title MFA Platform Login

participant Authenticator App as app
participant Mobile SDK as sdk
participant Login Page\n(Browser) as codepad
participant Landing Page as landing
participant MFA Platform as mfa

note over codepad
    User chooses to login
    and the Login Page
    displays a QR Code
end note

app<-->codepad: Scan QR Code of the form <landing-url>#<access-code>
app->landing: GET <landing-url>/service
landing-->app: OK, data: {"name": <service-name>, "url": <backend-url>, ...}
app->sdk: SetBackend(<backend-url>)
sdk->mfa: GET clientSetting
mfa-->sdk: OK, data: <client-settings>
sdk-->app: OK
app->sdk: GetSessionDetails(<access-code>)
sdk->mfa: POST /codeStatus, data: {"status": "wid", "wid": <access-code>}
mfa-->sdk: OK, data: {"prerollId": <preroll-id>, "appName": <app-name>, "appLogoURL": <app-icon>}
sdk-->app: OK, {<preroll-id>, <app-name>, <app-icon>}
app->sdk: ListUsers(<users-list>)
sdk-->app: OK, populated <users-list>
alt <preroll-id> is not empty
    alt <preroll-id> is not in <users-list>
        app->app: Start registration of <preroll-id>
    end alt
    app->app: Select <preroll-id>
    note right of app
        NOTE: The registration flow is listed separately
    end note
else
    alt End user chooses to register a new identity
        app->app: Start registration of new identity
        app->app: Select newly registered identity
    else End user selects an identity from the list
        app->app: Select existing identity
    end alt
end alt
app->sdk: StartAuthentication(<identity>, <access-code>)
sdk->mfa: POST /codeStatus, data: {"status": "user", "wid": <access-code>, "userId": <identity>}
mfa-->sdk: OK
sdk<-->mfa: Fetch Time Permits, if required
sdk-->app: OK
app->app: Read <PIN> from end user
app->sdk: FinishAuthenticationAN(<identity>, <PIN>, <access-code>)
sdk<-->mfa: Authenticate <identity>, using <PIN>
sdk-->app: <Status>
alt <Status> == OK
        app->app: Display "Successfull Login" message
else <Status> == INCORRECT_PIN
    alt User State == BLOCKED
        app->app: Display "User blocked" message
    else
        app->app: Display "Wrong PIN" message
    end alt
end alt