lamassu-server/lib/commission-math.js
2022-02-18 20:15:39 +00:00

41 lines
1.5 KiB
JavaScript

const BN = require('./bn')
const configManager = require('./new-config-manager')
const { utils: coinUtils } = require('@lamassu/coins')
function truncateCrypto (cryptoAtoms, cryptoCode) {
const DECIMAL_PLACES = 6
if (cryptoAtoms.eq(0)) return cryptoAtoms
const scale = coinUtils.getCryptoCurrency(cryptoCode).unitScale
const scaleFactor = BN(10).pow(scale)
return new BN(cryptoAtoms).integerValue(BN.ROUND_DOWN).div(scaleFactor)
.decimalPlaces(DECIMAL_PLACES).times(scaleFactor)
}
function fiatToCrypto (tx, rec, deviceId, config) {
const usableFiat = rec.fiat - rec.cashInFee
const commissions = configManager.getCommissions(tx.cryptoCode, deviceId, config)
const tickerRate = new BN(tx.rawTickerPrice)
const discount = getDiscountRate(tx.discount, commissions[tx.direction])
const rate = tickerRate.times(discount).decimalPlaces(5)
const unitScale = coinUtils.getCryptoCurrency(tx.cryptoCode).unitScale
const unitScaleFactor = new BN(10).pow(unitScale)
return truncateCrypto(new BN(usableFiat).div(rate.div(unitScaleFactor)), tx.cryptoCode)
}
function getDiscountRate (discount, commission) {
const bnDiscount = discount ? new BN(discount) : new BN(0)
const bnCommission = new BN(commission)
const percentageDiscount = new BN(1).minus(bnDiscount.div(100))
const percentageCommission = bnCommission.div(100)
return new BN(1).plus(percentageDiscount.times(percentageCommission))
}
module.exports = {
truncateCrypto,
fiatToCrypto,
getDiscountRate
}