package thousands

import (
	"fmt"
	"strings"
)

func Separate(Number interface{}, language ...string) (string, error) {

	switch Number.(type) {
	case int:
	case int8:
	case int16:
	case int32:
	case int64:
	case float32:
	case float64:

	default:
		return "", fmt.Errorf("no valid number format")
	}

	formattedNumber := fmt.Sprintf("%.2f", Number)

	if len(language) < 1 {
		language[0] = "en"
	}

	switch language[0] {
	case "de":

		formattedNumber = strings.ReplaceAll(formattedNumber, ",", ".")

		dec := ""

		if strings.Index(formattedNumber, ".") != -1 {
			dec = formattedNumber[strings.Index(formattedNumber, ".")+1 : len(formattedNumber)]
			formattedNumber = formattedNumber[0:strings.Index(formattedNumber, ".")]

		}

		for i := 0; i <= len(formattedNumber); i = i + 4 {

			a := formattedNumber[0 : len(formattedNumber)-i]
			b := formattedNumber[len(formattedNumber)-i : len(formattedNumber)]
			formattedNumber = a + "." + b

		}

		if formattedNumber[0:1] == "." {
			formattedNumber = formattedNumber[1:len(formattedNumber)]
		}

		if formattedNumber[len(formattedNumber)-1:len(formattedNumber)] == "." {
			formattedNumber = formattedNumber[0 : len(formattedNumber)-1]
		}

		if dec != "" {
			formattedNumber = formattedNumber + "," + dec
		}

		return formattedNumber, nil

	case "en":

		formattedNumber = strings.ReplaceAll(formattedNumber, ",", "")

		dec := ""

		if strings.Index(formattedNumber, ".") != -1 {
			dec = formattedNumber[strings.Index(formattedNumber, ".")+1 : len(formattedNumber)]
			formattedNumber = formattedNumber[0:strings.Index(formattedNumber, ".")]

		}

		for i := 0; i <= len(formattedNumber); i = i + 4 {

			a := formattedNumber[0 : len(formattedNumber)-i]
			b := formattedNumber[len(formattedNumber)-i : len(formattedNumber)]
			formattedNumber = a + "," + b

		}

		if formattedNumber[0:1] == "," {
			formattedNumber = formattedNumber[1:len(formattedNumber)]
		}

		if formattedNumber[len(formattedNumber)-1:len(formattedNumber)] == "," {
			formattedNumber = formattedNumber[0 : len(formattedNumber)-1]
		}

		if dec != "" {
			formattedNumber = formattedNumber + "." + dec
		}

		return formattedNumber, nil
	}

	return formattedNumber, nil
}