Program To Get All Available Links For Conquer Clients

using System;
using System.IO;
using System.Net.Http;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        private const int DefaultTimeout = 15000;
        private static readonly HttpClient httpClient = new HttpClient { Timeout = TimeSpan.FromMilliseconds(DefaultTimeout) };

        static async Task Main()
        {
            Console.WriteLine("Choose the language you want to check:");
            Console.WriteLine("1. Arabic");
            Console.WriteLine("2. English");
            Console.WriteLine("3. Spanish");
            Console.WriteLine("4. Chinese");

            if (!int.TryParse(Console.ReadLine(), out int languageChoice) || languageChoice < 1 || languageChoice > 4)
            {
                Console.WriteLine("Invalid language choice.");
                return;
            }

            string baseUrl = GetBaseUrl(languageChoice);
            int endNumber = GetEndNumber(languageChoice);
            string namefile = GetFileName(languageChoice);

            using (var writer = new StreamWriter(namefile))
            {
                for (int i = 0; i <= endNumber; i++)
                {
                    string executableUrl = $"{baseUrl}{i:D4}.exe";
                    string zipUrl = $"{baseUrl}{i:D4}.zip";

                    bool isExecutableResponseReceived = await IsReachableUrlAsync(executableUrl);
                    bool isZipResponseReceived = await IsReachableUrlAsync(zipUrl);

                    if (isExecutableResponseReceived || isZipResponseReceived)
                    {
                        string receivedUrl = isExecutableResponseReceived ? executableUrl : zipUrl;
                        Console.WriteLine($"Received a response from the URL: {receivedUrl}");
                        writer.WriteLine(receivedUrl);
                    }
                    else
                    {
                        Console.WriteLine($"No response received for {i:D4}");
                    }
                }
            }

            Console.WriteLine("Finished checking URLs.");
            Console.ReadKey();
        }

        private static string GetFileName(int languageChoice)
        {
            switch (languageChoice)
            {
                case 1: return "Arabic Client Links.txt";
                case 2: return "English Client Links.txt";
                case 3: return "Spanish Client Links.txt";
                case 4: return "Chinese Client Links.txt";
                default: throw new ArgumentException("Invalid language choice.");
            }
        }

        private static string GetBaseUrl(int languageChoice)
        {
            switch (languageChoice)
            {
                case 1: return "https://arconquer.download.99.com/ar_zf/Arabic_Conquer_v";
                case 2: return "https://codl.99.com/en_zf/Conquer_v";
                case 3: return "https://codl.99.com/sp_zf/Conquista_v";
                case 4: return "https://zfcdndownload.99.com/zf/zf_";
                default: throw new ArgumentException("Invalid language choice.");
            }
        }

        private static int GetEndNumber(int languageChoice)
        {
            switch (languageChoice)
            {
                case 1: return 10000;
                case 2: return 10000;
                case 3: return 10000;
                case 4: return 10000;
                default: throw new ArgumentException("Invalid language choice.");
            }
        }

        private static async Task<bool> IsReachableUrlAsync(string url)
        {
            try
            {
                using (var response = await httpClient.GetAsync(url, HttpCompletionOption.ResponseHeadersRead))
                {
                    return response.IsSuccessStatusCode;
                }
            }
            catch (HttpRequestException)
            {
                return false;
            }
        }

    }
}