using System.Globalization;

namespace View_by_Distance.Shared.Models.Stateless.Methods;

internal abstract class PersonBirthday
{

    internal static DateTime GetDefaultValue() => DateTime.MinValue; // {{1}}SingletonValue

    // ...
    internal static string GetFormatted(Models.PersonBirthday personBirthday) => personBirthday.Value.ToString(Stateless.IPersonBirthday.Format);
    internal static string GetFileName(Models.PersonBirthday personBirthday) => $"{personBirthday.Value.ToString(Stateless.IPersonBirthday.Format)}.json";
    internal static bool DoesBirthDateExits(Properties.IStorage storage, Models.PersonBirthday personBirthday) => File.Exists(GetFileFullName(storage, personBirthday));
    internal static Models.PersonBirthday GetNextBirthDate(Properties.IStorage storage) => throw new Exception(storage.ToString()); // Person.GetNextBirthDate(storage);
    internal static string GetFileFullName(Properties.IStorage storage, Models.PersonBirthday personBirthday) => Path.Combine(storage.PeopleRootDirectory, "{}", GetFileName(personBirthday));
    internal static DateTime? GetDateTime(string personKey) => DateTime.TryParseExact(personKey, Stateless.IPersonBirthday.Format, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime dateTime) ? dateTime : null;

    internal static Models.PersonBirthday? GetPersonBirthday(string personKey)
    {
        Models.PersonBirthday? result;
        DateTime? dateTime = GetDateTime(personKey);
        if (dateTime is null)
            result = null;
        else
            result = new(dateTime.Value);
        return result;
    }

    internal static TimeSpan? GetTimeSpan(DateTime minimumDateTime, bool? isWrongYear, Models.PersonBirthday personBirthday)
    {
        TimeSpan? timeSpan;
        if (isWrongYear is null || isWrongYear.Value || personBirthday.Value.Year < 1900)
            timeSpan = null;
        else
            timeSpan = new(minimumDateTime.Ticks - personBirthday.Value.Ticks);
        return timeSpan;
    }

    internal static (int, TimeSpan) GetAge(DateTime dateTime, Models.PersonBirthday birthday)
    {
        TimeSpan result;
        int years;
        if (birthday?.Value is null)
            throw new NullReferenceException(nameof(birthday.Value));
        (years, result) = Age.GetAge(dateTime, birthday.Value);
        return (years, result);
    }

    internal static (int, double) GetAge(DateTime dateTime, DateTime dayBeforeLeapDate, Models.PersonBirthday birthday)
    {
        double result;
        (int years, TimeSpan timeSpan) = GetAge(dateTime, birthday);
        if (!DateTime.IsLeapYear(dateTime.Year) || dateTime < dayBeforeLeapDate.AddDays(1))
            result = timeSpan.TotalDays / 365;
        else
            result = timeSpan.TotalDays / 366;
        return (years, result);
    }

    internal static double? GetAge(Models.PersonBirthday birthday)
    {
        double? result;
        if (birthday is null)
            result = null;
        else
        {
            DateTime dateTime = DateTime.Now;
            DateTime dayBeforeLeapDate = new(dateTime.Year, 2, 28);
            (int years, double r) = GetAge(dateTime, dayBeforeLeapDate, birthday);
            result = years + r;
        }
        return result;
    }

}