feat: WIP relationships and threads

src/api/client_server/threads.rs

@@ -0,0 +1,49 @@
+use ruma::api::client::{error::ErrorKind, threads::get_threads};
+
+use crate::{services, Error, Result, Ruma};
+
+/// # `GET /_matrix/client/r0/rooms/{roomId}/threads`
+pub async fn get_threads_route(
+    body: Ruma<get_threads::v1::Request>,
+) -> Result<get_threads::v1::Response> {
+    let sender_user = body.sender_user.as_ref().expect("user is authenticated");
+
+    // Use limit or else 10, with maximum 100
+    let limit = body
+        .limit
+        .and_then(|l| l.try_into().ok())
+        .unwrap_or(10)
+        .min(100);
+
+    let from = if let Some(from) = &body.from {
+        from.parse()
+            .map_err(|_| Error::BadRequest(ErrorKind::InvalidParam, ""))?
+    } else {
+        u64::MAX
+    };
+
+    let threads = services()
+        .rooms
+        .threads
+        .threads_until(sender_user, &body.room_id, from, &body.include)?
+        .take(limit)
+        .filter_map(|r| r.ok())
+        .filter(|(_, pdu)| {
+            services()
+                .rooms
+                .state_accessor
+                .user_can_see_event(sender_user, &body.room_id, &pdu.event_id)
+                .unwrap_or(false)
+        })
+        .collect::<Vec<_>>();
+
+    let next_batch = threads.last().map(|(count, _)| count.to_string());
+
+    Ok(get_threads::v1::Response {
+        chunk: threads
+            .into_iter()
+            .map(|(_, pdu)| pdu.to_room_event())
+            .collect(),
+        next_batch,
+    })
+}