casper-node 2.0.3

use std::fmt::Debug;

use crate::components::consensus::{
    protocols::zug::{Fault, RoundId, Zug},
    traits::Context,
    utils::ValidatorIndex,
};

/// A map of status (faulty, inactive) by validator ID.
#[derive(Debug)]
// False positive, as the fields of this struct are all used in logging validator participation.
#[allow(dead_code)]
pub(super) struct Participation<C>
where
    C: Context,
{
    pub(super) instance_id: C::InstanceId,
    pub(super) faulty_stake_percent: u8,
    pub(super) inactive_stake_percent: u8,
    pub(super) inactive_validators: Vec<(ValidatorIndex, C::ValidatorId, ParticipationStatus)>,
    pub(super) faulty_validators: Vec<(ValidatorIndex, C::ValidatorId, ParticipationStatus)>,
}

/// A validator's participation status: whether they are faulty or inactive.
#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
pub(super) enum ParticipationStatus {
    LastSeenInRound(RoundId),
    Inactive,
    EquivocatedInOtherEra,
    Equivocated,
}

impl ParticipationStatus {
    /// Returns a `Status` for a validator unless they are honest and online.
    pub(super) fn for_index<C: Context + 'static>(
        idx: ValidatorIndex,
        zug: &Zug<C>,
    ) -> Option<ParticipationStatus> {
        if let Some(fault) = zug.faults.get(&idx) {
            return Some(match fault {
                Fault::Banned | Fault::Indirect => ParticipationStatus::EquivocatedInOtherEra,
                Fault::Direct(..) => ParticipationStatus::Equivocated,
            });
        }

        let last_seen_round = zug
            .active
            .get(idx)
            .and_then(Option::as_ref)
            .map(|signed_msg| signed_msg.round_id);
        match last_seen_round {
            // not seen at all
            None => Some(ParticipationStatus::Inactive),
            // seen, but not within last 2 rounds
            Some(r_id) if r_id.saturating_add(2) < zug.current_round => {
                Some(ParticipationStatus::LastSeenInRound(r_id))
            }
            // seen recently
            _ => None,
        }
    }
}