Fix forced reconnections when replacing tracks

When tracks are replaced the forced reconnections were based on whether
the call was started with local media active or not. However, in some
cases a forced reconnection was needed even if the call was started with
local media active. For example, if after joining a call the user
removed the audio and video devices and then added them again, as if
another participant joined the call in the meantime that participant
would not try to establish a connection after the devices were selected
again, as currently the clients only establish a connection if another
participant has media when the list of participants in the call change.

Besides that, when the flags are updated now the flags are based only in
the current tracks rather than on the previous flags, as if the flags
were updated again before the previous request finished the second
update would be based on the original flags.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

1 files changed, 29 insertions, 35 deletions

diff --git a/src/utils/webrtc/webrtc.js b/src/utils/webrtc/webrtc.js
index 8f499abd0..4da540f1e 100644
--- a/src/utils/webrtc/webrtc.js
+++ b/src/utils/webrtc/webrtc.js
@@ -1422,49 +1422,43 @@ export default function initWebRtc(signaling, _callParticipantCollection, _local
 		signaling.updateCurrentCallFlags(expectedCallFlags)
 	})
 
-	webrtc.on('localTrackReplaced', function(newTrack, oldTrack/*, stream */) {
-		// Device disabled, just update the call flags.
-		if (!newTrack) {
-			if (oldTrack && oldTrack.kind === 'audio') {
-				signaling.updateCurrentCallFlags(signaling.getCurrentCallFlags() & ~PARTICIPANT.CALL_FLAG.WITH_AUDIO)
-			} else if (oldTrack && oldTrack.kind === 'video') {
-				signaling.updateCurrentCallFlags(signaling.getCurrentCallFlags() & ~PARTICIPANT.CALL_FLAG.WITH_VIDEO)
-			}
-
-			return
+	/**
+	 * Return whether there are sender peers, either already created or about to
+	 * be created (if there is a pending connection).
+	 *
+	 * If the MCU is used then there will be a single sender peer (the own
+	 * peer). Otherwise every peer is both a sender and a receiver peer.
+	 *
+	 * @return {boolean} true if there are sender peers, false otherwise.
+	 */
+	function hasSenderPeers() {
+		if (signaling.hasFeature('mcu')) {
+			return !!ownPeer
 		}
 
-		// If the call was started with media the connections will be already
-		// established. The flags need to be updated if a device was enabled
-		// (but not if it was switched to another one).
-		if (startedWithMedia) {
-			if (newTrack.kind === 'audio' && !oldTrack) {
-				signaling.updateCurrentCallFlags(signaling.getCurrentCallFlags() | PARTICIPANT.CALL_FLAG.WITH_AUDIO)
-			} else if (newTrack.kind === 'video' && !oldTrack) {
-				signaling.updateCurrentCallFlags(signaling.getCurrentCallFlags() | PARTICIPANT.CALL_FLAG.WITH_VIDEO)
-			}
+		return webrtc.webrtc.getPeers(null, 'video').length > 0 || Object.keys(delayedConnectionToPeer).length > 0
+	}
 
-			return
-		}
+	webrtc.on('localTrackReplaced', function(newTrack, oldTrack/*, stream */) {
+		const callFlags = getCallFlagsFromLocalMedia()
+
+		// A reconnection is not needed if a device is disabled or if there are
+		// no other participants in the call. Even if there are other
+		// participants a reconnection is not needed if there are already sender
+		// peers (as "negotiationneeded" will be automatically triggered by them
+		// if needed, which will cause the reconnection). Only if there are no
+		// sender peers or there are, but the previous call flags were just "in
+		// call", a reconnection is needed to ensure that the other participants
+		// will try to connect with the local one.
+		if (newTrack && previousUsersInRoom.length > 0 && (!hasSenderPeers() || signaling.getCurrentCallFlags() === PARTICIPANT.CALL_FLAG.IN_CALL)) {
+			forceReconnect(signaling, callFlags)
 
-		// If the call has not started with media yet the connections will be
-		// established once started, as well as the flags.
-		if (startedWithMedia === undefined) {
 			return
 		}
 
-		// If the call was originally started without media the participant
-		// needs to reconnect to establish the sender connections.
-		startedWithMedia = true
-
-		let flags = signaling.getCurrentCallFlags()
-		if (newTrack.kind === 'audio') {
-			flags |= PARTICIPANT.CALL_FLAG.WITH_AUDIO
-		} else if (newTrack.kind === 'video') {
-			flags |= PARTICIPANT.CALL_FLAG.WITH_VIDEO
+		if (signaling.getCurrentCallFlags() !== callFlags) {
+			signaling.updateCurrentCallFlags(callFlags)
 		}
-
-		forceReconnect(signaling, flags)
 	})
 
 	webrtc.on('localMediaStarted', function(/* configuration */) {