// SPDX-FileCopyrightText: 2026 Echolot contributors
// SPDX-License-Identifier: GPL-3.0-or-later

// Everything under public/ is served straight from the edge without invoking
// this Worker. The Worker exists for the short stable URLs (/apk, /fdroid,
// /source) — short enough for a QR code — and to resolve "/apk" to the newest
// release asset at request time, so tagging a release in Gitea is the only
// publish step. No site redeploy, no URL to update.

const STATIC_ROUTES = {
  "/fdroid": "FDROID_URL",
  "/source": "SOURCE_URL",
};

// Resolve the newest APK from the Gitea "latest release" API. Cached at the
// edge for 5 minutes so a release becomes visible quickly, while Gitea sees
// at most one API hit per POP per 5 min regardless of download traffic.
async function latestApkUrl(env) {
  if (!env.GITEA_REPO_API) return null;
  const res = await fetch(`${env.GITEA_REPO_API}/releases/latest`, {
    headers: { Accept: "application/json", "User-Agent": "echolot-site" },
    cf: { cacheTtl: 300, cacheEverything: true },
  });
  if (!res.ok) return null;
  const rel = await res.json();
  const apk = rel.assets?.find((a) => a.name?.endsWith(".apk"));
  return apk?.browser_download_url ?? null;
}

function redirect(location) {
  return new Response(null, {
    status: 302,
    headers: {
      Location: location,
      "Cache-Control": "no-store",
      "Referrer-Policy": "no-referrer",
    },
  });
}

export default {
  async fetch(request, env) {
    const { pathname } = new URL(request.url);
    const path = pathname.replace(/\/$/, "");
    const fallback = new URL("/#install", request.url).toString();

    if (path === "/apk" || path === "/download") {
      // Order: live Gitea release → manual override → install section.
      let target = null;
      try {
        target = await latestApkUrl(env);
      } catch {
        // Gitea unreachable — fall through rather than 500 on a download link.
      }
      return redirect(target || env.DOWNLOAD_URL || fallback);
    }

    const varName = STATIC_ROUTES[path];
    if (varName) return redirect(env[varName] || fallback);

    return env.ASSETS.fetch(request);
  },
};