From e4e35eecfd5bde60d8d4be0dcd2a21eb1bcb2f91 Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Fri, 25 Aug 2023 13:19:23 +0100
Subject: [PATCH] Use Matrix room membership to look up room member

Rather than the matrixRTC memberships. We're essentially trusting
LiveKit's view of weho is connected here, so we may as well include
the real names of anyone we don't think is a matrixRTC participant,
for whatever reason.
---
 src/room/InCallView.tsx | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/src/room/InCallView.tsx b/src/room/InCallView.tsx
index 7e6aafd7..e5f56668 100644
--- a/src/room/InCallView.tsx
+++ b/src/room/InCallView.tsx
@@ -27,6 +27,7 @@ import classNames from "classnames";
 import { DisconnectReason, Room, RoomEvent, Track } from "livekit-client";
 import { MatrixClient } from "matrix-js-sdk/src/client";
 import { RoomMember } from "matrix-js-sdk/src/models/room-member";
+import { Room as MatrixRoom } from "matrix-js-sdk/src/models/room";
 import { Ref, useCallback, useEffect, useMemo, useRef } from "react";
 import { useTranslation } from "react-i18next";
 import useMeasure from "react-use-measure";
@@ -241,7 +242,7 @@ export function InCallView({
   const reducedControls = boundsValid && bounds.width <= 400;
   const noControls = reducedControls && bounds.height <= 400;
 
-  const items = useParticipantTiles(livekitRoom, memberships);
+  const items = useParticipantTiles(livekitRoom, rtcSession.room);
   const { fullscreenItem, toggleFullscreen, exitFullscreen } =
     useFullscreen(items);
 
@@ -454,19 +455,33 @@ export function InCallView({
   );
 }
 
+function findMatrixMember(
+  room: MatrixRoom,
+  id: string
+): RoomMember | undefined {
+  const parts = id.split(":");
+  if (parts.length < 2) {
+    logger.warn(
+      "Livekit participants ID doesn't look like a userId:deviceId combination"
+    );
+    return undefined;
+  }
+
+  parts.pop();
+  const userId = parts.join(":");
+
+  return room.getMember(userId) ?? undefined;
+}
+
 function useParticipantTiles(
   livekitRoom: Room,
-  memberships: CallMembership[]
+  matrixRoom: MatrixRoom
 ): TileDescriptor<ItemData>[] {
   const sfuParticipants = useParticipants({
     room: livekitRoom,
   });
 
   const items = useMemo(() => {
-    const matrixParticipants: Map<string, RoomMember> = new Map(
-      memberships.map((m) => [`${m.member.userId}:${m.deviceId}`, m.member])
-    );
-
     const hasPresenter =
       sfuParticipants.find((p) => p.isScreenShareEnabled) !== undefined;
     let allGhosts = true;
@@ -482,10 +497,12 @@ function useParticipantTiles(
             : false;
 
         const id = sfuParticipant.identity;
-        const member = matrixParticipants.get(id);
-        if (member === undefined) {
+        const member = findMatrixMember(matrixRoom, id);
+        // We always start with a local participant wit the empty string as their ID before we're
+        // connected, this is fine and we'll be in "all ghosts" mode.
+        if (id !== "" && member === undefined) {
           logger.warn(
-            `Ruh, roh! No matrix member found for SFU participant ${id}: creating g-g-g-ghost!`
+            `Ruh, roh! No matrix member found for SFU participant '${id}': creating g-g-g-ghost!`
           );
         }
         allGhosts &&= member === undefined;
@@ -539,7 +556,7 @@ function useParticipantTiles(
     // If every item is a ghost, that probably means we're still connecting and
     // shouldn't bother showing anything yet
     return allGhosts ? [] : tiles;
-  }, [memberships, sfuParticipants]);
+  }, [matrixRoom, sfuParticipants]);
 
   return items;
 }