#!/usr/bin/perl

package Counter;

use strict;
use Coro::Continuation;

our $id_gen = 0;

sub new {
  my $class = shift;
  my $self = { @_ };
  bless $self, $class;
  $self->{count} = 0;
  $self->{id} = $id_gen++;
  $self->{continuation} = continuation { $self->main };
  return $self;
}

sub process {
  my ($self, $request) = @_;
  $self->{continuation}->();
}

sub main {
  my $self = shift;
  while(1) {
    my $action = $self->{request}->param("action-$self->{id}");
    if($action eq 'add') {
      $self->{count}++;
    } elsif($action eq 'sub') {
      $self->{count}--;
    }
    $self->{output} = qq{
      Count: $self->{count}<br>
      <a href="?action-$self->{id}=add">++</a><br>
      <a href="?action-$self->{id}=sub">--</a><br>
    };
    yield;
  }
}


package main;

use strict;
use Continuity;

Continuity->new( port => 8080 )->loop;

sub main {
  my ($request) = @_;

  my $output;

  my @counters;
  for my $i (1..10) {
    my $counter = Counter->new( request => $request );
    push @counters, $counter;
  }

  while(1) {
    foreach my $counter (@counters) {
      $counter->process();
      $request->print($counter->{output});
    }
    $request->next;
  }
}