// Generates favicons / PWA icons / Apple touch icon / favicon.ico from public/brand/rareindex-mark.svg.
// Run from apps/web:  node scripts/brand-assets.mjs
import { readFileSync, writeFileSync, copyFileSync } from 'node:fs';
import sharp from 'sharp';

const svg = readFileSync('public/brand/rareindex-mark.svg');
const png = (size) => sharp(svg, { density: Math.ceil((size / 64) * 72) }).resize(size, size).png().toBuffer();

const out = {
  'src/app/icon.png': 32,
  'src/app/apple-icon.png': 180,
  'public/apple-touch-icon.png': 180,
  'public/icon-192.png': 192,
  'public/icon-512.png': 512,
};
for (const [path, size] of Object.entries(out)) writeFileSync(path, await png(size));

// maskable: the mark on a full-bleed ink square with safe-zone padding (icon at 80 %)
const inner = await png(410);
const maskable = await sharp({ create: { width: 512, height: 512, channels: 4, background: '#0B0F19' } })
  .composite([{ input: inner, gravity: 'centre' }])
  .png()
  .toBuffer();
writeFileSync('public/icon-maskable-512.png', maskable);

// favicon.ico = PNG-in-ICO container with 16, 32 and 48 px images
const sizes = [16, 32, 48];
const images = await Promise.all(sizes.map((s) => png(s)));
const header = Buffer.alloc(6);
header.writeUInt16LE(0, 0); // reserved
header.writeUInt16LE(1, 2); // type: icon
header.writeUInt16LE(images.length, 4);
const dir = Buffer.alloc(16 * images.length);
let offset = 6 + dir.length;
images.forEach((img, i) => {
  const s = sizes[i];
  dir.writeUInt8(s === 256 ? 0 : s, i * 16 + 0);
  dir.writeUInt8(s === 256 ? 0 : s, i * 16 + 1);
  dir.writeUInt8(0, i * 16 + 2); // palette
  dir.writeUInt8(0, i * 16 + 3); // reserved
  dir.writeUInt16LE(1, i * 16 + 4); // planes
  dir.writeUInt16LE(32, i * 16 + 6); // bpp
  dir.writeUInt32LE(img.length, i * 16 + 8);
  dir.writeUInt32LE(offset, i * 16 + 12);
  offset += img.length;
});
writeFileSync('src/app/favicon.ico', Buffer.concat([header, dir, ...images]));
copyFileSync('public/brand/rareindex-mark.svg', 'src/app/icon.svg');
copyFileSync('public/brand/rareindex-mark.svg', 'public/icon.svg');
console.log('brand assets written');