# The LearningOnline Network with CAPA
#
# $Id: lonstathelpers.pm,v 1.5 2004/03/03 22:57:31 matthew 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

Apache::lonstathelpers - helper routines used by statistics

=head1 SYNOPSIS

This module provides a place to consolidate much of the statistics 
routines that are needed across multiple statistics functions.

=head1 OVERVIEW


=over 4

=cut

####################################################
####################################################
package Apache::lonstathelpers;

use strict;
use Apache::lonnet();
use Apache::loncommon();
use Apache::lonhtmlcommon();
use Apache::loncoursedata();
use Apache::lonstatistics;
use Apache::lonlocal;
use HTML::Entities();
use Time::Local();
use Spreadsheet::WriteExcel();

####################################################
####################################################

=pod

=item &render_resource($resource)

Input: a resource generated from 
&Apache::loncoursedata::get_sequence_assessment_data().

Retunrs: a scalar containing html for a rendering of the problem
within a table.

=cut

####################################################
####################################################
sub render_resource {
    my ($resource) = @_;
    ##
    ## Render the problem
    my $base;
    ($base,undef) = ($resource->{'src'} =~ m|(.*/)[^/]*$|);
    $base = "http://".$ENV{'SERVER_NAME'}.$base;
    my $rendered_problem = 
        &Apache::lonnet::ssi_body($resource->{'src'});
    $rendered_problem =~ s/<\s*form\s*/<nop /g;
    $rendered_problem =~ s|(<\s*/form\s*>)|<\/nop>|g;
    return '<table bgcolor="ffffff"><tr><td>'.
        '<base href="'.$base.'" />'.
        $rendered_problem.
        '</td></tr></table>';
}

####################################################
####################################################

=pod

=item &ProblemSelector($AcceptedResponseTypes)

Input: scalar containing regular expression which matches response
types to show.  '.' will yield all, '(option|radiobutton)' will match
all option response and radiobutton problems.

Returns: A string containing html for a table which lists the sequences
and their contents.  A radiobutton is provided for each problem.

=cut

####################################################
####################################################
sub ProblemSelector {
    my ($AcceptedResponseTypes) = @_;
    my $Str;
    $Str = "\n<table>\n";
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        next if ($seq->{'num_assess'}<1);
        my $seq_str = '';
        foreach my $res (@{$seq->{'contents'}}) {
            next if ($res->{'type'} ne 'assessment');
            foreach my $part (@{$res->{'parts'}}) {
                my $partdata = $res->{'partdata'}->{$part};
                for (my $i=0;$i<scalar(@{$partdata->{'ResponseTypes'}});$i++){
                    my $respid = $partdata->{'ResponseIds'}->[$i];
                    my $resptype = $partdata->{'ResponseTypes'}->[$i];
                    if ($resptype =~ m/$AcceptedResponseTypes/) {
                        my $value = &make_target_id({symb=>$res->{'symb'},
                                                     part=>$part,
                                                     respid=>$respid,
                                                     resptype=>$resptype});
                        my $checked = '';
                        if ($ENV{'form.problemchoice'} eq $value) {
                            $checked = 'checked ';
                        }
                        my $title = $res->{'title'};
                        if (! defined($title) || $title eq '') {
                            ($title) = ($res->{'src'} =~ m:/([^/]*)$:);
                        }
                        $seq_str .= '<tr><td>'.
  '<input type="radio" name="problemchoice" value="'.$value.'" '.$checked.'/>'.
  '</td><td>'.          
  $resptype.'</td><td>'.
  '<a href="'.$res->{'src'}.'">'.$title.'</a> ';
#  '<a href="'.$res->{'src'}.'">'.$resptype.' '.$res->{'title'}.'</a> ';
                        if (scalar(@{$partdata->{'ResponseIds'}}) > 1) {
                            $seq_str .= &mt('response').' '.$respid;
                        }
                        $seq_str .= "</td></tr>\n";
                    }
                }
            }
        }
        if ($seq_str ne '') {
            $Str .= '<tr><td>&nbsp</td><td colspan="2"><b>'.$seq->{'title'}.'</b></td>'.
                "</tr>\n".$seq_str;
        }
    }
    $Str .= "</table>\n";
    return $Str;
}

####################################################
####################################################

=pod

=item &make_target_id($target)

Inputs: Hash ref with the following entries:
    $target->{'symb'}, $target->{'part'}, $target->{'respid'}, 
    $target->{'resptype'}.

Returns: A string, suitable for a form parameter, which uniquely identifies
the problem, part, and response to do statistical analysis on.

Used by Apache::lonstathelpers::ProblemSelector().

=cut

####################################################
####################################################
sub make_target_id {
    my ($target) = @_;
    my $id = &Apache::lonnet::escape($target->{'symb'}).':'.
             &Apache::lonnet::escape($target->{'part'}).':'.
             &Apache::lonnet::escape($target->{'respid'}).':'.
             &Apache::lonnet::escape($target->{'resptype'});
    return $id;
}

####################################################
####################################################

=pod

=item &get_target_from_id($id)

Inputs: $id, a scalar string from Apache::lonstathelpers::make_target_id().

Returns: A hash reference, $target, containing the following keys:
    $target->{'symb'}, $target->{'part'}, $target->{'respid'}, 
    $target->{'resptype'}.

=cut

####################################################
####################################################
sub get_target_from_id {
    my ($id) = @_;
    my ($symb,$part,$respid,$resptype) = split(':',$id);
    return ({ symb    =>&Apache::lonnet::unescape($symb),
             part     =>&Apache::lonnet::unescape($part),
             respid   =>&Apache::lonnet::unescape($respid),
             resptype =>&Apache::lonnet::unescape($resptype)});
}

####################################################
####################################################

=pod

=item &get_prev_curr_next($target)

Determine the problem parts or responses preceeding and following the
current resource.

Inputs: $target (see &Apache::lonstathelpers::get_target_from_id())
  $AcceptableResponseTypes, regular expression matching acceptable
                            response types,
  $granularity, either 'part' or 'response'

Returns: three hash references, $prev, $curr, $next, which refer to the
preceeding, current, or following problem parts or responses, depending
on the value of $granularity.  Values of undef indicate there is no
previous or next part/response.  A value of undef for all three indicates
there was no match found to the current part/resource.

The hash references contain the following keys:
    symb, part, resource

If $granularity eq 'response', the following ADDITIONAL keys will be present:
    respid, resptype

=cut

####################################################
####################################################
sub get_prev_curr_next {
    my ($target,$AcceptableResponseTypes,$granularity) = @_;
    #
    # Build an array with the data we need to search through
    my @Resource;
    foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
        foreach my $res (@{$seq->{'contents'}}) {
            next if ($res->{'type'} ne 'assessment');
            foreach my $part (@{$res->{'parts'}}) {
                my $partdata = $res->{'partdata'}->{$part};
                if ($granularity eq 'part') {
                    push (@Resource,
                          { symb     => $res->{symb},
                            part     => $part,
                            resource => $res,
                        } );
                } elsif ($granularity eq 'response') {
                    for (my $i=0;
                         $i<scalar(@{$partdata->{'ResponseTypes'}});
                         $i++){
                        my $respid = $partdata->{'ResponseIds'}->[$i];
                        my $resptype = $partdata->{'ResponseTypes'}->[$i];
                        next if ($resptype !~ m/$AcceptableResponseTypes/);
                        push (@Resource,
                              { symb     => $res->{symb},
                                part     => $part,
                                respid   => $partdata->{'ResponseIds'}->[$i],
                                resource => $res,
                                resptype => $resptype
                                } );
                    }
                }
            }
        }
    }
    #
    # Get the index of the current situation
    my $curr_idx;
    for ($curr_idx=0;$curr_idx<$#Resource;$curr_idx++) {
        my $curr_item = $Resource[$curr_idx];
        if ($granularity eq 'part') {
            if ($curr_item->{'symb'} eq $target->{'symb'} &&
                $curr_item->{'part'} eq $target->{'part'}) {
                last;
            }
        } elsif ($granularity eq 'response') {
            if ($curr_item->{'symb'} eq $target->{'symb'} &&
                $curr_item->{'part'} eq $target->{'part'} &&
                $curr_item->{'respid'} eq $target->{'respid'} &&
                $curr_item->{'resptype'} eq $target->{'resptype'}) {
                last;
            }
        }
    }
    my $curr_item = $Resource[$curr_idx];
    if ($granularity eq 'part') {
        if ($curr_item->{'symb'}     ne $target->{'symb'} ||
            $curr_item->{'part'}     ne $target->{'part'}) {
            # bogus symb - return nothing
            return (undef,undef,undef);
        }
    } elsif ($granularity eq 'response') {
        if ($curr_item->{'symb'}     ne $target->{'symb'} ||
            $curr_item->{'part'}     ne $target->{'part'} ||
            $curr_item->{'respid'}   ne $target->{'respid'} ||
            $curr_item->{'resptype'} ne $target->{'resptype'}){
            # bogus symb - return nothing
            return (undef,undef,undef);
        }
    }
    #
    # Now just pick up the data we need
    my ($prev,$curr,$next);
    if ($curr_idx == 0) {
        $prev = undef;
        $curr = $Resource[$curr_idx  ];
        $next = $Resource[$curr_idx+1];
    } elsif ($curr_idx == $#Resource) {
        $prev = $Resource[$curr_idx-1];
        $curr = $Resource[$curr_idx  ];
        $next = undef;
    } else {
        $prev = $Resource[$curr_idx-1];
        $curr = $Resource[$curr_idx  ];
        $next = $Resource[$curr_idx+1];
    }
    return ($prev,$curr,$next);
}


#####################################################
#####################################################

=pod

=item analyze_problem_as_student

Analyzes a homework problem for a student and returns the correct answer
for the student.  Attempts to put together an answer for problem types 
that do not natively support it.

Inputs: $resource: a resource object
        $sname, $sdom, $partid, $respid

Returns: $answer

=cut

#####################################################
#####################################################
sub analyze_problem_as_student {
    my ($resource,$sname,$sdom,$partid,$respid) = @_;
    my $returnvalue;
    my $url = $resource->{'src'};
    my $symb = $resource->{'symb'};
    my $courseid = $ENV{'request.course.id'};
    my $Answ=&Apache::lonnet::ssi($url,('grade_target' => 'analyze',
                                        'grade_domain' => $sdom,
                                        'grade_username' => $sname,
                                        'grade_symb' => $symb,
                                        'grade_courseid' => $courseid));
    (my $garbage,$Answ)=split(/_HASH_REF__/,$Answ,2);
    my %Answer=&Apache::lonnet::str2hash($Answ);
    my $prefix = $partid.'.'.$respid;
    my $key = $prefix.'.answer';
    if (exists($Answer{$key})) {
        my $student_answer = $Answer{$key}->[0];
        if (! defined($student_answer)) {
            $student_answer = $Answer{$key}->[1];
        }
        $returnvalue = $student_answer;
    } else {
        if (exists($Answer{$prefix.'.shown'})) {
            # The response has foils
            my %values;
            while (my ($k,$v) = each(%Answer)) {
                next if ($k !~ /^$prefix\.foil\.(value|area)\.(.*)$/);
                my $foilname = $2;
                $values{$foilname}=$v;
            }
            foreach my $foil (@{$Answer{$prefix.'.shown'}}) {
                if (ref($values{$foil}) eq 'ARRAY') {
                    $returnvalue.=&HTML::Entities::encode($foil).'='.
                        join(',',map {&HTML::Entities::encode($_)} @{$values{$foil}}).'&';
                } else {
                    $returnvalue.=&HTML::Entities::encode($foil).'='.
                        &HTML::Entities::encode($values{$foil}).'&';
                }
            }
            $returnvalue =~ s/ /\%20/g;
            chop ($returnvalue);
        }
    }
    return $returnvalue;
}


##
## The following is copied from datecalc1.pl, part of the 
## Spreadsheet::WriteExcel CPAN module.
##
##
######################################################################
#
# Demonstration of writing date/time cells to Excel spreadsheets,
# using UNIX/Perl time as source of date/time.
#
# Copyright 2000, Andrew Benham, adsb@bigfoot.com
#
######################################################################
#
# UNIX/Perl time is the time since the Epoch (00:00:00 GMT, 1 Jan 1970)
# measured in seconds.
#
# An Excel file can use exactly one of two different date/time systems.
# In these systems, a floating point number represents the number of days
# (and fractional parts of the day) since a start point. The floating point
# number is referred to as a 'serial'.
# The two systems ('1900' and '1904') use different starting points:
#  '1900'; '1.00' is 1 Jan 1900 BUT 1900 is erroneously regarded as
#          a leap year - see:
#            http://support.microsoft.com/support/kb/articles/Q181/3/70.asp
#          for the excuse^H^H^H^H^H^Hreason.
#  '1904'; '1.00' is 2 Jan 1904.
#
# The '1904' system is the default for Apple Macs. Windows versions of
# Excel have the option to use the '1904' system.
#
# Note that Visual Basic's "DateSerial" function does NOT erroneously
# regard 1900 as a leap year, and thus its serials do not agree with
# the 1900 serials of Excel for dates before 1 Mar 1900.
#
# Note that StarOffice (at least at version 5.2) does NOT erroneously
# regard 1900 as a leap year, and thus its serials do not agree with
# the 1900 serials of Excel for dates before 1 Mar 1900.
#
######################################################################
#
# Calculation description
# =======================
#
# 1900 system
# -----------
# Unix time is '0' at 00:00:00 GMT 1 Jan 1970, i.e. 70 years after 1 Jan 1900.
# Of those 70 years, 17 (1904,08,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68)
# were leap years with an extra day.
# Thus there were 17 + 70*365 days = 25567 days between 1 Jan 1900 and
# 1 Jan 1970.
# In the 1900 system, '1' is 1 Jan 1900, but as 1900 was not a leap year
# 1 Jan 1900 should really be '2', so 1 Jan 1970 is '25569'.
#
# 1904 system
# -----------
# Unix time is '0' at 00:00:00 GMT 1 Jan 1970, i.e. 66 years after 1 Jan 1904.
# Of those 66 years, 17 (1904,08,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68)
# were leap years with an extra day.
# Thus there were 17 + 66*365 days = 24107 days between 1 Jan 1904 and
# 1 Jan 1970.
# In the 1904 system, 2 Jan 1904 being '1', 1 Jan 1970 is '24107'.
#
######################################################################
#
# Copyright (c) 2000, Andrew Benham.
# This program is free software. It may be used, redistributed and/or
# modified under the same terms as Perl itself.
#
# Andrew Benham, adsb@bigfoot.com
# London, United Kingdom
# 11 Nov 2000
#
######################################################################
#-----------------------------------------------------------
# calc_serial()
#
# Called with (up to) 2 parameters.
#   1.  Unix timestamp.  If omitted, uses current time.
#   2.  GMT flag. Set to '1' to return serial in GMT.
#       If omitted, returns serial in appropriate timezone.
#
# Returns date/time serial according to $DATE_SYSTEM selected
#-----------------------------------------------------------
sub calc_serial {
    # Use 1900 date system on all platforms other than Apple Mac (for which
    # use 1904 date system).
    my $DATE_SYSTEM = ($^O eq 'MacOS') ? 1 : 0;
    my $time = (defined $_[0]) ? $_[0] : time();
    my $gmtflag = (defined $_[1]) ? $_[1] : 0;
    #
    # Divide timestamp by number of seconds in a day.
    # This gives a date serial with '0' on 1 Jan 1970.
    my $serial = $time / 86400;
    #
    # Adjust the date serial by the offset appropriate to the
    # currently selected system (1900/1904).
    if ($DATE_SYSTEM == 0) {        # use 1900 system
        $serial += 25569;
    } else {                        # use 1904 system
        $serial += 24107;
    }
    #
    unless ($gmtflag) {
        # Now have a 'raw' serial with the right offset. But this
        # gives a serial in GMT, which is false unless the timezone
        # is GMT. We need to adjust the serial by the appropriate
        # timezone offset.
        # Calculate the appropriate timezone offset by seeing what
        # the differences between localtime and gmtime for the given
        # time are.
        #    
        my @gmtime = gmtime($time);
        my @ltime  = localtime($time);
        #
        # For the first 7 elements of the two arrays, adjust the
        # date serial where the elements differ.
        for (0 .. 6) {
            my $diff = $ltime[$_] - $gmtime[$_];
            if ($diff) {
                $serial += _adjustment($diff,$_);
            }
        }
    }
    #
    # Perpetuate the error that 1900 was a leap year by decrementing
    # the serial if we're using the 1900 system and the date is prior to
    # 1 Mar 1900. This has the effect of making serial value '60'
    # 29 Feb 1900.
    #
    # This fix only has any effect if UNIX/Perl time on the platform
    # can represent 1900. Many can't.
    #
    unless ($DATE_SYSTEM) {
        $serial-- if ($serial < 61);    # '61' is 1 Mar 1900
    }
    return $serial;
}

sub _adjustment {
    # Based on the difference in the localtime/gmtime array elements
    # number, return the adjustment required to the serial.
    #
    # We only look at some elements of the localtime/gmtime arrays:
    #    seconds    unlikely to be different as all known timezones
    #               have an offset of integral multiples of 15 minutes,
    #               but it's easy to do.
    #    minutes    will be different for timezone offsets which are
    #               not an exact number of hours.
    #    hours      very likely to be different.
    #    weekday    will differ when localtime/gmtime difference
    #               straddles midnight.
    #
    # Assume that difference between localtime and gmtime is less than
    # 5 days, then don't have to do maths for day of month, month number,
    # year number, etc...
    #
    my ($delta,$element) = @_;
    my $adjust = 0;
    #
    if ($element == 0) {            # Seconds
        $adjust = $delta/86400;         # 60 * 60 * 24
    } elsif ($element == 1) {       # Minutes
        $adjust = $delta/1440;          # 60 * 24
    } elsif ($element == 2) {       # Hours
        $adjust = $delta/24;            # 24
    } elsif ($element == 6) {       # Day of week number
        # Catch difference straddling Sat/Sun in either direction
        $delta += 7 if ($delta < -4);
        $delta -= 7 if ($delta > 4);
        #    
        $adjust = $delta;
    }
    return $adjust;
}

###########################################################
###########################################################

=pod

=item get_problem_data

Returns a data structure describing the problem.

Inputs: $url

Returns: %Partdata

=cut

## note: we must force each foil and option to not begin or end with
##       spaces as they are stored without such data.
##
###########################################################
###########################################################
sub get_problem_data {
    my ($url) = @_;
    my $Answ=&Apache::lonnet::ssi($url,('grade_target' => 'analyze'));
    (my $garbage,$Answ)=split(/_HASH_REF__/,$Answ,2);
    my %Answer;
    %Answer=&Apache::lonnet::str2hash($Answ);
    my %Partdata;
    foreach my $part (@{$Answer{'parts'}}) {
        while (my($key,$value) = each(%Answer)) {
            #
            # Logging code:
            if (1) {
                &Apache::lonnet::logthis($part.' got key "'.$key.'"');
                if (ref($value) eq 'ARRAY') {
                    &Apache::lonnet::logthis('    @'.join(',',@$value));
                } else {
                    &Apache::lonnet::logthis('    '.$value);
                }
            }
            # End of logging code
            next if ($key !~ /^$part/);
            $key =~ s/^$part\.//;
            if (ref($value) eq 'ARRAY') {
                if ($key eq 'options') {
                    $Partdata{$part}->{'_Options'}=$value;
                } elsif ($key eq 'concepts') {
                    $Partdata{$part}->{'_Concepts'}=$value;
                } elsif ($key =~ /^concept\.(.*)$/) {
                    my $concept = $1;
                    foreach my $foil (@$value) {
                        $Partdata{$part}->{'_Foils'}->{$foil}->{'_Concept'}=
                                                                      $concept;
                    }
                } elsif ($key =~ /^(incorrect|answer|ans_low|ans_high)$/) {
                    $Partdata{$part}->{$key}=$value;
                }
            } else {
                if ($key=~ /^foil\.text\.(.*)$/) {
                    my $foil = $1;
                    $Partdata{$part}->{'_Foils'}->{$foil}->{'name'}=$foil;
                    $value =~ s/(\s*$|^\s*)//g;
                    $Partdata{$part}->{'_Foils'}->{$foil}->{'text'}=$value;
                } elsif ($key =~ /^foil\.value\.(.*)$/) {
                    my $foil = $1;
                    $Partdata{$part}->{'_Foils'}->{$foil}->{'value'}=$value;
                }
            }
        }
    }
    return %Partdata;
}

####################################################
####################################################

=pod

=item &limit_by_time()

=cut

####################################################
####################################################
sub limit_by_time_form {
    my $Starttime_form = '';
    my $starttime = &Apache::lonhtmlcommon::get_date_from_form
        ('limitby_startdate');
    my $endtime = &Apache::lonhtmlcommon::get_date_from_form
        ('limitby_enddate');
    if (! defined($endtime)) {
        $endtime = time;
    }
    if (! defined($starttime)) {
        $starttime = $endtime - 60*60*24*7;
    }
    my $state;
    if (&limit_by_time()) {
        $state = '';
    } else {
        $state = 'disabled';
    }
    my $startdateform = &Apache::lonhtmlcommon::date_setter
        ('Statistics','limitby_startdate',$starttime,undef,undef,$state);
    my $enddateform = &Apache::lonhtmlcommon::date_setter
        ('Statistics','limitby_enddate',$endtime,undef,undef,$state);
    my $Str;
    $Str .= '<script language="Javascript" >';
    $Str .= 'function toggle_limitby_activity(state) {';
    $Str .= '    if (state) {';
    $Str .= '        limitby_startdate_enable();';
    $Str .= '        limitby_enddate_enable();';
    $Str .= '    } else {';
    $Str .= '        limitby_startdate_disable();';
    $Str .= '        limitby_enddate_disable();';
    $Str .= '    }';    
    $Str .= '}';
    $Str .= '</script>';
    $Str .= '<fieldset>';
    my $timecheckbox = '<input type="checkbox" name="limit_by_time" ';
    if (&limit_by_time()) {
        $timecheckbox .= ' checked ';
    } 
    $timecheckbox .= 'OnChange="javascript:toggle_limitby_activity(this.checked);" ';
    $timecheckbox .= ' />';
    $Str .= '<legend>'.&mt('[_1] Limit by time',$timecheckbox).'</legend>';
    $Str .= &mt('Start Time: [_1]',$startdateform).'<br />';
    $Str .= &mt('&nbsp;End Time: [_1]',$enddateform).'<br />';
    $Str .= '</fieldset>';
    return $Str;
}

sub limit_by_time {
    if (exists($ENV{'form.limit_by_time'}) &&
        $ENV{'form.limit_by_time'} ne '' ) {
        return 1;
    } else {
        return 0;
    }
}

sub get_time_limits {
    my $starttime = &Apache::lonhtmlcommon::get_date_from_form
        ('limitby_startdate');
    my $endtime = &Apache::lonhtmlcommon::get_date_from_form
        ('limitby_enddate');
    return ($starttime,$endtime);
}

####################################################
####################################################

=pod

=back

=cut

####################################################
####################################################

1;

__END__