# Module: ai_availability_status

## Purpose

Thread-safe status tracker for the AI engine lifecycle (downloading, converting, uploading, enabled, warning, error).

## Public Interface

### Enum: AIAvailabilityEnum

| Value | Name | Meaning |
|-------|------|---------|
| 0 | NONE | Initial state, not yet initialized |
| 10 | DOWNLOADING | Model download in progress |
| 20 | CONVERTING | ONNX-to-TensorRT conversion in progress |
| 30 | UPLOADING | Converted model upload in progress |
| 200 | ENABLED | Engine ready for inference |
| 300 | WARNING | Operational with warnings |
| 500 | ERROR | Failed, not operational |

### Class: AIAvailabilityStatus

| Field | Type | Description |
|-------|------|-------------|
| `status` | AIAvailabilityEnum | Current status |
| `error_message` | str or None | Error/warning details |

| Method | Signature | Description |
|--------|-----------|-------------|
| `__init__` | `()` | Sets status=NONE, error_message=None |
| `__str__` | `() -> str` | Thread-safe formatted string: `"StatusText ErrorText"` |
| `serialize` | `() -> bytes` | Thread-safe msgpack serialization `{s: status, m: error_message}` **(legacy — not called in current codebase)** |
| `set_status` | `(AIAvailabilityEnum status, str error_message=None) -> void` | Thread-safe status update; logs via constants_inf (error or info) |

## Internal Logic

All public methods acquire a `threading.Lock` before reading/writing status fields. `set_status` logs the transition: errors go to `constants_inf.logerror`, normal transitions go to `constants_inf.log`.

## Dependencies

- **External**: `msgpack`, `threading`
- **Internal**: `constants_inf` (logging)

## Consumers

- `inference` — creates instance, calls `set_status` during engine lifecycle, exposes `ai_availability_status` for health checks
- `main` — reads `ai_availability_status` via inference for `/health` endpoint

## Data Models

- `AIAvailabilityEnum` — status enum
- `AIAvailabilityStatus` — stateful status holder

## Configuration

None.

## External Integrations

None.

## Security

Thread-safe via Lock — safe for concurrent access from FastAPI async + ThreadPoolExecutor.

## Tests

None found.