changes according to the test

repositories/orderOutlet_test.go

@@ -0,0 +1,62 @@
+package repositories
+
+import (
+	"strings"
+	"testing"
+)
+
+// The block that stopped orders being placed: no outlet on the order.
+//
+// Stock is per-outlet, so a missing locationid read as zero available and the
+// order was refused as "insufficient stock" — for Cadbury Dairy Milk at Suriya
+// Peelamedu, which had 25 on the shelf. These pin the message on the actual
+// cause.
+func TestAnOrderWithNoOutletIsRefusedForTheRightReason(t *testing.T) {
+	err := assertOutletNamed([]stockLine{
+		{Productid: 7086, Productname: "Cadbury Dairy Milk 100g", Locationid: 0, Quantity: 1},
+	})
+	if err == nil {
+		t.Fatal("an order with no outlet was accepted")
+	}
+	if strings.Contains(strings.ToLower(err.Error()), "insufficient stock") {
+		t.Errorf("still blames the stock: %v", err)
+	}
+	if !strings.Contains(err.Error(), "locationid") {
+		t.Errorf("does not say what to send: %v", err)
+	}
+	if !strings.Contains(err.Error(), "Cadbury Dairy Milk 100g") {
+		t.Errorf("does not name the line: %v", err)
+	}
+}
+
+// One good line does not excuse a bad one — a mixed order would deduct part of
+// the basket at a real outlet and the rest at nowhere.
+func TestOneLineWithoutAnOutletFailsTheWholeOrder(t *testing.T) {
+	err := assertOutletNamed([]stockLine{
+		{Productid: 7086, Productname: "Dairy Milk", Locationid: 1170},
+		{Productid: 7085, Productname: "5 Star", Locationid: 0},
+	})
+	if err == nil {
+		t.Fatal("a mixed order was accepted")
+	}
+	if !strings.Contains(err.Error(), "5 Star") {
+		t.Errorf("blamed the wrong line: %v", err)
+	}
+}
+
+func TestAnOrderThatNamesItsOutletPasses(t *testing.T) {
+	if err := assertOutletNamed([]stockLine{
+		{Productid: 7086, Productname: "Dairy Milk", Locationid: 1170},
+	}); err != nil {
+		t.Errorf("a valid order was refused: %v", err)
+	}
+}
+
+// An unnamed product still has to produce a usable message — the id is all
+// there is to go on.
+func TestAnUnnamedLineIsIdentifiedById(t *testing.T) {
+	err := assertOutletNamed([]stockLine{{Productid: 7086, Locationid: 0}})
+	if err == nil || !strings.Contains(err.Error(), "7086") {
+		t.Errorf("want the product id in the message, got: %v", err)
+	}
+}

repositories/orderRepository.go

@@ -1522,6 +1522,23 @@ func (r *orderRepository) createOrderTx(tx *gorm.DB, data models.Orders) (models
 		})
 	}
 
+	// An order has to name the outlet it is placed at, and one that did not was
+	// rejected as though the shop were empty.
+	//
+	// Stock is held per outlet: availableStock filters `locationid = ?`, so with
+	// 0 it matches no ledger row and returns 0 for every product. Each line then
+	// failed the check below with "insufficient stock ... available 0" — for a
+	// product sitting on the shelf with 25 of them. The message named the wrong
+	// thing entirely and sent people hunting for stock that was already there,
+	// which is the most expensive kind of error: confidently wrong.
+	//
+	// Checked per line, because a line may carry its own outlet and otherwise
+	// falls back to the header's.
+	if err := assertOutletNamed(lines); err != nil {
+		tx.Rollback()
+		return models.Orders{}, err
+	}
+
 	if err := lockStockRows(tx, data.Tenantid, lines); err != nil {
 		tx.Rollback()
 		return models.Orders{}, err

repositories/stockLedger.go

@@ -180,3 +180,31 @@ func legacyOrderQty(quantity float64) int {
 	}
 	return q
 }
+
+// assertOutletNamed refuses an order that does not say which shop it is for.
+//
+// Stock is held per outlet — availableStock filters `locationid = ?` — so a
+// line with no outlet matches no ledger row and reads as zero available. Every
+// such order was then refused as "insufficient stock ... available 0", naming
+// the shelf as the problem when the shelf was full and the request was what was
+// incomplete. A merchant reading that goes and checks their stock, finds it,
+// and has nowhere else to look.
+//
+// Per line rather than per order: a line may carry its own outlet, and only
+// falls back to the header's when it does not.
+func assertOutletNamed(lines []stockLine) error {
+	for _, line := range lines {
+		if line.Locationid != 0 {
+			continue
+		}
+		name := line.Productname
+		if name == "" {
+			name = fmt.Sprintf("ID %d", line.Productid)
+		}
+		return fmt.Errorf(
+			"this order names no outlet, so there is no shelf to sell '%s' from: "+
+				"send locationid on the order, or on each item", name,
+		)
+	}
+	return nil
+}