import { CodeError } from '@libp2p/interfaces/errors'
import { toString as uint8ArrayToString } from 'uint8arrays/to-string'
import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'

const namespace = '/record/'

export function encodeBase32 (buf: Uint8Array): string {
  return uint8ArrayToString(buf, 'base32')
}

/**
 * converts a binary record key to a pubsub topic key
 */
export function keyToTopic (key: Uint8Array | string): string {
  // Record-store keys are arbitrary binary. However, pubsub requires UTF-8 string topic IDs
  // Encodes to "/record/base64url(key)"
  if (typeof key === 'string' || key instanceof String) {
    key = uint8ArrayFromString(key.toString())
  }

  const b64url = uint8ArrayToString(key, 'base64url')

  return `${namespace}${b64url}`
}

/**
 * converts a pubsub topic key to a binary record key
 */
export function topicToKey (topic: string): Uint8Array {
  if (topic.substring(0, namespace.length) !== namespace) {
    throw new CodeError('topic received is not from a record', 'ERR_TOPIC_IS_NOT_FROM_RECORD_NAMESPACE')
  }

  const key = topic.substring(namespace.length)

  return uint8ArrayFromString(key, 'base64url')
}