From 8a7d414a013a329c3fbf173a835c5c0ea3c46652 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Fri, 27 Dec 2024 15:35:45 +0100
Subject: [PATCH] Add command abstraction

---
 Cargo.toml                   |   1 +
 euphoxide-bot/Cargo.toml     |   1 +
 euphoxide-bot/src/command.rs | 172 +++++++++++++++++++++++++++++++++++
 euphoxide-bot/src/lib.rs     |   1 +
 4 files changed, 175 insertions(+)
 create mode 100644 euphoxide-bot/src/command.rs

diff --git a/Cargo.toml b/Cargo.toml
index 97995e8..be45ac0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ version = "0.5.1"
 edition = "2021"
 
 [workspace.dependencies]
+async-trait = "0.1.83"
 caseless = "0.2.1"
 cookie = "0.18.1"
 futures-util = "0.3.31"
diff --git a/euphoxide-bot/Cargo.toml b/euphoxide-bot/Cargo.toml
index e3ad556..9f657c5 100644
--- a/euphoxide-bot/Cargo.toml
+++ b/euphoxide-bot/Cargo.toml
@@ -4,6 +4,7 @@ version = { workspace = true }
 edition = { workspace = true }
 
 [dependencies]
+async-trait = { workspace = true }
 cookie = { workspace = true }
 euphoxide = { path = "../euphoxide" }
 log = { workspace = true }
diff --git a/euphoxide-bot/src/command.rs b/euphoxide-bot/src/command.rs
new file mode 100644
index 0000000..a36bc4f
--- /dev/null
+++ b/euphoxide-bot/src/command.rs
@@ -0,0 +1,172 @@
+use std::future::Future;
+
+use async_trait::async_trait;
+use euphoxide::{
+    api::{Data, Message, MessageId, ParsedPacket, Send, SendEvent, SendReply},
+    client::{
+        conn::ClientConnHandle,
+        state::{Joined, State},
+    },
+};
+
+#[non_exhaustive]
+pub struct Context {
+    pub conn: ClientConnHandle,
+    pub joined: Joined,
+}
+
+impl Context {
+    pub async fn send<S: ToString>(
+        &self,
+        content: S,
+    ) -> euphoxide::Result<impl Future<Output = euphoxide::Result<SendReply>>> {
+        self.conn
+            .send(Send {
+                content: content.to_string(),
+                parent: None,
+            })
+            .await
+    }
+
+    pub async fn send_only<S: ToString>(&self, content: S) -> euphoxide::Result<()> {
+        let _ignore = self.send(content).await?;
+        Ok(())
+    }
+
+    pub async fn reply<S: ToString>(
+        &self,
+        parent: MessageId,
+        content: S,
+    ) -> euphoxide::Result<impl Future<Output = euphoxide::Result<SendReply>>> {
+        self.conn
+            .send(Send {
+                content: content.to_string(),
+                parent: Some(parent),
+            })
+            .await
+    }
+
+    pub async fn reply_only<S: ToString>(
+        &self,
+        parent: MessageId,
+        content: S,
+    ) -> euphoxide::Result<()> {
+        let _ignore = self.reply(parent, content).await?;
+        Ok(())
+    }
+}
+
+#[derive(Default)]
+pub struct Info {
+    pub trigger: Option<String>,
+    pub description: Option<String>,
+}
+
+impl Info {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn with_trigger(mut self, trigger: impl ToString) -> Self {
+        self.trigger = Some(trigger.to_string());
+        self
+    }
+
+    pub fn with_description(mut self, description: impl ToString) -> Self {
+        self.description = Some(description.to_string());
+        self
+    }
+
+    pub fn prepend_trigger(&mut self, trigger: impl ToString) {
+        let cur_trigger = self.trigger.get_or_insert_default();
+        if !cur_trigger.is_empty() {
+            cur_trigger.insert(0, ' ');
+        }
+        cur_trigger.insert_str(0, &trigger.to_string());
+    }
+
+    pub fn with_prepended_trigger(mut self, trigger: impl ToString) -> Self {
+        self.prepend_trigger(trigger);
+        self
+    }
+}
+
+/// Whether a message should propagate to subsequent commands.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Propagate {
+    No,
+    Yes,
+}
+
+#[allow(unused_variables)]
+#[async_trait]
+pub trait Command<B, E> {
+    fn info(&self, ctx: &Context) -> Info {
+        Info::default()
+    }
+
+    async fn execute(
+        &self,
+        arg: &str,
+        msg: &Message,
+        ctx: &Context,
+        bot: &mut B,
+    ) -> Result<Propagate, E>;
+}
+
+pub struct Commands<B, E = euphoxide::Error> {
+    commands: Vec<Box<dyn Command<B, E>>>,
+}
+
+impl<B, E> Commands<B, E> {
+    pub fn new() -> Self {
+        Self { commands: vec![] }
+    }
+
+    pub fn add(&mut self, command: impl Command<B, E> + 'static) {
+        self.commands.push(Box::new(command));
+    }
+
+    pub fn then(mut self, command: impl Command<B, E> + 'static) -> Self {
+        self.add(command);
+        self
+    }
+
+    pub fn infos(&self, ctx: &Context) -> Vec<Info> {
+        self.commands.iter().map(|c| c.info(ctx)).collect()
+    }
+
+    pub async fn execute(
+        &self,
+        conn: ClientConnHandle,
+        state: State,
+        packet: ParsedPacket,
+        bot: &mut B,
+    ) -> Result<Propagate, E> {
+        let Ok(Data::SendEvent(SendEvent(msg))) = &packet.content else {
+            return Ok(Propagate::Yes);
+        };
+
+        let State::Joined(joined) = state else {
+            return Ok(Propagate::Yes);
+        };
+
+        let ctx = Context { conn, joined };
+
+        for command in &self.commands {
+            let propagate = command.execute(&msg.content, msg, &ctx, bot).await?;
+            if propagate == Propagate::No {
+                return Ok(Propagate::No);
+            }
+        }
+
+        Ok(Propagate::Yes)
+    }
+}
+
+// Has fewer restrictions on generic types than #[derive(Default)].
+impl<B, E> Default for Commands<B, E> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/euphoxide-bot/src/lib.rs b/euphoxide-bot/src/lib.rs
index 6eeeba5..3a6acc7 100644
--- a/euphoxide-bot/src/lib.rs
+++ b/euphoxide-bot/src/lib.rs
@@ -1,2 +1,3 @@
 pub mod bot;
+pub mod command;
 pub mod instance;