#! perl -slw
use strict;
use Data::Dump qw[ pp ];
use threads qw[ yield ];
use threads::shared;
use thread::queue;

our $THREADS ||= 5;
our $MAX     ||= 1e3;

--$THREADS;

my $Qin  = Thread::Queue->new;
my $Qout = Thread::Queue->new;

sub worker {
    my $tid = threads->tid;
    warn "$tid: starting\n";
    my( $Qin, $Qout ) = @_;

    while( my $work = $Qin->dequeue ) {
        $Qout->enqueue( "$work - processed by thread $tid" );
    }
    warn "$tid: ending\n";
}


my @threads = map threads->new( \&worker, $Qin, $Qout ), 0 .. $THREADS;

my $tOut = async{
    while( my $out = $Qout->dequeue ) {
        print $out;
    }
    warn "output thread finished\n";
};

my $i = 0;
while( <> ) {
    printf STDERR "\rPending: %d (%d)", $Qin->pending, $i++;
    $Qin->enqueue( $_ );
#    yield while $Qin->pending > $MAX;
}
warn "Finished reading & queing file\n";

$Qin->enqueue( undef ) for @threads;

$_->join for @threads;

$Qout->enqueue( undef );
$tOut->join;

warn "main finished\n";