index.js

'use strict'

const PayStack = require('./src/PayStack/index.js')

PayStack.prototype.version = '0.3.0'

const Fees = function (cap, additionalCharge, percentage, threshold) {
  this.additionalCharge = additionalCharge || Fees.INIT_ADDITIONAL_CHARGE
  this.percentage = percentage || Fees.INIT_PERCENT
  this.threshold = threshold || Fees.INIT_THRESHOLD
  this.cap = cap || Fees.INIT_CAP

  this.compute()
}

Fees.INIT_THRESHOLD = 250000
Fees.INIT_CAP = 200000
Fees.INIT_PERCENT = 0.015
Fees.INIT_ADDITIONAL_CHARGE = 10000

Fees.prototype.resetDefaults = function () {

}

Fees.prototype.withAdditionalCharge = function (additionalCharge) {
  this.additionalCharge = additionalCharge
  return this
}

Fees.prototype.withThreshold = function (threshold) {
  this.threshold = threshold
  return this
}

Fees.prototype.withCap = function (cap) {
  this.cap = cap
  return this
}

Fees.prototype.compute = function () {
  this.chargeDivider = this.__chargeDivider()
  this.crossover = this.__crossover()
  this.flatlinePlusCharge = this.__flatlinePlusCharge()
  this.flatline = this.__flatline()
}

Fees.prototype.__chargeDivider = function () {
  return 1 - this.percentage
}

Fees.prototype.__crossover = function () {
  return (this.threshold * this.chargeDivider) - this.additionalCharge
}

Fees.prototype.__flatlinePlusCharge = function () {
  return (this.cap - this.additionalCharge) / this.percentage
}

Fees.prototype.__flatline = function () {
  return this.flatlinePlusCharge - this.cap
}

Fees.prototype.addFor = function (amountinkobo) {
  this.compute()

  if (amountinkobo > this.flatline) {
    return parseInt(Math.ceil(amountinkobo + this.cap))
  } else if (amountinkobo > this.crossover) {
    return parseInt(Math.ceil((amountinkobo + this.additionalCharge) / this.chargeDivider))
  } else {
    return parseInt(Math.ceil(amountinkobo / this.chargeDivider))
  }
}

Fees.prototype.calculateFor = function (amountinkobo) {
  this.compute()

  let fee = this.percentage * amountinkobo
  if (amountinkobo >= this.threshold) {
    fee += this.additionalCharge
  }

  if (fee > this.cap) {
    fee = this.cap
  }

  return parseInt(Math.ceil(fee))
}

PayStack.Fees = Fees

module.exports = PayStack