Add offline monthly insights with Ollama

src/lib/insights.test.ts

@@ -0,0 +1,91 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("@/lib/db", () => {
+  const monthlyInsight = {
+    upsert: vi.fn(async ({ where, update, create }: { where: { month: string }; update: Record<string, unknown>; create: Record<string, unknown> }) => ({
+      id: "insight-1",
+      month: where.month,
+      year: (update.year ?? create.year) as number,
+      summary: (update.summary ?? create.summary) as string,
+      recommendations: (update.recommendations ?? create.recommendations) as string,
+      inputSnapshot: (update.inputSnapshot ?? create.inputSnapshot) as string,
+      generatedAt: new Date("2026-03-23T12:00:00.000Z"),
+    })),
+    findUnique: vi.fn(),
+  };
+
+  return {
+    db: {
+      expense: { findMany: vi.fn() },
+      paycheck: { findMany: vi.fn() },
+      monthlyInsight,
+    },
+  };
+});
+
+describe("generateMonthlyInsight", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("stores a fallback for sparse months", async () => {
+    const { db } = await import("@/lib/db");
+    const { generateMonthlyInsight } = await import("@/lib/insights");
+
+    vi.mocked(db.expense.findMany).mockResolvedValue([]);
+    vi.mocked(db.paycheck.findMany).mockResolvedValue([]);
+
+    const result = await generateMonthlyInsight("2026-03");
+
+    expect(result.source).toBe("fallback");
+    expect(result.insight.summary).toContain("not enough activity");
+  });
+
+  it("stores model output when Ollama responds", async () => {
+    const { db } = await import("@/lib/db");
+    const { generateMonthlyInsight } = await import("@/lib/insights");
+
+    vi.mocked(db.expense.findMany).mockResolvedValue([
+      {
+        id: "expense-1",
+        title: "Groceries",
+        date: "2026-03-23",
+        amountCents: 3200,
+        category: "FOOD",
+        createdAt: new Date("2026-03-23T10:00:00.000Z"),
+      },
+      {
+        id: "expense-2",
+        title: "Rent",
+        date: "2026-03-02",
+        amountCents: 120000,
+        category: "RENT",
+        createdAt: new Date("2026-03-02T10:00:00.000Z"),
+      },
+    ]);
+    vi.mocked(db.paycheck.findMany).mockResolvedValue([
+      {
+        id: "paycheck-1",
+        payDate: "2026-03-01",
+        amountCents: 180000,
+        createdAt: new Date("2026-03-01T10:00:00.000Z"),
+      },
+    ]);
+
+    vi.spyOn(globalThis, "fetch").mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        response: JSON.stringify({
+          summary: "Spending is stable.",
+          recommendations: "Keep food spending under watch.",
+        }),
+      }),
+    } as Response);
+
+    const result = await generateMonthlyInsight("2026-03");
+
+    expect(result.source).toBe("model");
+    expect(result.insight.summary).toBe("Spending is stable.");
+    expect(result.insight.recommendations).toBe("Keep food spending under watch.");
+  });
+});