use crate::std::fmt;

use crate::{builder, parser};

/// A general error that can occur when working with UUIDs.

// TODO: improve the doc

// BODY: This detail should be fine for initial merge

#[derive(Clone, Debug, Eq, Hash, PartialEq)]

pub struct Error(Inner);

// TODO: write tests for Error

// BODY: not immediately blocking, but should be covered for 1.0

#[derive(Clone, Debug, Eq, Hash, PartialEq)]

enum Inner {

    /// An error occurred while handling [`Uuid`] bytes.

    ///

    /// See [`BytesError`]

    ///

    /// [`BytesError`]: struct.BytesError.html

    /// [`Uuid`]: struct.Uuid.html

    Build(builder::Error),

    /// An error occurred while parsing a [`Uuid`] string.

    ///

    /// See [`parser::ParseError`]

    ///

    /// [`parser::ParseError`]: parser/enum.ParseError.html

    /// [`Uuid`]: struct.Uuid.html

    Parser(parser::Error),

}

impl From<builder::Error> for Error {

    fn from(err: builder::Error) -> Self {

        Error(Inner::Build(err))

    }

}

impl From<parser::Error> for Error {

    fn from(err: parser::Error) -> Self {

        Error(Inner::Parser(err))

    }

}

impl fmt::Display for Error {

    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

        match self.0 {

            Inner::Build(ref err) => fmt::Display::fmt(&err, f),

            Inner::Parser(ref err) => fmt::Display::fmt(&err, f),

        }

    }

}

#[cfg(feature = "std")]

mod std_support {

    use super::*;

    use crate::std::error;

    impl error::Error for Error {

        fn source(&self) -> Option<&(dyn error::Error + 'static)> {

            match self.0 {

                Inner::Build(ref err) => Some(err),

                Inner::Parser(ref err) => Some(err),

            }

        }

    }

}

#[cfg(test)]

mod test_util {

    use super::*;

    impl Error {

        pub(crate) fn expect_parser(self) -> parser::Error {

            match self.0 {

                Inner::Parser(err) => err,

                _ => panic!("expected a `parser::Error` variant"),

            }

        }

    }

}