sigit.io/src/utils/nostr.ts

import { nip19, verifyEvent } from 'nostr-tools'
import { SignedEvent } from '../types'
import axios from 'axios'
import { NIP05_REGEX } from '../constants'

/**
 * @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
 * HEX provided - it will return HEX
 *
 * @param pubKey in NPUB, HEX format
 * @returns HEX format
 */
export const npubToHex = (pubKey: string): string | null => {
  // If key is NPUB
  if (pubKey.startsWith('npub1')) {
    try {
      return nip19.decode(pubKey).data as string
    } catch (error) {
      return null
    }
  }

  // valid hex key
  if (validateHex(pubKey)) return pubKey

  // Not a valid hex key
  return 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): `npub1${string}` => {
  if (hexPubkey.startsWith('npub1')) return hexPubkey as `npub1${string}`

  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.'
    )
  }
}

/**
 * Function to query NIP-05 data and return the public key and relays.
 *
 * @param {string} nip05 - The NIP-05 identifier in the format "name@domain".
 * @returns {Promise<{ pubkey: string, relays: string[] }>} - The public key and an array of relay URLs.
 * @throws Will throw an error if the NIP-05 identifier is invalid or if there is an issue with the network request.
 */
export const queryNip05 = async (
  nip05: string
): Promise<{
  pubkey: string
  relays: string[]
}> => {
  const match = nip05.match(NIP05_REGEX)

  // Throw an error if the NIP-05 identifier is invalid
  if (!match) throw new Error('Invalid nip05')

  // Destructure the match result, assigning default value '_' to name if not provided
  const [_, name = '_', domain] = match

  // Construct the URL to query the NIP-05 data
  const url = `https://${domain}/.well-known/nostr.json?name=${name}`

  // Perform the network request to get the NIP-05 data
  const res = await axios(url)
    .then((res) => {
      return res.data
    })
    .catch((err) => {
      console.log('err :>> ', err)
      throw err
    })

  // Extract the public key from the response data
  const pubkey = res.names[name]
  const relays: string[] = []

  // If a public key is found
  if (pubkey) {
    // Function to add relays if they exist and are not empty
    const addRelays = (relayList?: string[]) => {
      if (relayList && relayList.length > 0) {
        relays.push(...relayList)
      }
    }

    // Check for user-specific relays in the NIP-46 section of the response data
    if (res.nip46) {
      addRelays(res.nip46[pubkey] as string[])
    }

    // Check for user-specific relays in the relays section of the response data if not found in NIP-46
    if (relays.length === 0 && res.relays) {
      addRelays(res.relays[pubkey] as string[])
    }

    // If no user-specific relays are found, check for root user relays
    if (relays.length === 0) {
      const root = res.names['_']
      if (root) {
        // Check for root user relays in both NIP-46 and relays sections
        addRelays(res.nip46?.[root] as string[])
        addRelays(res.relays?.[root] as string[])
      }
    }
  }

  // Return the public key and the array of relays
  return {
    pubkey,
    relays
  }
}

export const base64EncodeSignedEvent = (event: SignedEvent) => {
  try {
    const authEventSerialized = JSON.stringify(event)
    const token = btoa(authEventSerialized)
    return token
  } catch (error) {
    throw new Error('An error occurred in JSON.stringify of signedAuthEvent')
  }
}

export const base64DecodeAuthToken = (authToken: string): SignedEvent => {
  const decodedToken = atob(authToken)

  try {
    const signedEvent = JSON.parse(decodedToken)
    return signedEvent
  } catch (error) {
    throw new Error('An error occurred in JSON.parse of the auth token')
  }
}

/**
 * @param pubkey in hex or npub format
 * @returns robohash.org url for the avatar
 */
export const getRoboHashPicture = (
  pubkey?: string,
  set: number = 1
): string => {
  if (!pubkey) return ''
  const npub = hexToNpub(pubkey)
  return `https://robohash.org/${npub}.png?set=set${set}`
}