Technical Architecture - DigiSchool / SafeSchool ePass

flowchart LR
    subgraph UI["User-facing applications"]
        POS["DigiSchool.POS WPF"]
        BackOffice["BackOffice WebForms"]
        Portal["WebPortal WebForms"]
        WebAPI["WebAPI ASMX"]
    end

    subgraph Services["Local/server services"]
        DSCore["DigiSchool.DSCore"]
        DSComm["DigiSchool.DSCommServer"]
        CloudSync["DigiSchool.CloudSync"]
    end

    subgraph Data["Data stores"]
        DB[("PostgreSQL ePass database")]
        CloudDB[("Cloud database")]
    end

    subgraph Hardware["Hardware"]
        Local["Local kiosk devices: COM, printer, camera, scanner"]
        Network["Network readers, gates, vending controllers"]
    end

    POS -->|"net.tcp WCF"| DSCore
    POS --> Local
    DSComm -->|"net.tcp WCF duplex"| DSCore
    DSComm --> Network
    DSCore --> DB
    BackOffice --> DB
    Portal --> DB
    WebAPI --> DB
    CloudSync -->|"ASMX SOAP"| CloudDB
          

flowchart TB
    subgraph Kiosk["POS / kiosk Windows machine"]
        WPF["DigiSchool.POS"]
        LocalDevices["Local COM/printer/scanner/webcam devices"]
    end

    subgraph ServiceHost["Service host / server machine"]
        DSCoreSvc["DSCore Windows Service"]
        DSCommSvc["DSComm Windows Service"]
        CloudSyncSvc["CloudSync Windows Service"]
        IIS["IIS web applications"]
        PG[("PostgreSQL")]
    end

    subgraph NetworkDevices["LAN hardware"]
        ReaderTCP["Network RFID readers"]
        GateUDP["Door/gate controllers"]
        VendingUDP["Vending controllers"]
    end

    WPF --> LocalDevices
    WPF -->|"WCF net.tcp localhost/LAN"| DSCoreSvc
    DSCommSvc -->|"WCF duplex"| DSCoreSvc
    DSCoreSvc --> PG
    IIS --> PG
    CloudSyncSvc -->|"SOAP over HTTP"| IIS
    ReaderTCP --> DSCommSvc
    DSCommSvc --> GateUDP
    DSCommSvc --> VendingUDP
          

flowchart LR
    DSCore["DSCore Program / Service"]
    Manager["DSServiceManager"]
    Products["ProductsService"]
    Security["SecurityService"]
    Users["UsersService"]
    Sales["SalesService"]
    Gates["GatesService"]
    GateEntries["GateEntriesService"]
    Apps["AppsService"]
    Core["ePassCore data facade"]
    DB[("PostgreSQL")]

    DSCore --> Manager
    Manager --> Products
    Manager --> Security
    Manager --> Users
    Manager --> Sales
    Manager --> Gates
    Manager --> GateEntries
    Manager --> Apps
    Products --> Core
    Security --> Core
    Users --> Core
    Sales --> Core
    Gates --> Core
    GateEntries --> Core
    Core --> DB
          

flowchart TB
    Program["Program / DSCommService"]
    Manager["DSCommManager"]
    GEManager["GateEntriesManager"]
    GEController["GateEntriesController callback client"]
    UDPManager["UDPManager"]
    TCPListener["TCP listener for readers"]
    ChannelLoop["Channel refresh loop"]
    UDPChannels["UDPChannel instances"]
    DSCore["DSCore GateEntriesService"]
    Readers["Network RFID readers"]
    Doors["Door/gate controllers"]
    Vending["Vending controllers"]

    Program --> Manager
    Manager --> GEManager
    Manager --> UDPManager
    GEManager --> GEController
    GEController <-->|"WCF duplex"| DSCore
    UDPManager --> TCPListener
    UDPManager --> ChannelLoop
    ChannelLoop --> UDPChannels
    Readers --> TCPListener
    UDPChannels --> Doors
    UDPChannels --> Vending
    UDPManager --> GEManager
          

flowchart LR
    POS["POS WPF"]
    DSCore["DSCore WCF"]
    DSComm["DSCommServer"]
    COM["Local COM devices"]
    TCP["TCP readers"]
    UDP["UDP gate/vending controllers"]
    DB[("Database")]

    POS -->|"WCF service calls"| DSCore
    POS -->|"SerialPort"| COM
    DSComm -->|"WCF duplex"| DSCore
    TCP -->|"TCP messages"| DSComm
    DSComm -->|"UDP messages"| UDP
    DSCore --> DB
          

sequenceDiagram
    autonumber
    participant Card as RFID card
    participant Reader as Network reader
    participant UDPManager as DSComm UDPManager
    participant GEManager as GateEntriesManager
    participant GateEntries as DSCore GateEntriesService
    participant AccessStore as AccessControlDataStore
    participant DB as PostgreSQL
    participant POS as Gate/canteen POS subscriber

    Card->>Reader: Token is read
    Reader->>UDPManager: TCP message with serial and device number
    UDPManager->>UDPManager: Resolve host and direction
    UDPManager->>GEManager: RequestAutorization(token, direction, host)
    GEManager->>GateEntries: WCF authorization request
    GateEntries->>AccessStore: Validate token, host, rules
    AccessStore->>DB: Read rules and write history
    DB-->>AccessStore: Data and save result
    AccessStore-->>GateEntries: Authorization result
    GateEntries-->>GEManager: Result
    GEManager-->>UDPManager: Result
    UDPManager-->>Reader: Accept or deny response
    UDPManager->>GEManager: NotifyActivity
    GateEntries-->>POS: Callback activity update
          

sequenceDiagram
    autonumber
    participant User
    participant Device as Bill/Coin device
    participant Driver as BillMachine/CoinMachine
    participant POSVM as PosViewModel
    participant Sales as DSCore SalesService
    participant DB as PostgreSQL
    participant Printer

    User->>Device: Inserts money
    Device->>Driver: Serial event
    alt Bill validator
        Driver->>Driver: Validate CRC and status
        Driver->>Device: ACK / HOLD / STACK
    else Coin acceptor
        Driver->>Driver: Parse coin code
        Driver->>Device: #AC-OK*
    end
    Driver->>POSVM: onDataInbound amount code
    POSVM->>POSVM: Map code to value and update cart/top-up
    POSVM->>Sales: Create or update transaction
    Sales->>DB: Persist sale/recharge
    DB-->>Sales: Saved
    Sales-->>POSVM: Result
    POSVM->>Printer: Print receipt when configured
          

sequenceDiagram
    autonumber
    participant UI as Gate UI or business rule
    participant GatesService as DSCore GatesService
    participant AccessStore as AccessControlDataStore
    participant GateEntries as GateEntriesService
    participant DSComm as DSComm callback client
    participant UDPManager
    participant Channel as UDPChannel
    participant Controller as Door/Gate controller

    UI->>GatesService: Open door command
    GatesService->>AccessStore: Create manual authorization/history
    GatesService->>GateEntries: SendCommand(open-door)
    GateEntries-->>DSComm: Duplex Execute(command)
    DSComm->>UDPManager: Execute open-door
    UDPManager->>Channel: OpenDoor(direction)
    Channel->>Controller: UDP open-door command
          

flowchart LR
    A["Document runtime contracts"]
    B["Protocol parser tests"]
    C["Diagnostics tool"]
    D["Device health and logs"]
    E["Hardware interfaces/adapters"]
    F["Modern local/API facade"]
    G["Gradual UI/runtime modernization"]

    A --> B --> C --> D --> E --> F --> G