using System;
using Amphora;
using UnitTestSharp;
using Vellum;

namespace Ariadne.Vellum.UnitTests
{
    /// <summary>
    /// Saves scripts paused on latches, and reloads them into a scheduler of their own.
    /// </summary>
    public class LatchWaitSaveTests : TestFixture
    {
        /// <summary>
        /// A lounge, a scheduler over it, and the ticks that drive them.
        /// </summary>
        public class Room
        {
            public readonly Lounge Lounge;
            public readonly ArcScheduler<Lounge> Scheduler = new ArcScheduler<Lounge>();
            private readonly ExceptionSandbox sandbox = new ExceptionSandbox(typeof(AriadneSites).Assembly);

            public Room(Lounge lounge)
            {
                Lounge = lounge;
            }

            public Room()
                : this(new Lounge())
            {
            }

            public void TickAt(double gameSeconds)
            {
                Scheduler.Tick(Lounge, new TickContext(sandbox, TimeSpan.FromMilliseconds(16),
                    TimeSpan.FromSeconds(gameSeconds)));
            }

            public string[] Log()
            {
                return Lounge.Log.ToArray();
            }
        }

        /// <summary>
        /// Saves <paramref name="lounge"/> and <paramref name="content"/> as one scene, so they share the latches, and
        /// loads it back.
        /// </summary>
        public static LoungeScene<ContentType> Reload<ContentType>(Lounge lounge, ContentType content)
        {
            SaveSession session = ArcConverterTests.Session();
            var scene = new LoungeScene<ContentType> { Lounge = lounge, Content = content };
            return (LoungeScene<ContentType>)session.FromNode(
                session.ToNode(scene, typeof(LoungeScene<ContentType>)), typeof(LoungeScene<ContentType>));
        }

        /// <summary>
        /// Adds the script of <paramref name="loaded"/> to a scheduler of its own over the lounge that was loaded.
        /// </summary>
        public static Room Resumed<ContentType>(LoungeScene<ContentType> loaded)
            where ContentType : Arc<Lounge>
        {
            var returnMe = new Room(loaded.Lounge);
            returnMe.Scheduler.Add(loaded.Content);
            return returnMe;
        }

        public class ReloadTests : TestFixture
        {
            public void WaitReloadedMidWait_ResumesWhenTheLoadedLatchIsSet()
            {
                var original = new Room();
                var script = new LoungeDoorScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.Lounge.Door.Set();
                room.TickAt(0.1);

                CheckEqual(new[] { "start", "door" }, room.Log());
            }

            public void WaitReloadedMidWait_StillWaitsUntilTheLoadedLatchIsSet()
            {
                var original = new Room();
                var script = new LoungeDoorScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(0.1);
                room.TickAt(0.2);

                CheckEqual(new[] { "start" }, room.Log());
                CheckEqual(1, room.Scheduler.SuspendedCount);
            }

            public void WaitReloadedAfterTheLatchWasSetBeforeTheArcRan_Resumes()
            {
                var original = new Room();
                var script = new LoungeDoorScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(0.1);

                CheckEqual(new[] { "start", "door" }, room.Log());
            }

            public void WaitReloadedSatisfied_WaitsAgainWhenTheLoadedLatchIsClearedBeforeTheArcRuns()
            {
                var original = new Room();
                var script = new LoungeDoorScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();

                Room room = Resumed(Reload(original.Lounge, script));
                room.Lounge.Door.Clear();
                room.TickAt(0.1);
                CheckEqual(new[] { "start" }, room.Log());
                room.Lounge.Door.Set();
                room.TickAt(0.2);

                CheckEqual(new[] { "start", "door" }, room.Log());
            }

            public void WaitForClearReloadedMidWait_ResumesWhenTheLoadedLatchIsCleared()
            {
                var original = new Room();
                original.Lounge.Door.Set();
                var script = new LoungeClearScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(0.1);
                CheckEqual(new[] { "start" }, room.Log());
                room.Lounge.Door.Clear();
                room.TickAt(0.2);

                CheckEqual(new[] { "start", "clear" }, room.Log());
            }

            public void WaitReloadedAfterItWasPassed_LeavesTheLoadedLatchWithoutSubscriptions()
            {
                var original = new Room();
                var script = new LoungeThenSleepScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();
                original.TickAt(0.1);

                Room room = Resumed(Reload(original.Lounge, script));

                CheckEqual(0, room.Lounge.Door.SubscriptionCount);
                CheckEqual(0, room.Lounge.Door.Inverse.SubscriptionCount);
            }

            public void WaitReloadedAfterItWasPassed_IsLeftAloneWhenTheLoadedLatchChanges()
            {
                var original = new Room();
                var script = new LoungeThenSleepScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();
                original.TickAt(0.1);

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(0.2);
                room.Lounge.Door.Clear();
                room.Lounge.Door.Set();

                CheckEqual(1, room.Scheduler.SleepingCount);
            }
        }

        public class ListTests : TestFixture
        {
            public void WaitAllReloadedWithOneLatchSet_ResumesWhenTheLoadedOtherIsSet()
            {
                var original = new Room();
                var script = new LoungeBothScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();
                original.TickAt(0.1);

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(0.2);
                CheckEqual(new[] { "start" }, room.Log());
                room.Lounge.Alarm.Set();
                room.TickAt(0.3);

                CheckEqual(new[] { "start", "both" }, room.Log());
            }

            public void WaitAllReloadedWithOneLatchSet_WaitsAgainWhenTheLoadedOneIsClearedAndSetOnlyLater()
            {
                var original = new Room();
                var script = new LoungeBothScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.Lounge.Door.Set();

                Room room = Resumed(Reload(original.Lounge, script));
                room.Lounge.Door.Clear();
                room.Lounge.Alarm.Set();
                room.TickAt(0.1);
                CheckEqual(new[] { "start" }, room.Log());
                room.Lounge.Door.Set();
                room.TickAt(0.2);

                CheckEqual(new[] { "start", "both" }, room.Log());
            }

            public void WaitAnyReloadedMidWait_ResumesWhenEitherLoadedLatchIsSet()
            {
                var original = new Room();
                var script = new LoungeEitherScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.Lounge.Alarm.Set();
                room.TickAt(0.1);

                CheckEqual(new[] { "start", "alarm" }, room.Log());
            }

            public void WaitAnyReloaded_SubscribesTheArcToBothLoadedLatches()
            {
                var original = new Room();
                var script = new LoungeEitherScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));

                CheckEqual(1, room.Lounge.Door.SubscriptionCount);
                CheckEqual(1, room.Lounge.Alarm.SubscriptionCount);
            }
        }

        public class TimeoutTests : TestFixture
        {
            public void WaitReloadedMidWait_ResumesWhenTheLoadedLatchIsSetInTime()
            {
                var original = new Room();
                var script = new LoungeTimedScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.Lounge.Alarm.Set();
                room.TickAt(1);

                CheckEqual(new[] { "start", "alarm" }, room.Log());
            }

            public void WaitReloadedMidWait_StillTimesOutAtTheSavedDeadline()
            {
                var original = new Room();
                var script = new LoungeTimedScript();
                original.Scheduler.Add(script);
                original.TickAt(0);

                Room room = Resumed(Reload(original.Lounge, script));
                room.TickAt(1.9);
                CheckEqual(new[] { "start" }, room.Log());
                room.TickAt(2);

                CheckEqual(new[] { "start", "timed out" }, room.Log());
            }

            public void WaitReloadedAfterItTimedOut_IsSubscribedToNothing()
            {
                var original = new Room();
                var script = new LoungeTimedScript();
                original.Scheduler.Add(script);
                original.TickAt(0);
                original.TickAt(2);

                Room room = Resumed(Reload(original.Lounge, script));

                CheckEqual(0, room.Lounge.Alarm.SubscriptionCount);
            }
        }
    }
}