platform

order/order.go

@@ -0,0 +1,53 @@
+// Package order is the platform's shared order seam: the exported wire shape of
+// the `order.created` domain event (B4.1). It is the contract between the order
+// service (producer) and every reactor — inventory commit, fulfillment
+// allocation, loyalty, ERP sync — none of which the order service knows about.
+//
+// Like platform/catalog and platform/inventory, it holds only the wire value
+// types + encode/decode, and imports only the stdlib.
+//
+// `order.created` is a FACT, not a request: by the time it is emitted the order
+// is placed and paid. Reactors must be idempotent (the transport is
+// at-least-once) and must not assume they can refuse it — the sale already
+// happened. Oversell on commit is reconciled downstream (backorder), not
+// prevented here.
+package order
+
+import "encoding/json"
+
+// Line is one ordered line item, reduced to what reactors need: the SKU, how
+// many units sold, and the inventory location to commit against. Pricing/tax
+// live in the order grain, not on this seam.
+type Line struct {
+	SKU      string `json:"sku"`
+	Quantity int    `json:"quantity"`
+	// Location is the inventory location / store id to decrement. Empty means
+	// "use the order's Country" (central stock) — see Created.Country.
+	Location string `json:"location,omitempty"`
+}
+
+// Created is the payload of an event.OrderCreated envelope.
+//
+// Country is the default inventory location for the commit (central stock). A
+// Line may override it with its own Location (store id); when a line's Location
+// is empty the commit falls back to Country. See docs/inventory-shape.md.
+type Created struct {
+	OrderID        string `json:"order_id"`
+	OrderReference string `json:"order_reference,omitempty"`
+	CartID         string `json:"cart_id,omitempty"`
+	Country        string `json:"country"`
+	Currency       string `json:"currency,omitempty"`
+	CustomerEmail  string `json:"customer_email,omitempty"`
+	Lines          []Line `json:"lines"`
+	PlacedAtMs     int64  `json:"placed_at_ms,omitempty"`
+}
+
+// Encode serialises the payload for event.Event.Payload.
+func (c Created) Encode() ([]byte, error) { return json.Marshal(c) }
+
+// Decode parses an order.created payload — the consumer side of Encode.
+func Decode(raw []byte) (Created, error) {
+	var c Created
+	err := json.Unmarshal(raw, &c)
+	return c, err
+}

order/order_test.go

@@ -0,0 +1,30 @@
+package order
+
+import "testing"
+
+func TestCreatedRoundTrip(t *testing.T) {
+	in := Created{
+		OrderID:        "ord-1",
+		OrderReference: "REF-1",
+		CartID:         "cart-9",
+		Country:        "se",
+		Currency:       "SEK",
+		CustomerEmail:  "a@b.c",
+		Lines:          []Line{{SKU: "ABC", Quantity: 2, Location: "store-7"}, {SKU: "DEF", Quantity: 1}},
+		PlacedAtMs:     123,
+	}
+	raw, err := in.Encode()
+	if err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	out, err := Decode(raw)
+	if err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if out.OrderID != in.OrderID || out.Country != in.Country || len(out.Lines) != 2 {
+		t.Fatalf("round-trip mismatch: got %+v, want %+v", out, in)
+	}
+	if out.Lines[0].SKU != "ABC" || out.Lines[0].Quantity != 2 || out.Lines[0].Location != "store-7" {
+		t.Errorf("line[0] mismatch: %+v", out.Lines[0])
+	}
+}