TW-1675: presence status updated too many times

[Te-Z]

Linked issue: linagora/twake-on-matrix#1675
Linked pull request: linagora/twake-on-matrix#1684

[hoangdat]

I still not get the idea for this change, can you explain a little bit @Te-Z

[Te-Z]

I still not get the idea for this change, can you explain a little bit @Te-Z

Sure @hoangdat

This was the previous code:

matrix-dart-sdk/lib/src/client.dart

Lines 1793 to 1799 in e0b6529

	for (final newPresence in sync.presence ?? []) {
	final cachedPresence = CachedPresence.fromMatrixEvent(newPresence);
	presences[newPresence.senderId] = cachedPresence;
	// ignore: deprecated_member_use_from_same_package
	onPresence.add(newPresence);
	onPresenceChanged.add(cachedPresence);
	}

The UI previously listened to onPresenceChanged which is a CachedStreamController . This instance had a new value added in the for each loop for every items in sync.presencelist. This means if there's different values in sync.presence , the UI will be updated 6 times.

To handle that I changed for this code:

matrix-dart-sdk/lib/src/client.dart

Lines 1809 to 1829 in b0c3411

	CachedPresence? lowestLastActivePresence;
	for (final newPresence in sync.presence ?? []) {
	final cachedPresence = CachedPresence.fromMatrixEvent(newPresence);
	presences[newPresence.senderId] = cachedPresence;
	// ignore: deprecated_member_use_from_same_package
	onPresence.add(newPresence);
	onPresenceChanged.add(cachedPresence);
	if (lowestLastActivePresence == null ||
	(cachedPresence.lastActiveTimestamp != null &&
	lowestLastActivePresence.lastActiveTimestamp != null &&
	cachedPresence.lastActiveTimestamp!
	.isBefore(lowestLastActivePresence.lastActiveTimestamp!))) {
	lowestLastActivePresence = cachedPresence;
	}
	}
	if (lowestLastActivePresence != null) {
	onlatestPresenceChanged.add(lowestLastActivePresence);
	}

Here lowestLastActivePresence is updated for each items in sync.presence list if it is null or if the current item's timestamp is before the one in lowestLastActivePresence. Then when the loop is over and we are sure to have the right value, we can update onLatestPresenceChange with the right value and this way update the UI.