package Resmon::Module;

use strict;
use Data::Dumper;
use UNIVERSAL qw/isa/;
my %coderefs;

my $rmloading = "Registering";

sub fetch_monitor {
  my $type = shift;
  my $coderef = $coderefs{$type};
  return $coderef if ($coderef);

  # First if the monitor name is raw and looks right:
  #   is a subclass of Resmon::Module and can 'handler'
  # then we will promote it into the Resmon::Module namespace
  # and use this one.
  eval "use $type;";
  if($type->isa(__PACKAGE__) && $type->can('handler')) {
    eval " 
      package Resmon::Module::$type;
      use vars qw/\@ISA/;
      \@ISA = qw($type);
      1;
    ";
    if($@) {
      die "Could not repackage $type as Resmon::Module::$type\n";
    }
    return undef;
  }
  eval "use Resmon::Module::$type;";
  return undef;
}

sub register_monitor {
  my ($type, $ref) = @_;
  if(ref $ref eq 'CODE') {
    $coderefs{$type} = $ref;
  }
  print STDERR "$rmloading $type monitor\n";
}
sub fresh_status {
  my $arg = shift;
  return undef unless $arg->{interval};
  my $now = time;
  if(($arg->{lastupdate} + $arg->{interval}) >= $now) {
    return $arg->{laststatus};
  }
  return undef;
}
sub set_status {
  my $arg = shift;
  $arg->{laststatus} = shift;
  $arg->{lastmessage} = shift;
  $arg->{lastupdate} = time;
  if($arg->{laststatus} =~ /^([A-Z]+)\((.*)\)$/s) {
    # This handles old-style modules that return just set status as
    #     STATE(message)
    $arg->{laststatus} = $1;
    $arg->{lastmessage} = $2;
  }
  return ($arg->{laststatus}, $arg->{lastmessage});
}
sub config_as_hash {
  my $self = shift;
  my $conf = {};
  while(my ($key, $value) = each %$self) {
    if(! ref $value) {
      # only stash scalars here.
      $conf->{$key} = $value;
    }
  }
  return $conf;
}
#### Begin actual monitor functions ####

package Resmon::Module::DATE;
use vars qw/@ISA/;
@ISA = qw/Resmon::Module/;

sub handler {
  my $arg = shift;
  my $os = $arg->fresh_status();
  return $arg->set_status("OK(".time().")");
}

package Resmon::Module::DISK;
use Resmon::ExtComm qw/cache_command/;
use vars qw/@ISA/;
@ISA = qw/Resmon::Module/;

sub handler {
  my $arg = shift;
  my $os = $arg->fresh_status();
  return $os if $os;
  my $devorpart = $arg->{'object'};
  my $output = cache_command("df -k", 120);
  my ($line) = grep(/$devorpart\s*/, split(/\n/, $output));
  if($line =~ /(\d+)%/) {
    if($1 <= $arg->{'limit'}) {
      return $arg->set_status("OK($1% full)");
    }
    return $arg->set_status("BAD($1% full)");
  }
  return $arg->set_status("BAD(no data)");
}

package Resmon::Module::LOGFILE;
use vars qw/@ISA/;
@ISA = qw/Resmon::Module/;

my %logfile_stats;
sub handler {
  my $arg = shift;
  my $os = $arg->fresh_status();
  return $os if $os;
  my $file = $arg->{'object'};
  my $match = $arg->{'match'};
  my $max = $arg->{'max'} || 8;
  my @statinfo = stat($file);
  if(exists($arg->{file_dev})) { 
    if(($arg->{file_dev} == $statinfo[0]) &&
       ($arg->{file_ino} == $statinfo[1])) {
      if($arg->{lastsize} == $statinfo[7]) {
        if($arg->{errors}) {
          return $arg->set_status("BAD($arg->{nerrs}: $arg->{errors})");
        }
        return $arg->set_status("OK(0)");
      }
    } else {
      # File is a different file now
      $arg->{lastsize} = 0;
      $arg->{nerrs} = 0;
      $arg->{errors} = '';
    }
  }
  if(!open(LOG, "<$file")) {
    return $arg->set_status("BAD(ENOFILE)");
  }
  seek(LOG, $arg->{lastsize}, 0);

  while(<LOG>) {
    chomp;
    if(/$match/) {
      if($arg->{nerrs} < $max) {
        $arg->{errors} .= " " if(length($arg->{errors}));
        $arg->{errors} .= $_;
      }
      $arg->{nerrs}++;
    }
  }

  # Remember where we were
  $arg->{file_dev} = $statinfo[0];
  $arg->{file_ino} = $statinfo[1];
  $arg->{lastsize} = $statinfo[7];

  if($arg->{nerrs}) {
    return $arg->set_status("BAD($arg->{nerrs}: $arg->{errors})");
  }
  return $arg->set_status("OK(0)");
}

package Resmon::Module::FILEAGE;
use vars qw/@ISA/;
@ISA = qw/Resmon::Module/;

sub handler {
  my $arg = shift;
  my $os = $arg->fresh_status();
  return $os if $os;
  my $file = $arg->{'object'};
  my @statinfo = stat($file);
  my $age = time() - $statinfo[9];
  return $arg->set_status("BAD(to old $age seconds)")
        if($arg->{maximum} && ($age > $arg->{maximum}));
  return $arg->set_status("BAD(to new $age seconds)")
        if($arg->{minimum} && ($age > $arg->{minimum}));
  return $arg->set_status("OK($age)");
}

package Resmon::Module::NETSTAT;
use Resmon::ExtComm qw/cache_command/;
use vars qw/@ISA/;
@ISA = qw/Resmon::Module/;

sub handler {
  my $arg = shift;
  my $os = $arg->fresh_status();
  return $os if $os;
  my $output = cache_command("netstat -an", 30);
  my @lines = split(/\n/, $output);
  @lines = grep(/\s$arg->{state}\s*$/, @lines) if($arg->{state});
  @lines = grep(/^$arg->{localip}/, @lines) if($arg->{localip});
  @lines = grep(/^[\w\d\*\.]+.*[\.\:]+$arg->{localport}/, @lines) if($arg->{localport});
  @lines = grep(/[\d\*\.]+\d+\s+$arg->{remoteip}/, @lines)
	if($arg->{remoteip});
  @lines = grep(/[\d\*\.]+\s+[\d\*\.]+[\.\:]+$arg->{remoteport}\s+/, @lines)
	if($arg->{remoteport});
  my $count = scalar(@lines);
  return $arg->set_status("BAD($count)")
	if($arg->{limit} && ($count > $arg->{limit}));
  return $arg->set_status("BAD($count)")
	if($arg->{atleast} && ($count < $arg->{atleast}));
  return $arg->set_status("OK($count)");
}

$rmloading = "Demand loading";
1;