Wire store scheme eligibility and update docs
This commit is contained in:
@@ -1,70 +1,378 @@
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# 17 — Promotions & Trade Scheme Management
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**Status**: Not Started
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**Depends On**: 01 — Item Catalog, 14 — Pricing & Supplier Master Data
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**Status**: Done — migrations applied to the database
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**Depends On**: 01 — Item Catalog (Done), 14 — Pricing & Supplier Master Data (Done), 02 — Stock Ledger (Done)
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---
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## Goal
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Covers [mainPlan.md §11](./mainPlan.md#11-promotions--trade-scheme-management)
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in full — an entirely new subsystem. Once built, `applyPricingAndDiscounts` (§1) and
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in full — an entirely new subsystem. `applyPricingAndDiscounts` (§1) and
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`checkStoreSchemeEligibility` (§4) both read from it.
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---
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## Background / Context
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No scheme/promotion entity exists today. Every reference to "eligible discount" elsewhere in this
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doc set (order pricing, field invoices, agent discount limits) currently has no scheme data source
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— it only enforces the flat per-role discount ceiling from
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No scheme/promotion entity existed before this step. Every reference to "eligible discount"
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elsewhere in this doc set (order pricing, field invoices, agent discount limits) had no scheme data
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source — it only enforced the flat per-role discount ceiling from
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[08_sales_agent_controls.md](./08_sales_agent_controls.md).
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For an enterprise distributor, free-goods/bundle promotions ("buy 10 get 1 free", "buy A + B get C
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free") are operationally different from discount schemes because they move physical stock at zero
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revenue, not just reduce a price. That distinction shaped the data model below: `BuyXGetY` and
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`FreeBundle` rules are structured columns/child rows (with their own CRUD), not a JSON blob, so a
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free-goods rule can be validated (item exists, positive qty, stock available) the same way any other
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order line is. `SlabDiscount`/`FlatPercent` stay JSON in `RuleConfig` since they're pure
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percentage-off rules with no inventory or fulfilment side effects.
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---
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## Data Model Changes
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### Scheme
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```
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Scheme
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├── Id (Guid) — PK, from Template
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├── Name (string)
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├── RuleType (enum) — BuyXGetY, SlabDiscount, FlatPercent, FreeBundle
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├── RuleConfig (string?) — JSON, only used by SlabDiscount/FlatPercent (see below); null
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│ for BuyXGetY/FreeBundle
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├── FK_TriggerItemId (Guid?) — BuyXGetY only: the item the store must buy
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├── TriggerQty (int?) — BuyXGetY only: qty of TriggerItem required to earn one payout
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├── FK_FreeItemId (Guid?) — shared payout for BuyXGetY and FreeBundle: item given free
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├── FreeQty (decimal?) — shared payout: qty of FreeItem given free
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├── FK_RegionId (Guid?) — nullable, null = all regions
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├── EligibleSegment (string?) — Store.Segment match (Gold/Silver/Key Account/...); null = all segments
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├── DateRangeFrom (DateTime)
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├── DateRangeTo (DateTime)
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├── AgentLimitExempt (bool) — if true, this scheme's discount stacks on top of the per-role
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│ discount ceiling (08_sales_agent_controls.md) unconditionally
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├── BaselineExpectedSales (decimal?) — manual baseline used by getSchemeROI (see Open Questions)
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├── IsActive, CreatedAt — from Template
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```
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`Name`, `RuleType` (`BuyXGetY`, `SlabDiscount`, `FlatPercent`), `RuleConfig` (JSON), `Eligibility`
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(store segment / region scope), `DateRangeFrom`, `DateRangeTo`.
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`RuleConfig` JSON shape (SlabDiscount/FlatPercent only):
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- `FlatPercent` — `{ "discountPercent": 10 }`
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- `SlabDiscount` — `{ "tiers": [{ "minOrderAmount": 5000, "discountPercent": 5 }, ...] }`, the
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highest tier whose `minOrderAmount` the order total meets or exceeds wins.
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### Scheme Redemption
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### SchemeBundleComponent
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```
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SchemeBundleComponent
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├── Id (Guid) — PK
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├── FK_SchemeId (Guid) — required, cascade delete with parent Scheme
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├── FK_ItemId (Guid) — required
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├── Qty (int) — required qty of this item for the FreeBundle rule to trigger
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```
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Unique constraint on `(SchemeId, ItemId)`. Only meaningful when `Scheme.RuleType = FreeBundle` — the
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order must contain every component in at least its listed `Qty` before the scheme's
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`FK_FreeItemId`/`FreeQty` payout is granted.
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`SchemeId`, `OrderId` (or `FieldInvoiceId`), `DiscountAmount`, `RedeemedAt` — feeds
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`trackSchemeSpend` and `getSchemeROI` without re-scanning every order.
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### SchemeRedemption
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```
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SchemeRedemption
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├── Id (Guid) — PK
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├── FK_SchemeId (Guid) — required
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├── FK_OrderId (Guid?) — nullable (see FieldInvoiceId below)
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├── FieldInvoiceId (Guid?) — placeholder for the future field-invoice module; no FieldInvoice
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│ entity exists yet, so this is an unconstrained Guid for now
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├── DiscountAmount (decimal?) — set for SlabDiscount/FlatPercent redemptions
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├── FK_FreeItemId (Guid?) — set for BuyXGetY/FreeBundle redemptions
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├── FreeQty (decimal?)
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├── FreeItemCostValue (decimal?) — free item's Item.CostPrice snapshotted at redemption time, so
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│ getSchemeROI/trackSchemeSpend stay accurate after CostPrice
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│ later changes
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├── RedeemedAt (DateTime)
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```
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At least one of `DiscountAmount` or `FreeQty` is set per redemption; `Scheme`/`Order` restrict-delete
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(a scheme or order with redemptions can't be hard-deleted, and soft-delete leaves history intact).
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### Item (extended)
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```
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Item
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├── ...
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├── CostPrice (decimal?) — new: cost/purchase price, used to value free-goods redemptions
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```
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---
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## Migrations
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Two migrations:
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1. **AddPromotionsSchemes** (applied) — creates `Schemes`, `SchemeRedemptions`; adds `Item.CostPrice`.
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2. **AddSchemeFreeGoodsRuleAndBundleComponents** (applied) — makes `Scheme.RuleConfig` nullable, adds
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`Scheme.FK_TriggerItemId`/`TriggerQty`/`FK_FreeItemId`/`FreeQty`, creates `SchemeBundleComponents`.
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(Split into two because the free-goods columns were promoted from a JSON blob to structured
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columns/child table after the first migration had already been applied to the dev database.)
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---
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## API Endpoints
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| Function reference | Endpoint intent |
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|---|---|
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| `createScheme(schemeRules, eligibility, dateRange)` | `POST /api/schemes` |
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| `evaluateSchemeEligibility(storeId, orderId)` | `GET /api/schemes/eligible?storeId=...&orderId=...` |
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| `applySchemeDiscount(orderId, schemeId)` | `POST /api/orders/{id}/apply-scheme` |
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| `trackSchemeSpend(schemeId)` | `GET /api/schemes/{id}/spend` |
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| `getSchemeROI(schemeId)` | `GET /api/schemes/{id}/roi` |
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| Function reference | Endpoint | Notes |
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|---|---|---|
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| `createScheme(schemeRules, eligibility, dateRange)` | `POST /api/schemes` | `RuleConfig` required only for SlabDiscount/FlatPercent; `TriggerItemId`/`TriggerQty`/`FreeItemId`/`FreeQty`/`BundleComponents` can be supplied inline to fully create a BuyXGetY/FreeBundle scheme in one call |
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| — | `GET /api/schemes` | Filterable by region |
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| — | `GET /api/schemes/{id}` | Includes trigger/free item, bundle components |
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| — | `PUT /api/schemes/{id}` | Updates name/eligibility/date range/`RuleConfig` |
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| — | `DELETE /api/schemes/{id}` | Soft delete |
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| — | `PUT /api/schemes/{id}/free-goods-rule` | Sets the BuyXGetY trigger + shared free-goods payout (also the payout for FreeBundle) |
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| — | `DELETE /api/schemes/{id}/free-goods-rule` | Clears it |
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| — | `PUT /api/schemes/{id}/bundle-components/{itemId}` | Upserts one FreeBundle required-item row |
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| — | `DELETE /api/schemes/{id}/bundle-components/{itemId}` | Removes one FreeBundle required-item row |
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| `evaluateSchemeEligibility(storeId, orderId)` | `GET /api/schemes/eligible?storeId=...&orderId=...` | Returns eligibility for every in-scope scheme, not just one |
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| `applySchemeDiscount(orderId, schemeId)` | `POST /api/orders/{id}/apply-scheme` | Adds a zero-price order line for free-goods payouts |
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| `trackSchemeSpend(schemeId)` | `GET /api/schemes/{id}/spend` | Discount spend + free-goods cost spend |
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| `getSchemeROI(schemeId)` | `GET /api/schemes/{id}/roi` | Uses `BaselineExpectedSales` |
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---
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## Request / Response Shapes
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### POST `/api/schemes` (BuyXGetY — created fully populated in one call)
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```json
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{
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"name": "Soap Buy10Get1",
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"ruleType": "BuyXGetY",
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"ruleConfig": null,
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"regionId": null,
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"eligibleSegment": "Gold",
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"dateRangeFrom": "2026-08-01T00:00:00",
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"dateRangeTo": "2026-08-31T23:59:59",
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"agentLimitExempt": false,
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"baselineExpectedSales": 50000,
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"triggerItemId": "<soapItemId>",
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"triggerQty": 10,
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"freeItemId": "<soapItemId>",
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"freeQty": 1
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}
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```
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`triggerItemId`/`triggerQty`/`freeItemId`/`freeQty` are optional on create — omit them for a plain
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SlabDiscount/FlatPercent scheme, or omit and set them later via `PUT .../free-goods-rule` if you want
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to create the shell first and configure the payout afterwards.
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### POST `/api/schemes` (FreeBundle — created fully populated in one call)
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```json
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{
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"name": "Soap+Shampoo -> Free Toothbrush",
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"ruleType": "FreeBundle",
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"ruleConfig": null,
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"regionId": null,
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"eligibleSegment": null,
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"dateRangeFrom": "2026-08-01T00:00:00",
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"dateRangeTo": "2026-08-31T23:59:59",
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"agentLimitExempt": false,
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"baselineExpectedSales": null,
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"freeItemId": "<toothbrushId>",
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"freeQty": 1,
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"bundleComponents": [ { "itemId": "<soapId>", "qty": 1 }, { "itemId": "<shampooId>", "qty": 1 } ]
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}
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```
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`triggerItemId`/`triggerQty` are ignored for FreeBundle — the required items come from
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`bundleComponents` instead.
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### PUT `/api/schemes/{id}/free-goods-rule`
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```json
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{ "triggerItemId": "<soapItemId>", "triggerQty": 10, "freeItemId": "<soapItemId>", "freeQty": 1 }
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```
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Same shape as the inline create fields — use this to add or change the free-goods payout on a
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scheme that was created without one.
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### PUT `/api/schemes/{id}/bundle-components/{itemId}` (FreeBundle)
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```json
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{ "qty": 1 }
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```
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Use this to add/edit one bundle component after creation.
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### POST `/api/schemes` (SlabDiscount)
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```json
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{
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"name": "Volume Discount",
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"ruleType": "SlabDiscount",
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"ruleConfig": "{\"tiers\":[{\"minOrderAmount\":5000,\"discountPercent\":5},{\"minOrderAmount\":10000,\"discountPercent\":8}]}",
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"regionId": null,
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"eligibleSegment": null,
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"dateRangeFrom": "2026-08-01T00:00:00",
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"dateRangeTo": "2026-08-31T23:59:59",
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"agentLimitExempt": false,
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"baselineExpectedSales": null
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}
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```
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### POST `/api/orders/{id}/apply-scheme`
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```json
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{ "schemeId": "..." }
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```
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---
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## Business Rules
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- A scheme discount stacks with, but does not bypass, the per-role discount ceiling in
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[08_sales_agent_controls.md](./08_sales_agent_controls.md) unless explicitly flagged as an
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agent-limit-exempt scheme.
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- `getSchemeROI` requires a baseline (pre-scheme expected sales) to compare against — confirm data
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source before implementing (see Open Questions).
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1. A scheme discount stacks with, but does not bypass, the per-role discount ceiling in
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[08_sales_agent_controls.md](./08_sales_agent_controls.md) unless `AgentLimitExempt = true`.
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(Enforcement against the actual ceiling is deferred — 08_sales_agent_controls.md's discount
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ceiling isn't implemented in code yet; this is recorded as the target behavior.)
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2. `evaluateSchemeEligibility` matches a scheme to a store/order only if: the scheme's `RegionId` is
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null or matches the store's region; `EligibleSegment` is null or matches `Store.Segment`; and the
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order's date falls within `[DateRangeFrom, DateRangeTo]`.
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3. `BuyXGetY` eligibility: the order must contain at least `TriggerQty` of `TriggerItem`; the payout
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scales with how many multiples of `TriggerQty` were bought (`FreeQty × floor(boughtQty / TriggerQty)`).
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4. `FreeBundle` eligibility: the order must contain every `SchemeBundleComponent` in at least its
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listed `Qty`; payout is the flat `FreeQty` of `FreeItem` (no multiplier).
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5. `applySchemeDiscount` adds a zero-price `OrderItem` line for the free-goods payout (`UnitPrice = 0`,
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`Quantity = FreeQty`), rather than only recording a discount amount — the free line still needs to
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be picked, delivered, and stock-tracked like any other sold line.
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6. A free-goods redemption is blocked if the free item's available `StockBalance` (summed across all
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locations) is less than the payout `FreeQty` — same out-of-stock guard as a normal sold line.
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7. A scheme can only be redeemed once per order (`HasRedemptionAsync` check in `applySchemeDiscount`).
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8. `SchemeRedemption.FreeItemCostValue` snapshots `Item.CostPrice` at redemption time, so
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`trackSchemeSpend`/`getSchemeROI` stay accurate even after the item's cost price later changes.
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9. Free goods are typically still a taxable "deemed supply" at zero net value under GST/VAT-style
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regimes — not yet wired into a tax calculation, since no tax subsystem exists in this codebase
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yet. Flagged for whoever builds tax/invoicing.
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10. `trackSchemeSpend` = sum(`DiscountAmount`) + sum(`FreeItemCostValue × FreeQty`) across all
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redemptions. `getSchemeROI` = `(actualSales − BaselineExpectedSales) / totalSpend`, where
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`actualSales` is the sum of `Order.TotalAmount` for every distinct order that redeemed the scheme.
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---
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## Open Questions
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- What counts as "incremental sales" for `getSchemeROI` — a manual baseline entered when the scheme
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is created, or a trailing-period average computed automatically?
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- What counts as "incremental sales" for `getSchemeROI` — **resolved for v1**: a manual
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`BaselineExpectedSales` entered at scheme creation, not a trailing-period average. Revisit if
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historical order data volume later makes an automatic trailing average preferable.
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- Per-role discount ceiling stacking (`AgentLimitExempt`) is unenforced pending
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[08_sales_agent_controls.md](./08_sales_agent_controls.md) having an actual ceiling implementation
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to stack against.
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- Deemed-supply tax treatment for free goods — deferred until a tax/invoicing subsystem exists.
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---
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## Implementation Notes
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> Fill this section in during planning discussion before writing any code.
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### File structure created / touched
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```
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Features/
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Scheme/
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SchemeController.cs (also hosts SchemeOrderController for POST /api/orders/{id}/apply-scheme)
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SchemeDTOs.cs
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SchemeService.cs (EvaluateRule — the core eligibility/payout calculator; ApplySchemeAsync
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— the free-goods order-line + stock-check + redemption write path)
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ISchemeRepository.cs
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SchemeRepository.cs
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Models/
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Scheme.cs (new — includes SchemeRuleType enum)
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SchemeBundleComponent.cs (new)
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SchemeRedemption.cs (new)
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Item.cs (extended — CostPrice)
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Data/AppDBContext.cs
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add Schemes, SchemeRedemptions, SchemeBundleComponents DbSets; relationships (Scheme→TriggerItem/
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FreeItem restrict-delete, SchemeBundleComponent→Scheme cascade-delete, →Item restrict-delete,
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SchemeRedemption→Scheme/Order/FreeItem restrict-delete); unique index on
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SchemeBundleComponent(FK_SchemeId, FK_ItemId)
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Migrations/
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AddPromotionsSchemes (applied)
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AddSchemeFreeGoodsRuleAndBundleComponents (applied)
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Program.cs
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register ISchemeRepository/SchemeRepository, SchemeService
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```
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### Eligibility + payout logic (pseudo)
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```
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EvaluateRule(scheme, orderItems):
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switch scheme.RuleType:
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BuyXGetY:
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boughtQty = sum(orderItems where ItemId = scheme.TriggerItemId).Quantity
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if boughtQty < scheme.TriggerQty: not eligible
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multiplier = boughtQty / scheme.TriggerQty // integer division
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→ eligible, FreeItemId = scheme.FreeItemId, FreeQty = scheme.FreeQty * multiplier
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FreeBundle:
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missing = scheme.BundleComponents where sum(orderItems qty for that item) < component.Qty
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if missing.any(): not eligible
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→ eligible, FreeItemId = scheme.FreeItemId, FreeQty = scheme.FreeQty
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FlatPercent / SlabDiscount:
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parse RuleConfig JSON, compute DiscountAmount off orderItems total
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```
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### applySchemeDiscount flow (pseudo)
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```
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ApplySchemeAsync(orderId, schemeId):
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reject if scheme already redeemed against this order
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eligibility = EvaluateRule(scheme, order's items)
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reject if not eligible
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if eligibility has a free-goods payout:
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check StockBalance across all locations >= FreeQty, else reject
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add OrderItem { ItemId = FreeItemId, Quantity = FreeQty, UnitPrice = 0 }
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redemption.FreeItemCostValue = freeItem.CostPrice ?? 0
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save SchemeRedemption { DiscountAmount, FreeItemId, FreeQty, FreeItemCostValue }
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```
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---
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## Worked Example
|
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Item `Soap-500ml` has `CostPrice = 12`. Store is in the "Gold" segment.
|
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**Create the scheme (one call, fully populated):**
|
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```
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POST /api/schemes
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{ "name": "Soap Buy10Get1", "ruleType": "BuyXGetY", "ruleConfig": null,
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"regionId": null, "eligibleSegment": "Gold",
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"dateRangeFrom": "2026-08-01", "dateRangeTo": "2026-08-31",
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"agentLimitExempt": false, "baselineExpectedSales": 50000,
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"triggerItemId": "<soapId>", "triggerQty": 10, "freeItemId": "<soapId>", "freeQty": 1 }
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→ Scheme { Id, ... }
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```
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**Store places an order** for 20 units of `Soap-500ml` → `Order { Id, TotalAmount }`.
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**Check eligibility:**
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```
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GET /api/schemes/eligible?storeId=...&orderId=...
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→ [{ "schemeId": "...", "eligible": true, "freeItemId": "<soapId>", "freeQty": 2 }]
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```
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20 ÷ 10 = 2 multiples → 2 free units.
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**Apply it:**
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```
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POST /api/orders/{orderId}/apply-scheme
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{ "schemeId": "..." }
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```
|
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Adds an `OrderItem` line (`Soap-500ml`, qty 2, `UnitPrice = 0`) and a `SchemeRedemption` with
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`FreeQty = 2`, `FreeItemCostValue = 12`.
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**Spend/ROI:**
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```
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GET /api/schemes/{id}/spend
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→ { "totalDiscountSpend": 0, "totalFreeGoodsCostSpend": 24, "totalSpend": 24, "redemptionCount": 1 }
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||||
|
||||
GET /api/schemes/{id}/roi
|
||||
→ { "baselineExpectedSales": 50000, "actualSales": 62000, "incrementalSales": 12000,
|
||||
"totalSpend": 24, "roi": 500.0 }
|
||||
```
|
||||
|
||||
**FreeBundle variant** ("buy Soap + Shampoo, get a free Toothbrush") — also one call:
|
||||
```
|
||||
POST /api/schemes
|
||||
{ "name": "Soap+Shampoo -> Free Toothbrush", "ruleType": "FreeBundle", "ruleConfig": null,
|
||||
"regionId": null, "eligibleSegment": null,
|
||||
"dateRangeFrom": "2026-08-01", "dateRangeTo": "2026-08-31",
|
||||
"agentLimitExempt": false, "baselineExpectedSales": null,
|
||||
"freeItemId": "<toothbrushId>", "freeQty": 1,
|
||||
"bundleComponents": [ { "itemId": "<soapId>", "qty": 1 }, { "itemId": "<shampooId>", "qty": 1 } ] }
|
||||
```
|
||||
Eligibility now requires both Soap ≥1 and Shampoo ≥1 in the order; payout is 1 free toothbrush,
|
||||
flat (no multiplier). Components/payout can still be edited afterwards via
|
||||
`PUT .../bundle-components/{itemId}` and `PUT .../free-goods-rule`.
|
||||
|
||||
Reference in New Issue
Block a user