#!/usr/bin/perl
use strict;
use warnings;

# objekt orientiert

my @dirs=map{ directory->new($_) }qw( /home/shared /home/topeg /home/test /var/log);

# erste zeile
print ';'.join(';', map{$_->path()}@dirs )."\n";

# alle user finden
my %users;
for my $dir (@dirs)
{
  for($dir->user_list())
  { $users{$_->name()}=$_; }
}

# alle user Ausgeben
for(sort(keys(%users)))
{
  my $user=$users{$_};
  my @list=map{ $user->has_dir($_) }@dirs;
  print $user->name().";".join(';',@list)."\n";
}
########################################################################
########################################################################
########################################################################
package directory;

my $gids;

sub new
{
  my $class=shift();
  my $dir=shift;

  $gids=gids->new() unless($gids);

  return undef unless(-d $dir);
  bless({dir=>$dir},$class);
}

sub path { shift()->{dir}; }

sub gid
{
  my $self=shift;
  return (stat($self->path()))[5] if(-d $self->path());
  return undef;
}

sub user_list
{
  my $self=shift;
  return $gids->user_list($self->gid());
}

sub has_user
{
  my $self=shift;
  my $user=shift;
  return 0 unless($user);
  return 0 unless($user->isa('user'));
  for($self->user_list())
  { return 1 if($_->name() eq $user->name()); }
  return 0;
}

########################################################################
package user;

sub new
{
  my $class=shift;
  my $name=shift;
  bless({name=>$name},$class);
}

sub name { shift()->{name}; }

sub has_dir
{
  my $self=shift;
  my $dir=shift;
  return 0 unless $dir->isa('directory');
  my $path=$dir->path();

  unless(exists($self->{dirs}->{$path}))
  { $self->{dirs}->{$path}=$dir->has_user($self); }

  return $self->{dirs}->{$path};
}

########################################################################
package gids;

sub new
{
  my $class=shift();
  my $gfile=shift() || '/etc/group';
  my $ufile=shift() || '/etc/passwd';
  return bless({ufile=>$ufile, gfile=>$gfile, user=>{}},$class);
}

sub user_list
{
  my $self=shift;
  my $gid=shift;
  $self->_read_groups();
  return () unless(defined($gid));
  return () unless(exists($self->{gids}->{$gid}));
  return @{$self->{gids}->{$gid}};
}

sub user
{
  my $self=shift;
  my $name=shift;
  unless($self->{user}->{$name})
  { $self->{user}->{$name}=user->new($name); }
  return $self->{user}->{$name};
}

# alle user zu einer gid
sub _read_groups
{
  my $self=shift;

  # update wenn nötig
  if(!$self->{update_g} || !$self->{update_u} || !$self->{gids} ||
     $self->{update_g} < (stat($self->{gfile}))[9] || $self->{update_u} < (stat($self->{ufile}))[9] || ref($self->{gids}) ne 'HASH')
  {

    my %gid_user;
    if(-e $self->{ufile} && open(my $fh, '<', $self->{ufile}))
    {
      while(my $line=<$fh>)
      {
        chomp($line);
        my ($user,undef,$uid,$gid)=split(/:/,$line);
        $user=$self->user($user);
        push(@{$gid_user{$gid}},$user);
      }
      close($fh);

      $self->{update_u} = (stat($self->{ufile}))[9]
    }

    if(-e $self->{gfile} && open(my $fh, '<', $self->{gfile}))
    {
      while(my $line=<$fh>)
      {
        chomp($line);
        my ($gname,undef,$gid,$users)=split(/:/,$line);
        for my $name (split(/,/,$users))
        {
          my $user=$self->user($name);
          push(@{$gid_user{$gid}}, $user);
        }
      }
      close($fh);

      $self->{update_g} = (stat($self->{gfile}))[9];
    }

    $self->{gids}=\%gid_user;
  }
}