import { describe, test, expect } from "vitest";
import { amount, buildCiiXml, escapeXml, type EInvoiceInput } from "./cii";
import { vatBreakdown } from "@/lib/vat";

function input(overrides: Partial<EInvoiceInput> = {}): EInvoiceInput {
  const items = [
    { name: "Waldhonig 500 g", quantity: 3, totalCents: 2697, vatRatePercent: 7 },
    { name: "Bienenwachskerze", quantity: 1, totalCents: 1290, vatRatePercent: 19 },
    { name: "Blütenhonig 250 g", quantity: 2, totalCents: 1198, vatRatePercent: 7 },
  ];
  return {
    kind: "invoice",
    number: "RE-2026-0042",
    issuedAt: new Date(2026, 9, 12, 10, 0),
    currency: "EUR",
    orderNumber: "WH-2026-0042",
    seller: {
      name: "Wabenhain",
      street: "Musterweg 1",
      zip: "12345",
      city: "Musterstadt",
      countryCode: "DE",
      vatId: "DE123456789",
      email: "hallo@wabenhain.com",
    },
    buyer: { name: "Erika Musterfrau", street: "Musterstraße 1", zip: "80331", city: "München", countryCode: "DE" },
    items,
    shippingCents: 490,
    discountCents: 300,
    discountCode: "SOMMER",
    totalCents: 2697 + 1290 + 1198 + 490 - 300,
    paymentNote: "Bereits bezahlt (Online-Zahlung über Stripe).",
    ...overrides,
  };
}

function values(xml: string, element: string): string[] {
  return [...xml.matchAll(new RegExp(`<${element}[^>]*>([^<]*)</${element}>`, "g"))].map((match) => match[1]);
}

function cents(value: string): number {
  return Math.round(Number(value) * 100);
}

function single(xml: string, element: string): number {
  const found = values(xml, element);
  expect(found).toHaveLength(1);
  return cents(found[0]);
}

function headerLineTotal(xml: string): number {
  const match = /<ram:SpecifiedTradeSettlementHeaderMonetarySummation><ram:LineTotalAmount>([^<]*)</.exec(xml);
  if (!match) throw new Error("BT-106 fehlt");
  return cents(match[1]);
}

function ok(data: EInvoiceInput): string {
  const result = buildCiiXml(data);
  if (!result.ok) throw new Error(result.reason);
  return result.xml;
}

describe("buildCiiXml", () => {
  test("Summen stimmen mit der Steueraufstellung des PDFs auf den Cent ueberein", () => {
    // Arrange
    const data = input();
    const rated = data.items.map((item) => ({ totalCents: item.totalCents, vatRatePercent: item.vatRatePercent ?? 0 }));
    const expected = vatBreakdown({ items: rated, shippingCents: 490, discountCents: 300 });

    // Act
    const xml = ok(data);

    // Assert
    expect(values(xml, "ram:BasisAmount").map(cents)).toEqual(expected.map((line) => line.netCents));
    expect(values(xml, "ram:CalculatedAmount").map(cents)).toEqual(expected.map((line) => line.vatCents));
    const basis = single(xml, "ram:TaxBasisTotalAmount");
    const tax = single(xml, "ram:TaxTotalAmount");
    expect(headerLineTotal(xml) - single(xml, "ram:AllowanceTotalAmount") + single(xml, "ram:ChargeTotalAmount")).toBe(basis);
    expect(basis + tax).toBe(data.totalCents);
    expect(single(xml, "ram:GrandTotalAmount")).toBe(data.totalCents);
    expect(single(xml, "ram:TotalPrepaidAmount")).toBe(data.totalCents);
    expect(single(xml, "ram:DuePayableAmount")).toBe(0);
  });

  test("Positionen ergeben zusammen genau die Positionssumme (BT-106)", () => {
    // Act
    const xml = ok(input());

    // Assert
    const lineAmounts = [
      ...xml.matchAll(/<ram:SpecifiedTradeSettlementLineMonetarySummation><ram:LineTotalAmount>([^<]*)</g),
    ].map((match) => cents(match[1]));
    expect(lineAmounts).toHaveLength(3);
    expect(lineAmounts.reduce((sum, value) => sum + value, 0)).toBe(headerLineTotal(xml));
    expect(values(xml, "ram:BilledQuantity")).toEqual(["3", "2", "1"]);
  });

  test("Kopfdaten: Profil EN 16931, Typ 380, Datum, Verkaeufer mit USt-IdNr.", () => {
    // Act
    const xml = ok(input());

    // Assert
    expect(xml).toContain("<ram:ID>urn:cen.eu:en16931:2017</ram:ID>");
    expect(xml).toContain("<ram:TypeCode>380</ram:TypeCode>");
    expect(xml).toContain('<udt:DateTimeString format="102">20261012</udt:DateTimeString>');
    expect(xml).toContain('<ram:ID schemeID="VA">DE123456789</ram:ID>');
    expect(xml).toContain("<ram:Reason>Rabatt (SOMMER)</ram:Reason>");
    expect(xml).toContain("<ram:Reason>Versand</ram:Reason>");
  });

  test("Stornorechnung ist eine Gutschrift (381) mit Bezug, offen zur Erstattung", () => {
    // Arrange
    const data = input({
      kind: "creditNote",
      number: "ST-2026-0001",
      precedingInvoice: { number: "RE-2026-0042", issuedAt: new Date(2026, 9, 1, 12, 0) },
      paymentNote: "Der Betrag wird über die ursprüngliche Zahlungsart erstattet.",
    });

    // Act
    const xml = ok(data);

    // Assert
    expect(xml).toContain("<ram:TypeCode>381</ram:TypeCode>");
    expect(xml).toMatch(
      /<ram:InvoiceReferencedDocument><ram:IssuerAssignedID>RE-2026-0042<\/ram:IssuerAssignedID><ram:FormattedIssueDateTime><qdt:DateTimeString format="102">20261001</
    );
    expect(single(xml, "ram:TotalPrepaidAmount")).toBe(0);
    expect(single(xml, "ram:DuePayableAmount")).toBe(data.totalCents);
  });

  test("Kleinunternehmer: Kategorie E mit Befreiungsgrund", () => {
    // Arrange
    const items = [{ name: "Honig", quantity: 1, totalCents: 1000, vatRatePercent: 0 }];

    // Act
    const xml = ok(input({ items, shippingCents: 0, discountCents: 0, totalCents: 1000 }));

    // Assert
    expect(values(xml, "ram:CategoryCode").every((code) => code === "E")).toBe(true);
    expect(xml).toContain("§ 19 UStG");
    expect(single(xml, "ram:TaxTotalAmount")).toBe(0);
  });

  test("ohne USt-IdNr. oder mit Position ohne Steuersatz keine E-Rechnung", () => {
    expect(buildCiiXml(input({ seller: { ...input().seller, vatId: " " } }))).toMatchObject({ ok: false });
    const items = [{ name: "Alt", quantity: 1, totalCents: 1000, vatRatePercent: null }];
    expect(buildCiiXml(input({ items, shippingCents: 0, discountCents: 0, totalCents: 1000 }))).toMatchObject({ ok: false });
  });

  test("Sonderzeichen im Namen werden maskiert", () => {
    // Act
    const xml = ok(input({ buyer: { ...input().buyer, name: 'Müller & Söhne <GmbH> "Bio"' } }));

    // Assert
    expect(xml).toContain("<ram:Name>Müller &amp; Söhne &lt;GmbH&gt; &quot;Bio&quot;</ram:Name>");
  });
});

describe("Hilfsfunktionen", () => {
  test("amount formatiert Cent ohne Gleitkommafehler", () => {
    expect(amount(0)).toBe("0.00");
    expect(amount(5)).toBe("0.05");
    expect(amount(123456)).toBe("1234.56");
    expect(amount(-250)).toBe("-2.50");
  });

  test("escapeXml maskiert alle fuenf Sonderzeichen", () => {
    expect(escapeXml(`<a href="x">'&'</a>`)).toBe("&lt;a href=&quot;x&quot;&gt;&apos;&amp;&apos;&lt;/a&gt;");
  });
});