core-package.md

Core package (@repo/core)

The core package holds application logic only: use cases (one class per action) and subscribers that react to domain events. It depends on ports (interfaces) from @repo/infra and on DTOs/entities/events from @repo/shared. It does not import Prisma, Express, or any HTTP or database implementation.

Use cases

Use cases are grouped by aggregate under packages/core/src/use-cases/. Each use case receives repository and/or event-publisher interfaces via the constructor and executes a single action (e.g. create user, get task by id).

User (use-cases/user/)

Use case	File	Role
CreateUserUseCase	CreateUserUseCase.ts	Create user; publish USER_CREATED
UpdateUserUseCase	UpdateUserUseCase.ts	Update user; publish USER_UPDATED
DeleteUserUseCase	DeleteUserUseCase.ts	Soft/hard delete; events as needed
ReactivateUserUseCase	ReactivateUserUseCase.ts	Reactivate soft-deleted user
GetUserByIdUseCase	GetUserByIdUseCase.ts	Find user by id
GetUsersOffsetUseCase	GetUsersOffsetUseCase.ts	List users with offset pagination
GetUsersCursorUseCase	GetUsersCursorUseCase.ts	List users with cursor pagination

Barrel: use-cases/user/index.ts.

Task (use-cases/task/)

Use case	File	Role
CreateTaskUseCase	CreateTaskUseCase.ts	Create task
UpdateTaskUseCase	UpdateTaskUseCase.ts	Update task
UpdateTaskStatusUseCase	UpdateTaskStatusUseCase.ts	Change status
MarkTaskAsCompletedUseCase	MarkTaskAsCompletedUseCase.ts	Mark done
CompleteTaskUseCase	CompleteTaskUseCase.ts	Complete task
DeleteTaskUseCase	DeleteTaskUseCase.ts	Delete task
GetTaskByIdUseCase	GetTaskByIdUseCase.ts	Get by id
GetTasksOffsetUseCase	GetTasksOffsetUseCase.ts	List with offset
GetTasksCursorUseCase	GetTasksCursorUseCase.ts	List with cursor

Barrel: use-cases/task/index.ts.

Project (use-cases/project/)

Use case	File	Role
CreateProjectUseCase	CreateProjectUseCase.ts	Create project
UpdateProjectUseCase	UpdateProjectUseCase.ts	Update project
DeleteProjectUseCase	DeleteProjectUseCase.ts	Delete project
GetProjectByIdUseCase	GetProjectByIdUseCase.ts	Get by id
GetProjectsOffsetUseCase	GetProjectsOffsetUseCase.ts	List with offset
GetProjectsCursorUseCase	GetProjectsCursorUseCase.ts	List with cursor

Barrel: use-cases/project/index.ts.

Activity (use-cases/activity/)

Use case	File	Role
CreateActivityUseCase	CreateActivityUseCase.ts	Create activity
UpdateActivityUseCase	UpdateActivityUseCase.ts	Update activity
DeleteActivityUseCase	DeleteActivityUseCase.ts	Delete activity
GetActivitiesByTaskIdUseCase	GetActivitiesByTaskIdUseCase.ts	List by task id
FindActivitiesUseCase	FindActivitiesUseCase.ts	Find activities

Barrel: use-cases/activity/index.ts.

Main barrel: packages/core/src/use-cases/index.ts re-exports user, project, task, activity.

Subscribers

Subscribers register with the event bus from @repo/infra and run when events are published (e.g. after a use case creates or updates an entity). They live in packages/core/src/subscribers/.

Subscriber	File	Events
User logging	userLogging.ts	USER_CREATED, USER_UPDATED
Task logging	taskLogging.ts	Task-related events
Project logging	projectLogging.ts	Project-related events
Activity logging	activityLogging.ts	Activity-related events

Registration happens in the API app (e.g. in app.ts): registerUserLoggingSubscribers(), registerTaskLoggingSubscribers(), etc. The event bus is in-memory and can be swapped for a transport like RabbitMQ later.

Ports (dependencies on infra)

Core depends only on interfaces from @repo/infra:

• IUserRepository, ITaskRepository, IProjectRepository, IActivityRepository — persistence; extend the generic IRepository<T, ID> with aggregate-specific methods (e.g. findByEmail, reactivate, offset/cursor list).
• IEventPublisher — publish domain events (e.g. publish(USER_CREATED, payload)).

Use cases receive these in the constructor (dependency injection). The API app instantiates the concrete repositories and event publisher from infra and passes them into the use cases. Core never imports Prisma or HTTP.