# Change History

> Architectural decisions and significant refactoring are recorded here.
> Every architectural decision MUST be documented in this file.

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## 2026-02-20: Seen Registry Deduplication by Partnumber

### Decision

Changed `qt_vendor_partnumber_seen` semantics to one row per `partnumber` (vendor/source are no longer part of uniqueness).

### Rationale

- Eliminates duplicate seen rows when the same partnumber appears both with vendor and without vendor.
- Keeps ignore behavior consistent regardless of vendor presence.
- Simplifies operational cleanup and prevents re-creation of vendor/no-vendor duplicates.

### Constraints

- `partnumber` is now the unique key in seen registry.
- Ignore checks are resolved by `partnumber` only.
- Stock provenance must be preserved (`source_type='stock'`) when stock data exists for the partnumber.

### Files

- Migration: `migrations/025_dedup_vendor_seen_by_partnumber.sql`
- Service: `internal/services/stock_import.go`
- Service: `internal/services/vendor_mapping.go`
- Model: `internal/models/lot.go`

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## 2026-02-18: Global Vendor Partnumber Mapping

### Decision

Implemented global vendor partnumber → LOT mapping with bundle support and seen-based ignore logic.

### Key rules

- `lot_partnumbers` is the canonical mapping contract (1:1 per key).
- Composite mappings use internal bundle tables (`qt_lot_bundles`, `qt_lot_bundle_items`).
- Ignore logic moved from `stock_ignore_rules` to `qt_vendor_partnumber_seen.is_ignored`.
- Resolver order: exact `(vendor, partnumber)` → fallback `(vendor='', partnumber)`.

### Rationale

- Preserves external/client contracts (`lot_partnumbers`, LOT-based pricelists).
- Avoids multi-row ambiguity in `lot_partnumbers`.
- Supports complex assembled vendor SKUs without client-side changes.
- Centralizes ignore behavior across all sources via seen-registry.

### Constraints

- Bundle LOT is internal and must stay hidden in regular LOT list by default.
- Resolver order is mandatory and fixed.
- Bundle allocation for missing estimate: fallback from previous active warehouse pricelist; if absent → `0`.

### Files

- Migration: `migrations/023_vendor_partnumber_global_mapping.sql`
- Backfill: `migrations/024_backfill_vendor_seen_from_stock_and_ignore.sql`
- Resolver: `internal/lotmatch/matcher.go`
- Service: `internal/services/vendor_mapping.go`
- Warehouse calc: `internal/warehouse/snapshot.go`
- Stock import: `internal/services/stock_import.go`
- API: `internal/handlers/pricing.go`, `cmd/pfs/main.go`

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## 2026-02-10: LOT Page Refactoring

### Decision

Moved LOT management to a dedicated `/lot` page. Removed LOT tab from Pricing Admin.

### What changed

- Created `web/templates/lot.html` — two tabs: LOT (component management) and Mappings (partnumber ↔ LOT).
- Removed LOT tab from `admin_pricing.html`; default tab changed to `estimate`.
- Removed "Сопоставление partnumber → LOT" section from Warehouse tab.
- Updated navigation: LOT → `/lot`, Pricing Admin → `/admin/pricing`.
- Added `Lot()` handler in `internal/handlers/web.go`.
- Added `/lot` route in `cmd/pfs/main.go`.

### Rationale

Separation of concerns: LOT/component management is distinct from pricing administration.

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## Warehouse Pricing: Weighted Average

### Decision

Warehouse pricelist uses `weighted_avg` (quantity-weighted average) as the sole price calculation method.
Commit `edff712` switched from `weighted_median` to `weighted_avg`.

- `price_method` field always contains `"weighted_avg"`.
- No `price_period_days`, `price_coefficient`, `manual_price`, `meta_prices` in warehouse pricelists.

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## Architecture Conventions

> All future architectural decisions must be documented here with:
> - Date
> - Decision summary
> - Rationale
> - Constraints / invariants
> - Affected files