add purchasing in analytics endpoint

internal/transformer/analytics_transformer.go

@@ -138,6 +138,91 @@ func SalesAnalyticsModelToContract(resp *models.SalesAnalyticsResponse) *contrac
 	}
 }
 
+// PurchasingAnalyticsContractToModel converts contract request to model
+func PurchasingAnalyticsContractToModel(req *contract.PurchasingAnalyticsRequest) *models.PurchasingAnalyticsRequest {
+	var dateFrom, dateTo time.Time
+
+	if fromTime, toTime, err := util.ParseDateRangeToJakartaTime(req.DateFrom, req.DateTo); err == nil {
+		if fromTime != nil {
+			dateFrom = *fromTime
+		}
+		if toTime != nil {
+			dateTo = *toTime
+		}
+	}
+
+	return &models.PurchasingAnalyticsRequest{
+		OrganizationID: req.OrganizationID,
+		OutletID:       parseOutletID(req.OutletID),
+		DateFrom:       dateFrom,
+		DateTo:         dateTo,
+		GroupBy:        req.GroupBy,
+	}
+}
+
+// PurchasingAnalyticsModelToContract converts model response to contract
+func PurchasingAnalyticsModelToContract(resp *models.PurchasingAnalyticsResponse) *contract.PurchasingAnalyticsResponse {
+	if resp == nil {
+		return nil
+	}
+
+	data := make([]contract.PurchasingAnalyticsData, len(resp.Data))
+	for i, item := range resp.Data {
+		data[i] = contract.PurchasingAnalyticsData{
+			Date:           item.Date,
+			Purchases:      item.Purchases,
+			PurchaseOrders: item.PurchaseOrders,
+			Quantity:       item.Quantity,
+			Ingredients:    item.Ingredients,
+			Vendors:        item.Vendors,
+		}
+	}
+
+	ingredientData := make([]contract.PurchasingIngredientData, len(resp.IngredientData))
+	for i, item := range resp.IngredientData {
+		ingredientData[i] = contract.PurchasingIngredientData{
+			IngredientID:       item.IngredientID,
+			IngredientName:     item.IngredientName,
+			Quantity:           item.Quantity,
+			TotalCost:          item.TotalCost,
+			AverageUnitCost:    item.AverageUnitCost,
+			PurchaseOrderCount: item.PurchaseOrderCount,
+		}
+	}
+
+	vendorData := make([]contract.PurchasingVendorData, len(resp.VendorData))
+	for i, item := range resp.VendorData {
+		vendorData[i] = contract.PurchasingVendorData{
+			VendorID:           item.VendorID,
+			VendorName:         item.VendorName,
+			TotalCost:          item.TotalCost,
+			PurchaseOrderCount: item.PurchaseOrderCount,
+			IngredientCount:    item.IngredientCount,
+			Quantity:           item.Quantity,
+		}
+	}
+
+	return &contract.PurchasingAnalyticsResponse{
+		OrganizationID: resp.OrganizationID,
+		OutletID:       resp.OutletID,
+		OutletName:     resp.OutletName,
+		DateFrom:       resp.DateFrom,
+		DateTo:         resp.DateTo,
+		GroupBy:        resp.GroupBy,
+		Summary: contract.PurchasingSummary{
+			TotalPurchases:            resp.Summary.TotalPurchases,
+			TotalPurchaseOrders:       resp.Summary.TotalPurchaseOrders,
+			TotalQuantity:             resp.Summary.TotalQuantity,
+			AveragePurchaseOrderValue: resp.Summary.AveragePurchaseOrderValue,
+			TotalIngredients:          resp.Summary.TotalIngredients,
+			TotalVendors:              resp.Summary.TotalVendors,
+		},
+		Data:           data,
+		IngredientData: ingredientData,
+		VendorData:     vendorData,
+	}
+}
+
 // ProductAnalyticsContractToModel converts contract request to model
 func ProductAnalyticsContractToModel(req *contract.ProductAnalyticsRequest) *models.ProductAnalyticsRequest {
 	var dateFrom, dateTo time.Time

internal/transformer/analytics_transformer_test.go

@@ -0,0 +1,76 @@
+package transformer
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"apskel-pos-be/internal/contract"
+	"apskel-pos-be/internal/models"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPurchasingAnalyticsContractToModelParsesDateRangeAndOutlet(t *testing.T) {
+	orgID := uuid.New()
+	outletID := uuid.New().String()
+
+	req := &contract.PurchasingAnalyticsRequest{
+		OrganizationID: orgID,
+		OutletID:       &outletID,
+		DateFrom:       "01-05-2026",
+		DateTo:         "02-05-2026",
+		GroupBy:        "week",
+	}
+
+	result := PurchasingAnalyticsContractToModel(req)
+
+	require.Equal(t, orgID, result.OrganizationID)
+	require.NotNil(t, result.OutletID)
+	require.Equal(t, outletID, result.OutletID.String())
+	require.Equal(t, "week", result.GroupBy)
+
+	location, err := time.LoadLocation("Asia/Jakarta")
+	require.NoError(t, err)
+	require.Equal(t, time.Date(2026, 5, 1, 0, 0, 0, 0, location), result.DateFrom)
+	require.Equal(t, time.Date(2026, 5, 2, 23, 59, 59, int(time.Second-time.Nanosecond), location), result.DateTo)
+}
+
+func TestPurchasingAnalyticsContractToModelIgnoresInvalidOutlet(t *testing.T) {
+	outletID := "not-a-uuid"
+
+	result := PurchasingAnalyticsContractToModel(&contract.PurchasingAnalyticsRequest{
+		OutletID: &outletID,
+		DateFrom: "01-05-2026",
+		DateTo:   "02-05-2026",
+	})
+
+	require.Nil(t, result.OutletID)
+}
+
+func TestPurchasingAnalyticsModelToContractCopiesOutletName(t *testing.T) {
+	outletID := uuid.New()
+	outletName := "Main Outlet"
+
+	result := PurchasingAnalyticsModelToContract(&models.PurchasingAnalyticsResponse{
+		OrganizationID: uuid.New(),
+		OutletID:       &outletID,
+		OutletName:     &outletName,
+	})
+
+	require.NotNil(t, result)
+	require.Equal(t, &outletID, result.OutletID)
+	require.NotNil(t, result.OutletName)
+	require.Equal(t, outletName, *result.OutletName)
+}
+
+func TestPurchasingAnalyticsModelToContractOmitsNilOutletName(t *testing.T) {
+	result := PurchasingAnalyticsModelToContract(&models.PurchasingAnalyticsResponse{
+		OrganizationID: uuid.New(),
+	})
+
+	payload, err := json.Marshal(result)
+	require.NoError(t, err)
+	require.NotContains(t, string(payload), "outlet_name")
+}