package utils

import "github.com/shopspring/decimal"

func Average(numbers []decimal.Decimal) decimal.Decimal {
	if len(numbers) == 0 {
		return decimal.Decimal{}
	}
	if len(numbers) == 1 {
		return numbers[0]
	}
	var sum decimal.Decimal
	for _, d := range numbers {
		sum = sum.Add(d)
	}
	return sum.Div(decimal.NewFromInt(int64(len(numbers))))
}

func Deviation(numbers []decimal.Decimal) decimal.Decimal {
	if len(numbers) == 0 || len(numbers) == 1 {
		return decimal.Decimal{}
	}
	avgNum := Average(numbers)
	var diffSquaredSum decimal.Decimal
	for _, n := range numbers {
		diff := n.Sub(avgNum)
		diffSquaredSum = diffSquaredSum.Add(diff.Mul(diff))
	}
	return diffSquaredSum.Div(decimal.NewFromInt(int64(len(numbers))))
}