use crate::How;

mod private {
    use crate::How;

    #[doc(hidden)]
    pub trait IntoResultHow: Sized {
        type T;

        fn into_result_how(self) -> Result<Self::T, How>;
    }
}

pub(crate) use private::IntoResultHow;

impl<T, E> IntoResultHow for Result<T, E>
where
    E: std::error::Error,
{
    type T = T;

    #[inline(always)]
    fn into_result_how(self) -> Result<Self::T, How> {
        #[inline(never)]
        fn into<E: std::error::Error>(e: E) -> How {
            How::new(e.to_string())
        }
        self.map_err(into)
    }
}

impl<T> IntoResultHow for Result<T, How> {
    type T = T;

    #[inline(always)]
    fn into_result_how(self) -> Result<Self::T, How> {
        self
    }
}

impl<T> IntoResultHow for Option<T> {
    type T = T;

    #[inline(always)]
    fn into_result_how(self) -> Result<Self::T, How> {
        #[inline(never)]
        fn into() -> How {
            How::new("Option::None")
        }
        self.ok_or_else(into)
    }
}