Add Prefixed command constructor

src/bot/command.rs

@@ -1,6 +1,7 @@
 mod bang;
 mod clap;
 mod hidden;
+mod prefixed;
 
 use std::future::Future;
 
@@ -12,6 +13,7 @@ use crate::conn::{self, ConnTx, Joined};
 pub use self::bang::*;
 pub use self::clap::*;
 pub use self::hidden::*;
+pub use self::prefixed::*;
 
 use super::instance::InstanceConfig;
 

src/bot/command/prefixed.rs

@@ -0,0 +1,39 @@
+use async_trait::async_trait;
+
+use crate::api::Message;
+
+use super::{Command, Context};
+
+pub struct Prefixed<C> {
+    prefix: String,
+    inner: C,
+}
+
+impl<C> Prefixed<C> {
+    pub fn new<S: ToString>(prefix: S, inner: C) -> Self {
+        Self {
+            prefix: prefix.to_string(),
+            inner,
+        }
+    }
+}
+
+#[async_trait]
+impl<B, E, C> Command<B, E> for Prefixed<C>
+where
+    B: Send,
+    C: Command<B, E> + Send + Sync,
+{
+    fn description(&self, ctx: &Context) -> Option<String> {
+        let inner = self.inner.description(ctx)?;
+        Some(format!("{} - {inner}", self.prefix))
+    }
+
+    async fn execute(&self, arg: &str, msg: &Message, ctx: &Context, bot: &mut B) -> Result<(), E> {
+        if let Some(rest) = arg.trim_start().strip_prefix(&self.prefix) {
+            self.inner.execute(rest, msg, ctx, bot).await
+        } else {
+            Ok(())
+        }
+    }
+}