#!/usr/bin/perl -w

use strict;
use warnings;
use JSON;
use Getopt::Long;
use File::Which;
use File::Path qw(make_path);
use File::Basename;
use Data::Dumper;

my $pvesh = which('pvesh');
my $json = {};
my $pretty = 0;
my ($cluster,$guest,$node,$storage,$pool) = undef;

# Max age of cached values
my $cache = 60;
my $cache_dir = '/tmp/zbx_pve_cache/';

GetOptions(
  'cluster'     => \$cluster,
  'guest=i'     => \$guest,
  'node=s'      => \$node,
  'storage=s'   => \$storage,
  'pool=s'      => \$pool,
  'pretty'      => \$pretty,
  'cache=i'     => \$cache,
  'cache-dir=s' => \$cache_dir
);

# Before Buster / PVE6, pvesh don't support (or need) --output-format=json
# So try to detect previous version and adapt opt
my $pvesh_opt = '--output-format=json';
if (-f '/etc/os-release'){
  open my $fh, '<', '/etc/os-release';
  foreach my $line (<$fh>){
    my ($var, $val) = split(/=/, $line);
    $val =~ s/"(.*)"/$1/;
    if ($var eq 'VERSION_ID' and int $val < 10){
      $pvesh_opt = '';
      last;
    }
  }
}

if ($cluster){
  my $cluster = get_api_data('/cluster/status');
  # Set default values so monitoring works for single node, without cluster setup
  $json->{status} = {
    all_online => 1,
    quorate    => 1,
    nodes      => 1,
    name       => 'default',
    version    => 1
  };
  # Set default global stats
  $json->{network} = {
    in  => 0,
    out => 0
  };
  $json->{disk} = {
    read  => 0,
    write => 0
  };
  my @nodes = ();
  foreach my $item (@{$cluster}){
    if ($item->{type} eq 'cluster'){
      $json->{status}->{$_} = $item->{$_} foreach (qw(quorate nodes name version));
    } elsif ($item->{type} eq 'node' and $item->{online}){
      push @nodes, $item->{name};
    } elsif ($item->{type} eq 'node'){
      $json->{status}->{all_online} = 0;
    }
  }
  foreach my $node (@nodes){
    my $n = get_api_data("/nodes/$node/status");
    # Here we gather (and sum) some info about individual nodes to get the total number of
    # CPU, the amount of memory etc...
    $json->{memory}->{$_}  += $n->{memory}->{$_}  foreach (qw(free total used));
    $json->{ksm}->{$_}     += $n->{ksm}->{$_}     foreach (qw(shared));
    $json->{cpuinfo}->{$_} += $n->{cpuinfo}->{$_} foreach (qw(cpus sockets));
    $json->{loadavg}[$_]   += $n->{loadavg}[$_]   foreach (0..2);
  }
  # We want average load avg of the cluster, not the sum of individual loads
  $json->{loadavg}[$_] = sprintf "%.2f", $json->{loadavg}[$_] / $json->{status}->{nodes} foreach (0..2);

  my $guests = get_api_data('/cluster/resources', '--type=vm');
  foreach my $guest (@{$guests}){
    $json->{network}->{in}  += $guest->{netin}     || 0;
    $json->{network}->{out} += $guest->{netout}    || 0;
    $json->{disk}->{read}   += $guest->{diskread}  || 0;
    $json->{disk}->{write}  += $guest->{diskwrite} || 0;
  }
} elsif ($node){
  foreach my $item (qw(status version subscription)){
    $json->{$item} = get_api_data("/nodes/$node/$item");
  }
} elsif ($guest){
  my $guests = get_api_data('/cluster/resources', '--type=vm');
  foreach my $g (@{$guests}){
    if ($g->{vmid} eq $guest){
      $json = $g;
      last;
    }
  }
} elsif ($pool){
  my $pool = get_api_data("/pools/$pool");
  $json->{comment} = $pool->{comment};
  foreach my $type (qw(qemu lxc)){
    $json->{$_}->{$type} = 0 foreach (qw(guests templates));
  }
  foreach my $item (@{$pool->{members}}){
    if ($item->{type} =~ m/^(qemu|lxc)$/ and !$item->{template}){
      $json->{guests}->{$_} += $item->{$_} foreach (qw(maxcpu diskread diskwrite maxdisk mem maxmem netin netout));
      $json->{guests}->{used_cpu} += $item->{cpu} * $item->{maxcpu};
      $json->{guests}->{$item->{type}}++;
    }
    if ($item->{type} =~ m/^(qemu|lxc)$/ and $item->{template}){
      $json->{templates}->{$_} += $item->{$_} foreach (qw(maxdisk));
      $json->{templates}->{$item->{type}}++;
    }
  }
  $json->{guests}->{$_}    //= 0 foreach (qw(cpu maxcpu diskread diskwrite maxdisk mem maxmem netin netout));
  $json->{templates}->{$_} //= 0 foreach (qw(maxdisk));
  $json->{guests}->{cpu} = ($json->{guests}->{maxcpu} == 0) ? 0 : $json->{guests}->{used_cpu} / $json->{guests}->{maxcpu};
} elsif ($storage){
  my $stores = get_api_data('/cluster/resources', '--type=storage');
  foreach my $s (@{$stores}){
    if ($s->{storage} eq $storage){
      $json->{maxdisk} = $s->{maxdisk};
      $json->{disk}    = $s->{disk};
      last;
    }
  }
} else{
  print 'ZBX_NOTSUPPORTED';
  exit 0;
}

print to_json($json, { pretty => $pretty }) . "\n";

# Helper which will either get data from
# the cache if its fresh enough, or query the API
# and save the result in the cache for later
sub get_api_data {
  my ($path, $query_opt) = @_;
  $query_opt ||= '';
  my $opt_filename = $query_opt;
  $opt_filename =~ s/[\-=]/_/g;
  my $res;
  # Is the cache existing and fresh enough ?
  if (-f $cache_dir . $path . $opt_filename and int((-M $cache_dir . $path . $opt_filename)*60*60*24) < $cache){
    {
      local $/; # Enable slurp
      open my $fh, "<", $cache_dir . $path . $opt_filename;
      $res = <$fh>;
      close $fh;
    }
  } else {
    $res = qx($pvesh get $path $query_opt $pvesh_opt 2>/dev/null);
    # Save the result in the cache for later retrival
    eval{
      my $dir = (fileparse($path))[1];
      make_path($cache_dir . $dir, { chmod => 700 });
    };
    open my $fh, ">", $cache_dir . $path . $opt_filename;
    print $fh $res;
    close $fh;
  }
  return from_json($res);
}