// simple express app
const express = require("express");
const cors = require("cors");

const app = express();

app.use(
  cors({
    origin: "*",
  })
);

/**
 * Extracts the CID from the given URL.
 *
 * @param {string} url - The URL from which to extract the CID
 * @return {string} The extracted CID
 */
function extractCID(url) {
  if (url.includes("dweb")) {
    let parts = url.split("/");
    let subParts = parts[2].split(".");
    return subParts[0];
  } else {
    return url.split("/").pop();
  }
}

const eachfilesize = {};

/**
 * Calculate the total size of the files associated with the given content identifiers (CIDs).
 *
 * @param {array} cids - An array of content identifiers
 * @return {number} The total size of the files in bytes
 */
async function getFileSize(cids) {
  var fileSize = 0;
  for (var cid of cids) {
    if (cid.includes("https://")) {
      cid = extractCID(cid);
    }

    const res = await fetch(`https://ipfs.particle.network/${cid}`, {
      method: "HEAD",
    });

    // console.log(res.headers.get("Content-Length") )

    fileSize += parseInt(res.headers.get("Content-Length"), 10);

    eachfilesize[cid] = parseInt(res.headers.get("Content-Length"), 10);
  }

  return fileSize;
}

/**
 * Formats the given number of bytes into a human-readable string representation.
 *
 * @param {number} bytes - The number of bytes to be formatted.
 * @param {number} [decimals=2] - The number of decimals to round the result to.
 * @return {string} The formatted string representation of the input bytes.
 */
function formatBytes(bytes, decimals = 2) {
  if (!+bytes) return "0 Bytes";

  const k = 1024;
  const dm = decimals < 0 ? 0 : decimals;
  const sizes = [
    "Bytes",
    "KiB",
    "MiB",
    "GiB",
    "TiB",
    "PiB",
    "EiB",
    "ZiB",
    "YiB",
  ];

  const i = Math.floor(Math.log(bytes) / Math.log(k));

  return `${parseFloat((bytes / Math.pow(k, i)).toFixed(dm))} ${sizes[i]}`;
}

/**
 * Asynchronously fetches data in chunks from the specified URL using the given headers and controller.
 *
 * @param {string} url - The URL to fetch data from
 * @param {Object} headers - The headers to include in the fetch request
 * @param {AbortController} controller - The controller to signal the fetch should be aborted
 * @param {number} start - The starting byte index for fetching data
 * @param {number} fileSize - The total size of the file being fetched
 */
async function customFetch(url, res, start, fileSize) {
    // console.log('Fetching ' + url);
    let chunkSize = 3 * 1024 * 1024; // 10 MB!
    for (; start < fileSize; start += chunkSize) {
        let end = Math.min(start + chunkSize - 1, fileSize - 1);
        // console.log('Fetch ' + start + ' - ' + end);
        let headers = { Range: `bytes=${start}-${end}` };
        let response = await fetch(url, { headers });

        // Process the chunk of data
    // let response = await fetch(url, { headers: { Range: `bytes=${start}-${fileSize - 1}` } });
        let chunkData = await response.arrayBuffer(); // Or other method for data type
        res.write(new Uint8Array(chunkData));
    }
}

app.get("/", async (req, res) => {
  // console.log('HERE');
  const shared = req.query.shared;
  const filename = req.query.filename;

  if (shared) {
    // Very gud code but it only serve <80MB file:>>
    // const originalUrl = `https://ipfs.particle.network/${shared}`;

    // const options = {};

    // if (req.headers.range) {
    // options.headers = { Range: req.headers.range };
    // }

    // const originalReq = http.request(
    // originalUrl,
    // options,
    // async (originalRes) => {
    //     const links = [originalUrl];
    //     const fileSize = await getFileSize(links);

    //     const blob = []; // Để nhận dữ liệu trả về từ response

    //     originalRes.on("data", (chunk) => {
    //     blob.push(chunk);
    //     });

    //     originalRes.on("end", () => {
    //     const response = Buffer.concat(blob);

    //     res.writeHead(originalRes.statusCode, originalRes.headers);
    //     res.end(response);
    //     });
    // }
    // );

    // originalReq.end();

    // My code lol
    // Api for getting data cids
    const APIRES = await fetch(
      "https://www.ufsdrive.com/api/reqdata?shared=" + shared
    );

    if (!APIRES.ok) {
      // ctx.waitUntil(log("Get data fail"));
      APIRES.status(404).send("Not found");
    }

    const data = await APIRES.json();
    const file = data.data;

    // console.log(file);

    var siez;

    if (file.profile_picture != "Multipart") {
      siez = await getFileSize([file.profile_picture]);
    } else {
      siez = await getFileSize(file.data);
    }

    // console.log(siez)

    var parts, start, end;
    if (req.headers.range != null) {
    //   console.log(req.headers.range);
      parts = req.headers.range.replace(/bytes=/, "").split("-");
      start = parseInt(parts[0], 10);
      end = parts[1] ? parseInt(parts[1], 10) : siez - 1;
    }

    data.filename = data.filename.replace(/[^a-zA-Z 0-9\.]+/g, "");

    var headers = {
      "content-type": data.contentType,
      "Cache-Control": "public, max-age=29030400",
      "Content-Disposition": `inline; filename="${filename ? filename : data.filename}"`,
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "GET",
      "Access-Control-Expose-Headers":
        "Content-Range, Content-Length, ETag, Access-Control-Allow-Methods, Access-Control-Allow-Origin",
      Vary: "Origin, Access-Control-Request-Headers, Access-Control-Request-Method, Accept-Encoding",
      Connection: "keep-alive",
      "Accept-Ranges": "bytes",
    };

    // if requested has content-range header then we need to change the headers
    if (req.headers.range) {
      headers["Content-Range"] = `bytes ${start}-${end}/${siez}`;
      headers["Content-Length"] = end - start + 1;
    } else {
      headers["Content-Length"] = siez;
    }

    // console.log(headers);

    // res.set(headers);
    if (req.headers.range) {
      res.writeHead(206, headers);
    } else {
      res.writeHead(200, headers);
    }

    if (req.headers.range) {
      // send only requested.
      // await log("Have range query")
      if (file.profile_picture != "Multipart") {
        // await log('One File Query');
        const res2 = await fetch(
          `https://ipfs.particle.network/${extractCID(file.profile_picture)}`,
          {
            method: "GET",
            headers: {
              Range: req.headers.range,
            },
          }
        );
        const blob = new Uint8Array(await res2.arrayBuffer());
        // controller.enqueue(blob);
        // controller.close();
        res.write(blob);
        res.end();
      } else {
        var content_range_start = start;
        var content_range_end = end;
        var current_range = 0;

        for (var cid of file.data) {
          if (cid.includes("https://")) {
            cid = extractCID(cid);
          }

          // Skip chunks completely outside the range
          if (current_range + eachfilesize[cid] <= content_range_start) {
            current_range += eachfilesize[cid];
            continue;
          }

          // Calculate the starting byte within the current chunk
          let start_byte = Math.max(content_range_start - current_range, 0);

          // Calculate the number of bytes to fetch from this chunk
          let bytes_to_fetch = Math.min(
            eachfilesize[cid] - start_byte,
            content_range_end - current_range
          );

          // Adjust the range for the fetch request
          let fetch_start = start_byte;
          let fetch_end = Math.min(
            start_byte + bytes_to_fetch,
            eachfilesize[cid]
          );

          await customFetch(
            `https://ipfs.particle.network/${cid}`,
            res,
            fetch_start,
            fetch_end
          )

        //   const res2 = await fetch(`https://ipfs.particle.network/${cid}`, {
        //     method: "GET",
        //     headers: {
        //       range: `bytes=${fetch_start}-${fetch_end}`,
        //     },
        //   });

          // Check if the response is partial content
        //   if (res2.status === 206) {
        //     // 206 Partial Content
        //     // Extract the Content-Range header
        //     const contentRange = res2.headers.get("Content-Range");
        //     // console.log(contentRange);

        //     // Ensure the range matches the request
        //     // if (rangeStart === fetch_start && rangeEnd === fetch_end) {
        //     // Enqueue the received chunk
        //     // controller.enqueue(new Uint8Array(await res.arrayBuffer()));
        //     res.write(new Uint8Array(await res2.arrayBuffer()));

        //     // } else {
        //     //     // Handle unexpected range mismatch
        //     //     console.error('Range mismatch in response');
        //     // }
        //   } else {
        //     // Handle unexpected response status
        //     console.error("Unexpected response status:", res2.status);
        //   }

          // // Enqueue the fetched data
        //   controller.enqueue(new Uint8Array(await res.arrayBuffer()));

          // // Update the current range
          // current_range += bytes_to_fetch;

          // // Break if we've reached the end of the requested range
          // if (current_range >= content_range_end) {
          //     break;
          // }

          // Update the current range
          current_range += bytes_to_fetch;

          // Check if the end of the requested range has been reached
          if (current_range >= content_range_end) {
            // controller.close();
            res.end();
            break;
          }
        }

        // controller.close();
        res.end();
      }
    } else {
      // await log("No range query")
      if (file.profile_picture != "Multipart") {
        // siez = await getFileSize([file.profile_picture]);
        // log("Comsume data")
        // const res2 = await fetch(
        //   `https://ipfs.particle.network/${extractCID(file.profile_picture)}`
        // );
        // const blob = new Uint8Array(await res2.arrayBuffer());
        // res.write(blob);
        await customFetch(
          `https://ipfs.particle.network/${extractCID(file.profile_picture)}`,
          res,
          0,
          eachfilesize[extractCID(file.profile_picture)]
        )
        res.end();
      } else {
        // siez = await getFileSize(file.data);
        // console.log("One MUL REq");
        for (var cid of file.data) {
          if (cid.includes("https://")) {
            cid = extractCID(cid);
          }
          // const res = await fetch(`https://ipfs.particle.network/${cid}`);
          // const blob = new Uint8Array(await res.arrayBuffer());
        //   console.log("process " + cid);
        //   const response = await fetch(`https://ipfs.particle.network/${cid}`);

        //   // console.log(response.headers.get('Content-Length'));

        //   const blob = new Uint8Array(await response.arrayBuffer());
        //   // controller.enqueue(blob);
        //   res.write(blob);
          await customFetch(
              `https://ipfs.particle.network/${cid}`,
              res,
              0,
              eachfilesize[cid]
          );
          // controller.enqueue(blob);
        }

        // console.log("Done");

        res.end();
      }
    }
    // log("Success")
    // const tstream = new TransformStream();
    // // ctx.waitUntil(readable.pipeTo(tstream.writable));
    // await readable.pipeTo(tstream.writable)
    // log("Sended!")

    // if (req.headers.range) {
    //     res.status(206).send(readable);
    // } else {
    //     res.status(200).send(readable);
    // }

    // tstream.readable.pipeTo(res);
    // res.pipe(tstream.readable);
  } else {
    res.status(400).send("Missing shared or filename parameter");
  }
});

app.listen(7860, "0.0.0.0", () => console.log("Server started on port 7860"));