//! Error-related functionality for RPC functions.

use std::collections::HashMap;

/// Alias for a type-erased value used in an error's `data` field

type ErrorDatum = Box<dyn erased_serde::Serialize + Send + 'static>;

/// An error type returned by failing RPC methods.

#[derive(serde::Serialize)]

pub struct RpcError {

    /// A human-readable message.

    message: String,

    /// An error code inspired by json-rpc.

    #[serde(serialize_with = "ser_code")]

    code: RpcErrorKind,

    /// The ErrorKind(s) of this error.

    #[serde(serialize_with = "ser_kind")]

    kinds: AnyErrorKind,

    /// Map from namespaced keyword to related data.

    #[serde(skip_serializing_if = "Option::is_none")]

    data: Option<HashMap<String, ErrorDatum>>,

}

impl RpcError {

    /// Construct a new `RpcError` with the provided message and error code.

    /// Change the declared kind of this error to `kind`.

    /// Replace the `data` field named `keyword`, if any, with the object `datum`.

    ///

    /// Note that to conform with the spec, keyword must be a C identifier prefixed with a

    /// namespace, as in `rpc:missing_features`

    /// Return true if this is an internal error.

            AnyErrorKind::Tor(tor_error::ErrorKind::Internal)

                | AnyErrorKind::Rpc(RpcErrorKind::InternalError)

        )

}

impl<T> From<T> for RpcError

where

    T: std::error::Error + tor_error::HasKind + Send + 'static,

{

        use tor_error::ErrorReport as _;

}

/// Helper: Serialize an AnyErrorKind in RpcError.

    // Our spec says that `kinds` is a list.  Any tor_error::ErrorKind is prefixed with `arti:`,

    // and any RpcErrorKind is prefixed with `rpc:`

    use serde::ser::SerializeSeq;

    }

/// Helper: Serialize an RpcErrorKind as a numeric code.

/// An ErrorKind as held by an `RpcError`

#[derive(Clone, Copy, Debug)]

enum AnyErrorKind {

    /// An ErrorKind representing a non-RPC problem.

    Tor(tor_error::ErrorKind),

    /// An ErrorKind originating within the RPC system.

    #[allow(unused)]

    Rpc(RpcErrorKind),

}

/// Error kinds for RPC errors.

///

/// Unlike `tor_error::ErrorKind`,

/// these codes do not represent a problem in an Arti function per se:

/// they are only visible to the RPC system, and should only be reported there.

///

/// For backward compatibility with json-rpc,

/// each of these codes has a unique numeric ID.

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

#[repr(i32)]

#[non_exhaustive]

pub enum RpcErrorKind {

    /// "The JSON sent is not a valid Request object."

    InvalidRequest = -32600,

    /// "The method does not exist."

    NoSuchMethod = -32601,

    /// "Invalid method parameter(s)."

    InvalidMethodParameters = -32602,

    /// "The server suffered some kind of internal problem"

    InternalError = -32603,

    /// "Some requested object was not valid"

    ObjectNotFound = 1,

    /// "Some other error occurred"

    RequestError = 2,

    /// This method exists, but wasn't implemented on this object.

    MethodNotImpl = 3,

    /// This request was cancelled before it could finish.

    RequestCancelled = 4,

    /// This request listed a required feature that doesn't exist.

    FeatureNotPresent = 5,

}

/// Helper: Return an error code (for backward compat with json-rpc) for an

/// ErrorKind.

///

/// These are not especially helpful and nobody should really use them.

    use tor_error::ErrorKind as EK;

    use RpcErrorKind as RC;

    }

impl std::fmt::Debug for RpcError {

}

#[cfg(test)]

mod test {

    // @@ begin test lint list maintained by maint/add_warning @@

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_duration_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->

    use super::*;

    #[derive(Debug, thiserror::Error, serde::Serialize)]

    enum ExampleError {

        #[error("The {} exploded because {}", what, why)]

        SomethingExploded { what: String, why: String },

        #[error("I'm hiding the {0} in my {1}")]

        SomethingWasHidden(String, String),

        #[error("The {0} was missing")]

        SomethingWasMissing(String),

        #[error("I don't feel up to it today")]

        ProgramUnwilling,

    }

    impl tor_error::HasKind for ExampleError {

        fn kind(&self) -> tor_error::ErrorKind {

            match self {

                Self::SomethingExploded { .. } => tor_error::ErrorKind::Other,

                Self::SomethingWasHidden(_, _) => tor_error::ErrorKind::RemoteHostNotFound,

                Self::SomethingWasMissing(_) => tor_error::ErrorKind::FeatureDisabled,

                Self::ProgramUnwilling => tor_error::ErrorKind::Internal,

            }

        }

    }

    /// Assert that two json strings deserialize to equivalent objects.

    macro_rules! assert_json_eq {

        ($a:expr, $b:expr) => {

            let json_a: serde_json::Value = serde_json::from_str($a).unwrap();

            let json_b: serde_json::Value = serde_json::from_str($b).unwrap();

            assert_eq!(json_a, json_b);

        };

    }

    #[test]

    fn serialize_error() {

        let err = ExampleError::SomethingExploded {

            what: "previous implementation".into(),

            why: "worse things happen at C".into(),

        };

        let err = RpcError::from(err);

        assert_eq!(err.code, RpcErrorKind::RequestError);

        let serialized = serde_json::to_string(&err).unwrap();

        let expected_json = r#"

          {

            "message": "error: The previous implementation exploded because worse things happen at C",

            "code": 2,

            "kinds": ["arti:Other"]

         }

        "#;

        assert_json_eq!(&serialized, expected_json);

        let err = ExampleError::SomethingWasHidden(

            "zircon-encrusted tweezers".into(),

            "chrome dinette".into(),

        );

        let err = RpcError::from(err);

        let serialized = serde_json::to_string(&err).unwrap();

        let expected = r#"

        {

            "message": "error: I'm hiding the zircon-encrusted tweezers in my chrome dinette",

            "code": 2,

            "kinds": ["arti:RemoteHostNotFound"]

         }

        "#;

        assert_json_eq!(&serialized, expected);

        let err = ExampleError::SomethingWasMissing("turbo-encabulator".into());

        let err = RpcError::from(err);

        let serialized = serde_json::to_string(&err).unwrap();

        let expected = r#"

        {

            "message": "error: The turbo-encabulator was missing",

            "code": 2,

            "kinds": ["arti:FeatureDisabled"]

         }

        "#;

        assert_json_eq!(&serialized, expected);

        let err = ExampleError::ProgramUnwilling;

        let err = RpcError::from(err);

        let serialized = serde_json::to_string(&err).unwrap();

        let expected = r#"

        {

            "message": "error: I don't feel up to it today",

            "code": -32603,

            "kinds": ["arti:Internal"]

         }

        "#;

        assert_json_eq!(&serialized, expected);

    }

    #[test]

    fn create_error() {

        let mut e = RpcError::new("Example error".to_string(), RpcErrorKind::RequestError);

        e.set_kind(tor_error::ErrorKind::CacheCorrupted);

        e.set_datum("rpc:example".to_string(), "Hello world".to_string())

            .unwrap();

        let serialized = serde_json::to_string(&e).unwrap();

        let expected = r#"

        {

            "message": "Example error",

            "code": 2,

            "kinds": ["arti:CacheCorrupted"],

            "data": {

                "rpc:example": "Hello world"

            }

        }

        "#;

        assert_json_eq!(&serialized, expected);

    }

}