@startuml
skinparam NoteBackgroundColor orange
skinparam sequenceMessageAlign center
title Audio clipping with Janus SIP plugin and FreeSwitch
autonumber

participant Caller
participant BusinessLogic
participant CallerAgent
participant JanusCore
participant JanusSIP as JanusSIP
participant FreeSwitch

group Init (on demand or recurring)
BusinessLogic -> JanusSIP: Register with FS (Ex: as user 1003)
JanusSIP -> FreeSwitch: SIP Register
end
autonumber 1
Caller -> BusinessLogic: Call FreeSwitch user
BusinessLogic -> CallerAgent: Create PC and SDP offer
BusinessLogic -> JanusCore: Call SIP user (behind FS) with webrtc SDP offer
JanusCore -> JanusCore: Initialize call, start ice etc
JanusCore -> JanusSIP: Handle request
JanusSIP -> FreeSwitch: SIP Invite /w SDP
FreeSwitch -> JanusSIP: SIP 200 OK with SDP answer
note over CallerAgent, FreeSwitch: Caller loses 1-2s of audio until webrtc conn is live
group parallel
JanusSIP <-[#blue]> FreeSwitch: FS leg active
FreeSwitch -[#blue]> FreeSwitch: Auto play IVR
else
JanusSIP -> JanusCore: Share SIP SDP answer
JanusCore -> BusinessLogic: Enrich answer with webrtc and fire event with SDP answer
BusinessLogic -> CallerAgent: Apply SDP answer
CallerAgent <-[#blue]> JanusCore: webrtc conn active
end
@enduml