From 4a077c7c65eced447c45389acf05007dd571bf26 Mon Sep 17 00:00:00 2001
From: Ilion Beyst <ilion.beyst@gmail.com>
Date: Sat, 1 Jan 2022 12:10:02 +0100
Subject: extract matchrunner crate from planetwars-cli

---
 planetwars-matchrunner/src/bot_runner.rs | 121 +++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 planetwars-matchrunner/src/bot_runner.rs

(limited to 'planetwars-matchrunner/src/bot_runner.rs')

diff --git a/planetwars-matchrunner/src/bot_runner.rs b/planetwars-matchrunner/src/bot_runner.rs
new file mode 100644
index 0000000..70fc060
--- /dev/null
+++ b/planetwars-matchrunner/src/bot_runner.rs
@@ -0,0 +1,121 @@
+use std::io;
+use std::path::PathBuf;
+use std::process::Stdio;
+use std::sync::Arc;
+use std::sync::Mutex;
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader, Lines};
+use tokio::process;
+use tokio::sync::mpsc;
+use tokio::time::timeout;
+
+use super::match_context::EventBus;
+use super::match_context::PlayerHandle;
+use super::match_context::RequestError;
+use super::match_context::RequestMessage;
+pub struct LocalBotHandle {
+    tx: mpsc::UnboundedSender<RequestMessage>,
+}
+
+impl PlayerHandle for LocalBotHandle {
+    fn send_request(&mut self, r: RequestMessage) {
+        self.tx
+            .send(r)
+            .expect("failed to send message to local bot");
+    }
+
+    fn send_info(&mut self, _msg: String) {
+        // TODO: log this somewhere
+        // drop info message
+    }
+}
+
+pub fn run_local_bot(player_id: u32, event_bus: Arc<Mutex<EventBus>>, bot: Bot) -> LocalBotHandle {
+    let (tx, rx) = mpsc::unbounded_channel();
+
+    let runner = LocalBotRunner {
+        event_bus,
+        rx,
+        player_id,
+        bot,
+    };
+    tokio::spawn(runner.run());
+
+    return LocalBotHandle { tx };
+}
+
+pub struct LocalBotRunner {
+    event_bus: Arc<Mutex<EventBus>>,
+    rx: mpsc::UnboundedReceiver<RequestMessage>,
+    player_id: u32,
+    bot: Bot,
+}
+
+impl LocalBotRunner {
+    pub async fn run(mut self) {
+        let mut process = self.bot.spawn_process();
+
+        while let Some(request) = self.rx.recv().await {
+            let resp_fut = process.communicate(&request.content);
+            let result = timeout(request.timeout, resp_fut)
+                .await
+                // TODO: how can this failure be handled cleanly?
+                .expect("process read failed");
+            let result = match result {
+                Ok(line) => Ok(line.into_bytes()),
+                Err(_elapsed) => Err(RequestError::Timeout),
+            };
+            let request_id = (self.player_id, request.request_id);
+
+            self.event_bus
+                .lock()
+                .unwrap()
+                .resolve_request(request_id, result);
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Bot {
+    pub working_dir: PathBuf,
+    pub argv: Vec<String>,
+}
+
+impl Bot {
+    pub fn spawn_process(&self) -> BotProcess {
+        let mut child = process::Command::new(&self.argv[0])
+            .args(&self.argv[1..])
+            .current_dir(self.working_dir.clone())
+            .kill_on_drop(true)
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::inherit())
+            .spawn()
+            .expect("spawning failed");
+
+        let stdout = child.stdout.take().unwrap();
+        let reader = BufReader::new(stdout).lines();
+
+        return BotProcess {
+            stdin: child.stdin.take().unwrap(),
+            stdout: reader,
+            child,
+        };
+    }
+}
+
+pub struct BotProcess {
+    #[allow(dead_code)]
+    child: process::Child,
+    stdin: process::ChildStdin,
+    stdout: Lines<BufReader<process::ChildStdout>>,
+}
+
+impl BotProcess {
+    // TODO: gracefully handle errors
+    pub async fn communicate(&mut self, input: &[u8]) -> io::Result<String> {
+        self.stdin.write_all(input).await?;
+        self.stdin.write_u8(b'\n').await?;
+        let line = self.stdout.next_line().await?;
+        line.ok_or_else(|| io::Error::new(io::ErrorKind::UnexpectedEof, "no response received"))
+    }
+}
-- 
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