import { strFromU8, strToU8, unzlibSync } from 'fflate';
import { type eventWithTimeAndPacker, MARK } from './base';
import type { UnpackFn, eventWithTime } from '@rrweb/types';

export const unpack: UnpackFn = (raw: string) => {
  if (typeof raw !== 'string') {
    return raw;
  }
  try {
    const e: eventWithTime = JSON.parse(raw) as eventWithTime;
    if (e.timestamp) {
      return e;
    }
  } catch (error) {
    // ignore and continue
  }
  try {
    const e: eventWithTimeAndPacker = JSON.parse(
      strFromU8(unzlibSync(strToU8(raw, true))),
    ) as eventWithTimeAndPacker;
    if (e.v === MARK) {
      return e;
    }
    throw new Error(
      `These events were packed with packer ${e.v} which is incompatible with current packer ${MARK}.`,
    );
  } catch (error) {
    console.error(error);
    throw new Error('Unknown data format.');
  }
};