# HTTP Server Setup and Dependency Injection

## Overview

The Tender Management API server has been successfully initialized with proper dependency injection following Clean Architecture principles. The server uses Echo v4 as the HTTP framework and implements a complete dependency injection chain.

## Architecture

### Dependency Injection Chain

```
MongoDB Connection Manager
         ↓
    Repositories
         ↓
     Services
         ↓
    Handlers
         ↓
    HTTP Server (Echo)
```

### Components

1. **MongoDB Connection Manager** (`pkg/mongo/connection.go`)
   - Manages database connections and pooling
   - Provides connection to repositories

2. **Repositories** (`internal/customer/repository.go`)
   - Data access layer
   - Implements repository pattern
   - Handles database operations

3. **Services** (`internal/customer/service.go`)
   - Business logic layer
   - Implements use cases
   - Depends on repositories

4. **Handlers** (`internal/customer/handler.go`)
   - HTTP request/response handling
   - Input validation
   - Depends on services

5. **HTTP Server** (`cmd/web/main.go`)
   - Echo v4 server with middleware
   - Route registration
   - Server lifecycle management

## Server Features

### Middleware Stack

1. **Recover** - Panic recovery
2. **RequestID** - Unique request identification
3. **Logger** - Request logging
4. **CORS** - Cross-origin resource sharing
5. **Custom Logging** - Structured request logging

### Endpoints

#### Health Check
- `GET /health` - Server health status

#### Customer Endpoints
- `POST /api/customers/login` - Customer login
- `POST /api/customers/refresh-token` - Token refresh
- `GET /api/customers/profile` - Get profile (protected)
- `PUT /api/customers/profile` - Update profile (protected)
- `PUT /api/customers/change-password` - Change password (protected)
- `POST /api/customers/device-token` - Add device token (protected)
- `DELETE /api/customers/device-token` - Remove device token (protected)
- `POST /api/customers/logout` - Logout (protected)

#### Admin Endpoints
- `POST /api/admin/customers/register` - Register customer (admin)
- `GET /api/admin/customers` - List customers (admin)
- `GET /api/admin/customers/:id` - Get customer by ID (admin)
- `PUT /api/admin/customers/:id/status` - Update customer status (admin)
- `GET /api/admin/customers/device-tokens` - Get all device tokens (admin)

## Configuration

### Server Configuration (`config.yaml`)

```yaml
server:
  host: "0.0.0.0"
  port: 8081
  timeout: 30s
  read_timeout: 10s
  write_timeout: 10s
```

### Database Configuration

```yaml
database:
  mongodb:
    uri: "mongodb://localhost:27017"
    name: "tender_management"
    timeout: 10s
    max_pool_size: 100
```

## Running the Server

### Prerequisites

1. **MongoDB** - Must be running locally or accessible
2. **Go 1.23+** - Required for compilation
3. **Configuration** - `config.yaml` must be present

### Build and Run

```bash
# Build the server
go build -o bin/web ./cmd/web

# Run the server
./bin/web
```

### Development

```bash
# Run with hot reload (if using air)
air

# Or run directly
go run ./cmd/web
```

## Testing

### Health Check

```bash
curl http://localhost:8081/health
```

Expected response:
```json
{
  "status": "healthy",
  "time": 1703123456,
  "version": "1.0.0"
}
```

### Customer Registration

```bash
curl -X POST http://localhost:8081/api/admin/customers/register \
  -H "Content-Type: application/json" \
  -d '{
    "full_name": "John Doe",
    "username": "johndoe",
    "email": "john@example.com",
    "mobile": "+1234567890",
    "password": "securepassword123",
    "national_id": "123456789",
    "gender": "male"
  }'
```

## Logging

The server implements structured logging with the following features:

- **Request Logging** - All HTTP requests are logged with timing
- **Error Logging** - Errors are logged with context
- **Structured Fields** - Logs include relevant metadata
- **File Rotation** - Logs are rotated based on size and age

### Log Configuration

```yaml
logging:
  level: "info"
  format: "json"
  output: "file"
  file:
    path: "./logs/app.log"
    max_size: 100
    max_backups: 5
    max_age: 30
    compress: true
```

## Security Features

### CORS Configuration

```go
middleware.CORSWithConfig(middleware.CORSConfig{
    AllowOrigins: []string{"*"}, // Configure for production
    AllowMethods: []string{http.MethodGet, http.MethodPost, http.MethodPut, http.MethodDelete, http.MethodOptions},
    AllowHeaders: []string{echo.HeaderOrigin, echo.HeaderContentType, echo.HeaderAccept, echo.HeaderAuthorization},
})
```

### Authentication (TODO)

- JWT token validation
- Role-based access control
- Token refresh mechanism

## Error Handling

### HTTP Status Codes

- `200` - Success
- `201` - Created
- `400` - Bad Request
- `401` - Unauthorized
- `404` - Not Found
- `409` - Conflict
- `422` - Validation Error
- `500` - Internal Server Error

### Response Format

```json
{
  "success": true,
  "message": "Operation successful",
  "data": {},
  "meta": {}
}
```

## Monitoring

### Health Check

The `/health` endpoint provides basic server status:

- Server status
- Current timestamp
- Version information

### Request Metrics

Each request is logged with:

- HTTP method
- Request path
- Response status
- Processing duration
- User agent
- Remote IP

## Future Enhancements

1. **Authentication Middleware** - Implement JWT validation
2. **Rate Limiting** - Add request rate limiting
3. **Metrics** - Add Prometheus metrics
4. **Tracing** - Add distributed tracing
5. **API Documentation** - Add Swagger/OpenAPI docs
6. **Testing** - Add comprehensive test suite

## Troubleshooting

### Common Issues

1. **MongoDB Connection Failed**
   - Ensure MongoDB is running
   - Check connection URI in config
   - Verify network connectivity

2. **Port Already in Use**
   - Change port in config.yaml
   - Kill existing process using the port

3. **Permission Denied**
   - Ensure write permissions for log directory
   - Check file permissions

### Debug Mode

To enable debug logging, change the log level in config.yaml:

```yaml
logging:
  level: "debug"
```

## Dependencies

### Core Dependencies

- `github.com/labstack/echo/v4` - HTTP framework
- `go.mongodb.org/mongo-driver` - MongoDB driver
- `github.com/google/uuid` - UUID generation
- `golang.org/x/crypto/bcrypt` - Password hashing
- `github.com/asaskevich/govalidator` - Input validation

### Development Dependencies

- `github.com/stretchr/testify` - Testing framework
- `go.uber.org/zap` - Logging framework