refactor: share tbank-sync claim and generation lock (WealthLedger/backend#166) (#188)

src/integrations/tbank/tbank-sync-claim.ts

@@ -0,0 +1,53 @@
+import type { Prisma } from '../../../generated/prisma/client';
+import type { TbankSyncAttempt } from './tbank-access.service';
+
+const NO_UPDATED_ROWS = 0;
+
+// Shared owners for the tbank-sync DB claim/lock protocol.
+// Both helpers are CAS fences: they run inside the caller's transaction and
+// keep the exact where/data shapes they replaced. Callers keep deciding
+// success from the claim count exactly as before.
+
+// Claims the active TbankSyncWork row: only the still-running attempt of a
+// valid connection may transition. `data` is the state transition to apply.
+export type ClaimOptions = {
+  // Overrides the default 'running' fence (e.g. an initiator row also
+  // accepts 'complete').
+  state: Prisma.TbankSyncWorkWhereInput['state'] | undefined;
+  // true drops the `connection: { invalidToken: false }` guard for fences
+  // that must also fire on an invalidated connection.
+  withoutConnectionFence: boolean | undefined;
+};
+export async function claimSyncWork(
+  tx: Prisma.TransactionClient,
+  attempt: TbankSyncAttempt,
+  data: Prisma.TbankSyncWorkUpdateManyMutationInput,
+  options: Partial<ClaimOptions> = {},
+): Promise<number> {
+  const result = await tx.tbankSyncWork.updateMany({
+    where: {
+      ...attempt,
+      state: options.state ?? 'running',
+      ...(options.withoutConnectionFence
+        ? {}
+        : { connection: { invalidToken: false } }),
+    },
+    data,
+  });
+  return result.count;
+}
+
+// Locks the connection generation before reserving or publishing work: the
+// row must still be the current revision with a valid token. `extra`
+// (e.g. account membership) is merged into the where clause.
+export async function lockConnectionGeneration(
+  tx: Prisma.TransactionClient,
+  owner: { revision: string; userId: string },
+  extra: Prisma.TbankConnectionWhereInput = {},
+): Promise<boolean> {
+  const result = await tx.tbankConnection.updateMany({
+    where: { ...owner, ...extra, invalidToken: false },
+    data: { membershipRevision: { increment: 0 } },
+  });
+  return result.count > NO_UPDATED_ROWS;
+}