// Baut Favicon, App-Icons und das Vorschaubild für geteilte Links aus den
// Marken-SVGs in public/. Aufruf: node scripts/icons-bauen.mjs
// Quelle des Favicons: das "la" auf Petrol aus dem Prototyp lara-webdesign.html.
import sharp from 'sharp';
import { readFileSync, writeFileSync } from 'node:fs';

const pub = (f) => new URL(`../public/${f}`, import.meta.url);
const papier = { r: 252, g: 250, b: 246, alpha: 1 };

const favicon = readFileSync(pub('favicon.svg'));
const logo = readFileSync(pub('logo.svg'));

const png = (svg, size) =>
  sharp(svg, { density: 72 * Math.ceil(size / 100) * 4 }).resize(size, size).png().toBuffer();

// Transparente Icons
for (const size of [48, 96, 192, 512]) {
  writeFileSync(pub(`icon-${size}.png`), await png(favicon, size));
}

// Apple-Icon braucht deckenden Grund (iOS füllt Transparenz schwarz)
const appleInner = await png(favicon, 148);
await sharp({ create: { width: 180, height: 180, channels: 4, background: papier } })
  .composite([{ input: appleInner, gravity: 'center' }])
  .png()
  .toFile(new URL('../public/apple-touch-icon.png', import.meta.url).pathname.replace(/^\/(\w:)/, '$1'));

// favicon.ico mit 16/32/48 als PNG-Einträge
const sizes = [16, 32, 48];
const bufs = await Promise.all(sizes.map((s) => png(favicon, s)));
const header = Buffer.alloc(6 + 16 * sizes.length);
header.writeUInt16LE(0, 0);
header.writeUInt16LE(1, 2);
header.writeUInt16LE(sizes.length, 4);
let offset = header.length;
sizes.forEach((s, i) => {
  const e = 6 + 16 * i;
  header.writeUInt8(s, e);
  header.writeUInt8(s, e + 1);
  header.writeUInt16LE(1, e + 4);
  header.writeUInt16LE(32, e + 6);
  header.writeUInt32LE(bufs[i].length, e + 8);
  header.writeUInt32LE(offset, e + 12);
  offset += bufs[i].length;
});
writeFileSync(pub('favicon.ico'), Buffer.concat([header, ...bufs]));

// Vorschaubild für WhatsApp, Signal, Facebook, LinkedIn & Co. (1200 x 630)
const logoPng = await sharp(logo, { density: 300 }).resize({ width: 860 }).png().toBuffer();
await sharp({ create: { width: 1200, height: 630, channels: 4, background: papier } })
  .composite([{ input: logoPng, gravity: 'center' }])
  .flatten({ background: papier })
  .jpeg({ quality: 88 })
  .toFile(new URL('../public/og-image.jpg', import.meta.url).pathname.replace(/^\/(\w:)/, '$1'));

console.log('Icons gebaut.');