Battery component Diagrams

The construction of a component such as our battery looks as follows.

flowchart TD
    A[Power Policy Service<br><i>Service initiates query</i>]
    B[Battery Subsystem Controller<br><i>Orchestrates component behavior</i>]
    C[Battery Component Trait Interface<br><i>Defines the functional contract</i>]
    D[Battery HAL Implementation<br><i>Implements trait using hardware-specific logic</i>]
    E[EC / Hardware Access<br><i>Performs actual I/O operations</i>]

    A --> B
    B --> C
    C --> D
    D --> E

    subgraph Service Layer
        A
    end

    subgraph Subsystem Layer
        B
    end

    subgraph Component Layer
        C
        D
    end

    subgraph Hardware Layer
        E
    end

When in operation, it conducts its operations in response to message events

sequenceDiagram
    participant Service as Power Policy Service
    participant Controller as Battery Subsystem Controller
    participant Component as Battery Component (Trait)
    participant HAL as Battery HAL (Hardware or Mock)

    Service->>Controller: query_battery_state()
    Note right of Controller: Subsystem logic directs call via trait
    Controller->>Component: get_battery_state()
    Note right of Component: Trait implementation calls into HAL
    Component->>HAL: read_charge_level()
    HAL-->>Component: Ok(82%)
    Component-->>Controller: Ok(BatteryState { charge_pct: 82 })
    Controller-->>Service: Ok(BatteryState)

    alt HAL returns error
        HAL-->>Component: Err(ReadError)
        Component-->>Controller: Err(BatteryError)
        Controller-->>Service: Err(BatteryUnavailable)
    end