#!/usr/local/bin/perl5 -w
use strict;

use Term::ReadKey;

$| = 1;
$0 = "whoson";

my $userdir = $ENV{HOME};

my $clearstring = `/usr/bin/clear`;

my $dotusersfile = "$userdir/.users";
my $changed = 0;
my $busy = 1;
my $wait = 1;

my %dotusers;

sub read_userfile {
  open(U, "<$dotusersfile") || die "Can't open $dotusersfile! ($!)\n";
  my @monitor = <U>;
  close(U);
  %dotusers = ();
  foreach (@monitor) {
    chomp;
    $dotusers{$_}{NAME} = $_;
    $dotusers{$_}{LAST} = 0;
  }
}

sub catch_alarm {
  $wait = 0;
}

$SIG{ALRM} = \&catch_alarm;
$SIG{HUP}  = \&read_userfile;

read_userfile;

ReadMode('cbreak');

do {
  $changed = 0;

  open(W, "/usr/bin/w -hi |") || die "Couldn't do `w`! ($!)\n";
  my @w = <W>;
  close(W);

  my %users = ();

  foreach (@w) {
    chomp;
    if ($_ =~ / \- hi /x) {
      print "$_\n";
      # this is our own process.  since it will always have zero idletime,
      # we'll skip it...
      next;
    }
    my $user = substr($_,  0,  8); $user =~ s/\s+$//;
    my $idle = substr($_, 50,  6); $idle =~ s/^\s+//;
    if (defined($users{$user})) {
      # `w` was sorted by idle time.  later occurrences have larger
      # idle times.  so we don't need these.
    } else {
      $users{$user} = $idle;
    }
  }

  print $clearstring;
  foreach (sort keys %dotusers) {
    if (defined ($users{$_})) {
      if ($dotusers{$_}{LAST} == 0) {
        $dotusers{$_}{LAST} = 1;
        $changed = 1;
        printf "\e[1m%-10s %7s\e[0m\n", $_, $users{$_};
      } else {
        printf "%-10s %7s\n", $_, $users{$_};
      }
    } else {
      $dotusers{$_}{LAST} = 0;
    }
  }

  if ($changed == 1) { print "\07"; }
  $wait = 1;
  alarm 3;
  while ($wait == 1) {
    select undef,undef,undef,0.1;
    if (defined (my $key = ReadKey(-1)) ) {
      if ($key =~ m/q/i) { $wait = 0; $busy = 0; }
    } else {
      ;
    }
  }
} while ($busy == 1);

ReadMode('normal');

exit(0);