// file: ks-store/src/contracts/health.rs
// version: 3

//! Backend-neutral health contracts for storage implementations.

/// Store backend health status.
#[derive(Clone, Copy, Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
pub enum StoreHealthStatus {
    /// Health is not known yet.
    Unknown,
    /// Backend is reachable and usable.
    Healthy,
    /// Backend is reachable but not fully usable.
    Degraded,
    /// Backend is not usable.
    Unhealthy,
}

/// Store backend health snapshot.
#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
pub struct StoreHealthSnapshot {
    /// Stable backend code such as `postgres` or `sqlite`.
    pub backend: std::string::String,
    /// Current health status.
    pub status: crate::StoreHealthStatus,
    /// Optional human-readable diagnostic message.
    pub message: std::option::Option<std::string::String>,
}

impl crate::StoreHealthSnapshot {
    /// Builds a store health snapshot after minimal validation.
    pub fn new(
        backend: impl std::convert::Into<std::string::String>,
        status: crate::StoreHealthStatus,
        message: std::option::Option<std::string::String>,
    ) -> ks_core::Result<Self> {
        let backend_value = backend.into();
        if backend_value.trim().is_empty() {
            return std::result::Result::Err(ks_core::Error::db(
                "store health backend must not be empty",
            ));
        }
        return std::result::Result::Ok(Self { backend: backend_value, status, message });
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn health_snapshot_rejects_empty_backend() {
        let result = crate::StoreHealthSnapshot::new(
            " ",
            crate::StoreHealthStatus::Unknown,
            std::option::Option::None,
        );
        assert!(result.is_err());
    }
}