using Microsoft.ServiceBus.Messaging;
using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
	static void Main(string[] args)
	{
		Console.WriteLine("Retrieving Messages...");

		string connectionString = "<Your Endpoint Here>";
		string queueName = "sample-queue";

		MessagingFactory factory = MessagingFactory.CreateFromConnectionString(connectionString);
		MessageReceiver messageReceiver = factory.CreateMessageReceiver(queueName, ReceiveMode.PeekLock);

		List<long> deferredMessages = new List<long>();

		Random randomWait = new Random();

		while (true)
		{
			try
			{
				if (deferredMessages.Any())
				{
					Console.WriteLine("Processing deferred messages...");

					foreach (long sequenceNumber in deferredMessages)
					{
						using (BrokeredMessage retrievedMessage = messageReceiver.Receive(sequenceNumber))
						{
							if (retrievedMessage != null)
							{
								if (retrievedMessage.Properties.ContainsKey("Say"))
								{
									Console.WriteLine(retrievedMessage.Properties["Say"].ToString());
								}

								retrievedMessage.Complete();
							}
						}
					}

					deferredMessages.Clear();
				}

				using (BrokeredMessage originalMessage = messageReceiver.Receive(TimeSpan.FromSeconds(1)))
				{
					try
					{
						if (originalMessage != null)
						{
							// defer some messages
							if ((originalMessage.SequenceNumber % 2) == 0)
							{
								Console.WriteLine("{0} - Deferred", originalMessage.SequenceNumber);
								originalMessage.Defer();
								deferredMessages.Add(originalMessage.SequenceNumber);
							}
							else
							{
								if (originalMessage.Properties.ContainsKey("Say"))
								{
									Console.WriteLine(originalMessage.Properties["Say"].ToString());
								}

								Console.WriteLine("{0} - Complete", originalMessage.SequenceNumber);
								originalMessage.Complete();
							}
						}
						else
						{
							Console.Write(".");
						}
					}
					catch (Exception ex)
					{
						Console.WriteLine(ex.ToString());
					}
				}
			}
			catch(Exception ex)
			{
				Console.WriteLine("Exception {0}", ex.Message);
			}

			TimeSpan wait = TimeSpan.FromSeconds(randomWait.Next(1, 10));
			System.Threading.Thread.Sleep(wait);
		}
	}
}