#!/usr/bin/perl

use warnings;
use strict;

# Tk support is enabled if the Tk module is used before POE itself.

use Tk;
use POE;

# Create the session that will drive the user interface.

POE::Session->create(
    inline_states => {
        _start => \&ui_start,
        ev_count => \&ui_count,
        ev_clear => \&ui_clear,
    }
);


$poe_kernel->run();

exit 0;

sub ui_start {
    my ( $kernel, $session, $heap ) = @_[ KERNEL, SESSION, HEAP ];

    $poe_main_window->Label( -text => "Counter" )->pack;

    $heap->{counter_widget} =
    $poe_main_window->Label( -textvariable => \$heap->{counter} )->pack;

    $poe_main_window->Button(
        -text => "Clear",
        -command => $session->postback("ev_clear")
    )->pack;

    $kernel->yield("ev_count");
}

sub ui_count {
    $_[HEAP]->{counter}++;
    $_[KERNEL]->yield("ev_count");
}

sub ui_clear {
    $_[HEAP]->{counter} = 0;
}

sub ui_count {
    for (1) {
        $_[HEAP]->{counter}++;
    }
}