flowchart TD
    Start([User logs into Umbraco]) --> Working[User working normally in Umbraco]
    
    Working --> TokenCheck{Background: Token check every 30s}
    TokenCheck --> |Token OK| Working
    
    TokenCheck --> |Token expires in <60s| WarningModal[⚠️ Session Timeout Warning Modal<br/>Shows countdown timer]
    
    WarningModal --> UserChoice{User decides}
    
    UserChoice --> |Clicks 'Continue'| ValidateToken[System validates/refreshes token]
    UserChoice --> |Clicks 'Logout'| LoggedOut[👋 User logged out]
    UserChoice --> |Ignores modal<br/>Timer expires| ValidateToken
    
    ValidateToken --> TokenValid{Token validation}
    TokenValid --> |Success| Working
    TokenValid --> |Fails| LoggedOut
    
    TokenCheck --> |Token already expired| AutoLogout[🚨 Automatic logout<br/>No warning given]
    AutoLogout --> LoggedOut
    
    LoggedOut --> LoginScreen[🔐 Redirected to login screen]
    LoginScreen --> |User logs in again| Start
    
    style WarningModal fill:#fff2cc,stroke:#d6b656
    style AutoLogout fill:#f8cecc,stroke:#b85450
    style LoggedOut fill:#f8cecc,stroke:#b85450
    style Working fill:#d5e8d4,stroke:#82b366
    style LoginScreen fill:#e1d5e7,stroke:#9673a6

sequenceDiagram
    participant AC as AuthContext
    participant ASTC as AuthSessionTimeoutController
    participant AF as AuthFlow
    participant TCW as TokenCheckWorker
    participant MM as ModalManager
    participant User as User

    Note over AC,ASTC: Initialization
    AC->>ASTC: constructor(host, authFlow)
    ASTC->>TCW: new SharedWorker(token-check.worker.js)
    ASTC->>TCW: port.start()
    
    Note over AF,TCW: Token Setup
    AF->>ASTC: token$ observable emits tokenResponse
    ASTC->>TCW: postMessage({command: 'init', tokenResponse})
    TCW->>TCW: setInterval(VALIDATION_INTERVAL: 30s)
    
    Note over TCW,TCW: Periodic Token Validation
    loop Every 30 seconds
        TCW->>TCW: isTokenExpired(tokenResponse)
        TCW->>TCW: Check if token expires in < 60s buffer
        
        alt Token is expired
            TCW->>ASTC: postMessage({command: 'logout'})
            ASTC->>AC: host.timeOut()
            AC->>ASTC: timeoutSignal emits
            ASTC->>TCW: postMessage({command: 'init'}) // stop worker
            ASTC->>MM: close('auth-timeout')
            
        else Token needs refresh (< 60s remaining)
            TCW->>ASTC: postMessage({command: 'refreshToken', secondsUntilLogout})
            ASTC->>ASTC: #timeoutModal(secondsUntilLogout)
            ASTC->>MM: open(UMB_MODAL_AUTH_TIMEOUT)
            MM->>User: Show timeout modal
            
            alt User clicks Continue
                User->>ASTC: onContinue()
                ASTC->>ASTC: #tryValidateToken()
                ASTC->>AC: validateToken()
                
                alt Token validation succeeds
                    AC->>ASTC: Token refreshed
                    Note over ASTC: Continue normal flow
                    
                else Token validation fails
                    AC->>ASTC: Error thrown
                    ASTC->>AC: host.timeOut()
                end
                
            else User clicks Logout
                User->>ASTC: onLogout()
                ASTC->>AC: signOut()
                
            else Modal times out/closes
                ASTC->>ASTC: #tryValidateToken()
                ASTC->>AC: validateToken()
            end
        end
    end