use crate::{How, IntoContext};

pub trait Explain: Sized {
    type T;

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

    fn context(self, context: impl IntoContext) -> Result<Self::T, How> {
        self.explained()
            .context(context)
    }
}

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

    fn explained(self) -> Result<Self::T, How> {
        self.map_err(Into::into)
    }
}

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

    fn explained(self) -> Result<Self::T, How> {
        self
    }

    #[inline(always)]
    fn context(self, context: impl IntoContext) -> Result<Self::T, How> {
        self.map_err(|e| e.context(context))
    }
}