#!/usr/ucb/perl
#
# CAPA Discussion Forum
# version 1.2c
#
# Michigan State University
# Department of Physics and Astronomy
#
# Ryan J. Shaltry
# tech4@msue.msu.edu

require "capadiscuss.setup";
require "capadiscuss_html";

################################################
## Configuration - Change these appropriately ##
################################################

# capadiscuss.setup

################################################
## End Configuration ###########################
################################################

print "Content-type: text/html\n\n";

&form_info;

$yp = "19";

  # define variables
  $class    = $form{'CLASS'};
  $snum     = $form{'SNUM'};
  $capaid   = $form{'CAPAID'};
  $setid    = $form{'SETID'};
  $action   = $form{'ACTION'};
  $file     = $form{'FILE'};
  $probnum  = $form{'PROBNUM'};
  $replynum = $form{'REPLYNUM'};
  $psetid   = $form{'PSETID'};
 
  if($psetid eq "") { $psetid = $setid; }
 
  &GetTeacherInfo;

  # check for valid studentnumber/capaid
  &ValidateUser;

  # grab username from student number
  &UserInfo($snum);
  &GetDateTime;

  # call appropriate sr
  if($action eq "newset"                   ) { &NewSet;                }
  if($action eq "viewset" || $action eq "" ) { &ViewSet;               }
  if($action eq "viewproblem"              ) { &ViewProblem;           }
  if($action eq "post"                     ) { &Post;                  }
  if($action eq "postsubmit"               ) { &PostSubmit;            }
  if($action eq "delmsgpre"                ) { &DelMsgPre;             }
  if($action eq "delmsg"                   ) { &DelMsg;                }
  if($action eq "hidemsgpre"               ) { &HideMsgPre;            }
  if($action eq "hidemsg"                  ) { &HideMsg;               }
  if($action eq "unhidemsgpre"             ) { &UnHideMsgPre;          }
  if($action eq "unhidemsg"                ) { &UnHideMsg;             }

  if($action eq "admin"                    ) { &AdminMain;             }
  if($action eq "adminusersearch"          ) { &AdminUserSearch;       }
  if($action eq "adminusersearchsubmit"    ) { &AdminUserSearchSubmit; }

  if($action eq "viewinfofile"             ) { &ViewInfoFile;          }

  if($action eq "topmsg"                   ) { &TopMsg("top");        }
  if($action eq "untopmsg"                 ) { &TopMsg("");            }

exit;

#######################
## Begin Subroutines ##
#######################

sub NewSet {
  &Log("NewSet");

  if($setid <= $psetid) {   #grab capaid
    @allcapaid = `allcapaid -s $setid -e $setid -stu $snum -c $capadir/$class -i`;

    $capaid = $allcapaid[2];
    chop $capaid;
    chop $capaid;
    &ViewSet;
  }

  opendir(DDIR,"$capadir/$class/discussion");
    @sets = grep(/[0-9]/,sort(readdir(DDIR)));
  closedir(DDIR);

  $pdset = "<select name=\"SETID\">\n";
  foreach $setnum(@sets) {
    $selected = "";
    if($setnum eq $setid) { $selected = "selected"; }
    $pdset .= "<option value=\"$setnum\" $selected>$setnum\n";
  }
  $pdset .= "</select>\n";

  &NewSetHTML;
  exit;
}

sub ViewSet {
  &Log("ViewSet");

  &CheckAdmin;

  $adminbutton = "";
  if($validadmin eq "yes") {
    $adminbutton = &AdminButtonHTML;
  }

  $capasbin = "$capasbin/$teachdir/capasbin";
  &SetJumpBox;

  opendir(FORUM,"$capadir/$class/discussion/$setid");
    @dir = sort(readdir(FORUM));
  closedir(FORUM);

  @infofiles = grep(/.info/,@dir);
  $infostring = "";
  $backfunction = "viewset";
  foreach $infofile(@infofiles) {
    $infodesc = $infofile;
    $infodesc =~ s/.info//g;
    $infodesc =~ s/_/ /g;
    $infostring .= &InfoButtonHTML;
  }


  foreach $i(@dir) {
    $probnum = &RemZero(substr($i,0,6));
    if($found[$probnum] eq "") { $found[$probnum] = "0"; }
    $found[$probnum] = $found[$probnum] + 1;
  }

  $maxprobs = &MaxProbs($setid);

  # split table (if more than 15 problems)
  $bigtable = "no";
  if($maxprobs > 5) {
    $bigtable = "yes";
    $col1size = int ($maxprobs / 2);
    $col2size = $maxprobs - $col1size;
    if($col1size < $col2size) {
      $t = $col1size;
      $col1size = $col2size;
      $col2size = $t;
    }
  }

  &ViewSetTitleHTML;

  if($bigtable eq "no") { &ViewSetTopSmallHTML; }
  else                  { &ViewSetTopBigHTML; }

  $col = 1;
  for($probnum=1; $probnum<=$maxprobs; $probnum++) {
    if($col eq "1" && $probnum > $col1size && $bigtable eq "yes") {
      $col = 2;
      &ViewSetEndColHTML;
      &ViewSetTopSmallHTML;
    }
    if($found[$probnum] ne "") {
      opendir(MSG,"$capadir/$class/discussion/$setid");
        @msgs = grep(/.msg/,sort(readdir(MSG)));
      closedir(MSG);
      foreach $msg(@msgs) {
        if(&RemZero(substr($msg,0,6)) eq $probnum) {
          push(@good,$msg);
        }
      }

      &OpenMsg("$capadir/$class/discussion/$setid/$good[$#good]");
      $lastpost = "$date at $time";
      $posts = $found[$probnum];
    }
    else {
      $lastpost = "--";
      $posts = "0"; }
    &ViewSetGutsHTML;
  }
  &ViewSetBotHTML;
  exit;
}

sub ViewProblem {
  &Log("ViewProblem");

  # check if user is administrator (for admin button)
  &CheckAdmin;
  if($validadmin eq "yes") {
    $adminbutton = &AdminButtonHTML;
  }
  else {
    $adminbutton = "";
  }

  opendir (MSGS,"$capadir/$class/discussion/$setid");
    @msgs = sort(readdir(MSGS));
  closedir(MSGS);

  # search for top message
  @top = grep (/top/, @msgs);
  $topmsg = "";
  print "$#top";
  if($#top ne "0") {
    $pnum = &AddZero($probnum);
    foreach $entry(@top) {
      $find = $entry =~ s/\A$pnum/$pnum/o;
      if($find eq "1") {
        $topmsg = $entry;
        @msgs = grep(!/$topmsg/,@msgs);
        unshift(@msgs,$topmsg);
        print "$topmsg";
      }
    }
  }

  $msgfind = "no";
  $msgcount = 0;

  $capasbin = "$capasbin/$teachdir/capasbin";

  foreach $i(@msgs) {
    $pn = &RemZero(substr($i,0,6));
    if($pn eq $probnum) {
      $msgcount++;
      $msgfind = "yes";
      &OpenMsg("$capadir/$class/discussion/$setid/$i");

      if($status eq "hidden" && $validadmin ne "yes") {
        $msgcount--;
        $msgfind = "no";
      }

      if($msgcount eq "1") {
        $postbutton = &ReplyButtonHTML;
        &ProblemJumpBox;
        &ViewProblemTopHTML;
      }

      ($token1,$token2) = split(/\|/,$poster);
      chop $token2;
      if($token1 eq "Anonymous") {
         if($validadmin eq "yes") {
           $poster = "$token2 (anonymously)";
         }
         else {
           $poster = "$token1";
           $email = "";
         }
      }
      $topfind = grep(/-top.msg/,$i);
      if($validadmin eq "yes") {
        $file = "$i";
        $delbutton = &DelButtonHTML;
        $hidebutton = &HideButtonHTML;
        $topbutton = &TopButtonHTML;
        if($topfind eq "1") { $topbutton = &UnTopButtonHTML; }
      }
      $subjectbgcolor = "#92D1D0";
      if($topfind eq "1") { $subjectbgcolor = "blue"; }
      $messagenote = "";
      if($validadmin eq "yes" || $status eq "public") {
        if($status eq "hidden") {
          $subjectbgcolor = "red";
          $hidebutton = &UnHideButtonHTML;
          $messagenote = "Hidden by $hiddenuser on $hiddendate at $hiddentime from $hiddenaddr";
        }
        &ViewProblemGutsHTML;
      }
    }
  }
  &ViewProblemBotHTML;

  if($msgfind eq "no") {
    $postbutton = &PostNewButtonHTML;
    &ProblemJumpBox;
    &ViewProblemTopHTML;
    &ViewProblemNoneHTML;
    &ViewProblemBotHTML;
  }
  
  exit;
}

sub ViewInfoFile {
  open(INFOFILE,"$capadir/$class/discussion/$setid/$file");
    @file = <INFOFILE>;
  closedir(INFOFILE);

  print "<html><head></head><body bgcolor=\"#ffffff\">";
  $backfunction = $form{'BACKFUNCTION'};
  &InfoBackButtonHTML;
  foreach $line(@file) {
    print "$line";
  }

  exit;
}

sub Post {
  local(@msgs,$pn,$msg);

  # grab last message in thread
  opendir(MSGS,"$capadir/$class/discussion/$setid");
    @msgs = grep(/.msg/,sort(readdir(MSGS)));
  closedir(MSGS); 

  foreach $msg(@msgs) {
    $pn = &RemZero(substr($msg,0,6));
    if($pn eq $probnum) {
      $lastfile = $msg;
    }
  }

  $PostType = "New Message";
  if($lastfile ne "") {
    &OpenMsg("$capadir/$class/discussion/$setid/$lastfile");
    if($status eq "public" || $validadmin eq "yes") {
      ($poster,$rposter) = split(/\|/,$poster);
      $inreplyto = &InReplyToHTML;
      $PostType = "Reply";
    }
  }

  &PostHTML;
  exit;
}

sub PostSubmit {
  local($message,$subject,$date);

  $message = $form{'message'};
  $subject = $form{'subject'};
  
  if($message eq "" || $subject eq "") { &MFPostReplyHTML; }

  &Log("Post");

  # find last message in thread
  opendir(FORUM,"$capadir/$class/discussion/$setid");
    @dir = sort(readdir(FORUM));
  closedir(FORUM);

  $probnum = &AddZero($probnum);
  $replynum = "000000";
  foreach $msg(@dir) {
    if(substr($msg,0,6) eq $probnum) {
        $replynum = &AddZero(&RemZero(substr($msg,7,6)) + 1);
    }
  }

  $date = substr($RunonDate,0,4) . $yp . substr($RunonDate,4,2);
  &WriteMsg("$capadir/$class/discussion/$setid/$probnum-$replynum-$date-000000.msg");

  $probnum = &RemZero($probnum);
  &PostDoneHTML;
  exit;
}

sub DelMsgPre {
  &CheckAdmin('kill');
  &OpenMsg("$capadir/$class/discussion/$setid/$file");
  &DelMsgPreHTML;
  exit;
}

sub DelMsg {
  &CheckAdmin('kill');
  unlink("$capadir/$class/discussion/$setid/$file");
  &DelMsgDoneHTML;
  exit;
}

sub HideMsgPre {
  &CheckAdmin('kill');
  &OpenMsg("$capadir/$class/discussion/$setid/$file");
  &HideMsgPreHTML;
  exit;
}

sub HideMsg {
  &CheckAdmin('kill');
  open(MSG,"$capadir/$class/discussion/$setid/$file");
    @msg = <MSG>;
  close(MSG);

  unlink("$capadir/$class/discussion/$setid/$file");

  open(MSG,">$capadir/$class/discussion/$setid/$file");
    for($i=0;$i<=5;$i++) {
      print MSG "$msg[$i]";
    }
    print MSG "hidden|$username|$HyphenDate|$Time|$ENV{'REMOTE_ADDR'}\n";
  close(MSG);

  &HideMsgDoneHTML;
}

sub UnHideMsgPre {
  &CheckAdmin('kill');
  &OpenMsg("$capadir/$class/discussion/$setid/$file");
  &UnHideMsgPreHTML;
  exit;
}

sub UnHideMsg {
  &CheckAdmin('kill');
  open(MSG,"$capadir/$class/discussion/$setid/$file");
    @msg = <MSG>;
  close(MSG);

  unlink("$capadir/$class/discussion/$setid/$file");

  open(MSG,">$capadir/$class/discussion/$setid/$file");
    for($i=0;$i<=5;$i++) {
      print MSG "$msg[$i]";
    }
    print MSG "public||||}\n";
  close(MSG);

  &UnHideMsgDoneHTML;
}


sub TopMsg {
  &CheckAdmin('kill');

  $ext = shift(@_);
  
  open(MSG,"$capadir/$class/discussion/$setid/$file");
    @msg = <MSG>;
  close(MSG);
  
  unlink("$capadir/$class/discussion/$setid/$file");
  
  ($filename, $extension) = split(/\./,$file);
  $filename = "$filename-$ext.msg";
  open(MSG,">$capadir/$class/discussion/$setid/$filename");
    for($i=0;$i<=6;$i++) {
      print MSG "$msg[$i]";
    }
  close(MSG);
  
  if($ext eq "") {
    $function = "restored to its original position in the thread.";
  }
  else {
    $function = "moved to the top of the thread list.";
  }

  &TopMsgDoneHTML;
}

###############################
## Administrator Subroutines ##
###############################

sub AdminMain {
  &CheckAdmin('kill');
  &AdminMainHTML;
  exit;
}


sub AdminUserSearch {
  &CheckAdmin('kill');
  &AdminUserSearchHTML;
  exit;
}


sub AdminUserSearchSubmit {
  local($sname,$semail,$saction,$sset,$sprob,$sdate,$stime);
  &CheckAdmin('kill');

  $query = $form{'usersearch'};
  open(LOG,"$capadir/$class/discussion/logs/access.log");
    @log = <LOG>;
  close(LOG);

  @linematches = grep /$query/, @log;
  
  foreach $line(@linematches) { print $line; }

  exit;
}

######################
## Misc Subroutines ##
######################

sub OpenMsg {
  local($filename,$statusl);

  $filename = shift(@_);
  
  open (MSG,"$filename");
    @msg = <MSG>;
  close(MSG);

  $poster   = $msg[0];
  $date     = $msg[1];
  $time     = $msg[2];
  $subject  = $msg[3];
  $email    = $msg[4];
  $message  = $msg[5];
  $statusl  = $msg[6];

  ($status, $hiddenuser, $hiddendate, $hiddentime, $hiddenaddr) = split(/\|/,$statusl);
}

sub WriteMsg {
  local($filename,$message);

  $filename = shift(@_);
  # add sr to grab e-mail address of user

  $message = $form{'message'};
  $message =~ s/\n\r\n/<p>/g;
  $message =~ s/\n/<br>/g;

  # check if posted anonymously
  if($form{'ANONYMOUS'} eq "yes") {
    $username = "Anonymous|$username";
  }

  open (MSG,">$filename");
    print MSG "$username\n";
    print MSG "$HyphenDate\n";
    print MSG "$Time\n";
    print MSG "$subject\n";
    print MSG "$email\n";
    print MSG "$message\n";
    print MSG "public||||\n";
  close(MSG);
}

sub GetTeacherInfo {
  local($capa5dir,$classname,$tdir,@classconf);

  # open/read class.conf file
  open (CLASSCONF,"$capabin/class.conf");
    @classconf = <CLASSCONF>;
  close(CLASSCONF);

  $found eq "no";
  foreach $line(@classconf) {
    ($classname,$capa5dir,$tdir) = split(/[\t\ ]+/,$line);

    if($classname eq $class) {
      $teachdir = $tdir;
      $capadir  = $capa5dir;
      $found    = "yes";
    }
  }
  if($found eq "no") { &InvalidVarsHTML; }
  chop $teachdir;
}

sub CheckAdmin {
  local($asection,@adminsections,$line,@capaconfig,$command,$value,
        $adminsection,@classl,$course,$coursenum,$section,$stunum,$a);

  $validadmin = "no";
  $mode = shift(@_);

  # open 'capa.config' file (for admin section read)
  open(CAPACONFIG,"$capadir/$class/capa.config");
    @capaconfig = <CAPACONFIG>;
  close(CAPACONFIG);
  foreach $line(@capaconfig) {
    chop $line;
    ($command,$value) = split(/\ =\ /,$line);
    if($command eq "admin_section") {
      $adminsection = $value;
    }
  }

  @adminsections = split(/\,/,$adminsection);

  # open 'classl' file
  open(CLASSL,"$capadir/$class/classl");
    @classl = <CLASSL>;
  close(CLASSL);

  foreach $line(@classl) {
    chop $line;
    ($course,$coursenum,$section,$stunum,$a) = split(/\ +/,$line);
    $snum =~ tr/a-z/A-Z/;
    $stunum =~ tr/a-z/A-Z/;
    $section = &RemZero($section);
    foreach $asection(@adminsections) {
      if(&RemZero($section) eq &RemZero($asection) && $stunum eq $snum) {
        $validadmin = "yes";
      }
    }
  }
  if($validadmin eq "no" && $mode eq "kill") { &NotAdminHTML; }
}

sub ValidateUser {
  local(@allcapaid,@classl,$line);

  open (CLASSL,"$capadir/$class/classl");
    @classl = <CLASSL>;
  close(CLASSL);

  $valid = "no";
  foreach $line(@classl) {
    if(substr($line,15,8) eq substr($snum,1,8)) {
      $valid = yes;
    }
  }
  if($valid eq "no") { &InvalidVarsHTML; }

  # check w/ allcapaid program
  @allcapaid = `allcapaid -s $setid -e $setid -stu $snum -c $capadir/$class -i`;

  chop $allcapaid[2];
  chop $allcapaid[2];
  if($allcapaid[2] ne $capaid) {
    if($action ne "newset") { &BadPassHTML; }
    &NewSet;
  }
}

sub UserInfo {
  local($line,@classl,$last,$first,$middle);

  open (CLASSL,"$capadir/$class/classl");
    @classl = <CLASSL>;
  close(CLASSL);

  foreach $line(@classl) {
    if(substr($line,15,8) eq substr($snum,1,8)) {
      $username = substr($line,24,36);
      $email    = substr($line,60,45);
    }
  }
  ($last, $first, $middle) = split(/\ +/,$username);

  chop $last;
  $username = "$first $last";
  $email    =~ s/\ //g;
  chop $email;
}

sub MaxProbs {
  open (SETRECORD,"$capadir/$class/records/set$setid.db");
    @setrecord = <SETRECORD>;
  close(SETRECORD);
  chop $setrecord[0];
  return $setrecord[0];
}

sub ProblemJumpBox {
  $pdprob = "<select name=\"PROBNUM\">\n";
  for($jumpnum=1;$jumpnum<=&MaxProbs;$jumpnum++) {
    $selected = "";
    if($jumpnum eq $probnum) { $selected = " selected"; }
    $pdprob .= "  <option value=$jumpnum$selected>$jumpnum\n";
  }
  $pdprob .= "</select>";
}

sub SetJumpBox {
  opendir(DDIR,"$capadir/$class/discussion");
    @sets = grep(/[0-9]/,sort(readdir(DDIR)));
  closedir(DDIR);

  $pdset = "<select name=\"SETID\">\n";
  foreach $set(@sets) {
    $selected = "";
    if($set eq $setid) { $selected = " selected"; }
    $pdset .= "  <option value=\"$set\"$selected>$set\n";
  }
  $pdset .= "</select>";
}

sub AddZero {
  $string = shift(@_);
  
  while(length($string) < 6) {
    $string = "0$string";
  }
  return $string;
}

sub RemZero {
  $string = shift(@_);
  
  $fc = substr($string,0,1);
  while($fc eq "0") {
    $string =~ s/.//;
    $fc = substr($string,0,1);
  }
  return $string;
}

sub FormatDate {
  $string = shift(@_);
  
  $month = substr($string,0,2);
  $day   = substr($string,2,2);
  $year  = substr($string,4,4);

  $string = "$month-$day-$year";

  return $string;
}

####################
## Get SubRoutine ##
####################
sub form_info {
  read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});

  # Split the name-value pairs
  @pairs = split(/&/, $buffer);

  foreach $pair (@pairs) {
     ($name, $value) = split(/=/, $pair);

     # Un-Webify plus signs and %-encoding
     $value =~ tr/+/ /;
     $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
     $value =~ s/<!--(.|\n)*-->//g;

     if ($allow_html != 1) {
        $value =~ s/<([^>]|\n)*>//g;
     }
     $form{$name} = $value;
  }
}

##################
## Date/Time sr ##
##################
sub GetDateTime  {
  ($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst) = localtime (time);
  $mon++;

  if ($hour < 12) {
  $AMPM = "AM";
  }

  if ($hour > 12) {
  $hour = $hour - 12;
    $AMPM = "PM";
  }  	
  if ($hour == 12) {
    $AMPM = "PM";
  }  	
	
  if ($hour == 0) {
    $hour = "12";
  }

  $min = sprintf ("%2d", $min);
  $min =~tr/ /0/;
  $mon = sprintf ("%2d", $mon);
  $mon =~tr/ /0/;
  $mday = sprintf ("%2d", $mday);
  $mday =~tr/ /0/;
  $HyphenDate = ("$mon" . "-" . "$mday" . "-" . "$year");
  $RunonDate = ("$mon$mday$year");
  $Time = ("$hour" . ":" . "$min" . " " . "$AMPM");
}

########################
## Logging Subroutine ##
########################
sub Log {
  $logmsg = shift(@_);
  
  &GetDateTime;

  &Lock("lock.file");
  open(LOG,">>$capadir/$class/discussion/logs/access.log");
    print LOG "$snum|$capaid|$username|$email|$logmsg|$setid|$probnum|$HyphenDate|$Time\n";
  close(LOG);
  &Unlock("lock.file");
}

############################
## Lock/Unlock Subroutine ##
############################
sub Lock {
  local ($lockname) = @_;
  local ($endtime);
  $endtime = 15;
  $endtime = time + $endtime;
  
  while (-e $lockname && time < $endtime) {
    open (LOCKFILE, ">$lockname");
  }
  
sub Unlock {
  local ($lockname) = @_;
  close (LOCKFILE);
  unlink ($lockname);
  }
}


######################
## HTML Subroutines ##
######################

## CapaDiscuss HTML Subroutines

# capadiscuss_html

## end capadiscuss