import { Response, Request } from "express";
const StreamSkip = require("stream-skip");

const awaitStreamVideo = (
  start: number,
  end: number,
  differenceStart: number,
  decipher: any,
  res: Response,
  req: Request,
  streamsToErrorCatch: any[],
  readStream: any
) => {
  return new Promise<void>((resolve, reject) => {
    req.on("close", () => {
      // readStream.close();
      decipher.destroy();
      resolve();
    });

    req.on("end", () => {
      streamsToErrorCatch.forEach((stream) => {
        stream.destroy();
      });
      resolve();
    });

    streamsToErrorCatch.forEach((currentStream) => {
      currentStream.on("error", (e: Error) => {
        reject({
          message: "Await Video Stream Input Error",
          code: 500,
          error: e,
        });
      });
    });

    readStream.on("close", () => {
      decipher.destroy();
    });

    if (+start === 0 && +end === 1) {
      // This is for Safari/iOS, for whatever reason they ask for the
      // First byte, but if I actually try to return the first byte
      // It will not work ???, but if I return the first 4 bytes it seems
      // To work fine.

      decipher.on("data", (data: Buffer | string) => {
        const dataCoverted = data.toString("hex");

        let neededData = dataCoverted.substring(0, 8);

        const dataBack = Buffer.from(neededData, "hex");

        res.write(dataBack);

        resolve();
      });
    } else {
      // This is where the differnce start comes into play, as I said before
      // There will be an offset caused by the 16 block size of AES256.
      // So if there was an offset we need to skip over those bytes
      // To make sure it returns the exact position the browser is requesting.
      // Most browsers will still work fine without this, such as Chrome and Firefox.
      // But one browser needs to be pampered and fed the exact right bytes in
      // Order to function correctly, can you guess what browser? If you
      // Guessed Safari you would be correct.

      const streamSkip = new StreamSkip({ skip: differenceStart });

      decipher.pipe(streamSkip).pipe(res);
    }
  });
};

export default awaitStreamVideo;