package math

import "math"

// CalculateAmountWithFee returns a calculated fee included amount on fee
func CalculateAmountWithFee(amount, fee float64) float64 {
	return amount + CalculateFee(amount, fee)
}

// CalculateFee returns a simple fee on amount
func CalculateFee(amount, fee float64) float64 {
	return amount * (fee / 100)
}

// CalculatePercentageGainOrLoss returns the percentage rise over a certain
// period
func CalculatePercentageGainOrLoss(priceNow, priceThen float64) float64 {
	return (priceNow - priceThen) / priceThen * 100
}

// CalculatePercentageDifference returns the percentage of difference between
// multiple time periods
func CalculatePercentageDifference(amount, secondAmount float64) float64 {
	return (amount - secondAmount) / ((amount + secondAmount) / 2) * 100
}

// CalculateNetProfit returns net profit
func CalculateNetProfit(amount, priceThen, priceNow, costs float64) float64 {
	return (priceNow * amount) - (priceThen * amount) - costs
}

// RoundFloat rounds your floating point number to the desired decimal place
func RoundFloat(x float64, prec int) float64 {
	var rounder float64
	pow := math.Pow(10, float64(prec))
	intermed := x * pow
	_, frac := math.Modf(intermed)
	intermed += .5
	x = .5
	if frac < 0.0 {
		x = -.5
		intermed--
	}
	if frac >= x {
		rounder = math.Ceil(intermed)
	} else {
		rounder = math.Floor(intermed)
	}

	return rounder / pow
}