using System;

using System.Collections.Generic;

using System.Linq;

using System.Globalization;

using System.Collections;   

​

public class Program

{

    public static void Main()

    {

        string[] datesToTest = {/**/ "23.05", "05.23", "23.5", "5.23", "abr2005", "apr2005", "1800", "2239", "2007", "2021", "052016", "122019", "23122022", "2017", "10122022", "20__", "23122019"

                        , "29122022", "21122022", "20122012", "20122011", "20/12/2011", "20-12-2011", "12/2019", "12-2019"

                        , "December2001"

                        , "Dezembro2019", "Dezembro/2001", "04 de Dezembro de 2001", "06Dezembro2001", "06Dez2001", "06Dec2001"};

        DateTime dateToTest = DateTime.MinValue;

        Console.WriteLine($"################################################ Dates ################################################");

        // Get the current UI culture

        //CultureInfo uiCulture = CultureInfo.CurrentUICulture;

        //Console.WriteLine($"The current UI culture is {uiCulture.Name}");

        // Set the current UI culture

        //CultureInfo.CurrentUICulture = new CultureInfo("pt-BR");      

        // https://phrase.com/blog/posts/all-you-need-to-know-about-cultureinfo-in-net-applications/

        CultureInfo culture = CultureInfo.CurrentCulture;

        Console.WriteLine($"The current culture DisplayName is {culture.DisplayName}");

        Console.WriteLine($"The current culture NativeName is {culture.NativeName}");

        Console.WriteLine($"The current culture IsNeutralCulture? {culture.IsNeutralCulture}");

        Console.WriteLine($"________________________________________________________________________________________________________");

        TestOrderAndReport(datesToTest, culture);       

        Console.WriteLine($"################################################ Dates ################################################");          

        //culture = CultureInfo.InvariantCulture; //= en-US

        culture = new CultureInfo("en-US"); 

        Console.WriteLine($"The current culture DisplayName is {culture.DisplayName}");

        Console.WriteLine($"The current culture NativeName is {culture.NativeName}");

        Console.WriteLine($"The current culture IsNeutralCulture? {culture.IsNeutralCulture}");

        Console.WriteLine($"________________________________________________________________________________________________________");

        TestOrderAndReport(datesToTest, culture);           

        // Set the current culture

        Console.WriteLine($"################################################ Dates ################################################");      

        culture = new CultureInfo("pt-BR");//("en-US");     

        Console.WriteLine($"After setting, CultureInfo is {culture.Name.ToString()}");

        Console.WriteLine($"After setting, CultureInfo DisplayName is {culture.DisplayName}");

        Console.WriteLine($"After setting, CultureInfo NativeName is {culture.NativeName}");

        Console.WriteLine($"The current culture IsNeutralCulture? {culture.IsNeutralCulture}");

        CultureInfo.CurrentCulture = culture;       

        Console.WriteLine($"________________________________________________________________________________________________________");

        TestOrderAndReport(datesToTest, culture);

    }

    internal static void TestOrderAndReport(string[] datesToTest, CultureInfo culture)

    {

        DateTime dateToTest = DateTime.MinValue;

        var orderedDates = new List<(DateTime date, string rawDate)>();

        foreach (var date in datesToTest)  

        {           

            var isDate = DateTryParseExact(date, out dateToTest, culture);

            orderedDates.Add((dateToTest, date));

        }

        orderedDates.Sort();

        Console.WriteLine($"######################################## na cultura {culture.DisplayName}: ########################################");

        foreach (var (date, rawDate) in orderedDates)  

        {           

            Console.WriteLine($"------------------------------------------------------------------------");

            var isDate = date != DateTime.MinValue;

            Console.WriteLine(@$"{rawDate, 25} é data? {isDate}{(isDate ? ": " + date.ToString() : "")}");

            //if (isDate) Console.WriteLine($"{rawDate}");          

        }           

    }

    internal static bool DateTryParseExact(string dateWithoutSpace, out DateTime testDate, CultureInfo cultureInfo)

    {

        //https://learn.microsoft.com/en-us/dotnet/standard/base-types/parsing-datetime

        return DateTime.TryParse(dateWithoutSpace, cultureInfo, DateTimeStyles.None, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "yyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MMMyyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "ddMMyyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MMMyyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MM/yyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "dd/MM/yyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MM-yyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MM.d", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "d.MM", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MM.dd", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "dd.MM", cultureInfo, DateTimeStyles.AssumeLocal, out testDate) ||

            DateTime.TryParseExact(dateWithoutSpace, "MMMyyyy", cultureInfo, DateTimeStyles.AssumeLocal, out testDate);

    }

}