package logic

import (
	"math"
	"sort"
)

func CalculateCardValue(baseSales, exactSales []float64, factors map[string]float64) float64 {
	bpRaw := calculateBasePrice(baseSales)
	emp := 0.0
	if len(exactSales) > 0 {
		emp = calculateBasePrice(exactSales)
	}
	bpFinal := calculateFinalBasePrice(bpRaw, emp, len(exactSales))
	value := (bpFinal * factors["GF"] * factors["RF"] * factors["EF"] * factors["ST"] * factors["DF"] * factors["AF"] * factors["MF"]) + factors["TAF"]
	return math.Round(value*100) / 100
}

func calculateBasePrice(sales []float64) float64 {
	cleanSales := removeOutliers(sales)
	median := calculateMedian(cleanSales)
	stdDev := calculateStdDev(cleanSales, median)
	vaf := 1 + (stdDev/median)*0.1
	return median * vaf
}

func calculateFinalBasePrice(bp, emp float64, exactCount int) float64 {
	weight := 0.0
	switch {
	case exactCount >= 10:
		weight = 0.8
	case exactCount >= 5:
		weight = 0.6
	case exactCount >= 2:
		weight = 0.4
	}
	return (bp * (1 - weight)) + (emp * weight)
}

func removeOutliers(sales []float64) []float64 {
	median := calculateMedian(sales)
	var filtered []float64
	for _, s := range sales {
		if s >= median*0.7 && s <= median*1.3 {
			filtered = append(filtered, s)
		}
	}
	return filtered
}

func calculateMedian(sales []float64) float64 {
	sort.Float64s(sales)
	n := len(sales)
	if n%2 == 0 {
		return (sales[n/2-1] + sales[n/2]) / 2
	}
	return sales[n/2]
}

func calculateStdDev(sales []float64, mean float64) float64 {
	var sum float64
	for _, s := range sales {
		sum += math.Pow(s-mean, 2)
	}
	return math.Sqrt(sum / float64(len(sales)))
}