import * as base64 from 'base-64';
import { bech32 } from 'bech32';
import BigNumber from 'bignumber.js';
import Decimaljs from 'decimal.js-light';
import { sha256 } from 'js-sha256';

import config from '../config';
import { Coin } from '../models';

Decimaljs.set({ precision: 40 });

export function bytesToValidatorPublic(bytes: number[]): string {
  return bech32.encode(config.prefix.valcons, bech32.toWords(bytes));
}

export function publicToValidatorConsensus(str: string): string {
  return bytesToValidatorPublic(
    getAddressFromPublicED25519(Array.from(Buffer.from(str, 'base64'))),
  );
}

export function consPublicKeyToBase64(str: string): string {
  return base64.encode(bech32.decode(str).words);
}

export function getAddressFromPublicED25519(bytes: number[]): number[] {
  return sha256.array(bytes).slice(0, 20);
}

export function signatureToValidatorConsensus(signature: string): string {
  return bytesToValidatorPublic(Array.from(Buffer.from(signature, 'hex')));
}

export function getCoinPrice(coin: Coin) {
  // reserve*(1 - (1 - 1/supply)^ (100/crr))

  // 100/crr
  const pow = new Decimaljs(100).dividedBy(new Decimaljs(coin.crr));

  // 1/supply
  let result = new Decimaljs(1).dividedBy(new Decimaljs(coin.volume));

  // 1 - 1/supply
  result = new Decimaljs(1).minus(result);

  // (1 - 1/supply)^ (100/crr)
  result = result.toPower(pow);

  // 1 - (1 - 1/supply)^ (100/crr)
  result = new Decimaljs(1).minus(new Decimaljs(result));

  // reserve*(1 - (1 - 1/supply)^ (100/crr))
  result = new Decimaljs(coin.reserve).times(result);

  return new BigNumber(result.toNumber()).shiftedBy(18).toString();
}

// Return = reserve * (1 - (1 - sellAmount / volume) ^ (100 / crr))
// Рассчитывает сколько DEL вы получите, если продадите sellAmount монет. (Продажа)
export function getBaseCoin(coin, sellAmount) {
  if (new Decimaljs(sellAmount).eq(new Decimaljs(0))) {
    return '0';
  }
  if (new Decimaljs(sellAmount).eq(new Decimaljs(coin.volume))) {
    return coin.reserve;
  }
  if (new Decimaljs(coin.crr).eq(new Decimaljs(100))) {
    const ret = new Decimaljs(coin.reserve).times(new Decimaljs(sellAmount)); //reserve * sellAmount

    return ret.div(new Decimaljs(coin.volume)).toFixed(0).toString(); //reserve * sellAmount / volume
  }
  const e1 = new Decimaljs(1).minus(new Decimaljs(sellAmount).div(new Decimaljs(coin.volume))); //(100 / crr)
  const e2 = new Decimaljs(100).div(new Decimaljs(coin.crr)); //(1 - sellAmount / volume)

  return new Decimaljs(coin.reserve)
    .times(new Decimaljs(1).minus(new Decimaljs(e1).pow(new Decimaljs(e2))))
    .toFixed(0)
    .toString(); //reserve * (1 - (1 - sellAmount / volume) ^ (100 / crr))
}