use std::io;

use derive_more::Display;
use serde::{Deserialize, Serialize};

/// General purpose error type that can be sent across the wire
#[derive(Clone, Debug, Display, PartialEq, Eq, Serialize, Deserialize)]
#[display(fmt = "{kind}: {description}")]
#[serde(rename_all = "snake_case", deny_unknown_fields)]
pub struct Error {
    /// Label describing the kind of error
    pub kind: ErrorKind,

    /// Description of the error itself
    pub description: String,
}

impl std::error::Error for Error {}

impl Error {
    /// Produces an [`io::Error`] from this error.
    pub fn to_io_error(&self) -> io::Error {
        io::Error::new(self.kind.into(), self.description.to_string())
    }
}

impl<'a> From<&'a str> for Error {
    fn from(x: &'a str) -> Self {
        Self::from(x.to_string())
    }
}

impl From<String> for Error {
    fn from(x: String) -> Self {
        Self {
            kind: ErrorKind::Other,
            description: x,
        }
    }
}

impl From<io::Error> for Error {
    fn from(x: io::Error) -> Self {
        Self {
            kind: ErrorKind::from(x.kind()),
            description: x.to_string(),
        }
    }
}

impl From<Error> for io::Error {
    fn from(x: Error) -> Self {
        Self::new(x.kind.into(), x.description)
    }
}

/// All possible kinds of errors that can be returned
#[derive(Copy, Clone, Debug, Display, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case", deny_unknown_fields)]
pub enum ErrorKind {
    /// An entity was not found, often a file
    NotFound,

    /// The operation lacked the necessary privileges to complete
    PermissionDenied,

    /// The connection was refused by the remote server
    ConnectionRefused,

    /// The connection was reset by the remote server
    ConnectionReset,

    /// The connection was aborted (terminated) by the remote server
    ConnectionAborted,

    /// The network operation failed because it was not connected yet
    NotConnected,

    /// A socket address could not be bound because the address is already in use elsewhere
    AddrInUse,

    /// A nonexistent interface was requested or the requested address was not local
    AddrNotAvailable,

    /// The operation failed because a pipe was closed
    BrokenPipe,

    /// An entity already exists, often a file
    AlreadyExists,

    /// The operation needs to block to complete, but the blocking operation was requested to not
    /// occur
    WouldBlock,

    /// A parameter was incorrect
    InvalidInput,

    /// Data not valid for the operation were encountered
    InvalidData,

    /// The I/O operation's timeout expired, causing it to be cancelled
    TimedOut,

    /// An error returned when an operation could not be completed because a
    /// call to `write` returned `Ok(0)`
    WriteZero,

    /// This operation was interrupted
    Interrupted,

    /// Any I/O error not part of this list
    Other,

    /// An error returned when an operation could not be completed because an "end of file" was
    /// reached prematurely
    UnexpectedEof,

    /// This operation is unsupported on this platform
    Unsupported,

    /// An operation could not be completed, because it failed to allocate enough memory
    OutOfMemory,

    /// When a loop is encountered when walking a directory
    Loop,

    /// When a task is cancelled
    TaskCancelled,

    /// When a task panics
    TaskPanicked,

    /// Catchall for an error that has no specific type
    Unknown,
}

impl From<io::ErrorKind> for ErrorKind {
    fn from(kind: io::ErrorKind) -> Self {
        match kind {
            io::ErrorKind::NotFound => Self::NotFound,
            io::ErrorKind::PermissionDenied => Self::PermissionDenied,
            io::ErrorKind::ConnectionRefused => Self::ConnectionRefused,
            io::ErrorKind::ConnectionReset => Self::ConnectionReset,
            io::ErrorKind::ConnectionAborted => Self::ConnectionAborted,
            io::ErrorKind::NotConnected => Self::NotConnected,
            io::ErrorKind::AddrInUse => Self::AddrInUse,
            io::ErrorKind::AddrNotAvailable => Self::AddrNotAvailable,
            io::ErrorKind::BrokenPipe => Self::BrokenPipe,
            io::ErrorKind::AlreadyExists => Self::AlreadyExists,
            io::ErrorKind::WouldBlock => Self::WouldBlock,
            io::ErrorKind::InvalidInput => Self::InvalidInput,
            io::ErrorKind::InvalidData => Self::InvalidData,
            io::ErrorKind::TimedOut => Self::TimedOut,
            io::ErrorKind::WriteZero => Self::WriteZero,
            io::ErrorKind::Interrupted => Self::Interrupted,
            io::ErrorKind::Other => Self::Other,
            io::ErrorKind::OutOfMemory => Self::OutOfMemory,
            io::ErrorKind::UnexpectedEof => Self::UnexpectedEof,
            io::ErrorKind::Unsupported => Self::Unsupported,

            // This exists because io::ErrorKind is non_exhaustive
            _ => Self::Unknown,
        }
    }
}

impl From<ErrorKind> for io::ErrorKind {
    fn from(kind: ErrorKind) -> Self {
        match kind {
            ErrorKind::NotFound => Self::NotFound,
            ErrorKind::PermissionDenied => Self::PermissionDenied,
            ErrorKind::ConnectionRefused => Self::ConnectionRefused,
            ErrorKind::ConnectionReset => Self::ConnectionReset,
            ErrorKind::ConnectionAborted => Self::ConnectionAborted,
            ErrorKind::NotConnected => Self::NotConnected,
            ErrorKind::AddrInUse => Self::AddrInUse,
            ErrorKind::AddrNotAvailable => Self::AddrNotAvailable,
            ErrorKind::BrokenPipe => Self::BrokenPipe,
            ErrorKind::AlreadyExists => Self::AlreadyExists,
            ErrorKind::WouldBlock => Self::WouldBlock,
            ErrorKind::InvalidInput => Self::InvalidInput,
            ErrorKind::InvalidData => Self::InvalidData,
            ErrorKind::TimedOut => Self::TimedOut,
            ErrorKind::WriteZero => Self::WriteZero,
            ErrorKind::Interrupted => Self::Interrupted,
            ErrorKind::Other => Self::Other,
            ErrorKind::OutOfMemory => Self::OutOfMemory,
            ErrorKind::UnexpectedEof => Self::UnexpectedEof,
            ErrorKind::Unsupported => Self::Unsupported,
            _ => Self::Other,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    mod error {
        use super::*;

        #[test]
        fn should_be_able_to_serialize_to_json() {
            let error = Error {
                kind: ErrorKind::AddrInUse,
                description: "some description".to_string(),
            };

            let value = serde_json::to_value(error).unwrap();
            assert_eq!(
                value,
                serde_json::json!({
                    "kind": "addr_in_use",
                    "description": "some description",
                })
            );
        }

        #[test]
        fn should_be_able_to_deserialize_from_json() {
            let value = serde_json::json!({
                "kind": "addr_in_use",
                "description": "some description",
            });

            let error: Error = serde_json::from_value(value).unwrap();
            assert_eq!(
                error,
                Error {
                    kind: ErrorKind::AddrInUse,
                    description: "some description".to_string(),
                }
            );
        }

        #[test]
        fn should_be_able_to_serialize_to_msgpack() {
            let error = Error {
                kind: ErrorKind::AddrInUse,
                description: "some description".to_string(),
            };

            // NOTE: We don't actually check the output here because it's an implementation detail
            // and could change as we change how serialization is done. This is merely to verify
            // that we can serialize since there are times when serde fails to serialize at
            // runtime.
            let _ = rmp_serde::encode::to_vec_named(&error).unwrap();
        }

        #[test]
        fn should_be_able_to_deserialize_from_msgpack() {
            // NOTE: It may seem odd that we are serializing just to deserialize, but this is to
            // verify that we are not corrupting or preventing issues when serializing on a
            // client/server and then trying to deserialize on the other side. This has happened
            // enough times with minor changes that we need tests to verify.
            let buf = rmp_serde::encode::to_vec_named(&Error {
                kind: ErrorKind::AddrInUse,
                description: "some description".to_string(),
            })
            .unwrap();

            let error: Error = rmp_serde::decode::from_slice(&buf).unwrap();
            assert_eq!(
                error,
                Error {
                    kind: ErrorKind::AddrInUse,
                    description: "some description".to_string(),
                }
            );
        }
    }

    mod error_kind {
        use super::*;

        #[test]
        fn should_be_able_to_serialize_to_json() {
            let kind = ErrorKind::AddrInUse;

            let value = serde_json::to_value(kind).unwrap();
            assert_eq!(value, serde_json::json!("addr_in_use"));
        }

        #[test]
        fn should_be_able_to_deserialize_from_json() {
            let value = serde_json::json!("addr_in_use");

            let kind: ErrorKind = serde_json::from_value(value).unwrap();
            assert_eq!(kind, ErrorKind::AddrInUse);
        }

        #[test]
        fn should_be_able_to_serialize_to_msgpack() {
            let kind = ErrorKind::AddrInUse;

            // NOTE: We don't actually check the output here because it's an implementation detail
            // and could change as we change how serialization is done. This is merely to verify
            // that we can serialize since there are times when serde fails to serialize at
            // runtime.
            let _ = rmp_serde::encode::to_vec_named(&kind).unwrap();
        }

        #[test]
        fn should_be_able_to_deserialize_from_msgpack() {
            // NOTE: It may seem odd that we are serializing just to deserialize, but this is to
            // verify that we are not corrupting or causing issues when serializing on a
            // client/server and then trying to deserialize on the other side. This has happened
            // enough times with minor changes that we need tests to verify.
            let buf = rmp_serde::encode::to_vec_named(&ErrorKind::AddrInUse).unwrap();

            let kind: ErrorKind = rmp_serde::decode::from_slice(&buf).unwrap();
            assert_eq!(kind, ErrorKind::AddrInUse);
        }
    }
}