import { writeFileSync } from 'fs';
import { deflateSync } from 'zlib';

function makePng(size, r, g, b) {
  const crcTable = new Uint32Array(256);
  for (let n = 0; n < 256; n++) {
    let c = n;
    for (let k = 0; k < 8; k++) {
      c = (c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1);
    }
    crcTable[n] = c;
  }

  function crc32(buf) {
    let c = ~0;
    for (let i = 0; i < buf.length; i++) {
      c = crcTable[(c ^ buf[i]) & 0xFF] ^ (c >>> 8);
    }
    return ~c >>> 0;
  }

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

  const ihdrData = Buffer.from([
    0x00, 0x00, 0x00, size, 0x00, 0x00, 0x00, size,
    0x08, 0x02, 0x00, 0x00, 0x00,
  ]);
  const ihdrChunk = writeChunk('IHDR', ihdrData);

  const raw = [];
  for (let y = 0; y < size; y++) {
    raw.push(0);
    for (let x = 0; x < size; x++) {
      raw.push(r, g, b, 255);
    }
  }
  const rawBuf = Buffer.from(raw);
  const compressed = deflateSync(rawBuf);
  const idatChunk = writeChunk('IDAT', compressed);
  const iendChunk = writeChunk('IEND', Buffer.alloc(0));

  const sig = Buffer.from([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]);
  return Buffer.concat([sig, ihdrChunk, idatChunk, iendChunk]);
}

writeFileSync('icons/icon16.png', makePng(16, 99, 102, 241));
writeFileSync('icons/icon48.png', makePng(48, 99, 102, 241));
writeFileSync('icons/icon128.png', makePng(128, 99, 102, 241));
console.log('Icons created');