import { describe, it, expect } from "vitest";
import { invoiceTotalWithVat } from "../services/invoices.service";

describe("invoiceTotalWithVat", () => {
  it("calculates subtotal without VAT when apply_vat is false", () => {
    const inv = {
      apply_vat: false,
      vat_rate: { toNumber: () => 21 },
      currency: "CZK",
      invoice_items: [
        {
          quantity: { toNumber: () => 2 },
          unit_price: { toNumber: () => 100 },
          vat_rate: { toNumber: () => 21 },
        },
      ],
    };
    expect(invoiceTotalWithVat(inv)).toBe(200);
  });

  it("rounds each line VAT to 2 decimals before accumulation", () => {
    // 3 items @ 33.33 with 21% VAT
    // Line VAT = 33.33 * 0.21 = 6.9993 -> rounded to 7.00
    // Total VAT = 7.00 * 3 = 21.00
    // Subtotal = 33.33 * 3 = 99.99
    // Total = 99.99 + 21.00 = 120.99
    const inv = {
      apply_vat: true,
      vat_rate: { toNumber: () => 21 },
      currency: "CZK",
      invoice_items: Array.from({ length: 3 }, () => ({
        quantity: { toNumber: () => 1 },
        unit_price: { toNumber: () => 33.33 },
        vat_rate: { toNumber: () => 21 },
      })),
    };
    expect(invoiceTotalWithVat(inv)).toBe(120.99);
  });

  it("handles null quantity and unit_price gracefully", () => {
    const inv = {
      apply_vat: true,
      vat_rate: { toNumber: () => 21 },
      currency: "CZK",
      invoice_items: [
        {
          quantity: { toNumber: () => 0 },
          unit_price: { toNumber: () => 0 },
          vat_rate: { toNumber: () => 21 },
        },
      ],
    };
    expect(invoiceTotalWithVat(inv)).toBe(0);
  });
});