responsemapper

class ResponseMapper<T> : RMapper<T> {
  private var errorString: String = "{}"

  override fun getErrorString() = errorString

  override fun apply(it: Response<T>): Single<T> {
    return when {
      it.isSuccessful -> Single.just(it.body()!!)
      it.errorBody() == null -> Single.error<T>(UnrecoverableException("Unknown exception"))
      else -> {
        if (it.errorBody()!!.byteStream().available() > 0) {
          errorString = it.errorBody()!!.string()
        }
        val json = JSONObject(getErrorString())
        //NOT interesting part starts here ----------->
        val str = if (json.has("errors") && json.getJSONArray("errors").length() > 0 &&
          (json.getJSONArray("errors").get(0) as JSONObject).length() > 0 &&
          (json.getJSONArray("errors").get(0) as JSONObject).keys().hasNext()) {
          val errorsObj = json.getJSONArray("errors").get(0) as JSONObject
          errorsObj.keys()
            .asSequence()
            .map { errorsObj.getString(it) }
            .joinToString("\n")
        } else if (json.has("error_description")) {
          json.getString("error_description")
        } else if (json.has("message")) {
          json.getString("message")
        } else {
          errorString
        }
        //NOT interesting part ends here -----------> 
        when (it.code()) {
          400 -> Single.error<T>(BadRequestException(str))
          401 -> Single.error<T>(UnauthorizedException(str))
          502, 503, 504 -> Single.error<T>(InternalServerException(str))
          else -> Single.error<T>(UnrecoverableException(str))
        }
      }
    }
  }
}