export default {
  async fetch(request) {
    const CORS = {
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "GET,OPTIONS",
      "Access-Control-Allow-Headers": "*",
      "Access-Control-Expose-Headers": "*",
      "Access-Control-Max-Age": "86400",
    };
    if (request.method === "OPTIONS") return new Response(null, { headers: CORS });

    const json = (obj, status = 200) =>
      new Response(JSON.stringify(obj), {
        status,
        headers: { ...CORS, "Content-Type": "application/json; charset=utf-8" },
      });

    try {
      const params = new URL(request.url).searchParams;

      // Media passthrough: ?url= — unblocks downloads + progress bar.
      const media = params.get("url") || "";
      if (media) {
        let host;
        try { host = new URL(media).hostname; } catch { return json({ error: "bad url" }, 400); }
        if (!/(^|\.)twimg\.com$/i.test(host)) return json({ error: "host not allowed" }, 403);
        const m = await fetch(media, { headers: { "User-Agent": "Mozilla/5.0", "Referer": "https://twitter.com/" } });
        const h = new Headers(m.headers);
        for (const [k, v] of Object.entries(CORS)) h.set(k, v);
        const dl = (params.get("dl") || "").replace(/[^\w.\-]/g, "_");
        if (dl) h.set("Content-Disposition", 'attachment; filename="' + dl + '"'); // force a real download (mobile/iOS)
        return new Response(m.body, { status: m.status, headers: h });
      }

      // Tweet/article passthrough: ?id=
      const id = params.get("id") || "";
      if (!/^\d+$/.test(id)) return json({ error: "missing or invalid id/url" }, 400);

      const token = ((Number(id) / 1e15) * Math.PI).toString(36).replace(/(0+|\.)/g, "");
      const upstream = `https://cdn.syndication.twimg.com/tweet-result?id=${id}&token=${token}&lang=en`;

      const r = await fetch(upstream, {
        headers: {
          "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
          "Accept": "application/json",
          "Referer": "https://platform.twitter.com/",
        },
      });

      const body = await r.text();
      return new Response(body, {
        status: r.status,
        headers: { ...CORS, "Content-Type": "application/json; charset=utf-8", "Cache-Control": "public, max-age=300" },
      });
    } catch (err) {
      return json({ error: "proxy_failed", detail: String((err && err.message) || err) }, 502);
    }
  },
};

export default {
  async fetch(request) {
    const url = new URL(request.url);
    // Forward /bot<token>/<method> straight to Telegram, preserving method, body and query.
    const upstream = "https://api.telegram.org" + url.pathname + url.search;
    const init = { method: request.method, headers: request.headers };
    if (request.method !== "GET" && request.method !== "HEAD") init.body = request.body;
    const r = await fetch(upstream, init);
    const h = new Headers(r.headers);
    h.set("Access-Control-Allow-Origin", "*");
    h.set("Access-Control-Allow-Methods", "GET,POST,OPTIONS");
    h.set("Access-Control-Allow-Headers", "*");
    return new Response(r.body, { status: r.status, headers: h });
  },
};