import { ECPair, address, networks } from 'bitcoinjs-lib'
import { randomBytes } from './encryption/cryptoRandom'
import { hashSha256Sync } from './encryption/sha2Hash'
import { hashRipemd160 } from './encryption/hashRipemd160'
import { config } from './config'

/**
 * 
 * @param numberOfBytes 
 * 
 * @ignore
 */
export function getEntropy(arg: number): Buffer {
  if (!arg) {
    arg = 32
  }
  return randomBytes(arg)
}

/**
* @ignore
*/
export function makeECPrivateKey() {
  const keyPair = ECPair.makeRandom({ rng: getEntropy })
  return keyPair.privateKey.toString('hex')
}

/**
* @ignore
*/
export function publicKeyToAddress(publicKey: string | Buffer) {
  const publicKeyBuffer = Buffer.isBuffer(publicKey) ? publicKey : Buffer.from(publicKey, 'hex')
  const publicKeyHash160 = hashRipemd160(hashSha256Sync(publicKeyBuffer))
  const result = address.toBase58Check(publicKeyHash160, networks.bitcoin.pubKeyHash)
  return result
}

/**
* @ignore
*/
export function getPublicKeyFromPrivate(privateKey: string | Buffer) {
  const privateKeyBuffer = Buffer.isBuffer(privateKey) ? privateKey : Buffer.from(privateKey, 'hex')
  const keyPair = ECPair.fromPrivateKey(privateKeyBuffer)
  return keyPair.publicKey.toString('hex')
}

/**
 * Time
 * @private
 * @ignore
 */
export function hexStringToECPair(skHex: string): ECPair.ECPairInterface {
  const ecPairOptions = {
    network: config.network.layer1,
    compressed: true
  }

  if (skHex.length === 66) {
    if (skHex.slice(64) !== '01') {
      throw new Error('Improperly formatted private-key hex string. 66-length hex usually '
                      + 'indicates compressed key, but last byte must be == 1')
    }
    return ECPair.fromPrivateKey(Buffer.from(skHex.slice(0, 64), 'hex'), ecPairOptions)
  } else if (skHex.length === 64) {
    ecPairOptions.compressed = false
    return ECPair.fromPrivateKey(Buffer.from(skHex, 'hex'), ecPairOptions)
  } else {
    throw new Error('Improperly formatted private-key hex string: length should be 64 or 66.')
  }
}

/**
 * 
 * @ignore
 */
export function ecPairToHexString(secretKey: ECPair.ECPairInterface) {
  const ecPointHex = secretKey.privateKey.toString('hex')
  if (secretKey.compressed) {
    return `${ecPointHex}01`
  } else {
    return ecPointHex
  }
}

/**
 * Creates a bitcoin address string from an ECPair
 * @private
 * @ignore
 */
export function ecPairToAddress(keyPair: ECPair.ECPairInterface) {
  const sha256 = hashSha256Sync(keyPair.publicKey)
  const hash160 = hashRipemd160(sha256)
  return address.toBase58Check(hash160, keyPair.network.pubKeyHash)
}