const _ = require('lodash/fp')
const { ALL_CRYPTOS } = require('@lamassu/coins')

const configManager = require('./new-config-manager')
const ccxt = require('./plugins/exchange/ccxt')
const mockExchange = require('./plugins/exchange/mock-exchange')
const accounts = require('./new-admin/config/accounts')

function lookupExchange(settings, cryptoCode) {
  const exchange = configManager.getWalletSettings(
    cryptoCode,
    settings.config,
  ).exchange
  if (exchange === 'no-exchange') return null
  return exchange
}

function fetchExchange(settings, cryptoCode) {
  return Promise.resolve().then(() => {
    const exchangeName = lookupExchange(settings, cryptoCode)
    if (exchangeName === 'mock-exchange')
      return { exchangeName, account: { currencyMarket: 'EUR' } }
    if (!exchangeName) throw new Error('No exchange set')
    const account = settings.accounts[exchangeName]

    return { exchangeName, account }
  })
}

function buy(settings, tradeEntry) {
  const { cryptoAtoms, fiatCode, cryptoCode } = tradeEntry
  return fetchExchange(settings, cryptoCode).then(r => {
    if (r.exchangeName === 'mock-exchange') {
      return mockExchange.buy(cryptoAtoms, fiatCode, cryptoCode)
    }
    return ccxt.trade('buy', r.account, tradeEntry, r.exchangeName)
  })
}

function sell(settings, tradeEntry) {
  const { cryptoAtoms, fiatCode, cryptoCode } = tradeEntry
  return fetchExchange(settings, cryptoCode).then(r => {
    if (r.exchangeName === 'mock-exchange') {
      return mockExchange.sell(cryptoAtoms, fiatCode, cryptoCode)
    }
    return ccxt.trade('sell', r.account, tradeEntry, r.exchangeName)
  })
}

function active(settings, cryptoCode) {
  return !!lookupExchange(settings, cryptoCode)
}

function getMarkets() {
  const filterExchanges = _.filter(
    it => it.class === 'exchange' && !it.dev && it.code !== 'no-exchange',
  )
  const availableExchanges = _.map(
    it => it.code,
    filterExchanges(accounts.ACCOUNT_LIST),
  )

  const fetchMarketForExchange = exchange =>
    ccxt
      .getMarkets(exchange, ALL_CRYPTOS)
      .then(markets => ({ exchange, markets }))
      .catch(error => ({
        exchange,
        markets: [],
        error: error.message,
      }))

  const transformToObject = _.reduce(
    (acc, { exchange, markets }) => ({
      ...acc,
      [exchange]: markets,
    }),
    {},
  )

  const promises = _.map(fetchMarketForExchange, availableExchanges)
  return Promise.all(promises).then(transformToObject)
}

module.exports = {
  fetchExchange,
  buy,
  sell,
  active,
  getMarkets,
}