fn main() {
    let container = Container::new();
    let messenger = messenger::new();

    let system = System::new(container, messenger);

    let velocity = Velocity::new();
    container
        .create_entity()
        .with::<PositionComponent>(Position::new())
        .with::<Velocity>(velocity)
        .build();
    container
        .create_entity()
        .with::<PositionComponent>(Position::new())
        .with::<Velocity>(velocity)
        .with::<Renderer>(Renderer::new())
        .build();

    system.add_tickable::<PositionProcessor>().priority(1);
    system.add_listener::<PrintLog>().on::<PrintLogMsg>();
    system.add_listener::<DisplayLog>().on::<PrintLogMsg>();
    system.add_listener::<MouseInputMsg>().on::<MouseInput>();

    while true {
        System.run()
    }
}

impl Tickable for PositionProcessor {
    fn tick(&self, container: &Container, messenger: &Messenger) {
        for (entity, position, velocity) in container
            .get_entities()
            .with::<PositionComponent, Velocity>()
        {
            entity.push_component::<Renderer>(Renderer::new());
            position.x += velocity.x;
            position.y += velocity.y;

            messenger.publish(PrintLogMsg::new("hello world!".to_string()));
        }
    }
}

impl Listener<PrintLogMsg> for PrintLog {
    fn trigger(self, container: &Container, messenger: &Messenger, msg: PrintLogMsg) {
        println!("{:?}", msg.content);
    }
}