# Python Detector Worker - CLAUDE.md

## Project Overview
This is a FastAPI-based computer vision detection worker that processes video streams from RTSP/HTTP sources and runs advanced YOLO-based machine learning pipelines for multi-class object detection and parallel classification. The system features comprehensive database integration, Redis support, and hierarchical pipeline execution designed to work within a larger CMS (Content Management System) architecture.

**IMPORTANT**: This project has been completely refactored from a monolithic 4,000+ line codebase into a modular, maintainable architecture with dependency injection, comprehensive testing, and clear separation of concerns.

### Key Features
- **Multi-Class Detection**: Simultaneous detection of multiple object classes (e.g., Car + Frontal)
- **Parallel Processing**: Concurrent execution of classification branches using ThreadPoolExecutor
- **Database Integration**: Automatic PostgreSQL schema management and record updates
- **Redis Actions**: Image storage with region cropping and pub/sub messaging
- **Pipeline Synchronization**: Branch coordination with `waitForBranches` functionality
- **Dynamic Field Mapping**: Template-based field resolution for database operations
- **Modular Architecture**: Clean separation of concerns with dependency injection
- **Thread-Safe Operations**: Singleton managers for global state management
- **Comprehensive Testing**: Unit, integration, and performance test suites

## Architecture & Technology Stack
- **Framework**: FastAPI with WebSocket support and modern async patterns
- **ML/CV**: PyTorch, Ultralytics YOLO, OpenCV with BoT-SORT tracking
- **Containerization**: Docker (Python 3.13-bookworm base)
- **Data Storage**: Redis integration for action handling + PostgreSQL for persistent storage
- **Database**: Automatic schema management with gas_station_1 database
- **Parallel Processing**: ThreadPoolExecutor for concurrent classification
- **Communication**: WebSocket-based real-time protocol
- **Design Patterns**: Dependency Injection, Singleton, Repository patterns
- **Testing**: Pytest with asyncio, mocking, and benchmarking support

## New Modular Architecture

### Core Directory Structure
```
detector_worker/
├── core/                    # Core infrastructure components
│   ├── config.py           # Multi-source configuration management
│   ├── constants.py        # Application constants
│   ├── exceptions.py       # Custom exception hierarchy
│   ├── singleton_managers.py  # Thread-safe singleton managers
│   └── dependency_injection.py  # IoC container implementation
├── detection/              # Computer vision and ML components
│   ├── yolo_detector.py    # YOLO model inference
│   ├── tracking_manager.py # BoT-SORT multi-object tracking
│   └── stability_validator.py  # Detection stability validation
├── pipeline/               # ML pipeline execution
│   ├── pipeline_executor.py   # Main pipeline orchestration
│   ├── action_executor.py     # Redis/DB action execution
│   └── field_mapper.py        # Template-based field mapping
├── streams/                # Video stream management
│   ├── stream_manager.py      # Stream lifecycle management
│   ├── frame_reader.py        # RTSP/HTTP frame reading
│   └── camera_monitor.py      # Connection state monitoring
├── communication/          # WebSocket and messaging
│   ├── websocket_handler.py   # WebSocket connection management
│   ├── message_processor.py   # Message routing and processing
│   └── response_formatter.py  # Response formatting
├── storage/                # Data persistence
│   ├── database_manager.py    # PostgreSQL operations
│   ├── redis_client.py        # Redis operations
│   └── session_cache.py       # Session and cache management
├── models/                 # Model and pipeline management
│   ├── model_manager.py       # YOLO model loading/caching
│   └── pipeline_loader.py     # MPTA pipeline loading
└── utils/                  # Utility functions
    ├── logging_utils.py       # Structured logging setup
    ├── image_utils.py         # Image processing utilities
    └── system_utils.py        # System monitoring utilities
```

### Main Application (`app.py`)
- **FastAPI application** with modern lifespan management (replacing deprecated @app.on_event)
- **Dependency injection container** initialization and service registration
- **WebSocket endpoint** delegation to communication layer
- **HTTP REST endpoint** for image retrieval (`/camera/{camera_id}/image`)
- **Clean separation** between framework code and business logic
- **Resource monitoring** integrated with singleton managers

### Core Infrastructure (`core/`)

#### Configuration Management (`core/config.py`)
- **Multi-source configuration** with environment variables, JSON files, and defaults
- **Type-safe configuration** with proper validation and error handling
- **Development/production** environment support
- **Configuration providers** pattern for extensible config sources

#### Singleton Managers (`core/singleton_managers.py`)
- **Thread-safe singleton implementation** using metaclass pattern
- **Six specialized managers**:
  - `SubscriptionManager`: WebSocket subscription lifecycle
  - `StreamManager`: RTSP/HTTP stream management with reference counting
  - `ModelManager`: YOLO model loading and caching
  - `PipelineManager`: MPTA pipeline loading and management
  - `SessionManager`: Session tracking and management
  - `SessionCacheManager`: Redis-backed session caching
- **Replaces global dictionaries** for thread-safe state management

#### Dependency Injection (`core/dependency_injection.py`)
- **Full IoC container** with automatic constructor injection
- **Three service lifetimes**: Singleton, Transient, Scoped
- **Interface-based registration** supporting both concrete types and factories
- **Circular dependency detection** and resolution
- **Scope management** for request-scoped services

### Detection System (`detection/`)

#### YOLO Detector (`detection/yolo_detector.py`)
- **YOLODetector class** for inference management
- **Multi-class detection** support (Car + Frontal simultaneously)
- **GPU/CPU optimization** with automatic device selection
- **Confidence filtering** and NMS post-processing
- **Integration with tracking system**

#### Tracking Manager (`detection/tracking_manager.py`)
- **BoT-SORT implementation** for multi-object tracking
- **Track lifecycle management** with unique ID assignment
- **Stability validation** integration for reliable detections
- **Performance optimization** with configurable parameters

#### Stability Validator (`detection/stability_validator.py`)
- **Detection stability analysis** over time windows
- **Confidence trend analysis** for reliable object detection
- **Configurable thresholds** for stability determination
- **Integration with tracking and pipeline systems**

### Pipeline System (`pipeline/`)

#### Pipeline Executor (`pipeline/pipeline_executor.py`)
- **PipelineExecutor class** for orchestrating MPTA pipeline execution
- **Hierarchical execution** with detection → classification branching
- **Parallel processing** using ThreadPoolExecutor for classification branches
- **Branch synchronization** with `waitForBranches` coordination
- **Error handling** and retry mechanisms

#### Action Executor (`pipeline/action_executor.py`)
- **ActionExecutor class** for Redis and database actions
- **Redis image storage** with region cropping and expiration
- **PostgreSQL operations** with automatic schema management
- **Pub/sub messaging** for real-time notifications
- **Template-based configuration** for dynamic action parameters

#### Field Mapper (`pipeline/field_mapper.py`)
- **FieldMapper class** for template-based field resolution
- **Dynamic field mapping** from classification results to database fields
- **Template syntax**: `{model_id.field_name}` → actual values
- **Type-safe field resolution** with error handling

### Stream Management (`streams/`)

#### Stream Manager (`streams/stream_manager.py`)
- **StreamManager class** for RTSP/HTTP stream lifecycle management
- **Reference counting** for shared stream optimization
- **Automatic reconnection** with exponential backoff
- **Thread-safe operations** with proper locking mechanisms

#### Frame Reader (`streams/frame_reader.py`)
- **FrameReader class** for RTSP stream processing
- **SnapshotReader class** for HTTP snapshot capture
- **Queue-based buffering** with latest frame optimization
- **Error handling** and connection recovery

#### Camera Monitor (`streams/camera_monitor.py`)
- **CameraMonitor class** for connection state tracking
- **Health monitoring** and status reporting
- **Integration with stream management** for failure detection

### Communication Layer (`communication/`)

#### WebSocket Handler (`communication/websocket_handler.py`)
- **WebSocketHandler class** for connection lifecycle management
- **Message routing** to appropriate processors
- **Error handling** and graceful disconnection
- **Integration with subscription management**

#### Message Processor (`communication/message_processor.py`)
- **MessageProcessor class** for message routing and handling
- **Type-safe message processing** with validation
- **Integration with detection pipeline** and state management
- **Real-time response formatting**

#### Response Formatter (`communication/response_formatter.py`)
- **ResponseFormatter class** for consistent message formatting
- **Detection result formatting** with timestamp and metadata
- **State report generation** with system metrics
- **JSON serialization** with type safety

### Storage Layer (`storage/`)

#### Database Manager (`storage/database_manager.py`)
- **DatabaseManager class** with Repository pattern implementation
- **Automatic schema management** for gas_station_1.car_frontal_info
- **Connection pooling** and transaction management
- **Combined update operations** with field mapping
- **Error handling** and retry mechanisms

#### Redis Client (`storage/redis_client.py`)
- **RedisClient class** for Redis operations
- **Image storage** with automatic expiration
- **Pub/sub messaging** for real-time notifications
- **Connection management** with retry logic
- **Type-safe operations** with proper error handling

#### Session Cache (`storage/session_cache.py`)
- **SessionCacheManager class** for session and cache management
- **Redis-backed caching** with configurable expiration
- **Session tracking** with UUID generation
- **Thread-safe operations** with singleton pattern

### Model Management (`models/`)

#### Model Manager (`models/model_manager.py`)
- **ModelManager class** for YOLO model lifecycle management
- **Model caching** with memory optimization
- **GPU/CPU device management** with automatic selection
- **Thread-safe model loading** and inference preparation

#### Pipeline Loader (`models/pipeline_loader.py`)
- **PipelineLoader class** for MPTA archive handling
- **ZIP archive extraction** and validation
- **Configuration parsing** with schema validation
- **Model file management** and loading coordination

## System Workflow

### Application Startup (app.py)
1. **Configuration Loading** - Multi-source configuration initialization
2. **Dependency Container Setup** - Service registration and IoC container configuration
3. **Singleton Manager Initialization** - Thread-safe global state managers
4. **FastAPI Application Creation** - Modern lifespan management setup
5. **Service Registration** - All components registered with dependency injection
6. **Server Launch** - Uvicorn server startup with WebSocket support

### WebSocket Connection Flow
1. **Client Connection** (`communication/websocket_handler.py:35`)
2. **Message Reception** (`communication/message_processor.py:42`)
3. **Subscription Processing** (`communication/message_processor.py:78`)
4. **Stream Initialization** (`streams/stream_manager.py:156`)
5. **Model Loading** (`models/model_manager.py:89`)
6. **Pipeline Setup** (`pipeline/pipeline_executor.py:67`)

### Detection Pipeline Flow
1. **Frame Capture** (`streams/frame_reader.py:123`)
2. **YOLO Detection** (`detection/yolo_detector.py:145`)
3. **Multi-Object Tracking** (`detection/tracking_manager.py:178`)
4. **Stability Validation** (`detection/stability_validator.py:92`)
5. **Pipeline Execution** (`pipeline/pipeline_executor.py:234`)
6. **Action Execution** (`pipeline/action_executor.py:189`)
7. **Field Mapping** (`pipeline/field_mapper.py:67`)
8. **Database Update** (`storage/database_manager.py:234`)
9. **Response Formatting** (`communication/response_formatter.py:89`)

## WebSocket Protocol

### Message Types
- **subscribe**: Start camera stream with model pipeline
- **unsubscribe**: Stop camera stream processing
- **requestState**: Request current worker status
- **setSessionId**: Associate display with session identifier
- **patchSession**: Update session data
- **stateReport**: Periodic heartbeat with system metrics
- **imageDetection**: Detection results with timestamp and model info

### Subscription Format
```json
{
  "type": "subscribe",
  "payload": {
    "subscriptionIdentifier": "display-001;cam-001",
    "rtspUrl": "rtsp://...",  // OR snapshotUrl
    "snapshotUrl": "http://...",
    "snapshotInterval": 5000,
    "modelUrl": "http://...model.mpta",
    "modelId": 101,
    "modelName": "Vehicle Detection",
    "cropX1": 100, "cropY1": 200,
    "cropX2": 300, "cropY2": 400
  }
}
```

## Model Pipeline (MPTA) Format

### Enhanced Structure
- **ZIP archive** containing models and configuration
- **pipeline.json** - Main configuration file with Redis + PostgreSQL settings
- **Model files** - YOLO .pt files for detection/classification
- **Multi-model support** - Detection + multiple classification models

### Advanced Pipeline Flow
1. **Multi-class detection stage** - YOLO detection of Car + Frontal simultaneously
2. **Validation stage** - Check for expected classes (flexible matching)
3. **Database initialization** - Create initial record with session_id
4. **Redis actions** - Save cropped frontal images with expiration
5. **Parallel classification** - Concurrent brand and body type classification
6. **Branch synchronization** - Wait for all classification branches to complete
7. **Database update** - Combined update with all classification results

### Enhanced Branch Configuration
```json
{
  "modelId": "car_frontal_detection_v1",
  "modelFile": "car_frontal_detection_v1.pt",
  "multiClass": true,
  "expectedClasses": ["Car", "Frontal"],
  "triggerClasses": ["Car", "Frontal"],
  "minConfidence": 0.8,
  "actions": [
    {
      "type": "redis_save_image",
      "region": "Frontal",
      "key": "inference:{display_id}:{timestamp}:{session_id}:{filename}",
      "expire_seconds": 600
    }
  ],
  "branches": [
    {
      "modelId": "car_brand_cls_v1",
      "modelFile": "car_brand_cls_v1.pt",
      "parallel": true,
      "crop": true,
      "cropClass": "Frontal",
      "triggerClasses": ["Frontal"],
      "minConfidence": 0.85
    }
  ],
  "parallelActions": [
    {
      "type": "postgresql_update_combined",
      "table": "car_frontal_info",
      "key_field": "session_id",
      "waitForBranches": ["car_brand_cls_v1", "car_bodytype_cls_v1"],
      "fields": {
        "car_brand": "{car_brand_cls_v1.brand}",
        "car_body_type": "{car_bodytype_cls_v1.body_type}"
      }
    }
  ]
}
```

## Testing Infrastructure

### Test Structure
```
tests/
├── unit/                   # Unit tests for individual components
│   ├── core/              # Core infrastructure tests
│   ├── detection/         # Computer vision component tests
│   ├── pipeline/          # Pipeline execution tests
│   ├── streams/           # Stream management tests
│   ├── communication/     # WebSocket and messaging tests
│   ├── storage/           # Database and Redis tests
│   └── models/            # Model management tests
├── integration/           # End-to-end workflow tests
├── performance/          # Performance benchmarks and load tests
└── fixtures/             # Test data and mock objects
```

### Test Commands
```bash
# Run all tests
make test

# Run specific test categories
make test-unit
make test-integration
make test-performance

# Run with coverage reporting
make test-coverage

# Run code quality checks
make lint
make format
```

## Development & Deployment

### Local Development Setup
```bash
# Install dependencies
make install-dev

# Run the application
make run

# Run with debug mode
make run-debug

# Run tests
make test

# Format code
make format

# Run quality checks
make quality
```

### Docker Deployment
```bash
# Build container
make docker-build

# Run container
make docker-run

# Development container with volume mounts
make docker-dev
```

### Configuration Management
- **Environment Variables**: Override default configuration
- **config.json**: Development and production settings
- **DETECTOR_WORKER_ENV**: Environment selection (dev/test/prod)

## Code Conventions & Patterns

### Design Patterns Used
- **Dependency Injection**: IoC container with automatic constructor injection
- **Singleton Pattern**: Thread-safe implementation using metaclass
- **Repository Pattern**: Database operations with interface abstraction
- **Factory Pattern**: Model and pipeline loading with configurable factories
- **Observer Pattern**: WebSocket communication and event handling

### Code Quality Standards
- **Type Hints**: Comprehensive type annotations throughout codebase
- **Error Handling**: Structured exception hierarchy with proper propagation
- **Logging**: Structured logging with context-aware messages
- **Testing**: Unit, integration, and performance tests with high coverage
- **Documentation**: Comprehensive docstrings and inline documentation

### Performance Optimizations
- **GPU Acceleration**: CUDA support with automatic fallback to CPU
- **Memory Management**: Model caching with automatic cleanup
- **Thread Safety**: Proper locking mechanisms for concurrent operations
- **Resource Monitoring**: CPU, memory, and GPU usage tracking
- **Connection Pooling**: Database and Redis connection optimization

## Security Considerations
- **Input Validation**: All WebSocket messages and configuration validated
- **Resource Limits**: Configurable limits for streams, models, and connections
- **Error Handling**: Graceful failure handling without information leakage
- **Authentication**: Redis and PostgreSQL connection security
- **Model Security**: MPTA file validation and secure model loading

## Database Integration

### Schema Management
The system automatically creates and manages PostgreSQL tables:

```sql
CREATE TABLE IF NOT EXISTS gas_station_1.car_frontal_info (
    display_id VARCHAR(255),
    captured_timestamp VARCHAR(255),
    session_id VARCHAR(255) PRIMARY KEY,
    license_character VARCHAR(255) DEFAULT NULL,
    license_type VARCHAR(255) DEFAULT 'No model available',
    car_brand VARCHAR(255) DEFAULT NULL,
    car_model VARCHAR(255) DEFAULT NULL,
    car_body_type VARCHAR(255) DEFAULT NULL,
    created_at TIMESTAMP DEFAULT NOW(),
    updated_at TIMESTAMP DEFAULT NOW()
);
```

### Workflow
1. **Detection**: When both "Car" and "Frontal" are detected, create initial database record with UUID session_id
2. **Redis Storage**: Save cropped frontal image to Redis with session_id in key
3. **Parallel Processing**: Run brand and body type classification concurrently
4. **Synchronization**: Wait for all branches to complete using `waitForBranches`
5. **Database Update**: Update record with combined classification results using field mapping

### Field Mapping
Templates like `{car_brand_cls_v1.brand}` are resolved to actual classification results:
- `car_brand_cls_v1.brand` → "Honda"
- `car_bodytype_cls_v1.body_type` → "Sedan"

## Migration from Legacy Code

### Key Changes
- **Monolithic to Modular**: 4,000+ lines split into 30+ focused modules
- **Global State Elimination**: Replaced with thread-safe singleton managers
- **Dependency Injection**: Automatic constructor injection with IoC container
- **Modern FastAPI**: Deprecated patterns replaced with current best practices
- **Comprehensive Testing**: Full test suite with unit, integration, and performance tests

### Breaking Changes
- **Import Paths**: All imports now use `detector_worker.` prefix
- **Configuration**: New multi-source configuration system
- **Dependencies**: New dependency injection requirements
- **Testing**: New test infrastructure and commands

## Dependencies
- **fastapi[standard]**: Web framework with WebSocket support
- **uvicorn**: ASGI server
- **torch, torchvision**: PyTorch for ML inference
- **ultralytics**: YOLO implementation
- **opencv-python**: Computer vision operations
- **websockets**: WebSocket client/server
- **redis**: Redis client for action execution
- **psycopg2-binary**: PostgreSQL database adapter
- **scipy**: Scientific computing for advanced algorithms
- **filterpy**: Kalman filtering and state estimation
- **pytest**: Testing framework with asyncio support
- **black, isort**: Code formatting tools
- **mypy**: Static type checking
- **flake8**: Code quality analysis

## References
- **ARCHITECTURE.md**: Comprehensive technical documentation with flow diagrams
- **test_protocol.py**: WebSocket communication validation
- **pipeline_webcam.py**: Local testing with visual output
- **Makefile**: Development workflow commands
- **tox.ini**: Multi-environment testing configuration