@startuml

autonumber

participant ApplicationManager
participant RialtoServerManager

ApplicationManager             ->  RialtoServerManager:               initiateApplication(application_id, AppState::Inactive, app_config)
note right: app_config allows app manager to specify the socket name to use for Rialto client/server session management and the socket name for communication with a display server 
opt session_management_socket_name not specified in app_config
RialtoServerManager            ->  RialtoServerManager:               Generate unique session_management_socket_name for Rialto Client to Rialto Application Session Server communication
end
alt There are no preloaded servers
RialtoServerManager            ->  RialtoServerManager:               Generate socketpair for Rialto Application Session Server to Server Manager communication
RialtoServerManager            ->  RialtoApplicationSessionServer **: Spawn(server_manager_socket)
RialtoServerManager            ->  RialtoServerManager:               Start [startup] second READY timer
RialtoServerManager            --> ApplicationManager:                OK/ERROR
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Set current_state = Uninitialised

alt RialtoApplicationSessionServer started successfully

RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Uninitialised)
RialtoServerManager            ->  RialtoServerManager:               Cancel READY timer
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Uninitialised)
RialtoServerManager
ref over ApplicationManager, RialtoApplicationSessionServer : [[#RialtoApplicationSessionManagement-Unitialized→Inactive Unitialized→Inactive]]  

else State transition failed
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Unbind/free SetConfiguration(session_ management_ socket_name, AppState::Inactive, resources, log_level)
note right
"resources" structure will specify the maximum decoder resources that the
application is permitted to use. For now it shall have a max_playback_sessions
property and a supports_web_audio flag. This may be enhanced for things like
HD/UHD, audio only etc in future.
end note
RialtoApplicationSessionServer --> RialtoServerManager:
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Create listening socket & bind to session_management_socket_name

alt State transition successful
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Set current_state = Inactive
RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Inactive)
RialtoServerManager            -// ApplicationManager:                StateChanged(application_id, AppState::Inactive)
ApplicationManager             ->  RialtoServerManager:               getAppConnectionInfo()
RialtoServerManager            --> ApplicationManager:                session_management_socket_name
else State transition failed
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Unbind/free session management socket (if created)
RialtoApplicationSessionServer -// RialtoServerManager:  (if created)
RialtoApplicationSessionServer -// RialtoServerManager:                  stateChanged(AppState::Error)
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer !!: Exit process
end

else Session Server initialisation failed

RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Unbind/free session management socket (if created)
RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Error)
RialtoServerManager            ->  RialtoServerManager:               Cancel READY timer
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer !!: Exit process
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)

else READY timer expired

RialtoServerManager            ->  RialtoServerManager:               Kill spawned Rialto Application Session Server process
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)

end
else There are preloaded servers
  ref over ApplicationManager, RialtoApplicationSessionServer : [[#RialtoApplicationSessionManagement-Unitialized→Inactive Unitialized→Inactive]]
RialtoServerManager            --> ApplicationManager:                OK/ERROR
end

@enduml