@startuml
skinparam BackgroundColor F0F0F0

[*] --> WaitForStartPermission

WaitForStartPermission -> PowerDown : PowerDownRequest && !isModemActive

WaitForStartPermission --> PowerUpRequest : PowerUpRequest

PowerDown --> PowerUpRequest : PowerUpRequest

PowerUpRequest --> PowerUpProcedure : board == T3 | Linux

PowerUpRequest -> StatusCheck : board == T4

StatusCheck --> PowerUpInPorgress : modemActive

StatusCheck -> PowerUpProcedure : !modemActive

PowerUpProcedure --> CellularConfProcedure : hotStart

PowerUpProcedure --> PowerUpInPorgress : coldStart || event: modem ACTIVE

PowerUpInPorgress --> BaudDetect

BaudDetect -> CellularConfProcedure : Success

BaudDetect --> ModemFatalFailure : Failure

CellularConfProcedure --> AudioConfigurationProcedure : Success

CellularConfProcedure -> Failed : Failed

AudioConfigurationProcedure -> AudioConfigurationProcedure : Failed

AudioConfigurationProcedure --> Failed : Baud setup fail | radio enabling/disabling fail

AudioConfigurationProcedure ---> Idle : reset called

AudioConfigurationProcedure --> APNConfProcedure : Success

APNConfProcedure --> SanityCheck

SanityCheck --> ModemOn : Success

SanityCheck --> ModemFatalFailure : Failure

ModemOn -> URCReady

Event:CellularSimProcedure --> SimSelect 

Event:SIM_READY --> SimInit

SimInit --> Failed : Failure

SimInit --> Ready : Success

Event:PowerDownDeregistering --> PowerDownStarted : state != PowerDownWaiting

Event:PowerDownDeregistered --> PowerDownWaiting

Event:PowerDownRequest -> PowerDownWaiting

PowerDownWaiting ---> PowerDown : (If T3 && timeout) \n || Event:modemInactive

PowerDown --> PowerUpRequest : nextPowerStateChangeAwaiting \n && nextPowerState == on

BaudDetect ---> PowerDownWaiting : nextPowerStateChangeAwaiting \n && nextPowerState == off

Event:PowerUpProcedureComplete --> CellularConfProcedure : board == T3 || Linux

Event:modemActive --> PowerDown : state != PowerUpProcedure

Event:powerDownRequest --> PowerDown : state != PowerDown,PowerDownWaiting,\n PowerUpProcedure,PowerUpInProgress

@enduml