use http::HeaderMap;
use std::sync::Arc;

/// Adds authentication headers to API requests.
///
/// Implementations should be cheap and non-blocking; any asynchronous
/// refresh or I/O should be handled by higher layers before requests
/// reach this interface.
pub trait AuthProvider: Send + Sync {
    fn add_auth_headers(&self, headers: &mut HeaderMap);
}

/// Shared auth handle passed through API clients.
pub type SharedAuthProvider = Arc<dyn AuthProvider>;

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub struct AuthHeaderTelemetry {
    pub attached: bool,
    pub name: Option<&'static str>,
}

pub fn auth_header_telemetry(auth: &dyn AuthProvider) -> AuthHeaderTelemetry {
    let mut headers = HeaderMap::new();
    auth.add_auth_headers(&mut headers);
    let name = headers
        .contains_key(http::header::AUTHORIZATION)
        .then_some("authorization");
    AuthHeaderTelemetry {
        attached: name.is_some(),
        name,
    }
}