// <https://github.com/soruly/trace.moe-www/blob/master/image-proxy.js>

addEventListener("fetch", async (event) => {
  event.respondWith(handleRequest(event.request));
});

const errorResponse = (errorMessage) =>
  new Response(errorMessage, {
    status: 400,
    statusText: "Bad Request",
  });

const handleRequest = async (originalRequest) => {
  let originalURL = new URL(originalRequest.url);
  if (!originalURL.searchParams.get("url")) {
    return errorResponse("Error: Cannot get url from param");
  }

  let imageURL = null;
  try {
    imageURL = new URL(originalURL.searchParams.get("url"));
  } catch (e) {}
  if (!imageURL) {
    return errorResponse("Error: Invalid URL string");
  }

  let imageRequest = new Request(imageURL, {
    redirect: "follow",
    headers: {
      referer: imageURL.origin,
    },
  });

  let response = await fetch(imageRequest, {
    cf: {
      polish: "lossy",
      cacheEverything: true,
    },
  });

  if (response.status >= 400) {
    return new Response(response.body, {
      status: response.status,
      statusText: response.statusText,
      headers: response.headers,
    });
  }

  // if (
  //   response.headers.get("Content-Type").toLowerCase() !==
  //     "application/octet-stream" &&
  //   !["image", "video"].includes(
  //     response.headers.get("Content-Type").split("/")[0].toLowerCase()
  //   )
  // ) {
  //   // retry as bot to get og:image
  //   let webResponse = await fetch(
  //     new Request(imageURL, {
  //       redirect: "follow",
  //       headers: {
  //         referer: imageURL.origin,
  //         "User-Agent": "googlebot",
  //       },
  //     })
  //   );
  //   if (response.status === 200) {
  //     const ogImageURL = (await webResponse.text())
  //       ?.match(/<[^<]+?"og:image".*?>/, "$1")?.[0]
  //       ?.match(/content="(.*?)"/, "$1")?.[1];

  //     if (ogImageURL && ogImageURL.match(/^https?:\/\//)) {
  //       response = await fetch(
  //         new Request(ogImageURL, {
  //           redirect: "follow",
  //           headers: {
  //             referer: imageURL.origin,
  //           },
  //         })
  //       );
  //       if (response.status >= 400) {
  //         return new Response(response.body, {
  //           status: response.status,
  //           statusText: response.statusText,
  //           headers: response.headers,
  //         });
  //       }
  //     }
  //   }
  // }
  // if (
  //   response.headers.get("Content-Type").toLowerCase() !==
  //     "application/octet-stream" &&
  //   !["image", "video"].includes(
  //     response.headers.get("Content-Type").split("/")[0].toLowerCase()
  //   )
  // ) {
  //   return errorResponse(
  //     "Error: Content-Type is not image or video or application/octet-stream"
  //   );
  // }

  return new Response(response.body, {
    status: response.status,
    statusText: response.statusText,
    headers: {
      "Cache-Control":
        "public, immutable, s-maxage=31536000, max-age=31536000, stale-while-revalidate=60",
      "Access-Control-Allow-Origin": "https://due.moe",
      ...response.headers,
    },
  });
};