using System;

using System.Threading;

using System.Threading.Tasks;

using System.Collections.Generic;

using System.Net.NetworkInformation;

public class Program

{

    private static int failed = 0;

    public static void Main()

    {

        //WaitForTaskWithTimeout();

        //WaitAllForTasks();

        //WaitForAnyTask();

        WhenAllForTasks();

        WhenAnyForTasks();

    }

    private static void WaitForTaskWithTimeout() 

    {

        Task taskA = Task.Run(() => DoComputation());

        // use < 50 for timeout interval

        if(!taskA.Wait(100))

            Console.WriteLine("The timeout interval elapsed");

    }

    private static void DoComputation()

    {

        Random rnd = new Random();

        long sum = 0;

        for (int i = 1; i <= 5000000; i++) {

            int number = rnd.Next(0, 101);

            sum += number;

        }

        Console.WriteLine("Total:   {0:N0}", sum);

    }

    private static Action<Object> PrintThreadInfo = (object input) => {

        int i = (int)input;

        if(i >= 2 && i <= 5)

        {

            throw new InvalidOperationException("Simulated Exception");

        }

        Console.WriteLine($"Task Id: {Task.CurrentId}, Input: {i}, TickCount: {Environment.TickCount}, ThreadId: {Thread.CurrentThread.ManagedThreadId}");

    };

​

​

    private static void WaitAllForTasks()

    {

        var tasks = new List<Task>();

        for(int i = 0; i < 10; i++)

        {

            tasks.Add(Task.Factory.StartNew(PrintThreadInfo, i));

        }

        try 

        {

            Task.WaitAll(tasks.ToArray());

        }

        catch(AggregateException e)

        {

            for(int j = 0; j < e.InnerExceptions.Count; j++)

            {

                Console.WriteLine(e.InnerExceptions[j].Message);

            }

        }

    }

    private static void WaitForAnyTask()

    {

        Task[] tasks = new Task[5];

        for (int i = 0; i <= 4; i++) {

            int factor = i;

            tasks[i] = Task.Run(() => Thread.Sleep(factor * 250 + 50));

        }

        int index = Task.WaitAny(tasks);

        Console.WriteLine("Wait ended because task #{0} completed.", tasks[index].Id);

        Console.WriteLine("Current Status of Tasks:");

        foreach (var t in tasks)

            Console.WriteLine("Task {0}: {1}", t.Id, t.Status);

    }

    private static void WhenAllForTasks()

    {

        List<Task> tasks = PingWebsites();

        Task t = Task.WhenAll(tasks);

        try

        {

            t.Wait();

        }

        catch {}

        if(t.Status == TaskStatus.RanToCompletion)

            Console.WriteLine("All tasks completed");

        else

            Console.WriteLine("{0} tasks failed", failed);

    }

    private static void WhenAnyForTasks()

    {

        List<Task> tasks = PingWebsites();

        Task t = Task.WhenAny(tasks);

        try

        {

            t.Wait();

        }

        catch {}

        if(t.Status == TaskStatus.RanToCompletion)

            Console.WriteLine("Any task completed");

        else

            Console.WriteLine("{0} tasks failed", failed);

    }

    private static List<Task> PingWebsites() 

    {

        failed = 0;

        string[] urls = {"www.websitenotfound1.com", "www.websitenotfound2.com", "www.google.com"};

        var tasks  = new List<Task>();

        foreach(var url in urls) 

        {

            tasks.Add(Task.Run(() => {

                //Console.WriteLine($"Url {url}, Thread Id: {Thread.CurrentThread.ManagedThreadId}");

                var ping = new Ping();

                try

                {

                    var reply = ping.Send(url);

                    //Console.WriteLine($"Url {url}, Thread Id: {Thread.CurrentThread.ManagedThreadId}, Status: {reply.Status}");

                    if(reply.Status != IPStatus.Success) 

                    {

                        Interlocked.Increment(ref failed);

                        throw new TimeoutException($"Unable to reach {url}");

                    }

                }

                catch(PingException e)

                {

                    Console.WriteLine($"Url {url}, Thread Id: {Thread.CurrentThread.ManagedThreadId}, Status: {e.Message}");

                    Interlocked.Increment(ref failed);

                    throw;

                }

            }));        

        }

        return tasks;

    }

}