import sharp from "sharp";
import { mkdir, writeFile } from "node:fs/promises";
import { fileURLToPath } from "node:url";
const assets = new URL("./assets/", import.meta.url);
await mkdir(assets, { recursive: true });
const source = fileURLToPath(new URL("../app/icon.png", import.meta.url));
await sharp(source)
  .resize(512, 512, { kernel: "nearest" })
  .png()
  .toFile(fileURLToPath(new URL("icon.png", assets)));
const sizes = [16, 24, 32, 48, 64, 128, 256];
const images = await Promise.all(
  sizes.map((size) =>
    sharp(source).resize(size, size, { kernel: "nearest" }).png().toBuffer(),
  ),
);
const header = Buffer.alloc(6 + 16 * sizes.length);
header.writeUInt16LE(1, 2);
header.writeUInt16LE(sizes.length, 4);
let offset = header.length;
sizes.forEach((size, index) => {
  const entry = 6 + index * 16;
  header[entry] = size === 256 ? 0 : size;
  header[entry + 1] = header[entry];
  header.writeUInt16LE(1, entry + 4);
  header.writeUInt16LE(32, entry + 6);
  header.writeUInt32LE(images[index].length, entry + 8);
  header.writeUInt32LE(offset, entry + 12);
  offset += images[index].length;
});
await writeFile(
  new URL("icon.ico", assets),
  Buffer.concat([header, ...images]),
);