# Mail Order Bot Migration Plan

## Goal

Migrate `mail_order_bot` to the new PLBA model:
- application assembled by `ApplicationModule`
- runtime execution owned by `Worker`
- business behavior implemented in routines/services

## Target structure

### Application module

`MailOrderBotModule` should:
- build domain services
- build routines
- register workers
- register optional health contributors

### Workers

Initial workers:
- `MailPollingWorker`
- `EmailProcessingWorker`
- optional `ReconciliationWorker`

Each worker should own only runtime behavior:
- start/stop
- execution loop
- thread model
- health/status

### Routines

Initial routines:
- `MailPollingRoutine`
- `EmailProcessingRoutine`
- `ReconciliationRoutine`

Each routine should own business behavior:
- fetch messages
- parse message payload
- call domain services
- persist changes
- report business failures upward

## Migration steps

1. Extract business logic from current worker-like components into routines/services.
2. Implement thin workers that call those routines.
3. Register workers from `MailOrderBotModule`.
4. Use runtime health and status only through worker state.
5. Keep any local queue only as an implementation detail if it still helps.

## Optional queue usage

If email processing still benefits from buffering, `InMemoryTaskQueue` may be used inside the application.

Important:
- it should remain an app-level detail
- it should not define the platform contract
- the main architecture should still be described through workers and routines