// tests/allocator.test.ts
import { describe, it, expect, beforeEach, afterAll } from "vitest";
import { prisma, resetUser, ensureUser, U, cid, pid, closePrisma } from "./helpers";
import { allocateIncome } from "../src/allocator";

describe("allocator — core behaviors", () => {
  beforeEach(async () => {
    await resetUser(U);
    await ensureUser(U);
  });

  afterAll(async () => {
    await closePrisma();
  });

  it("distributes remainder to variables by largest remainder with savings-first tie", async () => {
    const c1 = cid("c1");
    const c2 = cid("c2"); // make this savings to test the tiebreaker
    await prisma.variableCategory.createMany({
      data: [
        { id: c1, userId: U, name: "Groceries", percent: 60, priority: 2, isSavings: false, balanceCents: 0n },
        { id: c2, userId: U, name: "Saver",     percent: 40, priority: 1, isSavings: true,  balanceCents: 0n },
      ],
    });

    const p1 = pid("rent");
    await prisma.fixedPlan.create({
      data: {
        id: p1,
        userId: U,
        name: "Rent",
        cycleStart: new Date().toISOString(),
        dueOn: new Date(Date.now() + 7 * 864e5).toISOString(),
        totalCents: 10000n,
        fundedCents: 0n,
        priority: 1,
        fundingMode: "auto-on-deposit",
      },
    });

    // $100 income
    const result = await allocateIncome(prisma as any, U, 10000, new Date().toISOString(), "inc1");
    expect(result).toBeDefined();
    // rent should be funded first up to need
    const fixed = result.fixedAllocations ?? [];
    const variable = result.variableAllocations ?? [];

    // sanity
    expect(Array.isArray(fixed)).toBe(true);
    expect(Array.isArray(variable)).toBe(true);
  });

  it("handles zeros and single bucket", async () => {
    const cOnly = cid("only");
    await prisma.variableCategory.create({
      data: { id: cOnly, userId: U, name: "Only", percent: 100, priority: 1, isSavings: false, balanceCents: 0n },
    });

    const result = await allocateIncome(prisma as any, U, 0, new Date().toISOString(), "inc2");
    expect(result).toBeDefined();
    const variable = result.variableAllocations ?? [];
    const sum = variable.reduce((s, a: any) => s + (a.amountCents ?? 0), 0);
    expect(sum).toBe(0);
  });
});