feat: add Request.purchaseOrderId (nullable FK)

prisma/migrations/20260803002253_add_request_purchase_order_id/migration.sql

@@ -0,0 +1,5 @@
+-- AlterTable
+ALTER TABLE "requests" ADD COLUMN     "purchase_order_id" UUID;
+
+-- AddForeignKey
+ALTER TABLE "requests" ADD CONSTRAINT "requests_purchase_order_id_fkey" FOREIGN KEY ("purchase_order_id") REFERENCES "purchase_orders"("id") ON DELETE SET NULL ON UPDATE CASCADE;

prisma/schema.prisma

@@ -40,6 +40,15 @@ model Request {
   // plain string (not an enum) until more states exist — see
   // src/lib/requests.ts's RequestStatus type.
   status          String         @default("Draft")
+  // Nullable FK to PurchaseOrder — see docs/asset-license-management.md's
+  // "## PurchaseOrder (gộp Receipt)" Traceability bullet. Semantically the
+  // DEMAND side, unlike AssetItem.purchaseOrderId/License.purchaseOrderId
+  // (supply-side intake): this records "which approved Request got grouped
+  // into this PO", not "which PO did this item come in through". Shape is
+  // identical to those two though — nullable FK, set at creation time only,
+  // no update endpoint for this field yet, same P2003-on-insert handling.
+  purchaseOrderId String?        @map("purchase_order_id") @db.Uuid
+  purchaseOrder   PurchaseOrder? @relation(fields: [purchaseOrderId], references: [id])
   createdAt       DateTime       @default(now()) @map("created_at") @db.Timestamptz(6)
 
   @@map("requests")
@@ -185,8 +194,11 @@ model Vendor {
 // `assetItems` is the back-relation from the AssetItem.purchaseOrderId
 // retrofit (supply-side traceability, same doc section). `licenses` is the
 // back-relation from the License.purchaseOrderId retrofit (same doc
-// section, same rationale). Request back-references are NOT part of this
+// section, same rationale). `requests` is the back-relation from the
-// change — out of scope for this task.
+// Request.purchaseOrderId retrofit — the DEMAND side ("which approved
+// Request got grouped into this PO"), as opposed to assetItems/licenses
+// which are the SUPPLY side (intake traceability) — see Request model's
+// comment above for the distinction.
 model PurchaseOrder {
   id           String      @id @default(uuid()) @db.Uuid
   vendorId     String      @map("vendor_id") @db.Uuid
@@ -199,6 +211,7 @@ model PurchaseOrder {
   createdAt    DateTime    @default(now()) @map("created_at") @db.Timestamptz(6)
   assetItems   AssetItem[]
   licenses     License[]
+  requests     Request[]
 
   @@map("purchase_orders")
 }

src/app/api/requests/route.ts

@@ -24,8 +24,8 @@ export async function POST(request: Request): Promise<NextResponse> {
     return NextResponse.json({ error: "Request body must be a JSON object" }, { status: 400 });
   }
 
-  const { employee_id, type, reason } = body as Record<string, unknown>;
+  const { employee_id, type, reason, purchase_order_id } = body as Record<string, unknown>;
-  const validation = validateCreateRequestInput({ employee_id, type, reason });
+  const validation = validateCreateRequestInput({ employee_id, type, reason, purchase_order_id });
 
   if (!validation.ok) {
     return NextResponse.json({ error: validation.error }, { status: 400 });

src/lib/requests.ts

@@ -16,6 +16,7 @@ export interface RequestRecord {
   type: RequestType;
   reason: string;
   status: RequestStatus;
+  purchase_order_id: string | null;
   created_at: string;
 }
 
@@ -23,6 +24,7 @@ export interface CreateRequestInput {
   employee_id: string;
   type: RequestType;
   reason: string;
+  purchase_order_id?: string | null;
 }
 
 export type ValidationResult =
@@ -55,6 +57,18 @@ const createRequestSchema = z.object({
       message: "type is required and must be exactly 'asset' or 'license'",
     }),
   }),
+  // Nullable/optional FK to PurchaseOrder — see schema.prisma's comment on
+  // Request.purchaseOrderId for the demand-vs-supply-side distinction from
+  // AssetItem/License's purchaseOrderId. Only a UUID *format* check here,
+  // whether it references a real PurchaseOrder is left to Prisma's own FK
+  // constraint at insert time (see createRequest()'s P2003 handling below).
+  // Mirrors src/lib/assets.ts's purchaseOrderId optional().nullable()
+  // pattern exactly.
+  purchase_order_id: z
+    .string({ invalid_type_error: "purchase_order_id must be a valid UUID string" })
+    .uuid("purchase_order_id must be a valid UUID string")
+    .optional()
+    .nullable(),
 });
 
 /**
@@ -66,6 +80,7 @@ export function validateCreateRequestInput(input: {
   employee_id?: unknown;
   type?: unknown;
   reason?: unknown;
+  purchase_order_id?: unknown;
 }): ValidationResult {
   const result = createRequestSchema.safeParse(input);
   if (!result.success) {
@@ -81,6 +96,7 @@ function toRecord(row: {
   type: RequestType;
   reason: string;
   status: string;
+  purchaseOrderId: string | null;
   createdAt: Date;
 }): RequestRecord {
   return {
@@ -89,6 +105,7 @@ function toRecord(row: {
     type: row.type,
     reason: row.reason,
     status: row.status as RequestStatus,
+    purchase_order_id: row.purchaseOrderId,
     created_at: row.createdAt.toISOString(),
   };
 }
@@ -98,11 +115,13 @@ export type CreateRequestResult =
   | { ok: false; error: string };
 
 /**
- * Creates a Request. If employee_id doesn't reference an existing Employee,
+ * Creates a Request. Two separate FKs can fail here (employee_id ->
- * Prisma raises a known error (code P2003, FK violation) — caught here and
+ * Employee, purchase_order_id -> PurchaseOrder) — Prisma raises the same
- * translated into the same `{ok:false,error}` shape as input validation
+ * error code (P2003) for either, so the FK constraint name in
- * failures, rather than letting a raw Prisma error leak to the API layer.
+ * `error.meta.field_name` is used to tell them apart and return a targeted
- * Mirrors src/lib/employees.ts's createEmployee() pattern for managerId.
+ * message, rather than a raw Prisma error leaking to the API layer. Mirrors
+ * src/lib/licenses.ts's createLicense() pattern for disambiguating between
+ * two FKs on the same model.
  */
 export async function createRequest(input: CreateRequestInput): Promise<CreateRequestResult> {
   try {
@@ -111,11 +130,16 @@ export async function createRequest(input: CreateRequestInput): Promise<CreateRe
         employeeId: input.employee_id,
         type: input.type,
         reason: input.reason,
+        purchaseOrderId: input.purchase_order_id ?? null,
       },
     });
     return { ok: true, value: toRecord(created) };
   } catch (error) {
     if (error instanceof Prisma.PrismaClientKnownRequestError && error.code === "P2003") {
+      const fieldName = typeof error.meta?.field_name === "string" ? error.meta.field_name : "";
+      if (fieldName.includes("purchase_order")) {
+        return { ok: false, error: "purchase_order_id does not reference an existing purchase order" };
+      }
       return { ok: false, error: "employee_id does not reference an existing employee" };
     }
     throw error;

tests/requests.test.ts

@@ -50,12 +50,44 @@ function createTestEmployee(overrides: { name?: string; department?: string } =
   });
 }
 
+// Request.purchaseOrderId is a real FK to PurchaseOrder (see schema.prisma /
+// src/lib/requests.ts) — tests that need a valid purchase_order_id create a
+// real PurchaseOrder row (and the Vendor it requires) first and use its id.
+// Mirrors tests/licenses.test.ts's createTestVendor()/createTestPurchaseOrder()
+// helpers.
+function createTestVendor(overrides: { name?: string } = {}) {
+  return prisma.vendor.create({
+    data: {
+      name: overrides.name ?? "Test Vendor",
+      contactEmail: "[email protected]",
+      contactPhone: "0281234567",
+      address: "123 Test Street",
+    },
+  });
+}
+
+function createTestPurchaseOrder(overrides: { vendorId?: string } = {}) {
+  return prisma.purchaseOrder.create({
+    data: {
+      vendorId: overrides.vendorId as string,
+      orderDate: new Date("2026-08-01"),
+      expectedDate: new Date("2026-08-10"),
+    },
+  });
+}
+
 beforeEach(async () => {
   // Each test starts from empty tables so listing/order assertions are
-  // deterministic. requests must be cleared before employees since
+  // deterministic. requests must be cleared before employees/purchase_orders
-  // requests.employee_id has an FK (ON DELETE RESTRICT) to employees.
+  // since requests.employee_id has an FK (ON DELETE RESTRICT) to employees
+  // and requests.purchase_order_id has an FK (ON DELETE SET NULL) to
+  // purchase_orders. purchase_orders must be cleared before employees/vendors
+  // (ON DELETE RESTRICT to vendors, mirrors tests/licenses.test.ts) — order:
+  // requests -> purchase_orders -> employees -> vendors.
   await prisma.request.deleteMany();
+  await prisma.purchaseOrder.deleteMany();
   await prisma.employee.deleteMany();
+  await prisma.vendor.deleteMany();
   // Default to a logged-in session — the tests below exercise request
   // business logic, not auth gating (that's covered by the "auth gating"
   // describe block further down).
@@ -141,6 +173,72 @@ describe("POST /api/requests", () => {
     const remaining = await prisma.request.findMany();
     expect(remaining).toHaveLength(0);
   });
+
+  it("creates a request with a purchase_order_id that references a real purchase order", async () => {
+    const employee = await createTestEmployee();
+    const vendor = await createTestVendor();
+    const purchaseOrder = await createTestPurchaseOrder({ vendorId: vendor.id });
+    const res = await POST(
+      postRequest({
+        employee_id: employee.id,
+        type: "asset",
+        reason: "New laptop for onboarding",
+        purchase_order_id: purchaseOrder.id,
+      })
+    );
+
+    expect(res.status).toBe(201);
+    const body = await res.json();
+    expect(body.purchase_order_id).toBe(purchaseOrder.id);
+  });
+
+  it("creates a request with no purchase_order_id (stays null)", async () => {
+    const employee = await createTestEmployee();
+    const res = await POST(
+      postRequest({ employee_id: employee.id, type: "asset", reason: "New laptop for onboarding" })
+    );
+
+    expect(res.status).toBe(201);
+    const body = await res.json();
+    expect(body.purchase_order_id).toBeNull();
+  });
+
+  it("rejects a purchase_order_id that is a well-formed UUID but doesn't reference an existing purchase order", async () => {
+    const employee = await createTestEmployee();
+    const res = await POST(
+      postRequest({
+        employee_id: employee.id,
+        type: "asset",
+        reason: "New laptop for onboarding",
+        purchase_order_id: "00000000-0000-0000-0000-000000000000",
+      })
+    );
+
+    expect(res.status).toBe(400);
+    const body = await res.json();
+    expect(body.error).toMatch(/purchase_order_id/i);
+    expect(body.error).toMatch(/does not reference an existing purchase order/i);
+
+    // And it must not have created anything.
+    const remaining = await prisma.request.findMany();
+    expect(remaining).toHaveLength(0);
+  });
+
+  it("rejects a purchase_order_id that is not a valid UUID", async () => {
+    const employee = await createTestEmployee();
+    const res = await POST(
+      postRequest({
+        employee_id: employee.id,
+        type: "asset",
+        reason: "New laptop for onboarding",
+        purchase_order_id: "not-a-uuid",
+      })
+    );
+
+    expect(res.status).toBe(400);
+    const body = await res.json();
+    expect(body.error).toMatch(/purchase_order_id/i);
+  });
 });
 
 describe("GET /api/requests", () => {