#!/usr/bin/perl -w

use strict;
use warnings;
use JSON;
use Getopt::Long;
use File::Which;
use Date::Parse;
use Data::Dumper;

my $samba_tool = which('samba-tool');
my $pdbedit = which('pdbedit');
# Number of seconds in the past to count authentications
my $since = 300;
my $pretty = 0;
# This log is expected to be in JSON format. For example, in smb.conf :
# log level = 1 auth_audit:3 auth_json_audit:4@/var/log/samba/audit_auth.log
my $audit_auth_log = '/var/log/samba/audit_auth.log';

if (not defined $samba_tool or not defined $pdbedit){
  print 'ZBX_NOTSUPPORTED';
  exit 1;
}

GetOptions(
  'pretty'           => \$pretty,
  'since=i'          => \$since,
  'audit-auth-log=s' => \$audit_auth_log
);

my $json = {
  accounts => {
    users          => 0,
    inactive_users => 0,
    active_users   => 0,
    groups         => 0,
    computers      => 0
  },
  replication => 'UNKNWON',
  processes => {
    cldap_server => 0,
    kccsrv          => 0,
    dreplsrv        => 0,
    ldap_server     => 0,
    kdc_server      => 0,
    dnsupdate       => 0,
    'notify-daemon' => 0,
    rpc_server      => 0,
    winbind_server  => 0,
    nbt_server      => 0,
    dnssrv          => 0,
    samba           => 0,
  },
  gpo => 0,
  ou => 0,
  activity => {
    authentications => {
      users => {
        success => 0,
        failure => 0
      },
      computers => {
        success => 0,
        failure => 0
      }
    },
    authorizations => {
      users     => 0,
      computers => 0
    },
    since => $since
  }
};

# Get the numbers of users. pdbedit is prefered here because we can
# differentiate active and inactive users, which samba-tool can't do
# While at it, also get the computers
foreach (qx($pdbedit -L -v)){
  next unless (m/^Account Flags:\s+\[(.*)\]/);
  my $flags = $1;
  if ($flags =~ m/U/){
    $json->{accounts}->{users}++;
    if ($flags =~ m/D/){
      $json->{accounts}->{inactive_users}++;
    } else {
      $json->{accounts}->{active_users}++;
    }
  } elsif ($flags =~ m/W/){
    $json->{accounts}->{computers}++;
  }
}

# Now count groups
foreach (qx($samba_tool group list)){
  $json->{accounts}->{groups}++;
}

# Get replication status
# We want just a quick summary, so only output the first line
# manual checks will be needed to get the details, but if this field doesn't contains [ALL GOOD],
# then something is probably wrong
$json->{replication} = (split(/\n/, qx($samba_tool drs showrepl --summary)))[0];

# Get the list of workers
foreach (qx($samba_tool processes)){
  if (/^([^\(\s]+).+\d+$/){
    $json->{processes}->{$1}++;
  }
}

# Get the number of GPO
foreach (qx($samba_tool gpo listall)){
  next unless (/^GPO/);
  $json->{gpo}++;
}

# Get the number of OU
foreach (qx($samba_tool ou list)){
  $json->{ou}++;
}

if (-e $audit_auth_log){
  open (my $auth_log, '<', $audit_auth_log) or die "Couldn't open $audit_auth_log : $!\n";
  foreach my $line (<$auth_log>){
    my $event = from_json($line);
    my $type = $event->{type};
    # We're only interested in Authentication and Authorization messages
    next if ($type ne 'Authentication' and $type ne 'Authorization');
    # Parse the date in the timstamp field
    my $timestamp = str2time($event->{timestamp});

    # Only look at lines from the last $since seconds. Skip if date couldn't be parsed
    next if (not defined $timestamp or time() - $timestamp > $since);
  
    my $subject;
    if ($type eq 'Authentication'){
      # Accounts ending with $ are for computers
      $subject = ($event->{$type}->{mappedAccount} =~ m/\$$/) ? 'computers' : 'users';
      if ($event->{Authentication}->{status} eq 'NT_STATUS_OK'){
        $json->{activity}->{authentications}->{$subject}->{success}++;
      } else {
        $json->{activity}->{authentications}->{$subject}->{failure}++;
      }
    } else {
      $subject = ($event->{$type}->{account} =~ m/\$$/) ? 'computers' : 'users';
      $json->{activity}->{authorizations}->{$subject}++;
    }
  }
  close $auth_log;
}

print to_json($json, { pretty => $pretty });