package tools

import (
	"errors"
	"io/fs"
	"os"
	"regexp"
	"time"
)

func Createdir(path string, rights fs.FileMode) error {
	return os.Mkdir(path, rights)
}

func IsFilenameValid(filename string) bool {
	pattern := `^20[2-9][0-9]-(0[1-9]|1[0-2])-(0[0-9]|1[0-9]|2[0-9]|3[0-1])T(0[0-9]|1[0-9]|2[0-3]):([0-5][0-9]:[0-5][0-9])((\+00:00)|(\-00:00)|(\-0[3,9]:30)|(\-1[0-2]:00)|(-0[0-9]:00)|(\+0[0-9]:00)|(\+0[09,03,04,05,06]:30)|(\+10:30)|(\+1[0-4]:00)|(\+0[5,8]:45)|(\+12:45))-(CH|DE|EU|AT)-(stock|delivery).csv$`
	re := regexp.MustCompile(pattern)
	return re.MatchString(filename)
}

func ExtractDateAndConvertToDate(filename string) (time.Time, error) {
	dateStr := filename[0:24]
	t, err := RFC3339StringToTime(dateStr)
	if err != nil {
		return t, err
	}
	return t, nil
}

func CheckDir(path string) (bool, error) {
	info, err := os.Stat(path)
	if err == nil {
		return info.IsDir(), nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return false, err
}

func RFC3339StringToTime(rfc3339str string) (time.Time, error) {
	const MINUS12STUNDEN = -43200
	const PLUS24STUNDEN = 50400
	t, err := time.Parse("2006-01-02T15:04:05-07:00", rfc3339str)
	if err != nil {
		happybirthday := time.Date(1981, time.March, 1, 4, 15, 0, 0, time.UTC)
		return happybirthday, err
	}

	_, offset := t.Zone()
	if offset < MINUS12STUNDEN || offset > PLUS24STUNDEN {
		return time.Date(1981, time.March, 1, 4, 15, 0, 0, time.UTC), errors.New("timezone offset must be between -12:00 and +14:0")
	}
	return t, nil
}