#! perl -slw
use strict;
use threads ( stack_size => 4096 );
use threads::shared;
use Thread::Queue;

$|++;

our $VERBOSE :shared;
our $REMOTE :shared;
my $stop :shared = 0; ## Set true to terminate threads

my @logs = map glob, @ARGV; ## expand wildcards
my $Q = new Thread::Queue;

## One trhead per log file
threads->create( \&tail, $Q, $_, 1 )->detach for @logs;

my $remote; ## Remote watcher socket
if( $REMOTE ) {
    require IO::Socket;
    $remote = IO::Socket::INET->new( $REMOTE )
        or warn "Couldn't connect to $REMOTE : $!, $^E";
    print $remote "Hi there, Got your ears on?";
}

## Thread to monitor the Q, print locally and/or forward to remote
my $relay = async {
    for( 1 .. @logs ) { ## Waits for all tals to terminate
        while( my $line = $Q->dequeue ){
            chomp $line;
            print $line if $VERBOSE;
            print $remote $line if $remote;
        }
    }
};

## Local command loop
while( <STDIN> ) {
    my( $command, $value ) = split;

    if( $command =~ m[^(END|QUIT)]i ) {
        $stop = 1;
        warn "Quiting...\n";
        $relay->join;
        exit 0;
    }

    if( $command =~ m[^VERBOSE]i ) {
        $VERBOSE = $value;
        print "VERBOSE set to $value";
    }

    elsif( $command eq 'qs' ) {
        print $Q->pending;
    }

    else {
        print "Unrecognised command: $command";
    }
}

## Tail threads
sub tail {
    print threads->tid, ' : ', threads->self->get_stack_size;
    my( $Q, $path, $seconds ) = @_;
    $seconds = 1 unless $seconds;
    my $pid = open my $log, "tail -Fs $seconds $path |"
        or die $@;
    printf "Thread %d Following $path\n", threads->tid;
    $Q->enqueue( $_ ) while not $stop and defined( $_ = <$log> );
    kill 3, $pid;
    close $log;
    $Q->enqueue( undef );
}