chatty-catties/nebkor-maelstrom/src/protocol.rs

use serde::{Deserialize, Serialize};
use serde_json::{Map, Value};
use serde_repr::{Deserialize_repr, Serialize_repr};

pub type Payload = Map<String, Value>;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Message {
    pub src: String,
    pub dest: String,
    pub body: Body,
}

#[derive(Debug, Default, Clone, Serialize, Deserialize)]
pub struct Body {
    #[serde(rename = "type")]
    pub typ: String,
    #[serde(default, skip_serializing_if = "u64_zero_by_ref")]
    pub msg_id: u64,
    #[serde(default, skip_serializing_if = "u64_zero_by_ref")]
    pub in_reply_to: u64,
    #[serde(flatten)]
    pub payload: Payload,
}

impl Body {
    pub fn from_type(typ: &str) -> Self {
        Body {
            typ: typ.to_string(),
            ..Default::default()
        }
    }

    pub fn with_msg_id(self, msg_id: u64) -> Self {
        let mut b = self;
        b.msg_id = msg_id;
        b
    }

    pub fn with_in_reply_to(self, in_reply_to: u64) -> Self {
        let mut b = self;
        b.in_reply_to = in_reply_to;
        b
    }

    pub fn with_payload(self, payload: Payload) -> Self {
        let mut b = self;
        b.payload = payload;
        b
    }
}

pub fn init_ok(msg_id: u64, in_reply_to: u64) -> Body {
    Body::from_type("init_ok")
        .with_msg_id(msg_id)
        .with_in_reply_to(in_reply_to)
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(untagged)]
pub enum ErrorCode {
    Definite(DefiniteError),
    Indefinite(IndefiniteError),
}

#[derive(Debug, Clone, Serialize_repr, Deserialize_repr)]
#[repr(u64)]
pub enum DefiniteError {
    NodeNotFound = 2,
    NotSupported = 10,
    TemporarilyUnavailable = 11,
    MalformedRequest = 12,
    Abort = 14,
    KeyNotFound = 20,
    KeyAlreadyExists = 21,
    PreconditionFailed = 22,
    TxnConflict = 30,
}

#[derive(Debug, Clone, Serialize_repr, Deserialize_repr)]
#[repr(u64)]
pub enum IndefiniteError {
    Timeout = 0,
    Crash = 13,
}

pub fn error(msg_id: u64, in_reply_to: u64, code: ErrorCode, text: Option<&str>) -> Body {
    Body {
        typ: "error".to_string(),
        msg_id,
        in_reply_to,
        payload: [
            ("code".to_string(), serde_json::to_value(code).unwrap()),
            ("text".to_string(), serde_json::to_value(text).unwrap()),
        ]
        .into_iter()
        .collect(),
    }
}

#[allow(clippy::trivially_copy_pass_by_ref)]
fn u64_zero_by_ref(num: &u64) -> bool {
    *num == 0
}

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

    #[test]
    fn error_codes() {
        let ec = ErrorCode::Definite(DefiniteError::Abort);
        let e = serde_json::to_string(&ec).unwrap();
        assert_eq!(&e, "14");
    }
}