import crypto from 'node:crypto'
import * as ui8 from 'uint8arrays'
import { sha256 } from '@atproto/crypto'

export const OLD_PASSWORD_MAX_LENGTH = 512
export const NEW_PASSWORD_MAX_LENGTH = 256

export const genSaltAndHash = (password: string): Promise<string> => {
  const salt = crypto.randomBytes(16).toString('hex')
  return hashWithSalt(password, salt)
}

export const hashWithSalt = (
  password: string,
  salt: string,
): Promise<string> => {
  return new Promise((resolve, reject) => {
    crypto.scrypt(password, salt, 64, (err, hash) => {
      if (err) return reject(err)
      resolve(salt + ':' + hash.toString('hex'))
    })
  })
}

export const verify = async (
  password: string,
  storedHash: string,
): Promise<boolean> => {
  const [salt, hash] = storedHash.split(':')
  const derivedHash = await getDerivedHash(password, salt)
  return hash === derivedHash
}

export const getDerivedHash = (
  password: string,
  salt: string,
): Promise<string> => {
  return new Promise((resolve, reject) => {
    crypto.scrypt(password, salt, 64, (err, derivedHash) => {
      if (err) return reject(err)
      resolve(derivedHash.toString('hex'))
    })
  })
}

export const hashAppPassword = async (
  did: string,
  password: string,
): Promise<string> => {
  const sha = await sha256(did)
  const salt = ui8.toString(sha.slice(0, 16), 'hex')
  return hashWithSalt(password, salt)
}