#if SHRINK_EVENTBUS_HAS_SHARED_RUNTIME
using System;
using NUnit.Framework;
using ShrinkSDK.Runtime;

namespace ShrinkEventBus.Integration.Tests
{
    public sealed class SharedDispatcherTests
    {
        private sealed class Dispatcher : IShrinkMainThreadDispatcher
        {
            public bool IsMainThread => false;
            public Action Pending;
            public bool TryPost(Action action) { Pending = action; return true; }
        }

        [Test]
        public void AdapterPreservesAffinityAndPostsThroughSharedDispatcher()
        {
            var original = ShrinkEventBusRuntime.MainThreadDispatcher;
            try
            {
                var dispatcher = new Dispatcher();
                var adapter = new ShrinkSharedMainThreadDispatcher(dispatcher);
                ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(adapter);
                Assert.IsFalse(ShrinkEventBusRuntime.MainThreadDispatcher.IsMainThread);
                var hits = 0;
                Assert.IsTrue(ShrinkEventBusRuntime.MainThreadDispatcher.TryPost(() => hits++));
                Assert.AreEqual(0, hits);
                dispatcher.Pending();
                Assert.AreEqual(1, hits);
            }
            finally { ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(original); }
        }

        [Test]
        public void AdapterRejectsNullDispatcher()
        {
            Assert.Throws<ArgumentNullException>(() => new ShrinkSharedMainThreadDispatcher(null));
        }
    }
}
#endif