Design a task system with assignments

You are implementing an in-memory task management system (no database required). The system needs basic CRUD features and some ranking/sorting functionality.

Part A — Core data model

A Task can be assigned to multiple people. Model this using a separate Assignment concept.

Design classes (or data structures) such that:

• Task stores only general metadata , e.g. taskId , title , description , createdAt , priority , etc.
• Each Assignment represents “this task assigned to this person” and stores assignment-specific fields:
  • assigneeId
  • startTime
  • endTime
  • any other assignment-specific info
• A single task can have 0..N assignments.

Explain:

• What fields belong on Task vs Assignment , and why.
• How you will link assignments to tasks (IDs, references).

Part B — Operations (CRUD + ranking)

Specify and implement (at least at the interface level) operations such as:

• Create / read / update / delete tasks
• Create / update / delete assignments
• List tasks with a “ranking”/ordering requirement (e.g., sort by priority, due date, created time, or a composite key)

Clarify:

• What should happen when deleting a task that has assignments.
• What your ranking key is and whether ties are stable.

Part C — Production/refactor discussion

If this were production code, how would you refactor the solution? Discuss layering (API/service/storage), validation, error handling, testability, and how you’d evolve the design when requirements change.