use std::future::Future;

use tokio::task_local;

task_local! {
    static REQUEST_ID: String;
}

pub async fn with_request_id<F, S>(request_id: Option<S>, future: F) -> F::Output
where
    F: Future,
    S: AsRef<str>,
{
    match request_id {
        Some(request_id) => {
            REQUEST_ID
                .scope(request_id.as_ref().to_owned(), future)
                .await
        }
        None => future.await,
    }
}

pub fn request_id() -> Option<String> {
    REQUEST_ID.try_with(Clone::clone).ok()
}

/// Prefers an explicitly passed id, then the id of the current request scope.
pub fn resolve_request_id(explicit: Option<&str>) -> String {
    explicit
        .filter(|value| !value.is_empty())
        .map(str::to_owned)
        .or_else(request_id)
        .unwrap_or_default()
}