import { beforeEach, describe, expect, it, vi } from "vitest";
import type { Mock } from "vitest";
import type { Session } from "next-auth";

// Mirrors tests/employees.test.ts's @/auth mocking pattern.
vi.mock("@/auth", () => ({ auth: vi.fn() }));

import { GET, POST } from "@/app/api/assets/route";
import { prisma } from "@/lib/prisma";
import { auth } from "@/auth";

const mockedAuth = auth as unknown as Mock<() => Promise<Session | null>>;

const testSession: Session = {
  user: { id: "test-user-id" },
  expires: new Date(Date.now() + 60 * 60 * 1000).toISOString(),
};

function postRequest(body: unknown): Request {
  return new Request("http://localhost/api/assets", {
    method: "POST",
    headers: { "content-type": "application/json" },
    body: JSON.stringify(body),
  });
}

// AssetItem.purchaseOrderId is a real FK to PurchaseOrder (see
// schema.prisma / src/lib/assets.ts), and PurchaseOrder.vendorId is a real
// FK to Vendor — tests that need a valid purchaseOrderId create real rows
// first and use their ids. Mirrors tests/purchase-orders.test.ts's
// createTestVendor() helper.
function createTestVendor(overrides: { name?: string } = {}) {
  return prisma.vendor.create({
    data: {
      name: overrides.name ?? "Test Vendor",
      contactEmail: "sales@testvendor.example",
      contactPhone: "0281234567",
      address: "123 Test Street",
    },
  });
}

function createTestPurchaseOrder(overrides: { vendorId?: string } = {}) {
  return prisma.purchaseOrder.create({
    data: {
      vendorId: overrides.vendorId as string,
      orderDate: new Date("2026-08-01"),
      expectedDate: new Date("2026-08-10"),
    },
  });
}

beforeEach(async () => {
  // Each test starts from empty tables so listing/order assertions are
  // deterministic. asset_items must be cleared before purchase_orders/
  // vendors since asset_items has FKs (ON DELETE SET NULL to
  // purchase_orders) — deleteMany order avoids relying on that cascade
  // behavior in tests. purchase_orders must be cleared before vendors
  // (ON DELETE RESTRICT to vendors, mirrors tests/purchase-orders.test.ts).
  await prisma.assetItem.deleteMany();
  await prisma.purchaseOrder.deleteMany();
  await prisma.vendor.deleteMany();
  // Default to a logged-in session — the tests below exercise business
  // logic, not auth gating (that's covered by the "auth gating" describe
  // block further down).
  mockedAuth.mockResolvedValue(testSession);
});

describe("POST /api/assets", () => {
  it("creates an asset item in in_stock status on valid input, with no warrantyEndDate", async () => {
    const res = await POST(
      postRequest({ serialNumber: "SN-001", model: "Dell Latitude 5440", purchaseDate: "2026-01-15" })
    );

    expect(res.status).toBe(201);
    const body = await res.json();

    expect(body).toMatchObject({
      serial_number: "SN-001",
      model: "Dell Latitude 5440",
      status: "in_stock",
      warranty_end_date: null,
    });
    expect(typeof body.id).toBe("string");
    expect(body.id.length).toBeGreaterThan(0);
    expect(Number.isNaN(Date.parse(body.purchase_date))).toBe(false);
    expect(Number.isNaN(Date.parse(body.created_at))).toBe(false);
  });

  it("creates an asset item with a warrantyEndDate", async () => {
    const res = await POST(
      postRequest({
        serialNumber: "SN-002",
        model: "Dell Latitude 5440",
        purchaseDate: "2026-01-15",
        warrantyEndDate: "2029-01-15",
      })
    );

    expect(res.status).toBe(201);
    const body = await res.json();
    expect(Number.isNaN(Date.parse(body.warranty_end_date))).toBe(false);
  });

  it("rejects an empty serialNumber", async () => {
    const res = await POST(postRequest({ serialNumber: "", model: "Dell", purchaseDate: "2026-01-15" }));

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/serialNumber/i);
  });

  it("rejects an empty model", async () => {
    const res = await POST(postRequest({ serialNumber: "SN-003", model: "", purchaseDate: "2026-01-15" }));

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/model/i);
  });

  it("rejects an invalid purchaseDate", async () => {
    const res = await POST(
      postRequest({ serialNumber: "SN-004", model: "Dell", purchaseDate: "not-a-date" })
    );

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/purchaseDate/i);
  });

  it("rejects an invalid warrantyEndDate", async () => {
    const res = await POST(
      postRequest({
        serialNumber: "SN-005",
        model: "Dell",
        purchaseDate: "2026-01-15",
        warrantyEndDate: "not-a-date",
      })
    );

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/warrantyEndDate/i);
  });

  it("creates an asset item with a purchaseOrderId that references a real purchase order", async () => {
    const vendor = await createTestVendor();
    const purchaseOrder = await createTestPurchaseOrder({ vendorId: vendor.id });

    const res = await POST(
      postRequest({
        serialNumber: "SN-007",
        model: "Dell Latitude 5440",
        purchaseDate: "2026-01-15",
        purchaseOrderId: purchaseOrder.id,
      })
    );

    expect(res.status).toBe(201);
    const body = await res.json();
    expect(body.purchase_order_id).toBe(purchaseOrder.id);
  });

  it("creates an asset item with no purchaseOrderId (stays null)", async () => {
    const res = await POST(
      postRequest({ serialNumber: "SN-008", model: "Dell Latitude 5440", purchaseDate: "2026-01-15" })
    );

    expect(res.status).toBe(201);
    const body = await res.json();
    expect(body.purchase_order_id).toBeNull();
  });

  it("rejects a purchaseOrderId that is a well-formed UUID but doesn't reference an existing purchase order", async () => {
    const res = await POST(
      postRequest({
        serialNumber: "SN-009",
        model: "Dell Latitude 5440",
        purchaseDate: "2026-01-15",
        purchaseOrderId: "00000000-0000-0000-0000-000000000000",
      })
    );

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/purchaseOrderId/i);
    expect(body.error).toMatch(/does not reference an existing purchase order/i);

    // And it must not have created anything.
    const remaining = await prisma.assetItem.findMany();
    expect(remaining).toHaveLength(0);
  });

  it("rejects a purchaseOrderId that is not a valid UUID", async () => {
    const res = await POST(
      postRequest({
        serialNumber: "SN-012",
        model: "Dell Latitude 5440",
        purchaseDate: "2026-01-15",
        purchaseOrderId: "not-a-uuid",
      })
    );

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/purchaseOrderId/i);
  });

  it("rejects a duplicate serialNumber", async () => {
    await POST(postRequest({ serialNumber: "SN-006", model: "Dell", purchaseDate: "2026-01-15" }));
    const res = await POST(postRequest({ serialNumber: "SN-006", model: "HP", purchaseDate: "2026-02-01" }));

    expect(res.status).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/serialNumber already exists/i);

    // And it must not have created a second row.
    const remaining = await prisma.assetItem.findMany();
    expect(remaining).toHaveLength(1);
  });
});

describe("GET /api/assets", () => {
  it("lists created asset items, newest first", async () => {
    await POST(postRequest({ serialNumber: "SN-010", model: "Dell", purchaseDate: "2026-01-15" }));
    // Ensure a distinct created_at ordering even on fast filesystems/clocks.
    await new Promise((resolve) => setTimeout(resolve, 5));
    await POST(postRequest({ serialNumber: "SN-011", model: "HP", purchaseDate: "2026-02-01" }));

    const res = await GET();
    expect(res.status).toBe(200);

    const body = await res.json();
    expect(Array.isArray(body)).toBe(true);
    expect(body).toHaveLength(2);

    // newest first
    expect(body[0]).toMatchObject({ serial_number: "SN-011", model: "HP" });
    expect(body[1]).toMatchObject({ serial_number: "SN-010", model: "Dell" });
  });

  it("returns an empty list when there are no asset items", async () => {
    const res = await GET();
    expect(res.status).toBe(200);
    const body = await res.json();
    expect(body).toEqual([]);
  });
});

describe("auth gating on /api/assets", () => {
  // Mirrors tests/employees.test.ts's "auth gating" block — only checks
  // session presence, per the flat permission model (no role/permission
  // logic).
  it("POST /api/assets returns 401 without a session", async () => {
    mockedAuth.mockResolvedValue(null);

    const res = await POST(
      postRequest({ serialNumber: "SN-020", model: "Dell", purchaseDate: "2026-01-15" })
    );

    expect(res.status).toBe(401);
    const body = await res.json();
    expect(body).toEqual({ error: "Unauthorized" });

    // And it must not have created anything.
    const remaining = await prisma.assetItem.findMany();
    expect(remaining).toHaveLength(0);
  });

  it("GET /api/assets returns 401 without a session", async () => {
    mockedAuth.mockResolvedValue(null);

    const res = await GET();

    expect(res.status).toBe(401);
    const body = await res.json();
    expect(body).toEqual({ error: "Unauthorized" });
  });
});