CODE -->

using System;
using System.IO;
using System.Net;
using System.Net.Mail;
using System.Net.NetworkInformation;
using System.Text;
using System.Configuration;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Net.Http;
using System.Linq;

namespace showserverstatus
{
    class Program
    {
        static async Task<int> Main(string[] args)
        {
            System.Collections.Concurrent.ConcurrentDictionary<string, string> urlToStatus = new();

             IEnumerable < Task<bool> > tasks = args.Select(async url =>
            {
                bool result = await ServerStatusByAsync(url);
                return urlToStatus.TryAdd(url, result ? "WORKING" : "DOWN");
            });

            bool[] results = await Task.WhenAll(tasks);

            StringBuilder body = new("Please find the status of the DMZ servers below:");
            foreach (var kvp in urlToStatus)
            {
                body.AppendLine();
                body.AppendFormat("{0}: {1}", kvp.Key, kvp.Value);
            }

            await SendEmailAsync("DMZ Server Status", body.ToString());
            await Task.Delay(3000);

            // Return the number of servers which were down:
            return results.Count(result => !result);
        }
        static async Task<bool> ServerStatusByAsync(string url)
        {
            HttpClient http = new();
            using (HttpResponseMessage response = await http.GetAsync(url))
            {
                Console.WriteLine("GET {0}: {1}", url, response.StatusCode);

                if (response.IsSuccessStatusCode)
                {
                    await SendEmailAsync($"{url} WORKING", $"GET {url} returned {response.StatusCode}");
                    return true;
                }
                await SendEmailAsync($"{url} DOWN", $"GET {url} returned {response.StatusCode}");
                return false;
            }
        }

        static async Task SendEmailAsync(string subject, string body)
        {
            using MailMessage mm = new(ConfigurationManager.AppSettings["FromEmail"], "joeblow@gmail.com");
            mm.To.Add("janeblow@yahoo.com");
            mm.CC.Add("kevin.bruiner@hotmail.com");
            mm.Subject = subject;
            mm.Body = body;
            mm.IsBodyHtml = false;

            SmtpClient smtp = new()
            {
                Host = ConfigurationManager.AppSettings["Host"],
                Port = int.Parse(ConfigurationManager.AppSettings["Port"]),
                EnableSsl = true,
                UseDefaultCredentials = false,
                Credentials = new NetworkCredential(ConfigurationManager.AppSettings["Username"], ConfigurationManager.AppSettings["Password"]),
            };

            await smtp.SendMailAsync(mm);
        }
    }
}