# REST API Demo

A simple task management REST API demonstrating Lux's HTTP server effect and effect tracking.

## Features Demonstrated

- **HttpServer Effect**: Built-in HTTP server with effect tracking
- **Pattern Matching**: Route handling via pattern matching
- **JSON**: Serialization and parsing
- **ADTs**: `ApiResponse` type with Success/Error variants
- **Effect Signatures**: All side effects explicitly declared

## Running

```bash
cargo run -- projects/rest-api/main.lux
```

## API Endpoints

| Method | Endpoint      | Description       |
|--------|---------------|-------------------|
| GET    | /             | API info          |
| GET    | /tasks        | List all tasks    |
| GET    | /tasks/:id    | Get task by ID    |
| POST   | /tasks        | Create new task   |
| PUT    | /tasks/:id    | Update task       |
| DELETE | /tasks/:id    | Delete task       |

## Example Usage

```bash
# Get API info
curl http://localhost:8080/

# List tasks
curl http://localhost:8080/tasks

# Get specific task
curl http://localhost:8080/tasks/1

# Create task
curl -X POST -d '{"title":"New task","done":false}' http://localhost:8080/tasks

# Update task
curl -X PUT -d '{"done":true}' http://localhost:8080/tasks/1

# Delete task
curl -X DELETE http://localhost:8080/tasks/1
```

## Code Structure

```
main.lux
├── Data Types (Task, ApiResponse)
├── JSON Serialization (taskToJson, tasksToJson)
├── Route Handlers (handleGetTasks, handleCreateTask, etc.)
├── Router (route function with pattern matching)
├── Request Handler (handleRequest)
├── Server Loop (serveRequests - recursive)
└── Main Entry Point
```

## Effect Tracking

All functions declare their effects explicitly:

```lux
fn handleRequest(req: Request): Unit with {Console, HttpServer} = ...
fn serveRequests(count: Int, max: Int): Unit with {Console, HttpServer} = ...
fn main(): Unit with {Console, HttpServer} = ...
```

This ensures:
- Side effects are visible in function signatures
- Testing is easier (swap effects for mocks)
- Compiler verifies effect usage

## Notes

- Server handles 10 requests then stops (for demo purposes)
- Uses in-memory "database" (hardcoded tasks)
- Simplified JSON parsing for demonstration