import fs from "node:fs/promises";
import path from "node:path";
import sharp from "sharp";

const SRC_DIR = path.resolve("docs/public"); // change if needed
const OUT_DIR = path.resolve("docs/public/images"); // change if needed

const MAX_W = 800;
const MAX_H = 600;

const FORMAT = "webp";
const WEBP_QUALITY = 75; // tweak 60-85 if you want smaller/larger

async function walk(dir) {
  const entries = await fs.readdir(dir, { withFileTypes: true });
  const files = [];
  for (const e of entries) {
    const p = path.join(dir, e.name);
    if (e.isDirectory()) files.push(...(await walk(p)));
    else files.push(p);
  }
  return files;
}

function isImage(file) {
  return /\.(png|jpe?g|webp|avif)$/i.test(file);
}

async function ensureDir(p) {
  await fs.mkdir(p, { recursive: true });
}

async function processOne(inPath, outPathBase) {
  await ensureDir(path.dirname(outPathBase));

  await sharp(inPath)
    .rotate() // respects EXIF orientation
    .resize({
      width: MAX_W,
      height: MAX_H,
      fit: "inside", // preserve aspect, fit within box
      withoutEnlargement: true, // don't upscale small images
    })
    .toFormat(FORMAT, {
      quality: WEBP_QUALITY,
      effort: 4,
    })
    .toFile(`${outPathBase}.${FORMAT}`);
}

async function main() {
  const files = (await walk(SRC_DIR)).filter(isImage);
  await ensureDir(OUT_DIR);

  let done = 0;

  for (const inPath of files) {
    const rel = path.relative(SRC_DIR, inPath);

    // strip original extension and write same relative path
    const outBase = path
      .join(OUT_DIR, rel)
      .replace(/\.(png|jpe?g|webp|avif)$/i, "");

    const outPath = `${outBase}.${FORMAT}`;

    // simple cache: skip if output exists and is newer than input
    try {
      const [stIn, stOut] = await Promise.all([
        fs.stat(inPath),
        fs.stat(outPath),
      ]);
      if (stOut.mtimeMs >= stIn.mtimeMs) continue;
    } catch {
      // output missing -> process
    }

    await processOne(inPath, outBase);
    done++;
  }

  console.log(
    `Optimized ${done} image(s) to max ${MAX_W}x${MAX_H} (${FORMAT}).`,
  );
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});