TASK2.md

Task 2: Create the "Statistics" Feature

🎯 Objective

Create a REST endpoint /api/statistics that provides insights about Todo items.

📋 Requirements

1. API Endpoint

• Base path: /api/statistics

• Support query parameters:

  • from - Start date (e.g., 2023-01-01)
  • to - End date (e.g., 2023-12-31)
  • format - Response format (summary or detailed)
  • either from, to, or both can pe provided

2. Statistics to Include

• Total number of todos
• Number of completed todos
• Number of pending todos
• Todos per user breakdown

3. Technical Requirements

• Use MongoDB aggregations for efficient data processing (https://www.mongodb.com/resources/products/capabilities/aggregation-pipeline)
  • Minimize amount of queries to reduce chatiness! (https://en.wikipedia.org/wiki/Fallacies_of_distributed_computing)
• Create DTOs for API responses
• Handle input errors on the controller level
  • Handle HTTP status codes with appropriate error responses (400 Bad Request for invalid parameters, 200 OK for success, 500 Internal Server Error for server errors)
• Follow project architecture
• Controller integration test and Repository integration test
• Must use test containers, not mocks!

4. Summary Sample Response

{
  "totalTodos": 10,
  "completedTodos": 7,
  "pendingTodos": 3,
  "userStats": {
    "user1": 5,
    "user2": 3,
    "user3": 2
  }
}

5. Detailed Sample Response

{
  "totalTodos": 10,
  "completedTodos": 7,
  "pendingTodos": 3,
  "userStats": {
    "user1": 5,
    "user2": 3,
    "user3": 2
  },
  "todos": {
    "completed": [
      {
        "id": "1",
        "title": "Deploy to production",
        "createdBy": "user1",
        "createdAt": "2024-03-15T10:30:00Z",
        "completedAt": "2024-03-15T14:20:00Z"
      }
      // ... more completed todos
    ],
    "pending": [
      {
        "id": "8",
        "title": "Review pull request",
        "createdBy": "user2",
        "createdAt": "2024-03-15T09:00:00Z"
      }
      // ... more pending todos
    ]
  }
}