graph TD
    A[Current: Items API] -->|Refactor| B[Target: Tasks API v1]
    
    subgraph "Current Implementation"
        A1[/api/items] --> A2[{id, name, description}]
        A1 --> A3[In-memory storage]
    end
    
    subgraph "Target Implementation"
        B1[/api/v1/tasks] --> B2[{id, title, description, completed, createdAt, updatedAt}]
        B1 --> B3[Enhanced in-memory storage]
        B1 --> B4[Query parameters]
        B1 --> B5[Proper error handling]
    end

graph LR
    Client -->|Request| Router
    
    Router -->|/api/v1/*| V1[API v1 Router]
    Router -->|/health| Health[Health Check]
    Router -->|/| Root[API Info]
    
    V1 -->|/tasks| Tasks[Tasks Controller]
    
    Tasks --> Validation[Request Validation]
    Validation --> Handler[Business Logic]
    Handler --> Storage[In-Memory Store]
    Handler --> Response[Response Formatter]

interface Task {
    id: string;              // UUID format
    title: string;           // Required, max 200 chars
    description: string;     // Optional, max 1000 chars
    completed: boolean;      // Default: false
    createdAt: string;       // ISO 8601 timestamp
    updatedAt: string;       // ISO 8601 timestamp
}

interface TaskStore {
    tasks: Map<string, Task>;
    create(task: Partial<Task>): Task;
    findAll(filters?: TaskFilters): Task[];
    findById(id: string): Task | null;
    update(id: string, updates: Partial<Task>): Task | null;
    delete(id: string): boolean;
}

sequenceDiagram
    participant Client
    participant Middleware
    participant Controller
    participant ErrorHandler
    
    Client->>Middleware: Request
    Middleware->>Controller: Validated Request
    
    alt Success
        Controller->>Client: 2xx Response
    else Validation Error
        Controller->>ErrorHandler: ValidationError
        ErrorHandler->>Client: 400 Bad Request
    else Not Found
        Controller->>ErrorHandler: NotFoundError
        ErrorHandler->>Client: 404 Not Found
    else Server Error
        Controller->>ErrorHandler: InternalError
        ErrorHandler->>Client: 500 Internal Error
    end

graph TD
    A[Test Suite] --> B[Unit Tests]
    A --> C[Integration Tests]
    A --> D[API Tests]
    
    B --> B1[Storage Tests]
    B --> B2[Validation Tests]
    B --> B3[Utility Tests]
    
    C --> C1[Middleware Tests]
    C --> C2[Error Handling Tests]
    
    D --> D1[CRUD Operations]
    D --> D2[Query Parameters]
    D --> D3[Error Scenarios]
    D --> D4[Edge Cases]

const config = {
    server: {
        port: process.env.PORT || 3000,
        host: process.env.HOST || 'localhost'
    },
    api: {
        version: 'v1',
        basePath: '/api',
        pagination: {
            defaultLimit: 10,
            maxLimit: 100
        }
    },
    storage: {
        type: 'memory',
        seedData: true
    }
};

graph LR
    Dev[Development] -->|npm run dev| Nodemon[Nodemon Server]
    Test[Testing] -->|npm test| Jest[Jest Test Runner]
    Prod[Production] -->|npm start| Node[Node.js Server]
    
    Node --> PM2[PM2 Process Manager]
    PM2 --> Cluster[Cluster Mode]

rest-api-simple/
├── server.js                 # Main application file
├── server.test.js           # Comprehensive test suite
├── package.json             # Dependencies and scripts
├── .gitignore              # Git ignore file
├── README.md               # User documentation
├── api-specification.md    # API specification
├── architecture.md         # System architecture
├── implementation-plan.md  # SPARC execution plan
└── test-api.js            # Manual testing script