@startuml Power_Control
    participant TD                  as TD
    participant SW                  as SW
    participant UI                  as UI
    actor       USER                as US

    'Possible actions and interaction types
    ' External on CANBus
    ' TD -> SW: MSG: Message
    ' SW -> TD: MSG: Message

    ' Internal to the application
    ' XX -> YY: CMD: Command
    ' XX -> XX: ACT: Action

    ' External on OS/FS
    ' SW -> Script: ACT: Command
    ' Script -> OS: CMD: Command
    ' Script -> SW: MSG: Message
    ' OS -> Script: MSG: Message

    ' US -> UI: User actions are:
    '   ASK: Display a <message>
    '   ENT: User enters a value or string
    '   TCH: User touches a button (RadioButton, CheckBox, ...)
    '   SCL: User scrolls a flip-able area

    == Power Off Sequence ==
    US -> TD: TCH: Press Hard Power Button 

    alt Accepted
        TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                    \n\t(U32)  mId=0 (Shutdown)                                 \
                    \n\t(U32)  mCommand=0 (GENERIC_CONFIRM_CMD_REQUEST_OPEN)    \
                    \n\t(U32)  mReason=0
        SW -> UI: ACT: Power Off Request
        UI -> US: ACT: Display Confirm shutdown dialog

        alt User Presses Cancel
            US -> UI: TCH: Press Cancel
            UI -> SW: ACT: Shutdown confirm response
            SW -> TD: MSG: [xB6: #2]  Response      \
                        \n\t(U32) mId=0 (Shutdown)  \
                        \n\t(U32) mConfirm=0(cancel)   
            TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                    \n\t(U32)  mId=0 (Shutdown)                                 \
                    \n\t(U32)  mCommand=3 (GENERIC_CONFIRM_CMD_ACCEPT_CLOSE)    \
                    \n\t(U32)  mReason=0
            SW -> UI: ACT: Confirm Request close dialog
            UI -> US: ACT: Close Dialog
        else #LightBlue User Presses Shutdown
            US -> UI: TCH: Press Shutdown
            UI -> SW: ACT: Shutdown confirm response
            SW -> TD: MSG: [xB6: #2]  Response      \
                        \n\t(U32) mId=0 (Shutdown)  \
                        \n\t(U32) mConfirm=1 (shutdown) 
            alt Accepted
                TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                            \n\t(U32)  mId=0 (Shutdown)                                 \
                            \n\t(U32)  mCommand=3 (GENERIC_CONFIRM_CMD_ACCEPT_CLOSE)    \
                            \n\t(U32)  mReason=0
                SW -> UI: ACT: Confirm Request close dialog
                UI -> US: ACT: Close Dialog
                TD -> SW: MSG: [x22: #0] Power Off Warning         
                TD -> TD: ACT: Shutdown System ⟲ (May take a ~2 seconds)
                SW -> UI: ACT: Power Off Warning
                UI -> US: ACT: Display auto-close dialog (5 seconds)\
                            \n\tNotify user system is shutting down
            else #Pink Rejected
                TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                        \n\t(U32)  mId=0 (Shutdown)                                 \
                        \n\t(U32)  mCommand=2 (GENERIC_CONFIRM_CMD_REJECT)    \
                        \n\t(U32)  mReason>0
                SW -> UI: ACT: Confirm Request rejected
                UI -> US: ACT: Display rejection reason
            end
        end
    else #Pink Rejected
       TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                    \n\t(U32)  mId=0 (Shutdown)                                 \
                    \n\t(U32)  mCommand=2 (GENERIC_CONFIRM_CMD_REJECT)    \
                    \n\t(U32)  mReason>0
        SW -> UI: ACT: Confirm Request rejected
        UI -> US: ACT: Display Auto-Hide dialog with rejection reason
    end

    == Power Off Sequence Timeout ==
    loop Timeout
        US -> US: ACT: User idle for timeout limit 
    end
    TD -> SW: MSG: [xB5: #3] Confirm Request                                \
                \n\t(U32)  mId=0 (Shutdown)                                 \
                \n\t(U32)  mCommand=1 (GENERIC_CONFIRM_CMD_TIMEOUT_CLOSE)    \
                \n\t(U32)  mReason=0
    SW -> UI: ACT: Confirm Request timeout close
    UI -> US: ACT: Close Dialog
@enduml