Reset signalling state when answer a call after receiving 180/183 with SDP.

[cloudwebrtc]

I added state storage to flutter-webrtc.
flutter-webrtc/flutter-webrtc@396af85
Try to fix the error after receiving 180/183 with SDP.

[rlsutton1]

It works if this line is changed to

RTCSignalingState.RTCSignalingStateHaveLocalOffer) {

[cloudwebrtc]

It looks wrong. If the status is not RTCSignalingStateHaveLocalOffer after receiving 180/183 with SDP, maybe we should check if the early media is properly connected.

[ghenry]

Isn't the design already in JsSIP?

[cloudwebrtc]

Yes, there are already designs in JsSIP, but the expected state is inconsistent.
https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/signalingState#RTCSignalingState_enum_2

The explanation of stable is as follows:

There is no ongoing exchange of offer and answer underway. 
This may mean that the RTCPeerConnection object is new,
in which case both the localDescription and remoteDescription are null;
it may also mean that negotiation is complete and a connection has been established.

If you have already received 180/183 with SDP, the status here should be "have-remote-pranswer" because pc has completed an offer/answer process

[cloudwebrtc]

I use this branch to test the call on FreeSwitch, answered after receiving the early media, it seems to work fine.

[rlsutton1]

It's a holiday here tomorrow, but I can arrange access to an asterisk system next week if that helps.

[cloudwebrtc]

@rlsutton1 If you can, please send the asterisk test account to my Github email to reproduce the error, but I have a week holiday and go online again on October 3.

[cloudwebrtc]

The expected state should be RTCSignalingStateStable because the SDP negotiation has been completed.

The explanation of stable is as follows:

There is no ongoing exchange of offer and answer underway. 
This may mean that the RTCPeerConnection object is new,
in which case both the localDescription and remoteDescription are null;
**it may also mean that negotiation is complete and a connection has been established.**

==> it may also mean that negotiation is complete and a connection has been established. <==

So I think this PR is correct, and when you test on Asterisk, the state is RTCSignalingState.RTCSignalingStateHaveLocalOffer, I guess your state is after the completion of CreateOffer and SetLocalDescription, but before receiving the 180/183 SDP, but I don't understand why I can't setRemoteDescription.

[mohbadar]

I’ve been attempting to connect with FreeSWITCH using the provided example in this repo, but without success. Can anyone provide me with a working example for connecting with FreeSWITCH? I’ve even tried using code generated by ChatGPT, but it didn’t work. I’ve been stuck on this for days and would appreciate any help.
@cloudwebrtc @ghenry @rlsutton1 @DooMMasteR