# 🏥 Claim Guard Backend

> **NestJS application for managing ICD-9 and ICD-10 medical codes with Excel import functionality**

[![NestJS](https://img.shields.io/badge/NestJS-E0234E?style=for-the-badge&logo=nestjs&logoColor=white)](https://nestjs.com/)
[![TypeScript](https://img.shields.io/badge/TypeScript-007ACC?style=for-the-badge&logo=typescript&logoColor=white)](https://www.typescriptlang.org/)
[![PostgreSQL](https://img.shields.io/badge/PostgreSQL-316192?style=for-the-badge&logo=postgresql&logoColor=white)](https://www.postgresql.org/)
[![Docker](https://img.shields.io/badge/Docker-2CA5E0?style=for-the-badge&logo=docker&logoColor=white)](https://www.docker.com/)
[![Prisma](https://img.shields.io/badge/Prisma-3982CE?style=for-the-badge&logo=Prisma&logoColor=white)](https://www.prisma.io/)

## ✨ Features

- 🏥 **ICD Code Management** - Import and manage ICD-9 and ICD-10 medical codes
- 📊 **Excel Import** - Read data from Excel files and store in PostgreSQL
- 🔍 **Search & Filter** - Search codes by category, code, or display text
- 🌐 **REST API** - Full REST API with Swagger documentation
- 📄 **Pagination** - Built-in pagination for large datasets
- 🐳 **Docker Ready** - PostgreSQL with pgvector extension
- 🔄 **Database Migrations** - Prisma migration system
- ✅ **Input Validation** - Type-safe DTOs with validation
- 📚 **API Documentation** - Interactive Swagger UI

## 🚀 Quick Start

### Prerequisites

- Node.js 18+
- Docker & Docker Compose
- Git

### 1. Clone & Install

```bash
git clone <repository-url>
cd claim-guard-be
npm install
```

### 2. Start Database

```bash
# Start PostgreSQL with pgvector
docker-compose up -d

# Verify database is running
docker-compose ps
```

### 3. Setup Environment

```bash
# Copy environment template (edit as needed)
copy .env.example .env

# Update DATABASE_URL in .env:
DATABASE_URL=postgresql://postgres:postgres123@localhost:5432/claim_guard
```

### 4. Run Migrations

```bash
# Apply database schema
npx prisma migrate deploy

# Generate Prisma client
npx prisma generate
```

### 5. Start Application

```bash
# Development mode
npm run start:dev

# Production mode
npm run build
npm run start:prod
```

### 6. Access Services

- **API**: http://localhost:3000
- **Swagger Docs**: http://localhost:3000/docs
- **Health Check**: http://localhost:3000/health

## 📚 API Endpoints

### ICD Management

| Method | Endpoint          | Description                      |
| ------ | ----------------- | -------------------------------- |
| `POST` | `/icd/import`     | Import ICD data from Excel files |
| `GET`  | `/icd/search`     | Search ICD codes with filters    |
| `GET`  | `/icd/statistics` | Get database statistics          |

### Health & Monitoring

| Method | Endpoint        | Description                   |
| ------ | --------------- | ----------------------------- |
| `GET`  | `/health`       | Application health check      |
| `GET`  | `/health/ready` | Readiness probe               |
| `GET`  | `/health/live`  | Liveness probe                |
| `GET`  | `/docs`         | Interactive API documentation |

### Example Usage

```bash
# Import ICD data
curl -X POST http://localhost:3000/icd/import

# Search for diabetes codes
curl "http://localhost:3000/icd/search?search=diabetes&page=1&limit=10"

# Get statistics
curl http://localhost:3000/icd/statistics

# Health check
curl http://localhost:3000/health
```

## 🐳 Docker Setup

### Database Only (Recommended)

```bash
# Start PostgreSQL with pgvector
docker-compose up -d

# Stop database
docker-compose down

# Reset database (deletes all data!)
docker-compose down -v
```

### Connection Details

```env
DATABASE_URL=postgresql://postgres:postgres123@localhost:5432/claim_guard
Host: localhost
Port: 5432
Database: claim_guard
Username: postgres
Password: postgres123
```

### Verify pgvector Extension

```bash
docker-compose exec postgres psql -U postgres -d claim_guard -c "SELECT name, default_version, installed_version FROM pg_available_extensions WHERE name = 'vector';"
```

## 🗂️ Database Schema

### IcdCode Model

```prisma
model IcdCode {
  id        String   @id @default(uuid())
  code      String   @unique
  display   String
  version   String
  category  String   // "ICD9" or "ICD10"
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  @@map("icd_codes")
}
```

### Migration Commands

```bash
# Check migration status
npx prisma migrate status

# Create new migration
npx prisma migrate dev --name description

# Deploy to production
npx prisma migrate deploy

# Reset database (development)
npx prisma migrate reset
```

## ⚙️ Environment Configuration

### Development

```env
NODE_ENV=development
PORT=3000
DATABASE_URL=postgresql://postgres:postgres123@localhost:5432/claim_guard
CORS_ORIGINS=http://localhost:3000,http://localhost:3001
ENABLE_DOCS=true
DEBUG=true
LOG_LEVEL=debug
```

### Production

```env
NODE_ENV=production
PORT=3000
DATABASE_URL=postgresql://user:pass@host:5432/db
CORS_ORIGINS=https://yourdomain.com
ENABLE_DOCS=false
DEBUG=false
LOG_LEVEL=warn
JWT_SECRET=strong-production-secret
```

### Available Variables

| Variable       | Description                  | Default                 |
| -------------- | ---------------------------- | ----------------------- |
| `NODE_ENV`     | Environment mode             | `development`           |
| `PORT`         | Application port             | `3000`                  |
| `DATABASE_URL` | PostgreSQL connection string | Required                |
| `CORS_ORIGINS` | Allowed CORS origins         | `http://localhost:3000` |
| `ENABLE_DOCS`  | Enable Swagger documentation | `true`                  |
| `LOG_LEVEL`    | Logging level                | `info`                  |
| `JWT_SECRET`   | JWT signing secret           | Required for auth       |

## 🧪 Testing

### API Testing

Use the included `icd.http` file with VS Code REST Client extension:

```http
### Import ICD Data
POST http://localhost:3000/icd/import

### Search ICD Codes
GET http://localhost:3000/icd/search?search=diabetes&page=1&limit=10

### Get Statistics
GET http://localhost:3000/icd/statistics
```

### Unit Tests

```bash
# Run tests
npm run test

# Watch mode
npm run test:watch

# Coverage
npm run test:cov

# E2E tests
npm run test:e2e
```

## 🔧 Development

### Project Structure

```
src/
├── main.ts                 # Application entry point
├── app.module.ts           # Root module
├── icd/                    # ICD module
│   ├── icd.controller.ts   # REST endpoints
│   ├── icd.service.ts      # Business logic
│   ├── icd.module.ts       # Module definition
│   └── dto/                # Data transfer objects
├── health/                 # Health check module
└── prisma/                 # Database schema
```

### Scripts

```bash
# Development
npm run start:dev           # Start with hot reload
npm run start:debug         # Start with debugger

# Build
npm run build              # Build for production
npm run start:prod         # Start production build

# Database
npx prisma studio          # Open Prisma Studio
npx prisma db push         # Push schema changes (dev only)
npx prisma generate        # Generate Prisma client

# Code Quality
npm run lint               # Run ESLint
npm run format             # Format with Prettier
```

### Adding New Features

1. **Create DTOs** with validation decorators
2. **Add Swagger decorators** for API documentation
3. **Write unit tests** for services and controllers
4. **Update database schema** if needed
5. **Create migration** with descriptive name

## 📦 Deployment

### Docker Production

```dockerfile
# Build stage
FROM node:18-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
RUN npm run build

# Production stage
FROM node:18-alpine AS production
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
COPY package*.json ./
EXPOSE 3000
CMD ["node", "dist/main"]
```

### Environment Setup

1. **Production Database**: Use managed PostgreSQL (AWS RDS, Google Cloud SQL)
2. **Environment Variables**: Set secure values for production
3. **SSL/TLS**: Enable HTTPS in production
4. **Monitoring**: Add application monitoring (Prometheus, Grafana)
5. **Logging**: Configure centralized logging

## 🐛 Troubleshooting

### Common Issues

**Port 5432 already in use:**

```bash
# Check what's using the port
netstat -ano | findstr :5432
# Stop local PostgreSQL service
```

**Database connection failed:**

```bash
# Check if container is running
docker-compose ps
# Check logs
docker-compose logs
# Restart database
docker-compose restart
```

**Prisma can't connect:**

```bash
# Verify DATABASE_URL in .env
# Test connection
npx prisma db pull
```

**Build errors:**

```bash
# Clean install
rm -rf node_modules package-lock.json
npm install
```

## 📄 License

This project is licensed under the MIT License.

## 🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

## 📞 Support

For questions and support:

- Check the [API documentation](http://localhost:3000/docs)
- Review the troubleshooting section
- Create an issue in the repository

---

**Ready to manage ICD codes efficiently!** 🚀