%%{init: {"theme": "base", "themeVariables": {"background": "#fffdf7", "primaryTextColor": "#222222", "fontFamily": "Arial, sans-serif", "lineColor": "#565656"}}}%%
flowchart TD
    M["Selected backend mode"] --> API["HF API<br/>Qwen/Qwen3-4B"]
    M --> Local["ZeroGPU or local<br/>OpenBMB"]
    M --> D["Deterministic mode<br/>no token required"]

    API --> V["Validate structured output"]
    Local --> V
    D --> V

    API -->|"missing token<br/>timeout<br/>invalid JSON"| F["Deterministic fallback"]
    Local -->|"GPU unavailable<br/>load failure<br/>invalid output"| F
    V -->|"invalid after repair"| F
    F --> V

    V -->|"valid"| R["Stage beat"]
    R --> T["Sanitized trace export"]

    classDef stage fill:#fff2b8,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    classDef model fill:#dcecff,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    classDef runtime fill:#ece8ff,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    classDef fallback fill:#fbdada,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    classDef validate fill:#d9f3df,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    classDef trace fill:#f9e1ee,stroke:#2c2c2c,color:#222222,stroke-width:2px;
    class M runtime;
    class API,Local model;
    class D,F fallback;
    class V validate;
    class R stage;
    class T trace;