using System;
using Developpez.Dotnet.Windows.Service;
using NUnit.Framework;

namespace Developpez.Dotnet.Windows.Tests.Service
{
    [TestFixture]
    public class MediatorTests
    {
        [Test]
        public void Test_Mediator()
        {
            bool foo1Received = false;
            bool foo2Received = false;
            
            Foo foo1 = new Foo(m => foo1Received = true);
            Foo foo2 = new Foo(m => foo2Received = true);

            foo1.SendMessage("Hello");
            Assert.AreEqual(false, foo1Received);
            Assert.AreEqual(true, foo2Received);
            foo1Received = false;
            foo2Received = false;

            foo2.SendMessage("World");
            Assert.AreEqual(true, foo1Received);
            Assert.AreEqual(false, foo2Received);
            foo1Received = false;
            foo2Received = false;
            
            Mediator.Instance.Post(this, new Message("42"));
            Assert.AreEqual(true, foo1Received);
            Assert.AreEqual(true, foo2Received);
            foo1Received = false;
            foo2Received = false;

            foo1 = null;
            GC.Collect();

            Mediator.Instance.Post(this, new Message("42"));

            // foo1 should have been collected, so it shouldn't receive the message
            Assert.AreEqual(false, foo1Received);
            Assert.AreEqual(true, foo2Received);

            // Prevent premature garbage collection of foo2
            GC.KeepAlive(foo2);
        }

        class Foo
        {
            public Foo(Action<Message> receiveAction)
            {
                _receiveAction = receiveAction;
                Mediator.Instance.Subscribe<Message>(ReceiveMessage);
            }

            private readonly Action<Message> _receiveAction;

            public void SendMessage(string text)
            {
                Mediator.Instance.Post(this, new Message(text));
            }

            private void ReceiveMessage(object sender, Message m)
            {
                if (sender != this)
                {
                    _receiveAction(m);
                }
            }
        }

        class Message
        {
            public Message(string text)
            {
                this.Text = text;
            }

            public string Text { get; private set; }
        }
    }
}