview=~s/\<html\>//gi;
  $userview=~s/\<\/html\>//gi;
  $userview=~s/\<head\>//gi;
  $userview=~s/\<\/head\>//gi;
  $userview=~s/action\s*\=/would_be_action\=/gi;
  return $userview;
}

sub get_student_answers {
  my ($symb,$username,$domain,$courseid) = @_;
  my ($map,$id,$feedurl) = split(/___/,$symb);
  my (%old,%moreenv);
  my @elements=('symb','courseid','domain','username');
  foreach my $element (@elements) {
    $old{$element}=$ENV{'form.grade_'.$element};
    $moreenv{'form.grade_'.$element}=eval '$'.$element #'
  }
  $moreenv{'form.grade_target'}='answer';
  &Apache::lonnet::appenv(%moreenv);
  my $userview=&Apache::lonnet::ssi('/res/'.$feedurl);
  &Apache::lonnet::delenv('form.grade_');
  foreach my $element (@elements) {
    $ENV{'form.grade_'.$element}=$old{$element};
  }
  $userview=~s/\<body[^\>]*\>//gi;
  $userview=~s/\<\/body\>//gi;
  $userview=~s/\<html\>//gi;
  $userview=~s/\<\/html\>//gi;
  $userview=~s/\<head\>//gi;
  $userview=~s/\<\/head\>//gi;
  $userview=~s/action\s*\=/would_be_action\=/gi;
  return $userview;
}

sub get_unprocessed_cgi {
  my ($query)= @_;
  foreach (split(/&/,$query)) {
    my ($name, $value) = split(/=/,$_);
    $value =~ tr/+/ /;
    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
    if (!defined($ENV{'form.'.$name})) { $ENV{'form.'.$name}=$value; }
  }
}

sub cacheheader {
  unless ($ENV{'request.method'} eq 'GET') { return ''; }
  my $date=strftime("%a, %d %b %Y %H:%M:%S GMT",gmtime);
  my $output .='<meta HTTP-EQUIV="Expires" CONTENT="'.$date.'" />
                <meta HTTP-EQUIV="Cache-control" CONTENT="no-cache" />
                <meta HTTP-EQUIV="Pragma" CONTENT="no-cache" />';
  return $output;
}

sub no_cache {
  my ($r) = @_;
  unless ($ENV{'request.method'} eq 'GET') { return ''; }
  #my $date=strftime("%a, %d %b %Y %H:%M:%S GMT",gmtime);
  $r->no_cache(1);
  $r->header_out("Pragma" => "no-cache");
  #$r->header_out("Expires" => $date);
}
1;
__END__;


=head1 NAME

Apache::loncommon - pile of common routines

=head1 SYNOPSIS

Referenced by other mod_perl Apache modules.

Invocation:
 &Apache::loncommon::SUBROUTINENAME(ARGUMENTS);

=head1 INTRODUCTION

Common collection of used subroutines.  This collection helps remove
redundancy from other modules and increase efficiency of memory usage.

Current things done:

 Makes a table out of the previous homework attempts
 Inputs result_from_symbread, user, domain, course_id
 Reads in non-network-related .tab files

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

=head1 HANDLER SUBROUTINE

There is no handler subroutine.

=head1 OTHER SUBROUTINES

=over 4

=item *

BEGIN() : initialize values from language.tab, copyright.tab, filetypes.tab,
and filecategories.tab.

=item *

languageids() : returns list of all language ids

=item *

languagedescription() : returns description of a specified language id

=item *

copyrightids() : returns list of all copyrights

=item *

copyrightdescription() : returns description of a specified copyright id

=item *

filecategories() : returns list of all file categories

=item *

filecategorytypes() : returns list of file types belonging to a given file
category

=item *

fileembstyle() : returns embedding style for a specified file type

=item *

filedescription() : returns description for a specified file type

=item *

filedescriptionex() : returns description for a specified file type with
extra formatting

=item *

get_previous_attempt() : return string with previous attempt on problem

=item *

get_student_view() : show a snapshot of what student was looking at

=item *

get_student_answers() : show a snapshot of how student was answering problem

=item *

get_unprocessed_cgi() : get unparsed CGI parameters

=item *

cacheheader() : returns cache-controlling header code

=item *

nocache() : specifies header code to not have cache

=back

=cut