#!perl -w
use strict;
use threads;
use Thread::Queue;
use Data::Dumper;

my $q_display = Thread::Queue->new();
my $display_control = threads->create( sub {
    while (my $info = $q_display->dequeue()) {
        #warn Dumper $info;
        my ($command, @data) = @$info;
        if ($command eq 'status') {
            print "Status: $_\n" for @data;
        } elsif ($command eq 'prompt') {
            my ($prompt, $id, $response_queue) = @data;
            print "$prompt\n";
            my $response = <>;
            $response_queue->enqueue([$id, $response]);
        };
    };
});

sub get_info {
    my ($prompt) = @_;
    my $response = Thread::Queue->new();
    $prompt = "[thread " . threads->tid . " asks] $prompt";
    my $request_id = threads->tid;
    $q_display->enqueue([prompt => $prompt, $request_id, $response]);
    my $res = $response->dequeue;
    my ($id,$val) = @$res;
    if ($id ne $request_id) {
        die "Internal error. Asked for $request_id, got $id";
    };
    $val
};

sub send_status {
    my (@msg) = @_;
    
    $_ = "[thread " . threads->tid . " status] $_" for @msg;
    $q_display->enqueue([status => @msg]);
};


sub hello_world { sleep rand 5; my $name = get_info( 'What is your name?' ); sleep rand 10; send_status("Hello $name") };

my @running = map {
    async \&hello_world;
} 1..4;

# Wait for all child threads to finish
$_->join for @running;

# Stop the display thread
$q_display->enqueue(undef);
$display_control->join;
print "Done\n";