# Module Reference

Per-file reference for the refactored tree, plus the shared data structures.

## Core (`fgc_core` — SDK-independent, unit-tested)

| File | Contents |
|------|----------|
| [include/fgc/Config.h](../include/fgc/Config.h), [src/core/Config.cpp](../src/core/Config.cpp) | Typed `AppConfig` (General/Network/Serial/Camera/Paths/Features) + `ConfigLoader` (INI parse, env overrides, validation) |
| [include/fgc/Paths.h](../include/fgc/Paths.h), [src/core/Paths.cpp](../src/core/Paths.cpp) | `~`/`$ENV` expansion, executable dir, config search order, default output dir |
| [include/fgc/Logger.h](../include/fgc/Logger.h), [src/core/Logger.cpp](../src/core/Logger.cpp) | Leveled, thread-safe logger; `LOG_TRACE..LOG_ERROR` macros |
| [include/fgc/TelemetryParser.h](../include/fgc/TelemetryParser.h), [src/core/TelemetryParser.cpp](../src/core/TelemetryParser.cpp) | `parseTelemetryLine` → `std::optional<MotorTelemetry>` |
| [include/fgc/CommandParser.h](../include/fgc/CommandParser.h), [src/core/CommandParser.cpp](../src/core/CommandParser.cpp) | `parseCommand` whitespace tokenizer → `Command` |
| [include/fgc/CaptureScheduler.h](../include/fgc/CaptureScheduler.h), [src/core/CaptureScheduler.cpp](../src/core/CaptureScheduler.cpp) | Capture state machine over the interfaces; injectable clock |
| [include/fgc/Application.h](../include/fgc/Application.h), [src/core/Application.cpp](../src/core/Application.cpp) | Factory (real vs mock), wiring, control loop, console commands |
| [ini.c](../ini.c), [ini.h](../ini.h) | Bundled third-party inih INI parser |

## Interfaces

| File | Interface | Shared structs |
|------|-----------|----------------|
| [include/fgc/IMotorController.h](../include/fgc/IMotorController.h) | `IMotorController` | `MotorTelemetry` |
| [include/fgc/IControlChannel.h](../include/fgc/IControlChannel.h) | `IControlChannel` | `ControlCommand`, `CamEvent` |
| [include/fgc/ICameraSource.h](../include/fgc/ICameraSource.h) | `ICameraSource` | `Frame` |

## Real implementations (SDK-gated)

| File | Implements | Built when |
|------|-----------|-----------|
| [src/serial/SerialMotorController.cpp](../src/serial/SerialMotorController.cpp) | `IMotorController` over Boost.Asio serial (pImpl) | always |
| [src/mqtt/MqttControlChannel.cpp](../src/mqtt/MqttControlChannel.cpp) | `IControlChannel` over Eclipse Paho | `WITH_MQTT` |
| [src/camera/VimbaCameraSource.cpp](../src/camera/VimbaCameraSource.cpp) | `ICameraSource` over Vimba X (pImpl) | `WITH_VIMBA` |
| [src/camera/JpegXlEncoder.cpp](../src/camera/JpegXlEncoder.cpp) | libjxl encode-to-file | always |
| [src/camera/ImagePipeline.cpp](../src/camera/ImagePipeline.cpp) | frame → rotate → encode → write → CamEvent (worker thread) | always |

## Mock / null implementations

| File | Implements |
|------|-----------|
| [include/fgc/mock/MockMotorController.h](../include/fgc/mock/MockMotorController.h) | Simulated sweeping gimbal |
| [include/fgc/mock/NullControlChannel.h](../include/fgc/mock/NullControlChannel.h) | No-op channel; auto-sweep |
| [include/fgc/mock/MockCameraSource.h](../include/fgc/mock/MockCameraSource.h) | Synthetic gradient frames |

## Entry point & scripts

| File | Role |
|------|------|
| [main.cpp](../main.cpp) | CLI parsing → `AppConfig` + `RuntimeOptions` → `Application::run()` |
| [scripts/run.sh](../scripts/run.sh) | Path-independent launcher |
| [scripts/fire-gimbal-control.service](../scripts/fire-gimbal-control.service) | systemd unit template |

## Data structures

### `MotorTelemetry` ([IMotorController.h](../include/fgc/IMotorController.h))
`encoder`, `encoder_err`, `sgt_val`, `sgt_stat`, `is_moving`, `control_status`, `heading` (float),
`deviation_warn`, `humidity`, `temperature`, `fan_pwm`. Parsed from the `$;...;` line (humidity is field 9,
temperature field 10 — see [known-issues.md](known-issues.md)).

### `ControlCommand` ([IControlChannel.h](../include/fgc/IControlChannel.h))
`control_code` (0 = auto sweep, 1 = directed) + `target_heading`, each with an `*_available` flag.

### `CamEvent` ([IControlChannel.h](../include/fgc/IControlChannel.h))
`tower`, `camera` (RGB/ACR/NIR), `heading_decideg` (heading×10), `timestamp_ms`. Serialized to the CamEvent
JSON payload (see [mqtt-api.md](mqtt-api.md)).

### `Frame` ([ICameraSource.h](../include/fgc/ICameraSource.h))
Owned pixel buffer + `width`, `height`, `channels` (1 or 3), `timestamp_ms`, `cam_id`.

## On-disk artifacts

| Artifact | Path | Format |
|----------|------|--------|
| Captured images | `<output_dir>/<RGB\|ACR\|NIR>/<unix_ms>.jxl` | JPEG XL, rotated 90° CCW |
| Demo placeholder | `bin/x64/Release/test_smoke.jxl` | copied verbatim in demo mode |

State otherwise lives in memory; diagnostics go to stdout/stderr (no log files, no database).