@startuml
skinparam backgroundColor white

actor User
participant "Call" as Card
participant Microphone as Mic
actor Guest

opt <color:#43a047>**""live.microphone.always_connected""**</color> is enabled
  Card -> Mic : Microphone connection attempted (muted)
  note over Mic : Connected at card load, before (and independent of) any call
  Mic --> User : Microphone access granted
end

alt Outbound call
  User -> Card : Start a call
  note over User, Card
    Via Call menu button or <color:#43a047>**""call_start""**</color> action.
    Needs a camera that supports 2-way audio
  end note
else Inbound call
  Guest -> Card : Rings
  note over Card
    Via a <color:#43a047>**""view.triggers.actions.trigger: call""**</color> trigger, e.g. a doorbell.
    The card rings (<color:#43a047>**""live.controls.call.ringtone""**</color>) until answered,
    rejected, or <color:#43a047>**""live.controls.call.unanswered_timeout_seconds""**</color> elapses
  end note
  User -> Card : Answer the call
end

opt <color:#43a047>**""live.microphone.always_connected""**</color> not enabled
  Card -> Mic : Microphone connection attempted (muted)
  note over Mic : Stays muted by default (<color:#43a047>**""live.microphone.auto_unmute""**</color>)
  Mic --> User : Microphone access granted
end

note over User, Mic
  The microphone is connected when the call is answered -- immediately
  for an outbound call. An inbound call rings without it, so a doorbell
  can ring even where microphone access needs a tap to be granted
end note

note over Card
  The card opens an audio connection to the camera and holds it only while the
  call is in progress. If the camera has no 2-way audio, or another application
  is already using it, the call fails with an error
end note

Card --> User : You hear the caller
note over Card
  Inbound audio unmutes if configured (<color:#43a047>**""live.auto_unmute""**</color>)
  Menu, status bar & next/previous hide (<color:#43a047>**""auto_hide""**</color>)
  Camera navigation is locked (<color:#43a047>**""live.controls.call.lock""**</color>)
end note

User -> Mic : Unmute to talk
note over Mic : List 'call' in <color:#43a047>**""live.microphone.auto_unmute""**</color> to unmute automatically

loop Until the call ends
  User -[#red]> Guest : Talking
  Guest -[#red]-> User : Responding
end

User -> Card : End the call
note over User, Card
  Via Hang-up button, <color:#43a047>**""call_end""**</color> action, or -- when
  <color:#43a047>**""live.controls.call.lock""**</color> is disabled -- navigating away
end note

note over Card : The audio connection to the camera closes, releasing it for other applications
Card --> User : Inbound audio mutes (<color:#43a047>**""live.auto_mute""**</color>)
Card -> Mic : Microphone mutes and disconnects
note over Mic
  The browser stops reporting the microphone as in use, unless
  <color:#43a047>**""live.microphone.always_connected""**</color> holds it open
end note
@enduml