kjol/go/finance/helpers.go

package finance

import (
	. "kjol/basic"
	"fmt"
	"math"
	"strconv"
	"strings"
)

// takes a number such as 123456, and outputs (1234, 56) as strings
func SplitInt64(n int64) (string, string) {
	// Calculate the first part as string
	firstPart := fmt.Sprintf("%d", n/100)
	// Calculate the second part as string with leading zero if necessary
	secondPart := fmt.Sprintf("%02d", n%100)
	return firstPart, secondPart
}

func Int64ToMoney(value int64) string {
	decimalValue := float64(value) / 100.0
	moneyString := fmt.Sprintf("%.2f", decimalValue)
	return moneyString
}

func Int64ToMoneyWithCommas(value int64) string {
	decimalValue := float64(value) / 100.0
	moneyString := fmt.Sprintf("%.2f", decimalValue)

	parts := strings.Split(moneyString, ".")
	dollars := parts[0]
	cents := parts[1]

	negative := false
	if strings.HasPrefix(dollars, "-") {
		negative = true
		dollars = dollars[1:]
	}

	result := ""
	for i, char := range dollars {
		if i > 0 && (len(dollars)-i)%3 == 0 {
			result += ","
		}
		result += string(char)
	}

	if negative {
		result = "-" + result
	}

	return result + "." + cents
}

func MoneyToInt64(input string) int64 {
	if !strings.Contains(input, ".") {
		input += ".00"
	} else if strings.Count(input, ".") == 1 {
		digits := strings.Split(input, ".")
		if len(digits[1]) == 1 {
			input += "0"
		}
	}
	processedString := strings.ReplaceAll(input, ".", "")
	processedString = strings.ReplaceAll(processedString, ",", "")
	processedString = strings.ReplaceAll(processedString, " ", "")
	result, _ := strconv.Atoi(processedString)
	return int64(result)
}

func Int64ToRate(rate int64) string {
	decimalValue := float64(rate) / 1000.0
	rateString := fmt.Sprintf("%.3f", decimalValue)
	return rateString
}

func RoundUpToCeiling(input int64) int64 {
	remainder := input % 100
	if remainder == 0 {
		return input
	}
	return input + 100 - remainder
}

func RoundDownToFloor(input int64) int64 {
	remainder := input % 100
	if remainder == 0 {
		return input
	}
	return input - remainder
}

func MultiplyByPercentageS64(amount int64, percentage float64) int64 {
	amount_float64 := float64(amount) / 100
	out_float64 := (amount_float64 * (percentage / 100))

	out_int64 := int64(math.Round(out_float64 * 100))

	return out_int64
}

func MultiplyByPercentageF64(amount int64, percentage float64) float64 {
	amount_float64 := float64(amount) / 100

	return amount_float64 * percentage
}

func ProcessDiscount(discount string) float64 {
	discount_f64, _ := strconv.ParseFloat(discount, 64)

	if discount_f64 < 0 {
		return 0
	} else if discount_f64 > 100 {
		return 100
	}

	return discount_f64
}

// DaysToRateTerm Takes days as an input and outputs the string representation of the number of
// days, months, or years in the term based on which unit is the best fit for the amount of days
// along with the corresponding unit string.
func DaysToRateTerm(days int32) (string, string) {
	years := days / 365
	months := (days - years*365) / 30
	dayRemainder := days - years*365 - months*30

	if days == 0 { // Return empty string for value
		return "", "days"
	} else if days <= 270 || dayRemainder > 0 {
		return ToString(days), "days"
	} else if months > 0 {
		return ToString(months + years*12), "months"
	} else {
		return ToString(years), "years"
	}
}

func RateTermToDays(value string, unit string) int32 {
	valueInt := StringToInt32(value)
	switch unit {
	case "months":
		years := valueInt / 12
		months := valueInt % 12
		return years*365 + months*30
	case "years":
		return valueInt * 365
	default: // case "days":
		return valueInt
	}
}

func RateToString(rateValue float64) string {
	str, err := NumberToString(rateValue, 3, "%", true)
	if err != nil {
		fmt.Println(err)
		return fmt.Sprint(rateValue)
	}
	return str
}

func RatePlainToString(rateValue float64) string {
	str, err := NumberToString(rateValue, 3, "", false)
	if err != nil {
		fmt.Println(err)
		return fmt.Sprint(rateValue)
	}
	return str
}

func DollarAmountToString(amount float64) string {
	str, err := NumberToString(amount, 2, "", false)
	if err != nil {
		fmt.Println(err)
		return fmt.Sprint(amount)
	}
	return str
}

func DollarAmountPlainToString(amount float64) string {
	str, err := NumberToString(amount, 2, "$", false)
	if err != nil {
		fmt.Println(err)
		return fmt.Sprint(amount)
	}
	return str
}

func NumberToString(i any, precision int, symbol string, symbolLast bool) (string, error) {
	var numberFloat float64 = 0.0
	err := fmt.Errorf("error: could not convert %s to a decimal value", i)
	switch i.(type) {
	case int32, int64, int, uint64, uint32, uint, float32, float64:
		if val, ok := i.(float64); ok {
			numberFloat = val
		} else {
			return "", err
		}
	default:
		return "", fmt.Errorf("error: could not convert %s to a decimal value", i)
	}

	s := fmt.Sprintf("%.[2]*[1]f", numberFloat, precision)

	parts := strings.Split(s, ".")
	if len(parts) == 0 {
		return "", fmt.Errorf("error: could not convert '%s' to a decimal value", s)
	}

	numberLeftSide := parts[0][len(parts[0])-1:]

	for i := len(parts[0]) - 2; i >= 0; i-- {

		if len(strings.Replace(numberLeftSide, ",", "", -1))%3 == 0 {
			numberLeftSide = "," + numberLeftSide
		}
		numberLeftSide = string(parts[0][i]) + numberLeftSide

	}
	numberToReturn := numberLeftSide
	if len(parts) > 1 {
		numberToReturn = numberToReturn + "." + parts[1]
	}

	if symbol != "" {
		if symbolLast {
			numberToReturn = numberToReturn + symbol
		} else {
			numberToReturn = symbol + numberToReturn
		}
	}

	return numberToReturn, nil
}