package orders

import (
	"fmt"
	"math"
	"regexp"
	"strconv"
	"strings"
	"unicode"
)

func isValidPolishMobile(nineDigitNum string) bool {
	if len(nineDigitNum) != 9 {
		return false
	}

	firstDigit := nineDigitNum[0]

	if firstDigit < '4' || firstDigit > '8' {
		return false
	}

	prefix2 := nineDigitNum[:2]
	validPrefixes := map[string]bool{
		"45": true,
		"50": true, "51": true, "53": true, "57": true,
		"60": true, "66": true, "69": true,
		"72": true, "73": true, "78": true, "79": true,
		"88": true,
	}

	return validPrefixes[prefix2]
}

func parsePhone(input string) (string, error) {
	input = strings.TrimSpace(input)

	if strings.HasPrefix(input, "+48") {
		input = strings.TrimPrefix(input, "+48")
	} else if strings.HasPrefix(input, "0048") {
		input = strings.TrimPrefix(input, "0048")
	}

	re := regexp.MustCompile(`\D`)
	cleaned := re.ReplaceAllString(input, "")

	if len(cleaned) == 11 && strings.HasPrefix(cleaned, "48") {
		cleaned = cleaned[2:]
	}

	if len(cleaned) != 9 {
		return "", fmt.Errorf("Numer telefonu musi mieć 9 cyfr")
	}

	if !isValidPolishMobile(cleaned) {
		return "", fmt.Errorf("Nieprawidłowy numer telefonu — podaj polski numer komórkowy")
	}

	return cleaned, nil
}

func parseFloat(input string) (int, error) {
	val, err := strconv.ParseFloat(input, 64)
	if err != nil {
		return 0, fmt.Errorf("Nieprawidłowa wartość")
	}

	if val < 0 || val > 100 {
		return 0, fmt.Errorf("Wartość musi być między 0 a 100")
	}

	doubled := val * 2
	if math.Abs(doubled-math.Round(doubled)) > 1e-9 {
		return 0, fmt.Errorf("Wartość musi być wielokrotnością 0,5")
	}

	return int(math.Round(val * 10)), nil
}

func validName(name string) bool {
	if name == "" || len(name) > 100 {
		return false
	}
	return strings.IndexFunc(name, unicode.IsControl) == -1
}