use strict;
use warnings;

# perl snmp_server.pl | wc -l

use Time::HiRes qw( sleep time );
use Net::SNMPTrapd;
use MCE::Flow;
use MCE::Queue;

my $queue = MCE::Queue->new( await => 1, fast => 1 );
my $max_consumers = 30;
my $start = 0;

MCE::Flow::init {
    user_output => sub { print {*STDOUT} $_[0]; },
    user_error  => sub { print {*STDERR} $_[0]; },
};

mce_flow { max_workers => [ 1, $max_consumers ] }, \&listener, \&consumer;

printf {*STDERR} "duration : %0.03f seconds\n", time - $start;

exit(0);

sub set_start {
    $start = $_[0];
}

sub listener {
    my $snmptrapd = Net::SNMPTrapd->new( ReusePort => 1 );
    my $count = 0;
    my $start;

    while ( 1 ) {
        my $trap = $snmptrapd->get_trap();

        if ( !defined $trap ) {
            MCE->printf(\*STDERR, "$0: %s\n", Net::SNMPTrapd->error());
            next;
        }
        elsif ( $trap == 0 ) {
            next;
        }

        $start = time(), MCE->do('set_start', $start) unless $start;

        # important, remove the file handle inside the object
        delete $trap->{_UDPSERVER_};

        # enqueue the trap for a consumer to process
        $queue->enqueue($trap);

        # leave the loop after 10,000 traps
        last if ( ++$count >= 10000 );

        # safety to prevent the queue from consuming memory out of control
        # $queue->await(2000) if ( $count % 4000 == 0 );

        # if ( ( $count % 4000 == 0 ) && $queue->pending() > 3000 ) {
        #     MCE->say(\*STDERR, "Warn: blocking temporarily");
        #     $queue->await(2000);
        # }

        # reset the counter to not overflow
        $count = 0 if ( $count > 2e9 );
    }

    $queue->enqueue((undef) x $max_consumers);

    MCE->printf(\*STDERR, "enqueue  : %0.03f seconds\n", time - $start);
    MCE->printf(\*STDERR, "pending  : %d\n", $queue->pending());
}

sub consumer {
    while ( defined ( my $trap = $queue->dequeue() ) ) {
        $trap->process_trap();

        MCE->printf( "[$$] %s\t%i\t%i\t%s\n",
          $trap->remoteaddr, $trap->remoteport,
          $trap->version, $trap->community );

        sleep 0.004;
    }
}