#![allow(dead_code)]

use std::thread;

use futures;
use futures::stream::Stream;
use futures::stream::StreamExt;
use std::pin::Pin;

/// Spawn a thread with a function which returns an iterator.
/// Resulting iterator elements will be emitted as Stream.
pub fn stream_thread_spawn_iter<I, F, E>(
    f: F,
) -> Pin<Box<dyn Stream<Item = Result<I::Item, E>> + Send>>
where
    I: Iterator,
    F: FnOnce() -> I,
    F: Send + 'static,
    E: Send + 'static,
    I::Item: Send + 'static,
{
    let (sender, receiver) = futures::channel::mpsc::unbounded();
    thread::spawn(move || {
        for item in f() {
            sender.unbounded_send(item).expect("send");
        }
    });

    let receiver = receiver.map(Ok);

    Box::pin(receiver)
}