import base64js from "base64-js";
import { Buffer } from "buffer";
import PythonStruct from "python-struct";

export const unpack = async function (blob: Blob, str = "<II") {
  const unpackBuffer = await blob.slice(4, 12).arrayBuffer();
  const [jsonSize, binSize] = PythonStruct.unpack(
    str,
    Buffer.from(unpackBuffer),
  ) as number[];
  const jsonBlob = await blob.slice(12, 12 + jsonSize).text();
  const parsedData = JSON.parse(jsonBlob);
  return {
    parsedData,
    jsonSize,
    binSize,
  };
};
export const mergeBlob = (strArray: string[], target: Uint8Array) => {
  let offset = 0;
  strArray.forEach((str) => {
    const byteArray = base64js.toByteArray(str);
    target.set(byteArray, offset);
    offset += byteArray.byteLength;
  });
  const blob = new Blob([target]);
  return blob;
};