use std::{
    error::Error,
    fmt::{Debug, Display, Formatter},
};

#[derive(Debug)]
pub struct ErrorWithSuggestion<E, S> {
    error: E,
    suggestion: S,
}

impl<E: Display, S: Display> Display for ErrorWithSuggestion<E, S> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        self.error.fmt(f)?;
        writeln!(f)?;

        write!(f, "💡 ")?;
        self.suggestion.fmt(f)?;

        Ok(())
    }
}

impl<E: Error, S: Debug + Display> Error for ErrorWithSuggestion<E, S> {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        self.error.source()
    }
}

pub trait ResultExt {
    type O;
    type E;

    fn with_suggestion<Suggestion: Display>(
        self,
        suggestion: Suggestion,
    ) -> Result<Self::O, ErrorWithSuggestion<Self::E, Suggestion>>;
}

impl<Ok, Err> ResultExt for Result<Ok, Err> {
    type O = Ok;
    type E = Err;

    fn with_suggestion<Suggestion: Display>(
        self,
        suggestion: Suggestion,
    ) -> Result<Self::O, ErrorWithSuggestion<Self::E, Suggestion>> {
        self.map_err(|error| ErrorWithSuggestion { error, suggestion })
    }
}