added udner construction for file compaction, planning for unbloating

api/src/services/budget-session.ts

@@ -0,0 +1,70 @@
+import type { Prisma, PrismaClient } from "@prisma/client";
+
+type BudgetSessionAccessor =
+  | Pick<PrismaClient, "budgetSession">
+  | Pick<Prisma.TransactionClient, "budgetSession">;
+
+function normalizeAvailableCents(value: number): bigint {
+  if (!Number.isFinite(value)) return 0n;
+  return BigInt(Math.max(0, Math.trunc(value)));
+}
+
+export async function getLatestBudgetSession(
+  db: BudgetSessionAccessor,
+  userId: string
+) {
+  return db.budgetSession.findFirst({
+    where: { userId },
+    orderBy: { periodStart: "desc" },
+  });
+}
+
+export async function ensureBudgetSession(
+  db: BudgetSessionAccessor,
+  userId: string,
+  fallbackAvailableCents = 0,
+  now = new Date()
+) {
+  const existing = await getLatestBudgetSession(db, userId);
+  if (existing) return existing;
+
+  const start = new Date(
+    Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), 1, 0, 0, 0, 0)
+  );
+  const end = new Date(
+    Date.UTC(now.getUTCFullYear(), now.getUTCMonth() + 1, 1, 0, 0, 0, 0)
+  );
+  const normalizedAvailable = normalizeAvailableCents(fallbackAvailableCents);
+
+  return db.budgetSession.create({
+    data: {
+      userId,
+      periodStart: start,
+      periodEnd: end,
+      totalBudgetCents: normalizedAvailable,
+      allocatedCents: 0n,
+      fundedCents: 0n,
+      availableCents: normalizedAvailable,
+    },
+  });
+}
+
+export async function ensureBudgetSessionAvailableSynced(
+  db: BudgetSessionAccessor,
+  userId: string,
+  availableCents: number
+) {
+  const normalizedAvailable = normalizeAvailableCents(availableCents);
+  const session = await ensureBudgetSession(
+    db,
+    userId,
+    Number(normalizedAvailable)
+  );
+
+  if ((session.availableCents ?? 0n) === normalizedAvailable) return session;
+
+  return db.budgetSession.update({
+    where: { id: session.id },
+    data: { availableCents: normalizedAvailable },
+  });
+}