32 lines
1.5 KiB
Markdown
32 lines
1.5 KiB
Markdown
# Architect — F-019 Promotions v1
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## Feature
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F-019 adds server-side promo code validation and discount calculation. Discounts are recalculated from current cart totals and never trusted from the client.
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## Design
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### Module boundaries
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Create `project/src/modules/promotions/` with domain/application/infrastructure/api/tests. Promotions owns promo definitions and validation. Cart receives a public `PromotionServicePort` from the composition root and stores only the selected promo code, not discount amounts.
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### Data model
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Add migration `014_promotions.js`:
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- `promotions_promotions`: code, type (`percent`, `fixed_amount`), value, validity window, usage_limit, usage_count, active, timestamps.
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- Add `promo_code text` to `cart_carts`.
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### Rules
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- Percent discounts are basis points over current cart total.
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- Fixed amount discounts are cents and capped at current cart total.
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- Validity checks: active, starts_at <= now, ends_at >= now, usage_count < usage_limit when limit exists.
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- No stacking in v1: one promo code per cart.
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- Client discount fields are stripped/ignored by cart schemas.
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### API
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- Admin `POST /promotions` creates promo codes.
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- Public/authenticated cart endpoint `POST /cart/promo-code` stores a code after server validation.
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- `GET /cart` recalculates discount through `PromotionService`.
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## Acceptance trace
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- Valid promo: cart read applies recalculated server discount.
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- Expired/exhausted: applying code returns HTTP 422 reason.
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- Client discount ignored: schemas strip discount fields and cart stores no discount amount.
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