const sharp = require('sharp');
const fs = require('fs');
const path = require('path');

const svgPath = path.join(__dirname, '..', 'public', 'favicon.svg');
const svg = fs.readFileSync(svgPath);

async function generate() {
  await sharp(svg).resize(180, 180).png().toFile(path.join(__dirname, '..', 'public', 'apple-touch-icon.png'));
  console.log('apple-touch-icon.png (180x180) generated');

  await sharp(svg).resize(32, 32).png().toFile(path.join(__dirname, '..', 'public', 'favicon-32x32.png'));
  console.log('favicon-32x32.png generated');

  await sharp(svg).resize(16, 16).png().toFile(path.join(__dirname, '..', 'public', 'favicon-16x16.png'));
  console.log('favicon-16x16.png generated');

  const png32 = await sharp(svg).resize(32, 32).png().toBuffer();

  const header = Buffer.alloc(6);
  header.writeUInt16LE(0, 0);
  header.writeUInt16LE(1, 2);
  header.writeUInt16LE(1, 4);

  const entry = Buffer.alloc(16);
  entry.writeUInt8(32, 0);
  entry.writeUInt8(32, 1);
  entry.writeUInt8(0, 2);
  entry.writeUInt8(0, 3);
  entry.writeUInt16LE(1, 4);
  entry.writeUInt16LE(32, 6);
  entry.writeUInt32LE(png32.length, 8);
  entry.writeUInt32LE(22, 12);

  const ico = Buffer.concat([header, entry, png32]);
  fs.writeFileSync(path.join(__dirname, '..', 'public', 'favicon.ico'), ico);
  console.log('favicon.ico generated');

  console.log('All favicon files generated!');
}

generate().catch(err => console.error(err));