// Generate WebP variants of source PNGs in public/product/.
// Run after replacing/adding a source PNG; outputs are committed.
//
// For each <name>.png we emit:
//   <name>-1280.webp  (q=82, used as inline srcset for desktop ≤ ~1280 px)
//   <name>-1920.webp  (q=80, used as inline srcset for retina/wide viewports
//                      and as the lightbox-modal full-size source)
//
// The original .png is kept as a <picture> fallback for the rare browser
// without WebP support (~2 % globally).

import { readdir, stat } from 'node:fs/promises';
import { join, parse } from 'node:path';
import { fileURLToPath } from 'node:url';
import sharp from 'sharp';

const SRC_DIR = fileURLToPath(new URL('../public/product/', import.meta.url));

const VARIANTS = [
  { width: 1280, quality: 82, suffix: '-1280' },
  { width: 1920, quality: 80, suffix: '-1920' },
];

const entries = await readdir(SRC_DIR);
const pngs = entries.filter((f) => f.toLowerCase().endsWith('.png'));

if (pngs.length === 0) {
  console.error(`No PNGs found in ${SRC_DIR}`);
  process.exit(1);
}

for (const file of pngs) {
  const { name } = parse(file);
  const inputPath = join(SRC_DIR, file);
  const inputBytes = (await stat(inputPath)).size;
  console.log(`\n${file}  (${(inputBytes / 1024).toFixed(0)} KiB)`);

  for (const v of VARIANTS) {
    const outName = `${name}${v.suffix}.webp`;
    const outPath = join(SRC_DIR, outName);
    const info = await sharp(inputPath)
      .resize({ width: v.width, withoutEnlargement: true })
      .webp({ quality: v.quality, effort: 6 })
      .toFile(outPath);
    const pct = ((1 - info.size / inputBytes) * 100).toFixed(0);
    console.log(`  → ${outName}  ${(info.size / 1024).toFixed(0)} KiB  (-${pct}%)`);
  }
}