use hyper::Request;

/// Extract the effective request host for routing and scoped ACL checks.
///
/// Prefer the explicit `Host` header when present, otherwise fall back to the
/// URI authority used by HTTP/2 and HTTP/3 requests.
pub(crate) fn extract_request_host<B>(req: &Request<B>) -> Option<&str> {
    req.headers()
        .get("host")
        .and_then(|value| value.to_str().ok())
        .map(|host| host.split(':').next().unwrap_or(host))
        .or_else(|| req.uri().host())
}

#[cfg(test)]
mod tests {
    use bytes::Bytes;
    use http_body_util::Empty;
    use hyper::Request;

    use super::extract_request_host;

    #[test]
    fn extracts_host_header_before_uri_authority() {
        let req = Request::builder()
            .uri("https://uri.abc.xyz/test")
            .header("host", "header.abc.xyz:443")
            .body(Empty::<Bytes>::new())
            .unwrap();

        assert_eq!(extract_request_host(&req), Some("header.abc.xyz"));
    }

    #[test]
    fn falls_back_to_uri_authority_when_host_header_missing() {
        let req = Request::builder()
            .uri("https://outline.abc.xyz/test")
            .body(Empty::<Bytes>::new())
            .unwrap();

        assert_eq!(extract_request_host(&req), Some("outline.abc.xyz"));
    }
}