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use crate::{Handler, Result};

/// Represents a middleware parameter, which is a tuple that includes Requset and `BoxHandler`.
pub type Next<I, H> = (I, H);

/// Wraps around the remaining handler or middleware chain.
#[derive(Debug, Clone)]
pub struct Around<H, F> {
    h: H,
    f: F,
}

impl<H, F> Around<H, F> {
    /// Creates an [`Around`] handler.
    #[inline]
    pub fn new(h: H, f: F) -> Self {
        Self { h, f }
    }
}

#[crate::async_trait]
impl<H, F, I, O> Handler<I> for Around<H, F>
where
    I: Send + 'static,
    H: Handler<I, Output = Result<O>> + Clone,
    F: Handler<Next<I, H>, Output = H::Output>,
{
    type Output = F::Output;

    async fn call(&self, i: I) -> Self::Output {
        self.f.call((i, self.h.clone())).await
    }
}