package App::XScreenSaver::DBus::Saver;
use Moo;
use experimental 'signatures';
use curry;
use Log::Any;
use Try::Tiny;
use App::XScreenSaver::DBus::SaverProxy;

has reactor => ( is => 'ro', required => 1 );
has bus => ( is => 'lazy', builder => sub { Net::DBus->session() } );
has dbus_srv => (
    is => 'lazy',
    builder => sub { shift->bus->get_service('org.freedesktop.DBus') },
);
has dbus_obj => (
    is => 'lazy',
    builder => sub { shift->dbus_srv->get_object('/org/freedesktop/DBus') },
);

has service => (
    is => 'lazy',
    builder => sub {
        # this is the service name
        shift->bus->export_service('org.freedesktop.ScreenSaver');
    },
);
has paths => (
    is => 'ro',
    default => sub { [qw(/ScreenSaver /org/freedesktop/ScreenSaver)] },
);

has log => ( is => 'lazy', builder => sub { Log::Any->get_logger } );

has _impls => ( is => 'rw' );
has _prod_id => ( is => 'rw' );
has _inhibits => ( is => 'rw', default => sub { +{} } );

sub start($self) {
    my $inhibit_cb = $self->curry::weak::inhibit;
    my $uninhibit_cb = $self->curry::weak::uninhibit;

    $self->_impls([ map {
        App::XScreenSaver::DBus::SaverProxy->new(
            $self->service,
            $_,
            $inhibit_cb,
            $uninhibit_cb,
        )
    } $self->paths->@* ]);

    $self->_prod_id(
        $self->reactor->add_timeout(
            60_000,
            Net::DBus::Callback->new(
                method => $self->curry::weak::prod_screensaver
            ),
            0,
        ),
    );

    $self->dbus_obj->connect_to_signal(
        'NameOwnerChanged',
        $self->curry::weak::name_owner_changed,
    );

    return;
}

sub inhibit($self,$name,$reason,$message) {
    my $cookie;
    do {
        $cookie = int(rand(2**31))
    } until !exists $self->_inhibits->{$cookie};

    my $sender = $message->get_sender;
    $self->_inhibits->{$cookie} = [ $name, $reason, $sender ];

    $self->log->debugf(
        '<%s> (%s) stops screensaver for <%s> (cookie %d) - %d active',
        $name, $sender, $reason, $cookie, scalar(keys $self->_inhibits->%*),
    );
    $self->reactor->toggle_timeout($self->_prod_id, 1);

    return $cookie;
}

sub uninhibit($self,$cookie,$message) {
    my $inhibit = delete $self->_inhibits->{$cookie}
        or return;
    my ($name, $reason, $sender) = @$inhibit;
    my $this_sender = $message->get_sender;

    $self->log->debugf(
        '<%s> (was %s, is %s) resumed screensaver for <%s> (cookie %d) - %d left',
        $name, $sender, $this_sender, $reason, $cookie, scalar(keys $self->_inhibits->%*),
    );

    $self->reactor->toggle_timeout($self->_prod_id, 0)
        unless $self->_inhibits->%*;

    return;
}

sub name_owner_changed($self,$bus_name,$old,$new) {
    $self->log->tracef('<%s> changed from <%s> to <%s>',
                 $bus_name, $old, $new);

    for my $cookie (sort keys $self->_inhibits->%*) {
        my ($name, $reason, $sender) = @{$self->_inhibits->{$cookie}};
        # is this inhibit from that bus name?
        next unless $sender && $sender eq $bus_name;
        # did the bus owner just disconnect?
        next unless $old && !$new;

        # if so, remove the inhibit
        my $inhibit = delete $self->_inhibits->{$cookie};

        $self->log->debugf(
            '<%s> (%s) disconnected from the bus (it stopped screensaver for <%s>, cookie %d) - %d left',
            $name, $bus_name, $reason, $cookie, scalar(keys $self->_inhibits->%*),
        );
    }

    unless ($self->_inhibits->%*) {
        $self->reactor->toggle_timeout($self->_prod_id, 0);
    }
}

sub prod_screensaver($self) {
    $self->log->debug('prodding xscreensaver');
    system(qw(xscreensaver-command -deactivate));
}

1;