package LONCAPA::Enrollment;

use Apache::loncoursedata;
use Apache::lonnet;
use HTML::Entities;
use XML::Simple;
use LONCAPA::Configuration;

use strict;

sub update_LC {
    my ($dom,$crs,$adds,$drops,$startdate,$enddate,$authtype,$autharg,$classesref,$groupref,$logmsg,$context) = @_; 
# Get current LON-CAPA student enrollment for this class
    my $configvars = &LONCAPA::Configuration::read_conf('loncapa.conf');
    my $cid = $dom."_".$crs;
    my $roster = &Apache::loncoursedata::get_classlist($cid,$dom,$crs);
    my $cend = &Apache::loncoursedata::CL_END;
    my $cstart = &Apache::loncoursedata::CL_START; 
    my $stuid=&Apache::loncoursedata::CL_ID;
    my $sec=&Apache::loncoursedata::CL_SECTION;
    my $status=&Apache::loncoursedata::CL_STATUS;
    my $type=&Apache::loncoursedata::CL_TYPE;
    my @localstudents = ();
    my $currlist;
    foreach my $uname (keys %{$roster} ) {
        if ($uname =~ m/^(.+):$dom$/) {
            if ($$roster{$uname}[$status] eq "Active") {
                push @localstudents, $1;
                @{$$currlist{$1}} = @{$$roster{$uname}};
            }
        }
    }
    my $linefeed = '';
    my $addresult = '';
    my $dropresult = '';
    if ($context eq "updatenow") {
        $linefeed = "</li>\n<li>"; 
    } elsif ($context eq "automated") {
        $linefeed = "\n";
    }
    my $enrollcount = 0;
    my $dropcount = 0;

# Get mapping of IDs to usernames for current LON-CAPA student enrollment for this class 
    my @LCids = ();
    my %unameFromLCid = ();
    foreach my $uname (sort keys %{$currlist}) {
        my $stuID = $$currlist{$uname}[$stuid];
        if (!grep/^$stuID$/,@LCids) {
            push @LCids, $stuID;
            @{$unameFromLCid{$stuID}} = ();
        }
        push @{$unameFromLCid{$stuID}},$uname;
    }
 
# Get latest institutional enrollment for this class.
    my %allenrolled = ();
    my @reg_students = ();
    my %place = ();
    $place{'autharg'} = &CL_autharg();
    $place{'authtype'} = &CL_authtype();
    $place{'email'} = &CL_email();
    $place{'enddate'} = &CL_enddate();
    $place{'firstname'} = &CL_firstname();
    $place{'generation'} = &CL_generation();
    $place{'groupID'} = &CL_groupID();
    $place{'lastname'} = &CL_lastname();
    $place{'middlename'} = &CL_middlename();
    $place{'startdate'} = &CL_startdate();
    $place{'studentID'} = &CL_studentID();
    my %ucount = ();
    my %enrollinfo = ();
    foreach my $class (@{$classesref}) {
        my %enrolled = ();
        &parse_classlist($$configvars{'lonDaemons'},$dom,$crs,$class,\%place,$$groupref{$class},\%enrolled);
        foreach my $uname (sort keys %enrolled ) {
            if (!grep/^$uname$/,@reg_students) {
                push @reg_students,$uname;
                $ucount{$uname} = 0;
                @{$allenrolled{$uname}} = ();
            }
            @{$allenrolled{$uname}[$ucount{$uname}]} = @{$enrolled{$uname}};
            $ucount{$uname} ++;
        }
    }

# Check for multiple sections for a single student 
    my @okusers = ();
    foreach my $uname (@reg_students)  {
        if (@{$allenrolled{$uname}} > 1) {
            my @sections = ();
            my $saved;
            for (my $i=0; $i<@{$allenrolled{$uname}}; $i++) {
                my @stuinfo = @{$allenrolled{$uname}[$i]};
                my $secnum = $stuinfo[ $place{'groupID'} ];
                unless ($secnum eq '') {
                    unless (grep/^$secnum$/,@sections) {
                        $saved = $i; 
                        push @sections,$secnum;
                    }
                }
            }
            if (@sections == 0) {
                @{$enrollinfo{$uname}} = @{$allenrolled{$uname}[0]};
                push @okusers, $uname;
            }
            elsif (@sections == 1) {
                @{$enrollinfo{$uname}} = @{$allenrolled{$uname}[$saved]};
                push @okusers, $uname;
            }
            elsif (@sections > 1) {
                $$logmsg =  "$uname appears in classlists for the more than one section of this course, i.e. in sections: ";
                foreach (@sections) {
                    $$logmsg .= " $_,";
                }
                chop($$logmsg);
                $$logmsg .= " Because of this ambiguity, no enrollment action was taken for this student.".$linefeed;
            }
        } else {
            @{$enrollinfo{$uname}} = @{$allenrolled{$uname}[0]};
            push @okusers, $uname;
        }
    }
# Get mapping of student IDs to usernames for users in institutional data for this class  
    my @allINids = ();
    my %unameFromINid = ();
    foreach my $uname (@okusers) {
        $enrollinfo{$uname}[ $place{'studentID'} ] =~ tr/A-Z/a-z/;
        my $stuID = $enrollinfo{$uname}[ $place{'studentID'} ];
        if (grep/^$stuID$/,@allINids)  {
            push @{$unameFromINid{$stuID}},$uname;
        } else {
            push @allINids, $stuID;
            @{$unameFromINid{$stuID}} = $uname; 
        }
    }
# Explicitly allow access to creation/modification of students if called as an automated process.
    if ($context eq 'automated') {
        $ENV{'allowed.cst'}='F';
    }

# Compare IDs with existing LON-CAPA enrollment for this class
    foreach my $uname (@okusers) {
        unless ($uname eq '') {
            my %uidhash=&Apache::lonnet::idrget($dom,$uname);
            my @stuinfo = @{$enrollinfo{$uname}};
            if (grep/^$uname$/,@localstudents) {
# Check for studentID changes
                if ( ($uidhash{$uname}) && ($uidhash{$uname} !~ /error\:/) )  {
                    unless ( ($uidhash{$uname}) eq ($stuinfo[ $place{studentID} ]) ) {
                        $$logmsg .= "Change in ID for $uname in class: $crs. StudentID in LON-CAPA system is $uidhash{$uname}, StudentID in institutional data is $stuinfo[ $place{studentID} ]".$linefeed; 
                    }
                }

# Check for section changes
                unless ($$currlist{$uname}[$sec] eq $stuinfo[ $place{groupID} ]) {
                    if ( ($$currlist{$uname}[$type] eq "auto") && ($adds == 1) ) {
                        my $modify_section_result = &Apache::lonnet::modify_student_enrollment($dom,$uname,undef,undef,undef,undef,undef,$stuinfo[ $place{groupID} ],$$currlist{$uname}[$cend],$$currlist{$uname}[$cstart],'auto',$cid);
                        if ($modify_section_result =~ /^ok/) {
                            $$logmsg .= "Section for $uname switched from old section: ".$$currlist{$uname}[$sec] ."to new section: ".$stuinfo[ $place{groupID} ]." in class $crs".$linefeed;
                        } else {
                            $$logmsg .= "Error when attempting section change for $uname from old section ".$$currlist{$uname}[$sec]." to new section: ".$stuinfo[ $place{groupID} ]." -error: $modify_section_result".$linefeed;
                        }
                    }
                }
            } else {
# Check for changed usernames by checking studentIDs
                if ( ($stuinfo[ $place{studentID} ] ne '') && (grep/^$stuinfo[ $place{studentID} ]$/,@LCids) ) {
                    if (grep/^$$currlist{$uname}[ $place{'studentID'} ]$/,@allINids) {
                        foreach my $match ( @{ $unameFromLCid{ $stuinfo[ $place{studentID} ] } }  ) {
                            if (grep/^$match$/,@okusers) {
                                $$logmsg .= "A possible change in username has been detected for a student enrolled in $crs. The existing LON-CAPA classlist contains user: $uname and student ID: ".$$currlist{$uname}[ $place{studentID} ].".  This username has been dropped from the institutional classlist, but the same student ID is used for user: $match who still appears in the institutional classlist. You may need to move the student data files for user: $uname to $match".$linefeed;
                            }
                        }
                    }
                } elsif ($adds == 1) {
# Add student to LON-CAPA classlist
                    my $auth = $stuinfo[ $place{'authtype'} ];
                    my $authparam = $stuinfo[ $place{'autharg'} ];
                    my $first = $stuinfo[ $place{'firstname'} ];
                    my $middle = $stuinfo[ $place{'middlename'} ];
                    my $last = $stuinfo[ $place{'lastname'} ];
                    my $gene = $stuinfo[ $place{'generation'} ];
                    my $usec = $stuinfo[ $place{'groupID'} ];
                    my $end = $stuinfo[ $place{'enddate'} ];
                    my $start = $stuinfo[ $place{'startdate'} ];
                    my $emailaddr = $stuinfo[ $place{'email'} ];
                    my $pid = $stuinfo[ $place{'studentID'} ];

# remove non alphanumeric values from section
                    $usec =~ s/\W//g;

                    unless ($emailaddr =~/^[^\@]+\@[^\@]+$/) { $emailaddr =''; }
                    my $emailenc = &HTML::Entities::encode($emailaddr); 

# Use course defaults where entry is absent
                    if ( ($auth eq '') || (!defined($auth)) ) {
                        $auth =  $authtype;
                    }
                    if ( ($authparam eq '')  || (!defined($authparam)) )  {
                        $authparam = $autharg;
                    }
                    if ($auth =~ m/^krb/) {
                        $auth .= ":".$authparam;
                    }
                    if ( ($end eq '') || (!defined($end)) )  {
                         $end = $enddate;
                    }
                    if ( ($start eq '')  || (!defined($start)) )  {
                         $start = $startdate;
                    }
# Clean up whitespace
                    foreach (\$dom,\$uname,\$pid,\$first,\$middle,\$last,\$gene,\$usec) {
                         $$_ =~ s/(\s+$|^\s+)//g;
                    }

# Check for existing account in this LON-CAPA domain for this username
                    my $uhome=&Apache::lonnet::homeserver($uname,$dom);
                    if ($uhome eq 'no_host') { # User does not exist
                        my $create_passwd = 0;
                        my $authchk = '';
                        unless ($authparam eq '') { $authchk = 'ok'; };
# If no account exists and passwords should be generated
                        if ($authtype eq "int") {
                            if ($authparam eq '') {
                                ($authparam,$create_passwd,$authchk) = &create_password();
                            }
                        } elsif ($authtype eq "local") {
                            if ($authparam eq '') {
                                ($authparam,$create_passwd,$authchk) = &create_password();
                            }
                        } elsif ($authtype =~ m/^krb/) {
                            if ($authparam eq '') {
                                $$logmsg .= "No Kerberos domain available for the new user - $uname in course $crs - no enrollment occurred.".$linefeed;
                                $authchk = 'invalid';
                            }
                        } else {
                            $authchk = 'invalid';
                            $$logmsg .= "Invalid authentication type for new user - $uname in course $crs - no enrollment occurred.".$linefeed;
                        }
                        if ($authchk eq 'ok') { 
# Now create user.
                            my $reply=&Apache::lonnet::modifystudent($dom,$uname,$pid,$auth,$authparam,$first,$middle,$last,$gene,$usec,$end,$start,'',undef,$emailaddr,'auto',$cid);
                            if ($reply eq 'ok') {
                                $enrollcount ++;
                                $addresult .= "$first $last ($pid) - $uname enrolled in section/group $usec.".$linefeed;
                                $$logmsg .= "New user $uname added successfully. ";
                                unless ($emailenc eq '') {
                                    my %emailHash;
                                    $emailHash{'critnotification'}  = $emailenc;
                                    $emailHash{'notification'} = $emailenc;
                                    my $putresult = &Apache::lonnet::put('environment',\%emailHash,$dom,$uname);
                                }
                                if ($create_passwd) {
# Send e-mail with inital password to new user at $emailaddr
                                    $$logmsg .= "Initial password -  - sent to ".$emailaddr.$linefeed;
                                } else {
                                    $$logmsg .= $linefeed;
                                }
                            } else {
                                $$logmsg .= "An error occurred adding new user $uname - ".$reply.$linefeed;
                            }
                        }
                    } else {
# Get the user's information and authentication
                        my %userenv = &Apache::lonnet::get('environment',['firstname','middlename','lastname','generation','id','critnotification','notification'],$dom,$uname);
                        my ($tmp) = keys(%userenv);
                        if ($tmp =~ /^(con_lost|error)/i) {
                            %userenv = ();
                        }
# Get the user's e-mail address
                        if ($userenv{critnotification} =~ m/%40/) {
                            unless ($emailenc eq $userenv{critnotification}) {
                                $$logmsg .= "Current critical notification e-mail - ".$userenv{critnotification}." for $uname is different to e-mail address in Institutional classlist - ".$emailenc.$linefeed;
                            }
                        }
                        if ($userenv{notification} =~ m/%40/) {
                            unless ($emailenc eq $userenv{critnotification}) {
                                $$logmsg .= "Current standard notification e-mail - ".$userenv{notification}." for $uname is different to e-mail address in institutional classlist - ".$emailenc.$linefeed;
                            }
                        }                            
                        my $krbdefdom = '';
                        my $currentauth=&Apache::lonnet::queryauthenticate($uname,$dom);
                        if ($currentauth=~/^krb(4|5):/) {
                            $currentauth=~/^krb(4|5):(.*)/;
                            $krbdefdom=$1;
                        }
                        if ($currentauth=~/^krb(4|5):/ || 
                            $currentauth=~/^unix:/ ||
                            $currentauth=~/^internal:/ ||
                            $currentauth=~/^localauth:/) {
                               
                        } else {
                            $$logmsg .= "Invalid authentication method $currentauth for $uname.".$linefeed;  
                        }
# Report if authentication methods are different.
                        if ($currentauth ne $auth ) {
                            $$logmsg .= "Authentication mismatch for $uname - $currentauth in system, $auth for class $crs".$linefeed;
                        }
# Check user data
                        if ($first  ne $userenv{'firstname'}  ||
                            $middle ne $userenv{'middlename'} ||
                            $last   ne $userenv{'lastname'}   ||
                            $gene   ne $userenv{'generation'} ||
                            $pid    ne $userenv{'id'} ) {         
# Make the change(s)
                            my %changeHash;
                            $changeHash{'firstname'}  = $first;
                            $changeHash{'middlename'} = $middle;
                            $changeHash{'lastname'}   = $last;
                            $changeHash{'generation'} = $gene;
                            $changeHash{'id'} = $pid;
                            my $putresult = &Apache::lonnet::put('environment',\%changeHash,$dom,$uname);
                            if ($putresult eq 'ok') {
                                $$logmsg .= "User information updated for user: $uname prior to enrollment.".$linefeed;
                            } else {
                                $$logmsg .= "There was a problem modifying user data for existing user - $uname -error: $putresult, enrollment will still be attempted.".$linefeed;
                            }
                        }
 
# Assign the role of student in the course.
                        my $classlist_reply = &Apache::lonnet::modify_student_enrollment($dom,$uname,$pid,$first,$middle,$last,$gene,$usec,$end,$start,'auto',$cid);
                        if ($classlist_reply eq 'ok') {
                            $enrollcount ++;
                            $addresult .= "$first $last ($pid) - $uname enrolled in section/group $usec.".$linefeed;
                            $$logmsg .= "Existing user $uname enrolled successfully.".$linefeed;

                        } else {
                            $$logmsg .= "There was a problem updating the classlist db file for user $uname to show the new enrollment -error: $classlist_reply, so no enrollment occurred for this user.".$linefeed;
                        }
                    }
                }
            }
        }
    }
# Do drops
    if ( ($drops == 1) && (@reg_students > 0) ) {
        foreach my $uname (@localstudents) {
            if ($$currlist{$uname}[$type] eq "auto") {
                my @saved = ();
                if (!grep/^$uname$/,@reg_students) {
# Check for changed usernames by checking studentIDs
                    if (grep/^$$currlist{$uname}[ $stuid ]$/,@allINids) {
                        foreach my $match (@{$unameFromINid{$$currlist{$uname}[ $stuid ]}} ) {
                            $$logmsg .= "A possible change in username has been detected for a student enrolled in $crs. The existing LON-CAPA classlist contains user: $uname and student ID: $$currlist{$uname}[ $place{studentID} ].  This username has been dropped from the institutional classlist, but the same student ID is used for user: $match who still appears in the institutional classlist. You may need to move the student data files for user: $uname to $match.".$linefeed;
                            push @saved,$uname;
                        }
                    } elsif (@saved == 0) {
                        my $drop_reply = &Apache::lonnet::modifystudent($dom,$uname,'','','',undef,undef,undef,undef,$$currlist{$uname}[$sec],time,undef,undef,undef,undef,undef,$cid);
                        if ($drop_reply !~ /^ok/) {
                            $$logmsg .= "An error occured during the attempt to expire the $uname from the old section $$currlist{$uname}[$sec] - $drop_reply.".$linefeed;
                        } else {
                            $dropcount ++;
                            my %userenv = &Apache::lonnet::get('environment',['firstname','lastname','id'],$dom,$uname);
                            $dropresult .= $userenv{'firstname'}." ".$userenv{'lastname'}." (".$userenv{'id'}.") - ".$uname." dropped from section/group ".$$currlist{$uname}[$sec].$linefeed; 
                        }
                    }
                }
            }
        }
    }

# Terminated explictly allowed access to student creation/modification
    if ($context eq 'automated') {
        delete($ENV{'allowed.cst'});
    }
    if ($enrollcount > 0) {
        if ($context eq "updatenow") {
            $addresult = "The following $enrollcount student(s) was/were added to this LON-CAPA course:<br/><ul><li>".$addresult."</li></ul><br/><br/>";
        } else {
            $addresult = "The following $enrollcount student(s) was/were added to this LON-CAPA course:\n\n".$addresult."\n\n";    
        }      
    }
    if ($dropcount > 0) {
        if ($context eq "updatenow") {
            $dropresult = "The following $dropcount student(s) was/were expired from this LON-CAPA course:<br/><ul><li>".$dropresult."</li></ul><br/><br/>";
        } else {
            $dropresult = "The following $dropcount student(s) was/were expired from this LON-CAPA course:\n\n".$dropresult."\n\n";
        }
    }
    if ( ($adds) && ($enrollcount == 0) ) {
        $addresult = "There were no new students to add to the course.";
        if ($context eq "updatenow") {
            $addresult .="<br/><br/>";
        } else {
            $addresult .="\n";
        }
    }
    if ( ($drops) && ($dropcount == 0) ) {
        $dropresult = "There were no students with roles to expire because all active students previously added to the course from institutional classlist(s) are still officially registered.";
        if ($context eq "updatenow") {
            $dropresult .="<br/>";
        } else {
            $dropresult .="\n";
        }
    }
    my $changecount = $enrollcount + $dropcount;
    return ($changecount,$addresult.$dropresult); 
} 

sub parse_classlist {
    my ($tmpdir,$dom,$crs,$class,$placeref,$groupID,$studentsref) = @_;            
    my $configvars = &LONCAPA::Configuration::read_conf();
    my $xmlfile = $tmpdir."/tmp/".$dom."_".$crs."_".$class."_classlist.xml";
    my $enrolled = XMLin( $xmlfile, KeyAttr => ['username'] );
    foreach my $uname ( sort keys %{$$enrolled{'student'}} ) {
        @{ $$studentsref{$uname} } = ();
        foreach my $key (sort keys %{$$enrolled{'student'}{$uname}} ) {
            my $value = $$enrolled{'student'}{$uname}{$key};
            if (ref($value)) {
                $$studentsref{$uname}[ $$placeref{$key} ] = '';
            } else {
                if ($key eq 'groupID') {
                    $$studentsref{$uname}[ $$placeref{$key} ] = $groupID;
                } else {
                    $$studentsref{$uname}[ $$placeref{$key} ] = $value;
                }
            }
        }
    }
#    if (-e "$xmlfile") {
#        unlink $xmlfile;
#    }
    return;
}

sub create_password {
    my ($authparam,$create_passwd,$authreply);
    return ($authparam,$create_passwd,$authreply);
}

sub CL_autharg { return 0; }
sub CL_authtype { return 1;}
sub CL_email { return 2;}
sub CL_enddate { return 3;}
sub CL_firstname { return 4;}
sub CL_generation { return 5;}
sub CL_groupID { return 6;}
sub CL_lastname { return 7;}
sub CL_middlename { return 8;}
sub CL_startdate { return 9; }
sub CL_studentID { return 10; }

1;