// One-off generator for the PWA app icons: a rounded remote-control glyph
// on a dark background. Pure Node (zlib + zlib.crc32), no image deps.
import { deflateSync, crc32 } from "node:zlib";
import { writeFileSync, mkdirSync } from "node:fs";

const BG = [11, 13, 18]; // #0b0d12
const FG = [88, 214, 141]; // accent green
const FG_DIM = [46, 58, 74];

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

function inRoundedRect(x, y, w, h, left, top, right, bottom, radius) {
  if (x < left || x > right || y < top || y > bottom) return false;
  const cx = x < left + radius ? left + radius : x > right - radius ? right - radius : x;
  const cy = y < top + radius ? top + radius : y > bottom - radius ? bottom - radius : y;
  const dx = x - cx;
  const dy = y - cy;
  return dx * dx + dy * dy <= radius * radius || (x >= left + radius && x <= right - radius) || (y >= top + radius && y <= bottom - radius);
}

function makeIcon(size) {
  const margin = Math.round(size * 0.2);
  const left = margin;
  const right = size - margin;
  const top = Math.round(size * 0.08);
  const bottom = size - top;
  const radius = Math.round(size * 0.14);

  const btnRadius = Math.max(2, Math.round(size * 0.035));
  const btnCenters = [
    [size * 0.5, size * 0.28],
    [size * 0.5, size * 0.46],
    [size * 0.32, size * 0.62],
    [size * 0.68, size * 0.62],
    [size * 0.5, size * 0.78],
  ];

  const raw = Buffer.alloc(size * (1 + size * 4));
  for (let y = 0; y < size; y++) {
    let rowStart = y * (1 + size * 4);
    raw[rowStart] = 0; // filter type: none
    for (let x = 0; x < size; x++) {
      let [r, g, b] = BG;
      if (inRoundedRect(x, y, size, size, left, top, right, bottom, radius)) {
        [r, g, b] = FG_DIM;
        for (const [bx, by] of btnCenters) {
          const dx = x - bx;
          const dy = y - by;
          if (dx * dx + dy * dy <= btnRadius * btnRadius) {
            [r, g, b] = FG;
            break;
          }
        }
      }
      const off = rowStart + 1 + x * 4;
      raw[off] = r;
      raw[off + 1] = g;
      raw[off + 2] = b;
      raw[off + 3] = 255;
    }
  }

  const ihdr = Buffer.alloc(13);
  ihdr.writeUInt32BE(size, 0);
  ihdr.writeUInt32BE(size, 4);
  ihdr[8] = 8; // bit depth
  ihdr[9] = 6; // color type RGBA
  ihdr[10] = 0;
  ihdr[11] = 0;
  ihdr[12] = 0;

  const idat = deflateSync(raw);
  const signature = Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]);
  return Buffer.concat([
    signature,
    chunk("IHDR", ihdr),
    chunk("IDAT", idat),
    chunk("IEND", Buffer.alloc(0)),
  ]);
}

mkdirSync(new URL("../public/icons", import.meta.url), { recursive: true });
for (const size of [192, 512]) {
  const png = makeIcon(size);
  writeFileSync(new URL(`../public/icons/icon-${size}.png`, import.meta.url), png);
  console.log(`wrote icon-${size}.png (${png.length} bytes)`);
}