const fs = require('fs');
const zlib = require('zlib');

function createPNG(width, height, r, g, b) {
  const lineSize = width * 3 + 1;
  const rawSize = height * lineSize;
  const raw = Buffer.alloc(rawSize);

  for (let y = 0; y < height; y++) {
    raw[y * lineSize] = 0;
    for (let x = 0; x < width; x++) {
      const offset = y * lineSize + 1 + x * 3;
      raw[offset] = r;
      raw[offset + 1] = g;
      raw[offset + 2] = b;
    }
  }

  const compressed = zlib.deflateSync(raw);

  function chunk(type, data) {
    const typeBuf = Buffer.from(type, 'ascii');
    const len = Buffer.alloc(4);
    len.writeUInt32BE(data.length, 0);
    const crc = Buffer.alloc(4);
    const crcData = Buffer.concat([typeBuf, data]);
    crc.writeUInt32BE(zlib.crc32(crcData), 0);
    return Buffer.concat([len, typeBuf, data, crc]);
  }

  const ihdr = Buffer.alloc(13);
  ihdr.writeUInt32BE(width, 0);
  ihdr.writeUInt32BE(height, 4);
  ihdr[8] = 8;
  ihdr[9] = 2;
  ihdr[10] = 0;
  ihdr[11] = 0;
  ihdr[12] = 0;

  const sig = Buffer.from([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]);
  const ihdrChunk = chunk('IHDR', ihdr);
  const idatChunk = chunk('IDAT', compressed);
  const iendChunk = chunk('IEND', Buffer.alloc(0));

  return Buffer.concat([sig, ihdrChunk, idatChunk, iendChunk]);
}

fs.mkdirSync('icons', { recursive: true });
fs.writeFileSync('icons/icon16.png', createPNG(16, 16, 16, 185, 129));
fs.writeFileSync('icons/icon48.png', createPNG(48, 48, 16, 185, 129));
fs.writeFileSync('icons/icon128.png', createPNG(128, 128, 16, 185, 129));
console.log('Icons generated');