#!/usr/bin/env node
/**
 * Scans ./img recursively and writes ./images.json — the manifest the
 * single-page app fetches at runtime. No backend required.
 *
 * Usage:
 *   node scripts/generate-manifest.mjs
 *
 * Re-run this whenever you add, rename, or remove images.
 */
import { readdir, stat, writeFile } from "node:fs/promises";
import { join, relative, sep, extname } from "node:path";
import { fileURLToPath } from "node:url";

const ROOT = fileURLToPath(new URL("..", import.meta.url));
const IMG_DIR = join(ROOT, "img");
const OUT_FILE = join(ROOT, "images.json");

const IMAGE_EXTS = new Set([
  ".png", ".jpg", ".jpeg", ".gif", ".webp", ".avif",
  ".svg", ".bmp", ".ico", ".tif", ".tiff",
]);

const collator = new Intl.Collator(undefined, { numeric: true, sensitivity: "base" });

async function walk(dir) {
  const entries = await readdir(dir, { withFileTypes: true });
  const files = [];

  for (const entry of entries) {
    if (entry.name.startsWith(".")) continue; // skip dotfiles/dirs
    const full = join(dir, entry.name);

    if (entry.isDirectory()) {
      files.push(...(await walk(full)));
    } else if (entry.isFile() && IMAGE_EXTS.has(extname(entry.name).toLowerCase())) {
      const info = await stat(full);
      files.push({
        name: entry.name,
        path: relative(ROOT, full).split(sep).join("/"), // POSIX-style for URLs
        size: info.size,
        mtime: info.mtime.toISOString(),
      });
    }
  }
  return files;
}

async function main() {
  let files;
  try {
    files = await walk(IMG_DIR);
  } catch (err) {
    if (err.code === "ENOENT") {
      console.error(`✗ Image folder not found: ${IMG_DIR}`);
      console.error("  Create it and add some images, then re-run.");
      process.exit(1);
    }
    throw err;
  }

  files.sort((a, b) => collator.compare(a.path, b.path));

  const manifest = {
    generatedAt: new Date().toISOString(),
    count: files.length,
    images: files,
  };

  await writeFile(OUT_FILE, JSON.stringify(manifest, null, 2) + "\n", "utf8");
  console.log(`✓ Wrote ${files.length} image${files.length === 1 ? "" : "s"} to images.json`);
}

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