// Copyright 2015-2020 Benjamin Fry <benjaminfry@me.com>
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// https://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// https://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

use std::fmt;

use crate::proto::error::*;
use thiserror::Error;

#[cfg(feature = "backtrace")]
use crate::proto::{trace, ExtBacktrace};

/// An alias for results returned by functions of this crate
pub type Result<T> = ::std::result::Result<T, Error>;

/// The error kind for errors that get returned in the crate
#[derive(Debug, Error)]
#[non_exhaustive]
pub enum ErrorKind {
    /// An error that occurred when recovering from journal
    #[error("error recovering from journal: {}", _0)]
    Recovery(&'static str),

    /// The number of inserted records didn't match the expected amount
    #[error("wrong insert count: {} expect: {}", got, expect)]
    WrongInsertCount {
        /// The number of inserted records
        got: usize,
        /// The number of records expected to be inserted
        expect: usize,
    },

    // foreign
    /// An error got returned by the hickory-proto crate
    #[error("proto error: {0}")]
    Proto(#[from] ProtoError),

    /// An error got returned from the sqlite crate
    #[cfg(feature = "sqlite")]
    #[cfg_attr(docsrs, doc(cfg(feature = "sqlite")))]
    #[error("sqlite error: {0}")]
    Sqlite(#[from] rusqlite::Error),

    /// A request timed out
    #[error("request timed out")]
    Timeout,
}

/// The error type for errors that get returned in the crate
#[derive(Debug, Error)]
pub struct Error {
    kind: ErrorKind,
    #[cfg(feature = "backtrace")]
    backtrack: Option<ExtBacktrace>,
}

impl Error {
    /// Get the kind of the error
    pub fn kind(&self) -> &ErrorKind {
        &self.kind
    }
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        cfg_if::cfg_if! {
            if #[cfg(feature = "backtrace")] {
                if let Some(ref backtrace) = self.backtrack {
                    fmt::Display::fmt(&self.kind, f)?;
                    fmt::Debug::fmt(backtrace, f)
                } else {
                    fmt::Display::fmt(&self.kind, f)
                }
            } else {
                fmt::Display::fmt(&self.kind, f)
            }
        }
    }
}

impl From<ErrorKind> for Error {
    fn from(kind: ErrorKind) -> Self {
        Self {
            kind,
            #[cfg(feature = "backtrace")]
            backtrack: trace!(),
        }
    }
}

impl From<ProtoError> for Error {
    fn from(e: ProtoError) -> Self {
        match *e.kind() {
            ProtoErrorKind::Timeout => ErrorKind::Timeout.into(),
            _ => ErrorKind::from(e).into(),
        }
    }
}

#[cfg(feature = "sqlite")]
#[cfg_attr(docsrs, doc(cfg(feature = "sqlite")))]
impl From<rusqlite::Error> for Error {
    fn from(e: rusqlite::Error) -> Self {
        ErrorKind::from(e).into()
    }
}
