aboutsummaryrefslogtreecommitdiff
path: root/planetwars-matchrunner/src/match_context.rs
blob: 6e6a088fcefb1198938c222e83ec9c34891c7bcd (plain)
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
169
use futures::task::{Context, Poll};
use futures::{future::Future, task::AtomicWaker};
use serde::{Deserialize, Serialize};
use std::pin::Pin;
use std::time::Duration;
use std::{
    collections::HashMap,
    sync::{Arc, Mutex},
};
use tokio::task::JoinHandle;

use crate::match_log::{MatchLogMessage, MatchLogger};

#[derive(Serialize, Deserialize, Debug)]
pub struct RequestMessage {
    pub request_id: u32,
    pub timeout: Duration,
    pub content: Vec<u8>,
}

pub struct MatchCtx {
    event_bus: Arc<Mutex<EventBus>>,
    players: HashMap<u32, PlayerData>,
    match_logger: MatchLogger,
}

impl MatchCtx {
    pub fn new(
        event_bus: Arc<Mutex<EventBus>>,
        players: HashMap<u32, Box<dyn PlayerHandle>>,
        match_logger: MatchLogger,
    ) -> Self {
        MatchCtx {
            event_bus,
            players: players
                .into_iter()
                .map(|(id, handle)| {
                    let player_handle = PlayerData {
                        request_ctr: 0,
                        handle,
                    };
                    (id, player_handle)
                })
                .collect(),
            match_logger,
        }
    }

    // TODO: implement a clean way to handle the player not existing
    pub fn request(&mut self, player_id: u32, content: Vec<u8>, timeout: Duration) -> Request {
        let player = self.players.get_mut(&player_id).unwrap();
        let request_id = player.request_ctr;
        player.request_ctr += 1;

        player.handle.send_request(RequestMessage {
            request_id,
            content,
            timeout,
        });

        Request {
            player_id,
            request_id,
            event_bus: self.event_bus.clone(),
        }
    }

    pub fn players(&self) -> Vec<u32> {
        self.players.keys().cloned().collect()
    }

    pub fn log(&mut self, message: MatchLogMessage) {
        self.match_logger.send(message).expect("write failed");
    }

    pub async fn shutdown(self) {
        let join_handles = self
            .players
            .into_iter()
            .map(|(_player_id, player_data)| player_data.handle.into_join_handle());
        futures::future::join_all(join_handles).await;
    }
}

pub trait PlayerHandle: Send {
    fn send_request(&mut self, r: RequestMessage);
    fn into_join_handle(self: Box<Self>) -> JoinHandle<()>;
}

struct PlayerData {
    request_ctr: u32,
    handle: Box<dyn PlayerHandle>,
}

type RequestId = (u32, u32);
pub struct EventBus {
    request_responses: HashMap<RequestId, RequestResult<Vec<u8>>>,
    wakers: HashMap<RequestId, AtomicWaker>,
}

impl EventBus {
    pub fn new() -> Self {
        EventBus {
            request_responses: HashMap::new(),
            wakers: HashMap::new(),
        }
    }
}

impl Default for EventBus {
    fn default() -> Self {
        EventBus::new()
    }
}

impl EventBus {
    pub fn resolve_request(&mut self, id: RequestId, result: RequestResult<Vec<u8>>) {
        if self.request_responses.contains_key(&id) {
            // request already resolved
            // TODO: maybe report this?
            return;
        }
        self.request_responses.insert(id, result);
        if let Some(waker) = self.wakers.remove(&id) {
            waker.wake();
        }
    }
}

pub struct Request {
    player_id: u32,
    request_id: u32,
    event_bus: Arc<Mutex<EventBus>>,
}

impl Request {
    #[allow(dead_code)]
    pub fn player_id(&self) -> u32 {
        self.player_id
    }
}

impl Future for Request {
    type Output = RequestResult<Vec<u8>>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let mut event_bus = self.event_bus.lock().unwrap();
        let request_id = (self.player_id, self.request_id);

        if let Some(result) = event_bus.request_responses.get(&request_id) {
            return Poll::Ready(result.clone());
        }

        event_bus
            .wakers
            .entry(request_id)
            .or_insert_with(AtomicWaker::new)
            .register(cx.waker());
        Poll::Pending
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum RequestError {
    Timeout,
    BotTerminated,
}

pub type RequestResult<T> = Result<T, RequestError>;