const zlib = require('zlib');
const fs = require('fs');
const path = require('path');
const outDir = process.argv[2] || path.join(__dirname, '..', 'public', 'icons');
fs.mkdirSync(outDir, { recursive: true });
function writeChunk(type, data) {
  const chunk = Buffer.concat([Buffer.alloc(4), Buffer.from(type), data, Buffer.alloc(4)]);
  chunk.writeUInt32BE(data.length, 0);
  const crc = zlib.crc32(Buffer.concat([Buffer.from(type), data]));
  chunk.writeUInt32BE(crc >>> 0, 4 + 4 + data.length);
  return chunk;
}
function writePng(filename, width, height, r, g, b) {
  const signature = Buffer.from([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]);
  const ihdr = Buffer.alloc(13);
  ihdr.writeUInt32BE(width, 0);
  ihdr.writeUInt32BE(height, 4);
  ihdr.writeUInt8(8, 8);
  ihdr.writeUInt8(2, 9);
  ihdr.writeUInt8(0, 10);
  ihdr.writeUInt8(0, 11);
  ihdr.writeUInt8(0, 12);
  const rowLength = 1 + width * 3;
  const imageData = Buffer.alloc(rowLength * height);
  for (let y = 0; y < height; y++) {
    const rowStart = y * rowLength;
    imageData[rowStart] = 0;
    for (let x = 0; x < width; x++) {
      const offset = rowStart + 1 + x * 3;
      imageData[offset] = r;
      imageData[offset + 1] = g;
      imageData[offset + 2] = b;
    }
  }
  const compressed = zlib.deflateSync(imageData);
  const chunks = [signature, writeChunk('IHDR', ihdr), writeChunk('IDAT', compressed), writeChunk('IEND', Buffer.alloc(0))];
  fs.writeFileSync(filename, Buffer.concat(chunks));
}
const teal = [0x22, 0xD3, 0xEE];
writePng(path.join(outDir, 'icon16.png'), 16, 16, ...teal);
writePng(path.join(outDir, 'icon48.png'), 48, 48, ...teal);
writePng(path.join(outDir, 'icon128.png'), 128, 128, ...teal);
console.log('Icons generated');