use async_trait::async_trait;
use std::future::Future;
use tokio::task::JoinError;

#[async_trait]
pub trait ParSpawnAndAwait {
    type Awaited;

    async fn par_spawn_and_await(self) -> Result<Self::Awaited, JoinError>;
}

#[async_trait]
impl<F, R> ParSpawnAndAwait for Vec<F>
where
    R: Send + 'static,
    F: Future<Output = R> + Send + 'static,
{
    type Awaited = Vec<R>;

    async fn par_spawn_and_await(self) -> Result<Self::Awaited, JoinError> {
        let handles: Vec<_> = self.into_iter().map(|f| tokio::spawn(f)).collect();

        let mut results = Vec::new();
        for handle in handles {
            results.push(handle.await?);
        }

        Ok(results)
    }
}