From 54babddb38bee140ea1d7290fc6865746d4c619c Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Tue, 13 Oct 2020 15:08:23 +0100
Subject: [PATCH] Support glare for VoIP calls

The js-sdk supports glare but we didn't support it, which means the
js-sdk will still do glare but we didn't know about it, leaving the
UI in horribly broken states where the js-sdk would be on a call but
the app didn't think it was.

Fixes https://github.com/vector-im/element-web/issues/5770
---
 src/CallHandler.tsx | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/CallHandler.tsx b/src/CallHandler.tsx
index 6b66a614d2..fc24feb90f 100644
--- a/src/CallHandler.tsx
+++ b/src/CallHandler.tsx
@@ -179,8 +179,18 @@ export default class CallHandler {
         }
     }
 
+    private matchesCallForThisRoom(call: MatrixCall) {
+        // We don't allow placing more than one call per room, but that doesn't mean there
+        // can't be more than one, eg. in a glare situation. This checks that the given call
+        // is the call we consider 'the' call for its room.
+        const callForThisRoom = this.getCallForRoom(call.roomId);
+        return callForThisRoom && call.callId === callForThisRoom.callId;
+    }
+
     private setCallListeners(call: MatrixCall) {
         call.on(CallEvent.Error, (err) => {
+            if (!this.matchesCallForThisRoom(call)) return;
+
             console.error("Call error:", err);
             if (
                 MatrixClientPeg.get().getTurnServers().length === 0 &&
@@ -196,9 +206,13 @@ export default class CallHandler {
             });
         });
         call.on(CallEvent.Hangup, () => {
+            if (!this.matchesCallForThisRoom(call)) return;
+
             this.removeCallForRoom(call.roomId);
         });
         call.on(CallEvent.State, (newState: CallState, oldState: CallState) => {
+            if (!this.matchesCallForThisRoom(call)) return;
+
             this.setCallState(call, newState);
 
             switch (oldState) {
@@ -233,6 +247,21 @@ export default class CallHandler {
                     }
             }
         });
+        call.on(CallEvent.Replaced, (newCall: MatrixCall) => {
+            if (!this.matchesCallForThisRoom(call)) return;
+
+            console.log(`Call ID ${call.callId} is being replaced by call ID ${newCall.callId}`);
+
+            if (call.state === CallState.Ringing) {
+                this.pause(AudioID.Ring);
+            } else if (call.state === CallState.InviteSent) {
+                this.pause(AudioID.Ringback);
+            }
+
+            this.calls.set(newCall.roomId, newCall);
+            this.setCallListeners(newCall);
+            this.setCallState(newCall, newCall.state);
+        });
     }
 
     private setCallState(call: MatrixCall, status: CallState) {