#!/usr/bin/perl

use strict;
use warnings;

use Gtk;
use Socket;
use IO::Handle;
use Getopt::Long;

MAIN:
{
    my $window;
    my $button;
    my $pid;
    my %opts;
    
    my $at_start = 2;
    my $at_end   = 2;
    my $fork     = 2;
    GetOptions("at_start!" => \$at_start, "at_end!" => \$at_end, "fork!" => \$fork);
    
    if (2 == $at_start && 2 == $at_end) {
        print "You must select start or end\n";
        exit;
    }
    
    if (1 == $at_start) {
        print "Calling at start\n";
        set_locale Gtk;
        init Gtk;
    }

    if (1 == $fork) {
        socketpair(CHILD, PARENT, Socket::AF_UNIX, Socket::SOCK_STREAM, Socket::PF_UNSPEC)
            or  die "socketpair: $!";

        CHILD->autoflush(1);
        PARENT->autoflush(1);

        my $line;
        if ($pid = fork) {
            close PARENT;

            print CHILD "Parent Pid $$ is sending this\n";
            chomp($line = <CHILD>);
            print "Parent Pid $$ just read this: `$line'\n";

            close CHILD;
            waitpid($pid,0);

        } else {
            die "cannot fork: $!" unless defined $pid;
            close CHILD;

            chomp($line = <PARENT>);
            print "Child Pid $$ just read this: `$line'\n";
            print PARENT "Child Pid $$ is sending this\n";

            close PARENT;
            exit;
        }
    }

    if (1 == $at_end) {
        print "Calling at end\n";
        set_locale Gtk;
        init Gtk;
    }

    print("got here\n");
    $window = new Gtk::Window("toplevel");
    print("got there\n");
    $window->signal_connect("destroy", sub { Gtk->exit(0) });
    $window->set_title("testing");
    $button = new Gtk::Button("Quit");
    $button->signal_connect("clicked", sub { Gtk->exit(0) });
    $window->add($button);
    $window->show_all;

    main Gtk;
}