From b94dd3d0155962e80c0e99e2190338c2a94ef3c2 Mon Sep 17 00:00:00 2001
From: Mikhail Chusavitin <mchusavitin@mchusmbp.local>
Date: Wed, 18 Feb 2026 19:45:32 +0300
Subject: [PATCH] warehouse: switch stock pricing to weighted_avg

---
 .../pricelist/service_warehouse_test.go       |  4 +--
 internal/warehouse/snapshot.go                | 27 +++++++++++++++++--
 internal/warehouse/snapshot_test.go           |  4 +--
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/internal/services/pricelist/service_warehouse_test.go b/internal/services/pricelist/service_warehouse_test.go
index 3a14fb1..98046a7 100644
--- a/internal/services/pricelist/service_warehouse_test.go
+++ b/internal/services/pricelist/service_warehouse_test.go
@@ -66,7 +66,7 @@ func TestCreateWarehousePricelistFromStockLog(t *testing.T) {
 	if items[0].LotName != "CPU_X" {
 		t.Fatalf("unexpected lot name: %s", items[0].LotName)
 	}
-	if math.Abs(items[0].Price-200) > 0.001 {
-		t.Fatalf("expected weighted median price 200, got %f", items[0].Price)
+	if math.Abs(items[0].Price-180) > 0.001 {
+		t.Fatalf("expected weighted average price 180, got %f", items[0].Price)
 	}
 }
diff --git a/internal/warehouse/snapshot.go b/internal/warehouse/snapshot.go
index 56a51c2..f6172ad 100644
--- a/internal/warehouse/snapshot.go
+++ b/internal/warehouse/snapshot.go
@@ -58,11 +58,11 @@ func ComputePricelistItemsFromStockLog(db *gorm.DB) ([]SnapshotItem, error) {
 
 	items := make([]SnapshotItem, 0, len(grouped))
 	for lot, values := range grouped {
-		price := weightedMedian(values)
+		price := weightedAverage(values)
 		if price <= 0 {
 			continue
 		}
-		items = append(items, SnapshotItem{LotName: lot, Price: price, PriceMethod: "weighted_median", Category: ""})
+		items = append(items, SnapshotItem{LotName: lot, Price: price, PriceMethod: "weighted_avg", Category: ""})
 	}
 
 	// Load categories for all lots in a single query
@@ -272,3 +272,26 @@ func median(values []float64) float64 {
 	}
 	return cp[n/2]
 }
+func weightedAverage(values []weightedPricePoint) float64 {
+	if len(values) == 0 {
+		return 0
+	}
+	sumWeighted := 0.0
+	sumWeight := 0.0
+	prices := make([]float64, 0, len(values))
+	for _, v := range values {
+		if v.price <= 0 {
+			continue
+		}
+		prices = append(prices, v.price)
+		if v.weight > 0 {
+			sumWeighted += v.price * v.weight
+			sumWeight += v.weight
+		}
+	}
+	if sumWeight > 0 {
+		return sumWeighted / sumWeight
+	}
+	return median(prices)
+}
+
diff --git a/internal/warehouse/snapshot_test.go b/internal/warehouse/snapshot_test.go
index abc8688..6714127 100644
--- a/internal/warehouse/snapshot_test.go
+++ b/internal/warehouse/snapshot_test.go
@@ -45,8 +45,8 @@ func TestComputePricelistItemsFromStockLog(t *testing.T) {
 	if items[0].LotName != "CPU_X" {
 		t.Fatalf("expected lot CPU_X, got %s", items[0].LotName)
 	}
-	if math.Abs(items[0].Price-200) > 0.001 {
-		t.Fatalf("expected weighted median 200, got %f", items[0].Price)
+	if math.Abs(items[0].Price-190) > 0.001 {
+		t.Fatalf("expected weighted average 190, got %f", items[0].Price)
 	}
 }