1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168

use crate::{Operation, TopicName};
use bytes::{BufMut, Bytes, BytesMut};
use selium_std::errors::{ProtocolError, Result, SeliumError};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

type Headers = Option<HashMap<String, String>>;

const REGISTER_PUBLISHER: u8 = 0x0;
const REGISTER_SUBSCRIBER: u8 = 0x1;
const REGISTER_REPLIER: u8 = 0x2;
const REGISTER_REQUESTOR: u8 = 0x3;
const MESSAGE: u8 = 0x4;
const BATCH_MESSAGE: u8 = 0x5;
const ERROR: u8 = 0x6;
const OK: u8 = 0x7;

#[derive(Clone, Debug, PartialEq)]
pub enum Frame {
    RegisterPublisher(PublisherPayload),
    RegisterSubscriber(SubscriberPayload),
    RegisterReplier(ReplierPayload),
    RegisterRequestor(RequestorPayload),
    Message(MessagePayload),
    BatchMessage(Bytes),
    Error(Bytes),
    Ok,
}

impl Frame {
    pub fn get_length(&self) -> Result<u64> {
        Ok(match self {
            Self::RegisterPublisher(payload) => {
                bincode::serialized_size(payload).map_err(ProtocolError::SerdeError)?
            }
            Self::RegisterSubscriber(payload) => {
                bincode::serialized_size(payload).map_err(ProtocolError::SerdeError)?
            }
            Self::RegisterReplier(payload) => {
                bincode::serialized_size(payload).map_err(ProtocolError::SerdeError)?
            }
            Self::RegisterRequestor(payload) => {
                bincode::serialized_size(payload).map_err(ProtocolError::SerdeError)?
            }
            Self::Message(payload) => {
                bincode::serialized_size(payload).map_err(ProtocolError::SerdeError)?
            }
            Self::BatchMessage(bytes) => bytes.len() as u64,
            Self::Error(bytes) => bytes.len() as u64,
            Self::Ok => 0,
        })
    }

    pub fn get_type(&self) -> u8 {
        match self {
            Self::RegisterPublisher(_) => REGISTER_PUBLISHER,
            Self::RegisterSubscriber(_) => REGISTER_SUBSCRIBER,
            Self::RegisterReplier(_) => REGISTER_REPLIER,
            Self::RegisterRequestor(_) => REGISTER_REQUESTOR,
            Self::Message(_) => MESSAGE,
            Self::BatchMessage(_) => BATCH_MESSAGE,
            Self::Error(_) => ERROR,
            Self::Ok => OK,
        }
    }

    pub fn get_topic(&self) -> Option<&TopicName> {
        match self {
            Self::RegisterPublisher(p) => Some(&p.topic),
            Self::RegisterSubscriber(s) => Some(&s.topic),
            Self::RegisterReplier(s) => Some(&s.topic),
            Self::RegisterRequestor(c) => Some(&c.topic),
            Self::Message(_) => None,
            Self::BatchMessage(_) => None,
            Self::Error(_) => None,
            Self::Ok => None,
        }
    }

    pub fn write_to_bytes(self, dst: &mut BytesMut) -> Result<()> {
        match self {
            Frame::RegisterPublisher(payload) => bincode::serialize_into(dst.writer(), &payload)
                .map_err(ProtocolError::SerdeError)?,
            Frame::RegisterSubscriber(payload) => bincode::serialize_into(dst.writer(), &payload)
                .map_err(ProtocolError::SerdeError)?,
            Frame::RegisterReplier(payload) => bincode::serialize_into(dst.writer(), &payload)
                .map_err(ProtocolError::SerdeError)?,
            Frame::RegisterRequestor(payload) => bincode::serialize_into(dst.writer(), &payload)
                .map_err(ProtocolError::SerdeError)?,
            Frame::Message(payload) => bincode::serialize_into(dst.writer(), &payload)
                .map_err(ProtocolError::SerdeError)?,
            Frame::BatchMessage(bytes) => dst.extend_from_slice(&bytes),
            Frame::Error(bytes) => dst.extend_from_slice(&bytes),
            Frame::Ok => (),
        }

        Ok(())
    }

    pub fn unwrap_message(self) -> MessagePayload {
        match self {
            Self::Message(p) => p,
            _ => panic!("Attempted to unwrap non-Message Frame variant"),
        }
    }
}

impl TryFrom<(u8, BytesMut)> for Frame {
    type Error = SeliumError;

    fn try_from(
        (message_type, bytes): (u8, BytesMut),
    ) -> Result<Self, <Frame as TryFrom<(u8, BytesMut)>>::Error> {
        let frame = match message_type {
            REGISTER_PUBLISHER => Frame::RegisterPublisher(
                bincode::deserialize(&bytes).map_err(ProtocolError::SerdeError)?,
            ),
            REGISTER_SUBSCRIBER => Frame::RegisterSubscriber(
                bincode::deserialize(&bytes).map_err(ProtocolError::SerdeError)?,
            ),
            REGISTER_REPLIER => Frame::RegisterReplier(
                bincode::deserialize(&bytes).map_err(ProtocolError::SerdeError)?,
            ),
            REGISTER_REQUESTOR => Frame::RegisterRequestor(
                bincode::deserialize(&bytes).map_err(ProtocolError::SerdeError)?,
            ),
            MESSAGE => {
                Frame::Message(bincode::deserialize(&bytes).map_err(ProtocolError::SerdeError)?)
            }
            BATCH_MESSAGE => Frame::BatchMessage(bytes.into()),
            ERROR => Frame::Error(bytes.into()),
            OK => Frame::Ok,
            _type => return Err(ProtocolError::UnknownMessageType(_type))?,
        };

        Ok(frame)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct PublisherPayload {
    pub topic: TopicName,
    pub retention_policy: u64,
    pub operations: Vec<Operation>,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct SubscriberPayload {
    pub topic: TopicName,
    pub retention_policy: u64,
    pub operations: Vec<Operation>,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct ReplierPayload {
    pub topic: TopicName,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct RequestorPayload {
    pub topic: TopicName,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct MessagePayload {
    pub headers: Headers,
    pub message: Bytes,
}