package CBStats::MultiChannel;

use 5.12.2;
use Coro::Channel;
use Scalar::Util qw(weaken);

sub new
{
    my $class = shift;
    my $self = bless [], $class;

    $self;
}

# clear out any channels that have gone away

sub clean
{
    my $self = shift;
    @$self = grep { defined } @$self;

    # when we pull out the refs this way, they're
    # no longer weakened, so re-weaking everything.
    # (easier than using splice to pull undef items out -
    #  if we get too many readers, we'll re-evaluate if this
    #  is slow.)
    weaken($_) for @$self;
}

sub count
{
    my $self = shift;
    $self->clean();
    scalar @$self;
}

sub status
{
    my $self = shift;
    $self->clean();
    'Channel=size :: ' . join ":", map { $_ . "=" . $self->[$_]->size() } 0..$#$self;
}

# create new channel, add it to $self, ensure it's weakened, and return
# the non-weak version.
sub add
{
    my $self = shift;
    my $channel = Coro::Channel->new();
    push @$self, $channel;

    $self->clean();

    $channel;
}

# pass a message to all listeners.
sub put
{
    my $self = shift;

    $self->clean();

    for my $msg (@_)
    {
        # if we were really multi-threaded, we'd still
        # have to check if $_ was defined, but Coro eliminates
        # that possibility since nothing else really runs between
        # the clean() above and this (we don't cede)
        $_->put($msg) for (@$self);
    }
}

1;