use pom::types::HealthStatus;

#[derive(Debug, PartialEq, Eq)]
pub(crate) enum IncidentAction {
    None,
    Open,
    Close,
    CloseAndOpen,
}

pub(crate) fn incident_action(prev: HealthStatus, curr: HealthStatus) -> IncidentAction {
    if prev == curr {
        return IncidentAction::None;
    }
    let prev_op = prev == HealthStatus::Operational;
    let curr_op = curr == HealthStatus::Operational;
    match (prev_op, curr_op) {
        (true, false) => IncidentAction::Open,
        (false, true) => IncidentAction::Close,
        (false, false) => IncidentAction::CloseAndOpen,
        (true, true) => IncidentAction::None,
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn incident_operational_to_error_opens() {
        assert_eq!(
            incident_action(HealthStatus::Operational, HealthStatus::Error),
            IncidentAction::Open,
        );
    }

    #[test]
    fn incident_operational_to_degraded_opens() {
        assert_eq!(
            incident_action(HealthStatus::Operational, HealthStatus::Degraded),
            IncidentAction::Open,
        );
    }

    #[test]
    fn incident_error_to_operational_closes() {
        assert_eq!(
            incident_action(HealthStatus::Error, HealthStatus::Operational),
            IncidentAction::Close,
        );
    }

    #[test]
    fn incident_degraded_to_operational_closes() {
        assert_eq!(
            incident_action(HealthStatus::Degraded, HealthStatus::Operational),
            IncidentAction::Close,
        );
    }

    #[test]
    fn incident_degraded_to_error_closes_and_opens() {
        assert_eq!(
            incident_action(HealthStatus::Degraded, HealthStatus::Error),
            IncidentAction::CloseAndOpen,
        );
    }

    #[test]
    fn incident_error_to_degraded_closes_and_opens() {
        assert_eq!(
            incident_action(HealthStatus::Error, HealthStatus::Degraded),
            IncidentAction::CloseAndOpen,
        );
    }

    #[test]
    fn incident_operational_to_operational_none() {
        assert_eq!(
            incident_action(HealthStatus::Operational, HealthStatus::Operational),
            IncidentAction::None,
        );
    }

    #[test]
    fn incident_error_to_error_none() {
        assert_eq!(
            incident_action(HealthStatus::Error, HealthStatus::Error),
            IncidentAction::None,
        );
    }
}