Send a typing notice event when the user starts typing in the message…

… input box (#100)

The `RoomScreen` widget now handles UI-level actions emitted by the message input box widget, and submits an async request to send a "typing notice" to the current timeline's Room based on whether there is text present in the box.

src/home/room_screen.rs

@@ -585,6 +585,14 @@ impl Widget for RoomScreen {
                 }
             }
 
+            // Handle a typing action on the message input box.
+            if let Some(new_text) = self.text_input(id!(message_input)).changed(actions) {
+                submit_async_request(MatrixRequest::SendTypingNotice {
+                    room_id: self.room_id.clone().unwrap(),
+                    typing: !new_text.is_empty(),
+                });
+            }
+
             for action in actions {
                 // Handle the action that requests to show the user profile sliding pane.
                 if let ShowUserProfileAction::ShowUserProfile(avatar_info) = action.as_widget_action().cast() {

src/sliding_sync.rs

@@ -3,7 +3,7 @@ use clap::Parser;
 use eyeball_im::VectorDiff;
 use futures_util::{StreamExt, pin_mut};
 use imbl::Vector;
-use makepad_widgets::{SignalToUI, error, log};
+use makepad_widgets::{error, log, SignalToUI};
 use matrix_sdk::{
     config::RequestConfig, media::MediaRequest, room::RoomMember, ruma::{
         api::client::{
@@ -158,6 +158,15 @@ pub enum MatrixRequest {
     SendMessage {
         room_id: OwnedRoomId,
         message: RoomMessageEventContent,
+    },
+    /// Sends a notice to the given room that the current user is or is not typing.
+    ///
+    /// This request does not return a response or notify the UI thread, and
+    /// furthermore, there is no need to send a follow-up request to stop typing
+    /// (though you certainly can do so).
+    SendTypingNotice {
+        room_id: OwnedRoomId,
+        typing: bool,
     }
 }
 
@@ -360,6 +369,18 @@ async fn async_worker(mut receiver: UnboundedReceiver<MatrixRequest>) -> Result<
                     }
                 });
             }
+
+            MatrixRequest::SendTypingNotice { room_id, typing } => {
+                let Some(room) = CLIENT.get().and_then(|c| c.get_room(&room_id)) else {
+                    error!("BUG: client/room not found for typing notice request {room_id}");
+                    continue;
+                };
+                let _typing_task = Handle::current().spawn(async move {
+                    if let Err(e) = room.typing_notice(typing).await {
+                        error!("Failed to send typing notice to room {room_id}: {e:?}");
+                    }
+                });
+            }
 
             MatrixRequest::ResolveRoomAlias(room_alias) => {
                 let Some(client) = CLIENT.get() else { continue };