fixed issue in order cancellation

app/services/invoice/representativeInvoice.ts

@@ -0,0 +1,47 @@
+/**
+ * Selection helper for the "recent orders" / "recent drafts" lists.
+ *
+ * A single order can accumulate several invoice rows over its lifetime
+ * (regenerations bump the `version`, cancel-and-reissue cancels the old row
+ * and issues a new one). Crucially, a CANCELLED invoice can carry a HIGHER
+ * `version` than the current active one, so picking "highest version wins"
+ * would surface a stale cancelled invoice and hide the live one — the order
+ * would render as if it had no invoice ("Generate" button) even though a
+ * valid issued invoice exists.
+ *
+ * The correct representative for the UI is the latest NON-cancelled invoice;
+ * only when every row is cancelled do we fall back to the latest cancelled
+ * one (so the order can still show its "cancelled" state).
+ */
+
+export interface RepresentativeInvoiceRow {
+  orderId: string;
+  version: number;
+  cancelledAt: Date | null;
+}
+
+/**
+ * Build a map of orderId -> representative invoice.
+ *
+ * @param invoices Invoice rows for the relevant orders. MUST already be sorted
+ *   by `version` descending (then `createdAt` descending), matching the
+ *   Prisma query order, so the first non-cancelled row encountered per order
+ *   is the highest-version active invoice.
+ */
+export function buildRepresentativeInvoiceMap<T extends RepresentativeInvoiceRow>(
+  invoices: T[],
+): Map<string, T> {
+  const byOrder = new Map<string, T>();
+  for (const inv of invoices) {
+    const existing = byOrder.get(inv.orderId);
+    if (!existing) {
+      byOrder.set(inv.orderId, inv);
+      continue;
+    }
+    // Upgrade from a cancelled placeholder to the first active invoice seen.
+    if (existing.cancelledAt && !inv.cancelledAt) {
+      byOrder.set(inv.orderId, inv);
+    }
+  }
+  return byOrder;
+}