'use strict';
// Generates PNG icons with a Joker card motif on dark green background.
const fs   = require('fs');
const path = require('path');
const zlib = require('zlib');

const outDir = path.join(__dirname, 'public', 'icons');
if (!fs.existsSync(outDir)) fs.mkdirSync(outDir, { recursive: true });

function writePNG(filePath, size) {
  const channels = 4;
  const row = size * channels;
  const raw = Buffer.alloc(size * row);

  // Background: dark forest green #133025
  const bgR = 0x13, bgG = 0x30, bgB = 0x25;
  // Gold color for Joker diamond: #f5c518
  const gR = 0xf5, gG = 0xc5, gB = 0x18;

  const cx = size / 2, cy = size / 2;
  const dh = size * 0.35; // half-height of diamond
  const dw = size * 0.28; // half-width

  for (let y = 0; y < size; y++) {
    for (let x = 0; x < size; x++) {
      const px = (y * size + x) * channels;
      const nx = x + 0.5, ny = y + 0.5;

      // Rounded corners
      const cr = size * 0.2;
      const inCorner =
        (nx < cr && ny < cr && Math.hypot(nx - cr, ny - cr) > cr) ||
        (nx > size - cr && ny < cr && Math.hypot(nx - (size - cr), ny - cr) > cr) ||
        (nx < cr && ny > size - cr && Math.hypot(nx - cr, ny - (size - cr)) > cr) ||
        (nx > size - cr && ny > size - cr && Math.hypot(nx - (size - cr), ny - (size - cr)) > cr);
      if (inCorner) { raw[px + 3] = 0; continue; }

      // Draw a diamond / rhombus shape (Joker card symbol)
      const dx = Math.abs(nx - cx) / dw;
      const dy = Math.abs(ny - cy) / dh;
      const inDiamond = dx + dy <= 1;

      if (inDiamond) {
        raw[px]     = gR;
        raw[px + 1] = gG;
        raw[px + 2] = gB;
        raw[px + 3] = 255;
      } else {
        raw[px]     = bgR;
        raw[px + 1] = bgG;
        raw[px + 2] = bgB;
        raw[px + 3] = 255;
      }
    }
  }

  const chunks = [];
  chunks.push(Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]));

  function crc32(buf) {
    let c = 0xffffffff;
    const table = crc32.table || (crc32.table = (() => {
      const t = new Uint32Array(256);
      for (let i = 0; i < 256; i++) {
        let v = i;
        for (let k = 0; k < 8; k++) v = v & 1 ? 0xedb88320 ^ (v >>> 1) : v >>> 1;
        t[i] = v;
      }
      return t;
    })());
    for (let i = 0; i < buf.length; i++) c = table[(c ^ buf[i]) & 0xff] ^ (c >>> 8);
    return (c ^ 0xffffffff) >>> 0;
  }

  function chunk(type, data) {
    const len = Buffer.alloc(4); len.writeUInt32BE(data.length);
    const tp  = Buffer.from(type);
    const crc = Buffer.alloc(4);
    crc.writeUInt32BE(crc32(Buffer.concat([tp, data])));
    return Buffer.concat([len, tp, data, crc]);
  }

  const ihdr = Buffer.alloc(13);
  ihdr.writeUInt32BE(size, 0); ihdr.writeUInt32BE(size, 4);
  ihdr[8] = 8; ihdr[9] = 6;
  chunks.push(chunk('IHDR', ihdr));

  const filtered = Buffer.alloc(size * (row + 1));
  for (let y = 0; y < size; y++) {
    filtered[y * (row + 1)] = 0;
    raw.copy(filtered, y * (row + 1) + 1, y * row, (y + 1) * row);
  }
  chunks.push(chunk('IDAT', zlib.deflateSync(filtered)));
  chunks.push(chunk('IEND', Buffer.alloc(0)));

  fs.writeFileSync(filePath, Buffer.concat(chunks));
  console.log(`${path.basename(filePath)} written (${size}×${size})`);
}

writePNG(path.join(outDir, 'icon-192.png'), 192);
writePNG(path.join(outDir, 'icon-512.png'), 512);

// SVG icon (scalable, used as favicon)
const svg = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
  <rect width="100" height="100" rx="20" fill="#133025"/>
  <polygon points="50,10 80,50 50,90 20,50" fill="#f5c518"/>
  <text x="50" y="56" font-size="22" text-anchor="middle" fill="#133025" font-family="serif" font-weight="bold">J</text>
</svg>`;
fs.writeFileSync(path.join(outDir, 'icon.svg'), svg);
console.log('icon.svg written');
console.log('Icons generated.');