use std::future::Future;

pub enum AxiomError {
    Boom,
}
pub type AxiomResult = Result<String, AxiomError>;
pub type Message = String;
pub struct Context {
    pub aid: u32,
}

// ---- REAL CODE

pub trait Processor<State: Send + Sync, R: Future<Output=AxiomResult>>:
    (FnMut(&mut State, &Context, &Message) -> R) + Send + Sync
{
}

impl<F, R, State> Processor<State, R> for F
where
    State: Send + Sync + 'static,
    R: Future<Output=AxiomResult>,
    F: (FnMut(&mut State, &Context, &Message) -> R) + Send + Sync + 'static,
{
}

pub struct Handler<T, R: Future<Output=AxiomResult>> {
    state: T,
    processor: dyn Processor<T, R>,
}

impl<T, R: Future<Output=AxiomResult>> Handler<T, R> {
    pub async fn run(&mut self, context: &Context, message: &Message) -> R {
        (self.processor)(&mut self.state, context, message)
    }
}

// ---- Test

pub async fn do_it(_: &mut bool, _: &Context, _: &Message) -> AxiomResult {
    Ok("Done".to_string())
}