%% dvd-thing — ports and adapters.
%% Every dependency arrow points inward. domain knows nothing; application knows
%% only domain; adapters know both but are known by neither.
flowchart TB
    subgraph root["bin — composition root"]
        main["main.rs<br/><i>the only place that names Wayland</i>"]
    end

    subgraph adapters["adapters — std"]
        direction LR

        subgraph wayland["wayland"]
            display["WaylandDisplay<br/><i>layer-shell surface, frame pacing, signals</i>"]
            renderer["SoftwareRenderer<br/><i>double-buffered shm, damage tracking</i>"]
            logoimage["LogoImage<br/><i>decode, scale, tint cache</i>"]
            state["WaylandState<br/><i>protocol dispatch</i>"]
        end

        subgraph assets["assets"]
            filesource["FileLogoSource<br/><i>$DVD_LOGO, XDG / macOS / Windows</i>"]
        end
    end

    subgraph app["application — no_std, no alloc"]
        direction LR

        subgraph portsgroup["ports"]
            displayport["DisplayOverlayPort<br/><i>screen_dimensions, wait_for_frame</i>"]
            rendererport["RendererPort<br/><i>render_frame</i>"]
            logoport["LogoSourcePort<br/><i>load</i>"]
        end

        usecases["use_cases<br/><b>run</b> · blocking loop<br/><b>step</b> · one frame, for callback platforms"]
        apperror["ApplicationError<br/><i>heapless Message, 108 bytes</i>"]
    end

    subgraph dom["domain — no_std, no alloc"]
        direction LR

        scene["ScreensaverScene<br/><b>aggregate root</b><br/><i>sole entry point: tick, sprites</i>"]
        logo["BouncingLogo<br/><i>pub(crate)</i>"]
        sparkle["Sparkle<br/><i>pub(crate)</i>"]
        sprite["Sprite + SpriteKind<br/><i>what to draw, not how</i>"]
        vo["Value objects<br/>Point2D · Vector2D<br/>Dimensions · Color<br/><i>self-validating, const fn</i>"]
        domerror["DomainError<br/><i>InvalidDimensions</i>"]
    end

    main --> usecases
    main --> scene
    main -.->|constructs| display
    main -.->|constructs| renderer
    main -.->|constructs| filesource

    usecases --> displayport
    usecases --> rendererport
    usecases --> scene

    display -.->|implements| displayport
    renderer -.->|implements| rendererport
    filesource -.->|implements| logoport

    renderer -->|"sprites()"| scene
    renderer --> logoimage
    logoimage -->|"load()"| logoport
    renderer --> display
    display --> state

    scene -->|owns| logo
    scene -->|"owns [Option Sparkle; 108]"| sparkle
    logo --> sprite
    sparkle --> sprite
    sprite --> vo
    scene --> vo
    scene -.->|"new() rejects"| domerror
    apperror -.->|wraps| domerror

    classDef domainStyle fill:#1f4e3d,stroke:#41b883,color:#e8f5ee
    classDef appStyle fill:#1e3a5f,stroke:#4a9eff,color:#e6f0ff
    classDef adapterStyle fill:#4a3410,stroke:#d99a2b,color:#fdf3e0
    classDef rootStyle fill:#3d2645,stroke:#b06fc9,color:#f6ecfa

    style root fill:#88888810,stroke:#9a9a9a
    style adapters fill:#88888810,stroke:#9a9a9a
    style wayland fill:#88888810,stroke:#9a9a9a
    style assets fill:#88888810,stroke:#9a9a9a
    style app fill:#88888810,stroke:#9a9a9a
    style portsgroup fill:#88888810,stroke:#9a9a9a
    style dom fill:#88888810,stroke:#9a9a9a

    class scene,logo,sparkle,sprite,vo,domerror domainStyle
    class displayport,rendererport,logoport,usecases,apperror appStyle
    class display,renderer,logoimage,state,filesource adapterStyle
    class main rootStyle