From 86050fad15268a4a3d82a236a75fca49f07cef51 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Fri, 27 Dec 2024 22:30:51 +0100
Subject: [PATCH] Manage multiple instances

---
 euphoxide-bot/src/instances.rs | 209 +++++++++++++++++++++++++++++++++
 euphoxide-bot/src/lib.rs       |   1 +
 2 files changed, 210 insertions(+)
 create mode 100644 euphoxide-bot/src/instances.rs

diff --git a/euphoxide-bot/src/instances.rs b/euphoxide-bot/src/instances.rs
new file mode 100644
index 0000000..d9e5d2d
--- /dev/null
+++ b/euphoxide-bot/src/instances.rs
@@ -0,0 +1,209 @@
+use std::collections::HashMap;
+
+use euphoxide::{
+    api::ParsedPacket,
+    client::{conn::ClientConnHandle, state::State},
+};
+use tokio::{
+    select,
+    sync::{mpsc, oneshot},
+};
+
+use crate::instance::{Event as IEvent, Instance, InstanceConfig};
+
+#[derive(Debug)]
+pub enum Event {
+    Started {
+        instance: Instance,
+    },
+    Connecting {
+        instance: Instance,
+    },
+    Connected {
+        instance: Instance,
+        conn: ClientConnHandle,
+        state: State,
+    },
+    Joined {
+        instance: Instance,
+        conn: ClientConnHandle,
+        state: State,
+    },
+    Packet {
+        instance: Instance,
+        conn: ClientConnHandle,
+        state: State,
+        packet: ParsedPacket,
+    },
+    Disconnected {
+        instance: Instance,
+    },
+    Stopped {
+        instance: Instance,
+    },
+}
+
+impl Event {
+    fn from_instance_event(instance: Instance, event: IEvent) -> Self {
+        match event {
+            IEvent::Started { id: _ } => Self::Started { instance },
+            IEvent::Connecting { id: _ } => Self::Connecting { instance },
+            IEvent::Connected { id: _, conn, state } => Self::Connected {
+                instance,
+                conn,
+                state,
+            },
+            IEvent::Joined { id: _, conn, state } => Self::Joined {
+                instance,
+                conn,
+                state,
+            },
+            IEvent::Packet {
+                id: _,
+                conn,
+                state,
+                packet,
+            } => Self::Packet {
+                instance,
+                conn,
+                state,
+                packet,
+            },
+            IEvent::Disconnected { id: _ } => Self::Disconnected { instance },
+            IEvent::Stopped { id: _ } => Self::Stopped { instance },
+        }
+    }
+
+    pub fn instance(&self) -> &Instance {
+        match self {
+            Self::Started { instance } => instance,
+            Self::Connecting { instance, .. } => instance,
+            Self::Connected { instance, .. } => instance,
+            Self::Joined { instance, .. } => instance,
+            Self::Packet { instance, .. } => instance,
+            Self::Disconnected { instance } => instance,
+            Self::Stopped { instance } => instance,
+        }
+    }
+}
+
+#[allow(clippy::large_enum_variant)]
+enum Command {
+    GetInstances(oneshot::Sender<Vec<Instance>>),
+    AddInstance(InstanceConfig, oneshot::Sender<Instance>),
+}
+
+#[derive(Debug, Clone)]
+#[non_exhaustive]
+pub struct InstancesConfig {
+    pub cmd_channel_bufsize: usize,
+    pub event_channel_bufsize: usize,
+}
+
+impl Default for InstancesConfig {
+    fn default() -> Self {
+        Self {
+            cmd_channel_bufsize: 1,
+            event_channel_bufsize: 10,
+        }
+    }
+}
+
+struct InstancesTask {
+    next_id: usize,
+    instances: HashMap<usize, Instance>,
+
+    cmd_rx: mpsc::Receiver<Command>,
+    event_rx: mpsc::Receiver<IEvent>,
+    event_tx: mpsc::Sender<IEvent>,
+    out_tx: mpsc::Sender<Event>,
+}
+
+impl InstancesTask {
+    fn purge_instances(&mut self) {
+        self.instances.retain(|_, v| !v.stopped());
+    }
+
+    async fn on_event(&self, event: IEvent) {
+        if let Some(instance) = self.instances.get(&event.id()) {
+            let event = Event::from_instance_event(instance.clone(), event);
+            let _ = self.out_tx.send(event).await;
+        }
+    }
+
+    async fn on_cmd(&mut self, cmd: Command) {
+        match cmd {
+            Command::GetInstances(tx) => {
+                let _ = tx.send(self.instances.values().cloned().collect());
+            }
+            Command::AddInstance(config, tx) => {
+                let id = self.next_id;
+                assert!(!self.instances.contains_key(&id));
+                self.next_id += 1;
+
+                let instance = Instance::new(id, config, self.event_tx.clone());
+                self.instances.insert(id, instance.clone());
+
+                let _ = tx.send(instance);
+            }
+        }
+    }
+
+    async fn run(mut self) {
+        loop {
+            // Prevent potential memory leak
+            self.purge_instances();
+
+            let received = select! {
+                r = self.event_rx.recv() => Ok(r),
+                r = self.cmd_rx.recv() => Err(r),
+            };
+
+            match received {
+                Ok(None) => break,
+                Ok(Some(event)) => self.on_event(event).await,
+                Err(None) => break,
+                Err(Some(cmd)) => self.on_cmd(cmd).await,
+            }
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct Instances {
+    cmd_tx: mpsc::Sender<Command>,
+}
+
+impl Instances {
+    pub fn new(config: InstancesConfig, event_tx: mpsc::Sender<Event>) -> Self {
+        let out_tx = event_tx;
+
+        let (cmd_tx, cmd_rx) = mpsc::channel(config.cmd_channel_bufsize);
+        let (event_tx, event_rx) = mpsc::channel(config.event_channel_bufsize);
+
+        let task = InstancesTask {
+            next_id: 0,
+            instances: HashMap::new(),
+            cmd_rx,
+            event_rx,
+            event_tx,
+            out_tx,
+        };
+
+        tokio::task::spawn(task.run());
+
+        Self { cmd_tx }
+    }
+
+    pub async fn get_instances(&self) -> Vec<Instance> {
+        let (tx, rx) = oneshot::channel();
+        let _ = self.cmd_tx.send(Command::GetInstances(tx)).await;
+        rx.await.expect("task should still be running")
+    }
+
+    pub async fn add_instance(&self, config: InstanceConfig) -> Instance {
+        let (tx, rx) = oneshot::channel();
+        let _ = self.cmd_tx.send(Command::AddInstance(config, tx)).await;
+        rx.await.expect("task should still be running")
+    }
+}
diff --git a/euphoxide-bot/src/lib.rs b/euphoxide-bot/src/lib.rs
index 1d5ea99..d777157 100644
--- a/euphoxide-bot/src/lib.rs
+++ b/euphoxide-bot/src/lib.rs
@@ -1 +1,2 @@
 pub mod instance;
+pub mod instances;