chore: lay out the ground work for a Discord command router

src/command/mod.rs

@@ -0,0 +1,72 @@
+use std::{
+    ffi::{CStr, CString},
+    fmt::Debug,
+};
+
+use blart::TreeMap;
+use futures::future::BoxFuture;
+use twilight_model::application::{
+    command::Command, interaction::application_command::CommandData,
+};
+
+#[derive(Debug, Clone)]
+pub struct State {}
+
+type Return = ();
+type BoxedHandler = Box<dyn Fn(State, CommandData) -> BoxFuture<'static, Return>>;
+
+fn box_handler<Handler, Fut>(handler: Handler) -> BoxedHandler
+where
+    Fut: Future<Output = Return> + Send + 'static,
+    Handler: Fn(State, CommandData) -> Fut + 'static,
+{
+    Box::new(move |state, command_data| Box::pin(handler(state, command_data)))
+}
+
+pub fn all() -> Vec<(&'static Command, BoxedHandler)> {
+    vec![]
+}
+
+#[derive(Default)]
+pub struct Router {
+    map: TreeMap<CString, BoxedHandler>,
+}
+
+impl Router {
+    fn add_route<'s, 'a, Fut, Handler>(&'s mut self, name: &'a str, handler: Handler)
+    where
+        Fut: Future<Output = Return> + Send + 'static,
+        Handler: Fn(State, CommandData) -> Fut + 'static,
+    {
+        self.add_route_already_boxed(name, box_handler(handler));
+    }
+
+    fn add_route_already_boxed<'s, 'a>(&'s mut self, name: &'a str, boxed_handler: BoxedHandler) {
+        self.map.insert(name.parse().unwrap(), boxed_handler);
+    }
+
+    pub async fn handle(&self, args: State, command_data: CommandData) -> Return {
+        let name = &command_data.name;
+        let key = CStr::from_bytes_with_nul(name.as_bytes()).unwrap();
+
+        let handler = self
+            .map
+            .get(key)
+            .expect("asked to handle an inexistent command");
+
+        handler(args, command_data).await
+    }
+}
+
+impl<'a> FromIterator<(&'a CommandData, BoxedHandler)> for Router {
+    fn from_iter<T: IntoIterator<Item = (&'a CommandData, BoxedHandler)>>(iter: T) -> Self {
+        let mut router = Router::default();
+
+        for (command, handler) in iter {
+            let name = &command.name;
+            router.add_route(name, handler);
+        }
+
+        router
+    }
+}