import { reduce } from 'lodash';
import { isAddress, keccak256, toHex } from 'web3-utils';
import { pubToAddress } from 'ethereumjs-util';
import { ETH_ZERO_ADDR, ETH_ZERO_ADDR_SHORT } from 'lib/constants';

export const stripHexPrefix = (hex: string) => {
  return hex.startsWith('0x') ? hex.slice(2) : hex;
};

export const addHexPrefix = (hex: string) => {
  return hex.startsWith('0x') ? hex : `0x${hex}`;
};

export const isValidAddress = a => '0x0' === a || isAddress(a);

export const abbreviateAddress = address =>
  `${address.slice(0, 6)}…${address.slice(-4)}`;

export const isZeroAddress = a =>
  a === ETH_ZERO_ADDR || a === ETH_ZERO_ADDR_SHORT;

export const toChecksumAddress = address => {
  const addr = stripHexPrefix(address).toLowerCase();
  const hash = keccak256(addr).toString('hex');

  return reduce(
    addr,
    (acc, char, idx) =>
      parseInt(hash[idx], 16) >= 8 ? acc + char.toUpperCase() : acc + char,
    '0x'
  );
};

export const eqAddr = (addr0, addr1) =>
  toChecksumAddress(addr0) === toChecksumAddress(addr1);

export const publicToAddress = (publicKey: Buffer): string => {
  return toHex(pubToAddress(publicKey, true).toString('hex'));
};

export function sanitizeHex(hex: string): string {
  hex = hex.substring(0, 2) === '0x' ? hex.substring(2) : hex;
  if (hex === '') {
    return '';
  }
  hex = hex.length % 2 !== 0 ? '0' + hex : hex;
  return '0x' + hex;
}