const qs = require('querystring')
const axios = require('axios')
const _ = require('lodash/fp')

const { fetchRBF } = require('../../wallet/bitcoind/bitcoind')
module.exports = { authorize }

function highConfidence(confidence, txref, txRBF) {
  if (txref.double_spend) return 0
  if (txRBF) return 0
  if (txref.confirmations > 0 || txref.confidence * 100 >= confidence)
    return txref.value
  return 0
}

function authorize(
  account,
  toAddress,
  cryptoAtoms,
  cryptoCode,
  isBitcoindAvailable,
) {
  return Promise.resolve().then(() => {
    if (cryptoCode !== 'BTC')
      throw new Error('Unsupported crypto: ' + cryptoCode)

    const query = qs.stringify({
      token: account.token,
      includeConfidence: true,
    })

    const confidence = account.confidenceFactor
    const isRBFEnabled = account.rbf
    const url = `https://api.blockcypher.com/v1/btc/main/addrs/${toAddress}?${query}`

    return axios.get(url).then(r => {
      const data = r.data
      if (isBitcoindAvailable && isRBFEnabled && data.unconfirmed_txrefs) {
        const promises = _.map(
          unconfirmedTxref => fetchRBF(unconfirmedTxref.tx_hash),
          data.unconfirmed_txrefs,
        )
        return Promise.all(promises).then(values => {
          const unconfirmedTxsRBF = _.fromPairs(values)
          const sumTxRefs = txrefs =>
            _.sumBy(
              txref =>
                highConfidence(
                  confidence,
                  txref,
                  unconfirmedTxsRBF[txref.tx_hash],
                ),
              txrefs,
            )
          const authorizedValue =
            sumTxRefs(data.txrefs) + sumTxRefs(data.unconfirmed_txrefs)
          return cryptoAtoms.lte(authorizedValue)
        })
      }

      const sumTxRefs = txrefs =>
        _.sumBy(txref => highConfidence(confidence, txref), txrefs)
      const authorizedValue =
        sumTxRefs(data.txrefs) + sumTxRefs(data.unconfirmed_txrefs)
      return cryptoAtoms.lte(authorizedValue)
    })
  })
}