// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information. 

#if !NO_REMOTING
using System;
using System.Reactive.Concurrency;
using System.Reactive.PlatformServices;
using System.Runtime.CompilerServices;
using System.Threading;
using Xunit;

namespace ReactiveTests.Tests
{

    [Serializable]
    public class DefaultConcurrencyAbstractionLayerTest
    {
        private AppDomain _domain;

        public DefaultConcurrencyAbstractionLayerTest()
        {
            if (_domain == null)
            {
                _domain = AppDomain.CreateDomain("Default_CAL", null, new AppDomainSetup { ApplicationBase = AppDomain.CurrentDomain.BaseDirectory });
            }
        }

        private void Run(CrossAppDomainDelegate a)
        {
            _domain.DoCallBack(a);
        }

        [Fact]
        public void Sleep()
        {
            var ran = new MarshalByRefCell<bool>();
            _domain.SetData("state", ran);

            Run(() =>
            {
                Scheduler.Immediate.Schedule(TimeSpan.FromMilliseconds(1), () =>
                {
                    var state = (MarshalByRefCell<bool>)_domain.GetData("state");
                    state.Value = true;
                });
            });

            Assert.True(ran.Value);
        }

        [Fact]
        public void QueueUserWorkItem()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("state", e);

            Run(() =>
            {
                Scheduler.Default.Schedule(() =>
                {
                    var state = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("state");
                    state.Value.Set();
                });
            });

            e.Value.WaitOne();
        }

        [Fact]
        public void StartTimer()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("state", e);

            Run(() =>
            {
                Scheduler.Default.Schedule(TimeSpan.FromMilliseconds(10), () =>
                {
                    var state = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("state");
                    state.Value.Set();
                });
            });

            e.Value.WaitOne();
        }

        [Fact]
        public void StartTimer_Cancel()
        {
            Run(StartTimer_Cancel_Callback);
        }

        private static void StartTimer_Cancel_Callback()
        {
            Scheduler.Default.Schedule(TimeSpan.FromSeconds(60), () =>
            {
                throw new InvalidOperationException("This shouldn't have happened!");
            }).Dispose();
        }

        [Fact]
        public void StartPeriodicTimer()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("state", e);

            Run(() =>
            {
                var n = 0;

                Scheduler.Default.SchedulePeriodic(TimeSpan.FromMilliseconds(10), () =>
                {
                    var state = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("state");

                    if (n++ == 10)
                    {
                        state.Value.Set();
                    }
                });
            });

            e.Value.WaitOne();
        }

        [Fact]
        public void StartPeriodicTimer_Cancel()
        {
            Run(StartPeriodicTimer_Cancel_Callback);
        }

        private static void StartPeriodicTimer_Cancel_Callback()
        {
            Scheduler.Default.SchedulePeriodic(TimeSpan.FromSeconds(60), () =>
            {
                throw new InvalidOperationException("This shouldn't have happened!");
            }).Dispose();
        }

        [Fact]
        public void StartPeriodicTimer_Fast()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("state", e);

            Run(() =>
            {
                var n = 0;

                Scheduler.Default.SchedulePeriodic(TimeSpan.Zero, () =>
                {
                    var state = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("state");

                    if (n++ == 10)
                    {
                        state.Value.Set();
                    }
                });
            });

            e.Value.WaitOne();
        }

        [Fact]
        public void StartPeriodicTimer_Fast_Cancel()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("set_cancel", e);

            Run(() =>
            {
                var n = 0;

                var hasAtLeastOneValue = new ManualResetEvent(false);

                var schedule = Scheduler.Default.SchedulePeriodic(TimeSpan.Zero, () =>
                {
                    _domain.SetData("value", n++);
                    hasAtLeastOneValue.Set();
                });

                _domain.SetData("cancel", new MarshalByRefAction(schedule.Dispose));

                hasAtLeastOneValue.WaitOne();

                var setCancel = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("set_cancel");

                setCancel.Value.Set();
            });

            e.Value.WaitOne();

            var value = (int)_domain.GetData("value");

            var cancel = (MarshalByRefAction)_domain.GetData("cancel");
            cancel.Invoke();

            Thread.Sleep(TimeSpan.FromMilliseconds(50));

            var newValue = (int)_domain.GetData("value");

            Assert.True(newValue >= value);

            Thread.Sleep(TimeSpan.FromMilliseconds(50));

            value = (int)_domain.GetData("value");

            Assert.Equal(newValue, value);
        }

        [Fact]
        public void CreateThread()
        {
            var e = new MarshalByRefCell<ManualResetEvent> { Value = new ManualResetEvent(false) };
            _domain.SetData("state", e);

            var r = new MarshalByRefCell<string> { Value = "" };
            _domain.SetData("res", r);

            Run(() =>
            {
                var state = (MarshalByRefCell<ManualResetEvent>)_domain.GetData("state");
                var res = (MarshalByRefCell<string>)_domain.GetData("res");

                var svc = (IServiceProvider)Scheduler.Default;

                var per = (ISchedulerPeriodic)svc.GetService(typeof(ISchedulerPeriodic));
                if (per == null)
                {
                    res.Value = "Failed to get ISchedulerPeriodic.";
                    state.Value.Set();
                    return;
                }

                var slr = (ISchedulerLongRunning)svc.GetService(typeof(ISchedulerLongRunning));
                if (slr == null)
                {
                    res.Value = "Failed to get ISchedulerLongRunning.";
                    state.Value.Set();
                    return;
                }

                var success = false;
                try
                {
                    slr.ScheduleLongRunning(42, null);
                }
                catch (ArgumentNullException)
                {
                    success = true;
                }

                if (!success)
                {
                    res.Value = "Failed null check ScheduleLongRunning.";
                    state.Value.Set();
                    return;
                }

                state.Value.Set();
#if !NO_THREAD
                var w = new ManualResetEvent(false);

                var d = slr.ScheduleLongRunning(cancel =>
                {
                    while (!cancel.IsDisposed)
                    {
                        ;
                    }

                    w.Set();
                });

                Thread.Sleep(50);
                d.Dispose();
                w.WaitOne();
#else
                state.Value.Set();
#endif
            });

            e.Value.WaitOne();
            Assert.True(string.IsNullOrEmpty(r.Value));
        }

        [Fact]
        public void Cant_Locate_Scheduler()
        {

            Cant_Locate_Scheduler_NoPlib();

        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private void Cant_Locate_Scheduler_NoPlib()
        {
            var e = new MarshalByRefCell<bool>();
            _domain.SetData("state", e);

            Run(() =>
            {
                var state = (MarshalByRefCell<bool>)_domain.GetData("state");
                try
                {
                    state.Value = Scheduler.TaskPool != null;
                }
                catch (Exception)
                {
                    state.Value = false;
                }
            });

            Assert.True(e.Value);
        }

#if !NO_PERF
        [Fact]
        public void Stopwatch()
        {
            var e = new MarshalByRefCell<bool>();
            _domain.SetData("state", e);

            Run(() =>
            {
                var state = (MarshalByRefCell<bool>)_domain.GetData("state");

                var sw = Scheduler.Default.StartStopwatch();

                var fst = sw.Elapsed;
                Thread.Sleep(100);
                var snd = sw.Elapsed;

                state.Value = snd > fst;
            });

            Assert.True(e.Value);
        }
#endif

        [Fact]
        public void EnsureLoaded()
        {
            Assert.True(EnlightenmentProvider.EnsureLoaded());
        }
    }

    public class MarshalByRefCell<T> : MarshalByRefObject
    {
        public T Value;
        public override object InitializeLifetimeService()
        {
            return null;
        }
    }

    public class MarshalByRefAction : MarshalByRefObject
    {
        private readonly Action _action;

        public MarshalByRefAction(Action action)
        {
            _action = action;
        }

        public void Invoke()
        {
            _action();
        }
        public override object InitializeLifetimeService()
        {
            return null;
        }
    }
}
#endif