Add room_version argument and reorg convert_outgoing_federation_event.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/matrix/pdu.rs

@@ -1,5 +1,6 @@
 mod builder;
 mod count;
+pub mod format;
 mod hashes;
 mod id;
 mod raw_id;

src/core/matrix/pdu/format.rs

@@ -0,0 +1,39 @@
+use ruma::{CanonicalJsonObject, CanonicalJsonValue, RoomVersionId};
+
+use crate::{is_equal_to, matrix::room_version};
+
+pub fn into_outgoing_federation(
+	mut pdu_json: CanonicalJsonObject,
+	room_version: &RoomVersionId,
+) -> CanonicalJsonObject {
+	if let Some(unsigned) = pdu_json
+		.get_mut("unsigned")
+		.and_then(|val| val.as_object_mut())
+	{
+		unsigned.remove("transaction_id");
+	}
+
+	let Ok(room_rules) = room_version::rules(room_version) else {
+		pdu_json.remove("event_id");
+		return pdu_json;
+	};
+
+	if !room_rules.event_format.require_event_id {
+		pdu_json.remove("event_id");
+	}
+
+	if !room_rules
+		.event_format
+		.require_room_create_room_id
+	{
+		if pdu_json
+			.get("type")
+			.and_then(CanonicalJsonValue::as_str)
+			.is_some_and(is_equal_to!("m.room.create"))
+		{
+			pdu_json.remove("room_id");
+		}
+	}
+
+	pdu_json
+}