use futures::{future::{self, FutureResult}, prelude::*};
use holly::{Error, prelude::*};
use tokio_threadpool::ThreadPool;
use void::Void;

// Calculator messages.
enum Message {
    // Add some amount.
    Add(usize),
    // Tell the given actor the total sum.
    Sum(Addr<usize>)
}

// Calculating actor.
struct Calculator(usize);

impl Actor<Message, Error> for Calculator {
    type Result = Box<dyn Future<Item = State<Self, Message>, Error = Error> + Send>;

    fn process(mut self, _ctx: &mut Context<Message>, msg: Option<Message>) -> Self::Result {
        match msg {
            Some(Message::Add(n)) => {
                self.0 += n;
                Box::new(future::ok(State::Ready(self)))
            }
            Some(Message::Sum(a)) => {
                Box::new(a.send(self.0).map(|_| State::Done))
            }
            None => Box::new(future::ok(State::Done))
        }
    }
}

// Printing actor.
struct Printer;

impl Actor<usize, Void> for Printer {
    type Result = FutureResult<State<Self, usize>, Void>;

    fn process(self, _ctx: &mut Context<usize>, msg: Option<usize>) -> Self::Result {
        match msg {
            Some(n) => {
                println!("result = {}", n);
                future::ok(State::Done)
            }
            None => future::ok(State::Done)
        }
    }
}

#[test]
fn sum() -> Result<(), Error> {
    let pool = ThreadPool::new();
    let exec = Scheduler::new(pool.sender().clone());
    let mut calc = exec.spawn(Calculator(0))?;
    let printer = exec.spawn(Printer)?;
    for i in 0 .. 500 {
        calc.send_now(Message::Add(i))?
    }
    calc.send_now(Message::Sum(printer))?;
    pool.shutdown_on_idle().wait().unwrap();
    Ok(())
}