# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

INTERCEPT is a web-based Signal Intelligence (SIGINT) platform providing a unified Flask interface for software-defined radio (SDR) tools. It supports pager decoding, 433MHz sensors, ADS-B aircraft tracking, ACARS messaging, WiFi/Bluetooth scanning, satellite tracking, ISS SSTV decoding, AIS vessel tracking, weather satellite imagery (NOAA APT & Meteor LRPT), and Meshtastic mesh networking.

## Common Commands

### Docker (Primary)
```bash
# Build and run (basic profile)
docker compose --profile basic up -d

# Build and run with ADS-B history (Postgres)
docker compose --profile history up -d

# Rebuild after code changes
docker compose --profile basic up -d --build

# Multi-arch build (amd64 + arm64 for RPi)
./build-multiarch.sh
```

### Local Setup (Alternative)
```bash
# First-time setup (interactive wizard with install profiles)
./setup.sh

# Or headless full install
./setup.sh --non-interactive

# Or install specific profiles
./setup.sh --profile=core,weather

# Run with production server (gunicorn + gevent, handles concurrent SSE/WebSocket)
sudo ./start.sh

# Or for quick local dev (Flask dev server)
sudo -E venv/bin/python intercept.py

# Other setup utilities
./setup.sh --health-check      # Verify installation
./setup.sh --postgres-setup    # Set up ADS-B history database
./setup.sh --menu              # Force interactive menu
```

### Testing
```bash
# Run all tests
pytest

# Run specific test file
pytest tests/test_bluetooth.py

# Run with coverage
pytest --cov=routes --cov=utils

# Run a specific test
pytest tests/test_bluetooth.py::test_function_name -v
```

### Linting and Formatting
```bash
# Lint with ruff
ruff check .

# Auto-fix linting issues
ruff check --fix .

# Format with black
black .

# Type checking
mypy .
```

## Architecture

### Entry Points
- `setup.sh` - Menu-driven installer with profile system (wizard, health check, PostgreSQL setup, env configurator, update, uninstall). Sources `.env` on startup via `start.sh`.
- `start.sh` - Production startup script (gunicorn + gevent auto-detection, CLI flags, HTTPS, `.env` sourcing, fallback to Flask dev server)
- `intercept.py` - Direct Flask dev server entry point (quick local development)
- `app.py` - Flask application initialization, global state management, process lifecycle, SSE streaming infrastructure, conditional gevent monkey-patch

### Route Blueprints (routes/)
Each signal type has its own Flask blueprint:
- `pager.py` - POCSAG/FLEX decoding via rtl_fm + multimon-ng
- `sensor.py` - 433MHz IoT sensors via rtl_433
- `adsb.py` - Aircraft tracking via dump1090 (SBS protocol on port 30003)
- `acars.py` - Aircraft datalink messages via acarsdec
- `wifi.py`, `wifi_v2.py` - WiFi scanning (legacy and unified APIs)
- `bluetooth.py`, `bluetooth_v2.py` - Bluetooth scanning (legacy and unified APIs)
- `satellite.py` - Pass prediction using TLE data
- `sstv.py` - ISS SSTV image decoding via slowrx
- `weather_sat.py` - NOAA APT & Meteor LRPT via SatDump
- `ais.py` - AIS vessel tracking and VHF DSC distress monitoring
- `aprs.py` - Amateur packet radio via direwolf
- `rtlamr.py` - Utility meter reading
- `meshtastic_routes.py` - Meshtastic LoRa mesh networking

### Core Utilities (utils/)

**SDR Abstraction Layer** (`utils/sdr/`):
- `SDRFactory` with factory pattern for multiple SDR types (RTL-SDR, LimeSDR, HackRF, Airspy, SDRPlay)
- Each type has a `CommandBuilder` for generating CLI commands

**Bluetooth Module** (`utils/bluetooth/`):
- Multi-backend: DBus/BlueZ primary, fallback for systems without BlueZ
- `aggregator.py` - Merges observations across time
- `tracker_signatures.py` - 47K+ known tracker fingerprints (AirTag, Tile, SmartTag)
- `heuristics.py` - Behavioral analysis for device classification

**TSCM (Counter-Surveillance)** (`utils/tscm/`):
- `baseline.py` - Snapshot "normal" RF environment
- `detector.py` - Compare current scan to baseline, flag anomalies
- `device_identity.py` - Track devices despite MAC randomization
- `correlation.py` - Cross-reference Bluetooth and WiFi observations

**WiFi Utilities** (`utils/wifi/`):
- Platform-agnostic scanner with parsers for airodump-ng, nmcli, iw, iwlist, airport (macOS)
- `channel_analyzer.py` - Frequency band analysis

**Weather Satellite** (`utils/weather_sat.py`):
- Singleton `WeatherSatDecoder` using SatDump CLI for NOAA APT and Meteor LRPT
- Subprocess management with stdout parsing, image watcher via rglob
- Pass prediction using skyfield TLE data

**SSTV Decoder** (`utils/sstv.py`):
- ISS SSTV reception via slowrx with Doppler tracking
- Singleton pattern, image gallery with timestamped filenames

### Key Patterns

**Server-Sent Events (SSE)**: All real-time features stream via SSE endpoints (`/stream_pager`, `/stream_sensor`, etc.). Pattern uses `queue.Queue` with timeout and keepalive messages. Under gunicorn + gevent, each SSE connection is a lightweight greenlet instead of an OS thread.

**Process Management**: External decoders run as subprocesses with output threads feeding queues. Use `safe_terminate()` for cleanup. Global locks prevent race conditions.

**Data Stores**: `DataStore` class with TTL-based automatic cleanup (WiFi: 10min, Bluetooth: 5min, Aircraft: 5min).

**Input Validation**: Centralized in `utils/validation.py` - always validate frequencies, gains, device indices before spawning processes.

### External Tool Integrations

| Tool | Purpose | Integration |
|------|---------|-------------|
| rtl_fm | FM demodulation | Subprocess, pipes to multimon-ng |
| multimon-ng | Pager decoding | Reads from rtl_fm stdout |
| rtl_433 | 433MHz sensors | JSON output parsing |
| dump1090 | ADS-B decoding | SBS protocol socket (port 30003) |
| acarsdec | ACARS messages | Output parsing |
| airmon-ng/airodump-ng | WiFi scanning | Monitor mode, CSV parsing |
| bluetoothctl/hcitool | Bluetooth | Fallback when DBus unavailable |
| slowrx | SSTV decoding | Subprocess with audio pipe |
| SatDump | Weather satellites | CLI live mode, NOAA APT + Meteor LRPT |
| AIS-catcher | AIS vessel tracking | JSON output parsing |
| direwolf | APRS | TNC modem for packet radio |

### Frontend Structure
- **Templates**: `templates/index.html` (main SPA), `templates/partials/modes/*.html` (sidebar panels), `templates/partials/nav.html` (global nav)
- **JS Modules**: `static/js/modes/*.js` - IIFE pattern per mode (e.g., `WeatherSat`, `SSTV`, `Meshtastic`)
- **CSS**: `static/css/modes/*.css` - scoped styles per mode, CSS variables for theming (`--bg-card`, `--accent-cyan`, `--font-mono`)
- **Mode Integration**: Each mode needs entries in `index.html` at ~12 points: CSS include, welcome card, partial include, visuals container, JS include, `validModes` set, `modeGroups` map, classList toggle, `modeNames`, visuals display toggle, titles, and init call in `switchMode()`

### Docker
- `Dockerfile` - Single-stage build with all SDR tools compiled from source (dump1090, AIS-catcher, slowrx, SatDump, etc.). CMD runs `start.sh` (gunicorn + gevent)
- `docker-compose.yml` - Two profiles: `basic` (standalone) and `history` (with Postgres for ADS-B)
- `build-multiarch.sh` - Multi-arch build script for amd64 + arm64 (RPi5)
- Data persisted via `./data:/app/data` volume mount

### Configuration
- `config.py` - Environment variable support with `INTERCEPT_` prefix (e.g., `INTERCEPT_PORT`, `INTERCEPT_WEATHER_SAT_GAIN`)
- Database: SQLite in `instance/` directory for settings, baselines, history

## Testing Notes

Tests use pytest with extensive mocking of external tools. Key fixtures in `tests/conftest.py`. Mock subprocess calls when testing decoder integration.