//! Helper functions for the protocol.
use super::{Participant, ProtocolError, internal::SharedChannel};
use crate::participants::{ParticipantCounter, ParticipantList};

/// Gather exactly one message from each participant in a group before proceeding.
pub async fn recv_from_others<T>(
    chan: &SharedChannel,
    waitpoint: u64,
    participants: &ParticipantList,
    me: Participant,
) -> Result<Vec<(Participant, T)>, ProtocolError>
where
    T: serde::de::DeserializeOwned,
{
    let mut seen = ParticipantCounter::new(participants);
    seen.put(me);
    let mut messages = Vec::with_capacity(participants.others(me).count());

    while !seen.full() {
        let (from, msg) = chan.recv(waitpoint).await?;
        if seen.put(from) {
            messages.push((from, msg));
        }
    }

    Ok(messages)
}