import PDFDocument from "pdfkit";
import { formatPrice, formatDate } from "@/lib/format";
import { getCompanyInfo } from "@/lib/company-info";
import { getDictionary } from "@/i18n/get-dictionary";
import type { Locale } from "@/i18n/config";

interface InvoicePdfInput {
  locale: Locale;
  invoiceNumber: string;
  issuedAt: Date;
  totalCents: number;
  order: {
    orderNumber: string;
    firstName: string;
    lastName: string;
    street: string;
    zip: string;
    city: string;
    currency: string;
    subtotalCents: number;
    shippingCents: number;
    discountCents: number;
    discountCode?: { code: string } | null;
    items: { productName: string; weightGrams: number; quantity: number; unitPriceCents: number; totalCents: number }[];
  };
}

/**
 * Erzeugt die Rechnung als PDF (pdfkit — reine JS-Bibliothek ohne
 * Headless-Browser/native Abhaengigkeiten, haelt das Docker-Image schlank).
 * Wird on-the-fly beim Download erzeugt statt dauerhaft gespeichert. Nutzt
 * dieselben Uebersetzungen wie die HTML-Rechnungsansicht (t.invoicePage),
 * damit beide Darstellungen derselben Rechnung konsistent bleiben.
 */
export async function generateInvoicePdf(input: InvoicePdfInput): Promise<Buffer> {
  const t = getDictionary(input.locale).invoicePage;
  const company = await getCompanyInfo();
  const doc = new PDFDocument({ margin: 50, size: "A4" });
  const chunks: Buffer[] = [];
  doc.on("data", (chunk: Buffer) => chunks.push(chunk));
  const done = new Promise<Buffer>((resolve, reject) => {
    doc.on("end", () => resolve(Buffer.concat(chunks)));
    doc.on("error", reject);
  });

  doc.fontSize(20).fillColor("#24352B").text(company.name.toUpperCase(), { continued: false });
  doc
    .fontSize(9)
    .fillColor("#666666")
    .text(`${company.address.street}, ${company.address.zip} ${company.address.city}`);

  doc.moveDown(1.5);
  doc.fontSize(14).fillColor("#24352B").text(t.invoiceLabel(input.invoiceNumber));
  doc
    .fontSize(9)
    .fillColor("#666666")
    .text(t.orderLabel(input.order.orderNumber))
    .text(`${t.dateLabel} ${formatDate(input.issuedAt)}`);

  doc.moveDown(1);
  doc
    .fontSize(10)
    .fillColor("#242424")
    .text(`${input.order.firstName} ${input.order.lastName}`)
    .text(input.order.street)
    .text(`${input.order.zip} ${input.order.city}`);

  doc.moveDown(1.5);

  const tableTop = doc.y;
  const columns = { name: 50, qty: 320, price: 380, total: 470 };
  doc
    .fontSize(9)
    .fillColor("#666666")
    .text(t.itemHeader, columns.name, tableTop)
    .text(t.quantityHeader, columns.qty, tableTop)
    .text(t.priceHeader, columns.price, tableTop)
    .text(t.totalHeader, columns.total, tableTop);
  doc
    .moveTo(50, tableTop + 14)
    .lineTo(545, tableTop + 14)
    .strokeColor("#dddddd")
    .stroke();

  let y = tableTop + 22;
  doc.fontSize(10).fillColor("#242424");
  for (const item of input.order.items) {
    doc.text(`${item.productName} (${item.weightGrams} g)`, columns.name, y, { width: 260 });
    doc.text(String(item.quantity), columns.qty, y);
    doc.text(formatPrice(item.unitPriceCents, input.order.currency), columns.price, y);
    doc.text(formatPrice(item.totalCents, input.order.currency), columns.total, y);
    y += 20;
  }

  y += 10;
  doc.moveTo(350, y).lineTo(545, y).strokeColor("#dddddd").stroke();
  y += 10;

  doc.fontSize(10).fillColor("#666666").text(t.subtotalLabel, 350, y);
  doc.fillColor("#242424").text(formatPrice(input.order.subtotalCents, input.order.currency), columns.total, y);
  y += 16;
  doc.fillColor("#666666").text(t.shippingLabel, 350, y);
  doc
    .fillColor("#242424")
    .text(
      input.order.shippingCents === 0 ? t.freeShipping : formatPrice(input.order.shippingCents, input.order.currency),
      columns.total,
      y
    );
  if (input.order.discountCents > 0) {
    y += 16;
    doc
      .fillColor("#666666")
      .text(input.order.discountCode ? `${t.discountLabel} (${input.order.discountCode.code})` : t.discountLabel, 350, y);
    doc
      .fillColor("#242424")
      .text(`−${formatPrice(input.order.discountCents, input.order.currency)}`, columns.total, y);
  }
  y += 20;
  doc.fontSize(11).fillColor("#24352B").text(t.totalLabel, 350, y);
  doc.text(formatPrice(input.totalCents, input.order.currency), columns.total, y);

  doc
    .fontSize(8)
    .fillColor("#999999")
    .text(t.legalNote, 50, 760, { width: 495 });

  doc.end();
  return done;
}