sigit.io/src/utils/nostr.ts

import { nip05, nip19, verifyEvent } from 'nostr-tools'
import { SignedEvent } from '../types'

/**
 * @param hexKey hex private or public key
 * @returns whether or not is key valid
 */
const validateHex = (hexKey: string) => {
  return hexKey.match(/^[a-f0-9]{64}$/)
}

/**
 * NPUB provided - it will convert NPUB to HEX
 * NIP-05 provided - it will query NIP-05 profile and return HEX key if found
 * HEX provided - it will return HEX
 *
 * @param pubKey in NPUB, NIP-05 or HEX format
 * @returns HEX format
 */
export const pubToHex = async (pubKey: string): Promise<string | null> => {
  // If key is NIP-05
  if (pubKey.indexOf('@') !== -1)
    return Promise.resolve(
      (await nip05.queryProfile(pubKey).then((res) => res?.pubkey)) || null
    )

  // If key is NPUB
  if (pubKey.startsWith('npub')) {
    try {
      return nip19.decode(pubKey).data as string
    } catch (error) {
      return Promise.resolve(null)
    }
  }

  // valid hex key
  if (validateHex(pubKey)) return Promise.resolve(pubKey)

  // Not a valid hex key
  return Promise.resolve(null)
}

/**
 * If NSEC key is provided function will convert it to HEX
 * If HEX key Is provided function will validate the HEX format and return
 *
 * @param nsec or private key in HEX format
 */
export const nsecToHex = (nsec: string): string | null => {
  // If key is NSEC
  if (nsec.startsWith('nsec')) {
    try {
      return nip19.decode(nsec).data as string
    } catch (error) {
      return null
    }
  }

  // since it's not NSEC key we check if it's a valid hex key
  if (validateHex(nsec)) return nsec

  return null
}

export const hexToNpub = (hexPubkey: string | undefined): string => {
  if (!hexPubkey) return 'n/a'

  return nip19.npubEncode(hexPubkey)
}

export const verifySignedEvent = (event: SignedEvent) => {
  const isGood = verifyEvent(event)

  if (!isGood) {
    throw new Error(
      'Signed event did not pass verification. Check sig, id and pubkey.'
    )
  }
}