// Translatable strings for invoice rendering. Two languages: de (default), en.

export type InvoiceLanguage = "de" | "en";

export interface InvoiceStrings {
  invoice: string;
  stornoInvoice: string;
  offer: string;
  offerNumber: string;
  offerDate: string;
  offerValidUntil: (until: string) => string;
  stornoReference: (originalNumber: string) => string;
  invoiceNumber: string;
  invoiceDate: string;
  deliveryDate: string;
  customerVatId: string;
  position: string;
  description: string;
  quantity: string;
  unitPrice: string;
  totalPrice: string;
  netTotal: string;
  vatLine: (ratePct: string) => string;
  grossTotal: string;
  salutationGeneric: string;
  thankYouLine: string;
  closing: string;
  paymentTerms: (days: number, dueDate: string) => string;
  paymentTermsImmediate: string;
  giroCodeCaption: string;
  reverseChargeNotice: string;
  exportNotice: string;
  kleinunternehmerNotice: string;
  pieceUnit: string;
  page: (current: number, total: number) => string;
  legalCourtLabel: string;
  fnLabel: string;
  vatIdLabel: string;
  taxNumberLabel: string;
  ownerLabel: string;
  ibanLabel: string;
  bicLabel: string;
  bankLabel: string;
  recipientLabel: string;
  amountLabel: string;
  referenceLabel: string;
  addressHeading: string;
  contactHeading: string;
  legalHeading: string;
  bankHeading: string;
  emailLabel: string;
  webLabel: string;
  phoneLabel: string;
  paidStamp: string;
  paymentMethodLabel: string;
  paymentStatusLabel: string;
  paymentStatusPaid: string;
  paymentStatusUnpaid: string;
  paymentStatusPartial: string;
  paymentStatusRefunded: string;
}

/** Status displayed for the order's payment, derived from Shopify's
 *  `displayFinancialStatus`. */
export type PaymentStatus = "paid" | "unpaid" | "partial" | "refunded";

export function paymentStatusLabel(
  status: PaymentStatus,
  strings: InvoiceStrings,
): string {
  switch (status) {
    case "paid":
      return strings.paymentStatusPaid;
    case "partial":
      return strings.paymentStatusPartial;
    case "refunded":
      return strings.paymentStatusRefunded;
    default:
      return strings.paymentStatusUnpaid;
  }
}

/** Maps Shopify's `displayFinancialStatus` to our condensed enum. Values not
 *  signalling actual receipt of money map to "unpaid". */
export function derivePaymentStatus(
  displayFinancialStatus: string | null | undefined,
): PaymentStatus {
  const v = (displayFinancialStatus || "").toUpperCase();
  if (v === "PAID") return "paid";
  if (v === "PARTIALLY_PAID") return "partial";
  if (v === "REFUNDED" || v === "PARTIALLY_REFUNDED") return "refunded";
  return "unpaid";
}

const de: InvoiceStrings = {
  invoice: "Rechnung",
  stornoInvoice: "Stornorechnung",
  offer: "Angebot",
  offerNumber: "Angebots-Nr.",
  offerDate: "Angebotsdatum",
  offerValidUntil: (d) => `Dieses Angebot ist gültig bis ${d}.`,
  stornoReference: (n) => `Storno zu Rechnung Nr. ${n}`,
  invoiceNumber: "Rechnungs-Nr.",
  invoiceDate: "Rechnungsdatum",
  deliveryDate: "Lieferdatum",
  customerVatId: "Deine USt-Id.",
  position: "Pos.",
  description: "Beschreibung",
  quantity: "Menge",
  unitPrice: "Einzelpreis",
  totalPrice: "Gesamtpreis",
  netTotal: "Gesamtbetrag netto",
  vatLine: (r) => `zzgl. Umsatzsteuer ${r}`,
  grossTotal: "Gesamtbetrag brutto",
  salutationGeneric: "Hallo,",
  thankYouLine:
    "vielen Dank für deine Bestellung. Wir berechnen dir folgende Leistungen:",
  closing: "Danke für deinen Einkauf",
  paymentTerms: (days, due) =>
    `Bitte überweise den Rechnungsbetrag innerhalb von ${days} Tagen, spätestens bis zum ${due}, auf das unten angegebene Konto. Bei Fragen zur Rechnung sind wir gerne für dich da.`,
  paymentTermsImmediate:
    "Der Rechnungsbetrag ist sofort nach Erhalt zur Zahlung fällig.",
  giroCodeCaption: "GiroCode",
  reverseChargeNotice:
    "Steuerschuldnerschaft des Leistungsempfängers gemäß Art. 196 MwStSystRL (Reverse Charge).",
  exportNotice: "Steuerfreie Ausfuhrlieferung gemäß § 7 UStG.",
  kleinunternehmerNotice:
    "Gemäß § 6 Abs. 1 Z 27 UStG wird keine Umsatzsteuer ausgewiesen (Kleinunternehmer).",
  pieceUnit: "Stk",
  page: (c, t) => `${c}/${t}`,
  legalCourtLabel: "Amtsgericht",
  fnLabel: "FN",
  vatIdLabel: "UID",
  taxNumberLabel: "St.Nr.",
  ownerLabel: "Inhaber",
  ibanLabel: "IBAN",
  bicLabel: "BIC",
  bankLabel: "Bank",
  recipientLabel: "Empfänger",
  amountLabel: "Betrag",
  referenceLabel: "Referenz",
  addressHeading: "Adresse",
  contactHeading: "Kontakt",
  legalHeading: "Rechtliches",
  bankHeading: "Bankverbindung",
  emailLabel: "E-Mail",
  webLabel: "Web",
  phoneLabel: "Tel.",
  paidStamp: "BEZAHLT",
  paymentMethodLabel: "Zahlart",
  paymentStatusLabel: "Zahlstatus",
  paymentStatusPaid: "Bezahlt",
  paymentStatusUnpaid: "Offen",
  paymentStatusPartial: "Teilweise bezahlt",
  paymentStatusRefunded: "Erstattet",
};

const en: InvoiceStrings = {
  invoice: "Invoice",
  stornoInvoice: "Cancellation invoice",
  offer: "Offer",
  offerNumber: "Offer no.",
  offerDate: "Offer date",
  offerValidUntil: (d) => `This offer is valid until ${d}.`,
  stornoReference: (n) => `Cancels invoice no. ${n}`,
  invoiceNumber: "Invoice no.",
  invoiceDate: "Invoice date",
  deliveryDate: "Delivery date",
  customerVatId: "Your VAT ID",
  position: "Pos.",
  description: "Description",
  quantity: "Qty",
  unitPrice: "Unit price",
  totalPrice: "Total",
  netTotal: "Net total",
  vatLine: (r) => `plus VAT ${r}`,
  grossTotal: "Gross total",
  salutationGeneric: "Dear Sir or Madam,",
  thankYouLine:
    "Thank you for your order. We hereby invoice you for the following:",
  closing: "Thank you for your purchase.",
  paymentTerms: (days, due) =>
    `Please transfer the invoice amount within ${days} days, no later than ${due}, to the bank account shown below.`,
  paymentTermsImmediate: "The invoice amount is due immediately upon receipt.",
  giroCodeCaption: "GiroCode",
  reverseChargeNotice:
    "Reverse charge: VAT to be accounted for by the recipient pursuant to Art. 196 of Council Directive 2006/112/EC.",
  exportNotice: "Tax-exempt export delivery pursuant to § 7 UStG.",
  kleinunternehmerNotice:
    "VAT is not charged pursuant to § 6 (1) 27 UStG (small-business exemption).",
  pieceUnit: "pcs",
  page: (c, t) => `${c}/${t}`,
  legalCourtLabel: "Commercial court",
  fnLabel: "FN",
  vatIdLabel: "VAT ID",
  taxNumberLabel: "Tax no.",
  ownerLabel: "Owner",
  ibanLabel: "IBAN",
  bicLabel: "BIC",
  bankLabel: "Bank",
  recipientLabel: "Recipient",
  amountLabel: "Amount",
  referenceLabel: "Reference",
  addressHeading: "Address",
  contactHeading: "Contact",
  legalHeading: "Legal",
  bankHeading: "Bank details",
  emailLabel: "E-mail",
  webLabel: "Web",
  phoneLabel: "Tel.",
  paidStamp: "PAID",
  paymentMethodLabel: "Payment method",
  paymentStatusLabel: "Payment status",
  paymentStatusPaid: "Paid",
  paymentStatusUnpaid: "Outstanding",
  paymentStatusPartial: "Partially paid",
  paymentStatusRefunded: "Refunded",
};

// Locale → invoice language. We only render in German (`de`) when the
// caller is explicitly German-speaking (de, de-AT, de-DE, de_CH, …).
// Everything else (it, fr, es, en, …) falls back to English so that
// non-German-speaking customers don't receive a German invoice. Callers
// that have a per-shop default fall back to it via
// `pickLanguage(customerLocale ?? settings.defaultLanguage)`, which is why
// `null`/`undefined` still maps to `de` (the legacy default for the
// Austrian shops this app was built for).
export function pickLanguage(input: string | null | undefined): InvoiceLanguage {
  if (!input) return "de";
  const v = input.toLowerCase();
  if (v.startsWith("de")) return "de";
  return "en";
}

export function getStrings(language: InvoiceLanguage): InvoiceStrings {
  return language === "en" ? en : de;
}