# CLQMS Project Overview

## Project Purpose
CLQMS (Clinical Laboratory Quality Management System) is a headless REST API backend for clinical laboratory workflows. It provides comprehensive JSON endpoints for:
- Patient management
- Order/test management  
- Specimen tracking
- Result management and verification
- Reference ranges
- Laboratory instrument integration (Edge API)

## Tech Stack
- **Language**: PHP 8.1+
- **Framework**: CodeIgniter 4 (API-only mode)
- **Database**: MySQL with MySQLi driver
- **Authentication**: JWT (JSON Web Tokens)
- **Testing**: PHPUnit 10.5+
- **Documentation**: OpenAPI/Swagger YAML

## Architecture
- **API-First**: No view layer, headless REST API only
- **Stateless**: JWT-based authentication per request
- **UTC Dates**: All dates stored in UTC, converted for display
- **PSR-4 Autoloading**: `App\` → `app/`, `Config\` → `app/Config/`

## Key Directories
```
app/
  Controllers/     # API endpoint handlers
  Models/          # Database models
  Libraries/       # Helper classes (Lookups, ValueSet)
  Database/
    Migrations/    # Schema migrations
    Seeds/         # Test data seeders
  Helpers/         # json_helper.php, utc_helper.php
  Traits/          # ResponseTrait
  Config/          # Configuration files
  Filters/         # AuthFilter, CORS

public/            # Web root
  paths/           # OpenAPI path definitions
  components/schemas/  # OpenAPI schemas

tests/
  feature/         # Feature/integration tests
  unit/            # Unit tests
  _support/        # Test support files
```

## Key Dependencies
- `codeigniter4/framework` - Core framework
- `firebase/php-jwt` - JWT authentication
- `fakerphp/faker` - Test data generation (dev)
- `phpunit/phpunit` - Testing (dev)