using System;
using System.Linq;
using System.Collections.Generic;
using UnityEngine;
using NaughtyAttributes;

namespace UDE_HAND_INTERACTION
{
    public enum InteractorState
    {
        Normal,
        Hover,
        Select,
        Disabled
    };

    public enum InteractableState
    {
        Normal,
        Hover,
        Select,
        Disabled
    };

    public interface IActiveState
    {
        bool Active { get; }
    }

    public interface IGameObjectFilter
    {
        bool Filter(GameObject gameObject);
    }

    public struct InteractorStateChangeArgs
    {
        public InteractorState PreviousState { get; }
        public InteractorState NewState { get; }

        public InteractorStateChangeArgs(InteractorState previousState, InteractorState newState)
        {
            PreviousState = previousState;
            NewState = newState;
        }
    }


    public interface IInteractorView
    {
        int Identifier { get; }
        bool HasCandidate { get; }
        object CandidateProperties { get; }

        bool HasInteractable { get; }
        bool HasSelectedInteractable { get; }

        InteractorState State { get; }
        event Action<InteractorStateChangeArgs> WhenStateChanged;
        event Action WhenPreprocessed;
        event Action WhenProcessed;
        event Action WhenPostprocessed;
    }

    public interface IUpdateDriver
    {
        bool IsRootDriver { get; set; }
        void Drive();
    }

    public interface IInteractor : IInteractorView, IUpdateDriver
    {

        void Preprocess();
        void Process();
        void Postprocess();

        void ProcessCandidate();
        void Enable();
        void Disable();
        void Hover();
        void Unhover();
        void Select();
        void Unselect();

        bool ShouldHover { get; }
        bool ShouldUnhover { get; }
        bool ShouldSelect { get; }
        bool ShouldUnselect { get; }
    }

    public interface MAction<out T>
    {
        event Action<T> Action;
    }

    public class MultiAction<T> : MAction<T>
    {
        protected HashSet<Action<T>> actions = new HashSet<Action<T>>();

        public event Action<T> Action
        {
            add
            {
                actions.Add(value);
            }
            remove
            {
                actions.Remove(value);
            }
        }

        public void Invoke(T t)
        {
            foreach (Action<T> action in actions)
            {
                action(t);
            }
        }
    }
    public class UniqueIdentifier
    {
        public int ID { get; private set; }


        private UniqueIdentifier(int identifier)
        {
            ID = identifier;
        }

        private static System.Random Random = new();
        private static HashSet<int> _identifierSet = new();

        public static UniqueIdentifier Generate()
        {
            while (true)
            {
                int identifier = Random.Next(Int32.MaxValue);
                if (_identifierSet.Contains(identifier)) continue;
                _identifierSet.Add(identifier);
                return new UniqueIdentifier(identifier);
            }
        }

        public static void Release(UniqueIdentifier identifier)
        {
            _identifierSet.Remove(identifier.ID);
        }
    }

    public abstract class Interactor<interactor, interactable> : MonoBehaviour, IInteractor
                                    where interactor : Interactor<interactor, interactable>
                                    where interactable : Interactable<interactor, interactable>
    {
        private Func<interactable> _computeCandidateOverride;
        private bool _clearComputeCandidateOverrideOnSelect = false;
        private Func<bool> _computeShouldSelectOverride;
        private bool _clearComputeShouldSelectOverrideOnSelect = false;
        private Func<bool> _computeShouldUnselectOverride;
        private bool _clearComputeShouldUnselectOverrideOnUnselect;

        protected virtual void DoPreprocess() { }
        protected virtual void DoNormalUpdate() { }
        protected virtual void DoHoverUpdate() { }
        protected virtual void DoSelectUpdate() { }
        protected virtual void DoPostprocess() { }

        public virtual bool ShouldHover
        {
            get
            {
                if (State != InteractorState.Normal)
                {
                    return false;
                }

                return HasCandidate || ComputeShouldSelect();
            }
        }

        public virtual bool ShouldUnhover
        {
            get
            {
                if (State != InteractorState.Hover)
                {
                    return false;
                }

                return _interactable != _candidate || _candidate == null;
            }
        }

        public bool ShouldSelect
        {
            get
            {
                if (State != InteractorState.Hover)
                {
                    return false;
                }

                if (_computeShouldSelectOverride != null)
                {
                    return _computeShouldSelectOverride.Invoke();
                }

                return _candidate == _interactable && ComputeShouldSelect();
            }
        }

        public bool ShouldUnselect
        {
            get
            {
                if (State != InteractorState.Select)
                {
                    return false;
                }

                if (_computeShouldUnselectOverride != null)
                {
                    return _computeShouldUnselectOverride.Invoke();
                }

                return ComputeShouldUnselect();
            }
        }

        protected virtual bool ComputeShouldSelect()
        {
            return QueuedSelect;
        }

        protected virtual bool ComputeShouldUnselect()
        {
            return QueuedUnselect;
        }

        public interface ISelector
        {
            event Action WhenSelected;
            event Action WhenUnselected;
        }

        private InteractorState _state = InteractorState.Normal;
        public event Action<InteractorStateChangeArgs> WhenStateChanged = delegate { };
        public event Action WhenPreprocessed = delegate { };
        public event Action WhenProcessed = delegate { };
        public event Action WhenPostprocessed = delegate { };

        private ISelector _selector = null;

        [SerializeField, Label("Check Rate Per Frame")]
        private int _maxIterationsPerFrame = 3;
        public int MaxIterationsPerFrame
        {
            get
            {
                return _maxIterationsPerFrame;
            }
            set
            {
                _maxIterationsPerFrame = value;
            }
        }

        private Queue<bool> _selectorQueue = new();
        private bool QueuedSelect => _selectorQueue.Count > 0 && _selectorQueue.Peek();
        private bool QueuedUnselect => _selectorQueue.Count > 0 && !_selectorQueue.Peek();

        public InteractorState State
        {
            get
            {
                return _state;
            }
            private set
            {
                if (_state == value)
                {
                    return;
                }
                InteractorState previousState = _state;
                _state = value;

                WhenStateChanged(new InteractorStateChangeArgs(previousState, _state));

            }
        }

        protected interactable _candidate;
        protected interactable _interactable;
        protected interactable _selectedInteractable;

        public virtual object CandidateProperties
        {
            get
            {
                return null;
            }
        }

        public interactable Interactable => _interactable;
        public bool HasCandidate => _candidate != null;
        public bool HasInteractable => _interactable != null;
        public bool HasSelectedInteractable => _selectedInteractable != null;

        protected virtual void InteractableSelected(interactable interactable) { }


        private UniqueIdentifier _identifier;
        public int Identifier => _identifier.ID;

        protected bool _started;

        protected virtual void Awake()
        {
            _identifier = UniqueIdentifier.Generate();
        }

        protected virtual void Start()
        {
            this.BeginStart(ref _started);
            this.EndStart(ref _started);
        }

        protected virtual void OnEnable()
        {
            if (_started)
            {
                if (_selector != null)
                {
                    _selectorQueue.Clear();
                    _selector.WhenSelected += HandleSelected;
                    _selector.WhenUnselected += HandleUnselected;
                }
            }
        }

        protected virtual void OnDisable()
        {
            if (_started)
            {
                if (_selector != null)
                {
                    _selector.WhenSelected -= HandleSelected;
                    _selector.WhenUnselected -= HandleUnselected;
                }
                Disable();
            }
        }

        protected virtual void OnDestroy()
        {
            UniqueIdentifier.Release(_identifier);
        }

        public virtual void SetComputeCandidateOverride(Func<interactable> computeCandidate,
            bool shouldClearOverrideOnSelect = true)
        {
            _computeCandidateOverride = computeCandidate;
            _clearComputeCandidateOverrideOnSelect = shouldClearOverrideOnSelect;
        }

        public virtual void ClearComputeCandidateOverride()
        {
            _computeCandidateOverride = null;
            _clearComputeCandidateOverrideOnSelect = false;
        }

        public virtual void SetComputeShouldSelectOverride(Func<bool> computeShouldSelect,
            bool clearOverrideOnSelect = true)
        {
            _computeShouldSelectOverride = computeShouldSelect;
            _clearComputeShouldSelectOverrideOnSelect = clearOverrideOnSelect;
        }

        public virtual void ClearComputeShouldSelectOverride()
        {
            _computeShouldSelectOverride = null;
            _clearComputeShouldSelectOverrideOnSelect = false;
        }

        public virtual void SetComputeShouldUnselectOverride(Func<bool> computeShouldUnselect,
            bool clearOverrideOnUnselect = true)
        {
            _computeShouldUnselectOverride = computeShouldUnselect;
            _clearComputeShouldUnselectOverrideOnUnselect = clearOverrideOnUnselect;
        }

        public virtual void ClearComputeShouldUnselectOverride()
        {
            _computeShouldUnselectOverride = null;
            _clearComputeShouldUnselectOverrideOnUnselect = false;
        }

        public void Preprocess()
        {
            DoPreprocess();
            WhenPreprocessed();
        }

        public void Process()
        {
            switch (State)
            {
                case InteractorState.Normal:
                    DoNormalUpdate();
                    break;
                case InteractorState.Hover:
                    DoHoverUpdate();
                    break;
                case InteractorState.Select:
                    DoSelectUpdate();
                    break;
            }
            WhenProcessed();
        }

        public void Postprocess()
        {
            _selectorQueue.Clear();
            DoPostprocess();
            WhenPostprocessed();
        }

        public virtual void ProcessCandidate()
        {
            _candidate = null;

            if (_computeCandidateOverride != null)
            {
                _candidate = _computeCandidateOverride.Invoke();
            }
            else
            {
                _candidate = ComputeCandidate();
            }
        }

        public void InteractableChangesUpdate()
        {
            if (_selectedInteractable != null &&
                !_selectedInteractable.HasSelectingInteractor(this as interactor))
            {
                UnselectInteractable();
            }

            if (_interactable != null &&
                !_interactable.HasInteractor(this as interactor))
            {
                UnsetInteractable();
            }
        }

        public void Hover()
        {
            if (State != InteractorState.Normal)
            {
                return;
            }

            SetInteractable(_candidate);
            State = InteractorState.Hover;
        }

        public void Unhover()
        {
            if (State != InteractorState.Hover)
            {
                return;
            }

            UnsetInteractable();
            State = InteractorState.Normal;
        }


        public virtual void Select()
        {
            if (State != InteractorState.Hover)
            {
                return;
            }

            if (_clearComputeCandidateOverrideOnSelect)
            {
                ClearComputeCandidateOverride();
            }

            if (_clearComputeShouldSelectOverrideOnSelect)
            {
                ClearComputeShouldSelectOverride();
            }

            while (QueuedSelect)
            {
                _selectorQueue.Dequeue();
            }

            if (Interactable != null)
            {
                SelectInteractable(Interactable);
            }

            State = InteractorState.Select;
        }

        public virtual void Unselect()
        {
            if (State != InteractorState.Select)
            {
                return;
            }
            if (_clearComputeShouldUnselectOverrideOnUnselect)
            {
                ClearComputeShouldUnselectOverride();
            }
            while (QueuedUnselect)
            {
                _selectorQueue.Dequeue();
            }
            UnselectInteractable();

            State = InteractorState.Hover;
        }


        protected abstract interactable ComputeCandidate();

        private void SetInteractable(interactable interactable)
        {
            if (_interactable == interactable)
            {
                return;
            }
            UnsetInteractable();
            _interactable = interactable;
            interactable.AddInteractor(this as interactor);
        }

        private void UnsetInteractable()
        {
            interactable interactable = _interactable;
            if (interactable == null)
            {
                return;
            }
            _interactable = null;
            interactable.RemoveInteractor(this as interactor);
        }

        private void SelectInteractable(interactable interactable)
        {
            Unselect();
            _selectedInteractable = interactable;
            interactable.AddSelectingInteractor(this as interactor);
        }

        private void UnselectInteractable()
        {
            interactable interactable = _selectedInteractable;

            if (interactable == null)
            {
                return;
            }

            _selectedInteractable = null;
            interactable.RemoveSelectingInteractor(this as interactor);
        }

        public void Enable()
        {
            if (State == InteractorState.Disabled)
            {
                State = InteractorState.Normal;
                HandleEnabled();
            }
        }

        public void Disable()
        {
            if (State == InteractorState.Disabled)
            {
                return;
            }

            HandleDisabled();

            if (State == InteractorState.Select)
            {
                UnselectInteractable();
                State = InteractorState.Hover;
            }

            if (State == InteractorState.Hover)
            {
                UnsetInteractable();
                State = InteractorState.Normal;
            }

            if (State == InteractorState.Normal)
            {
                State = InteractorState.Disabled;
            }
        }

        protected virtual void HandleEnabled() { }
        protected virtual void HandleDisabled() { }

        protected virtual void HandleSelected()
        {
            _selectorQueue.Enqueue(true);
        }

        protected virtual void HandleUnselected()
        {
            _selectorQueue.Enqueue(false);
        }

        public bool IsRootDriver { get; set; } = true;

        protected virtual void Update()
        {
            if (!IsRootDriver)
            {
                return;
            }

            Drive();
        }

        public virtual void Drive()
        {
            Preprocess();
            Enable();

            InteractorState previousState = State;
            for (int i = 0; i < MaxIterationsPerFrame; i++)
            {
                if (State == InteractorState.Normal ||
                    (State == InteractorState.Hover && previousState != InteractorState.Normal))
                {
                    ProcessCandidate();
                }
                previousState = State;

                Process();

                if (State == InteractorState.Disabled)
                {
                    break;
                }

                if (State == InteractorState.Normal)
                {
                    if (ShouldHover)
                    {
                        Hover();
                        continue;
                    }
                    break;
                }

                if (State == InteractorState.Hover)
                {
                    if (ShouldSelect)
                    {
                        Select();
                        continue;
                    }
                    if (ShouldUnhover)
                    {
                        Unhover();
                        continue;
                    }
                    break;
                }

                if (State == InteractorState.Select)
                {
                    if (ShouldUnselect)
                    {
                        Unselect();
                        continue;
                    }
                    break;
                }
            }

            Postprocess();
        }

    }

    public struct InteractableStateChangeArgs
    {
        public InteractableState PreviousState { get; }
        public InteractableState NewState { get; }

        public InteractableStateChangeArgs(
            InteractableState previousState,
            InteractableState newState)
        {
            PreviousState = previousState;
            NewState = newState;
        }
    }

    public interface IInteractableView
    {
        InteractableState State { get; }
        event Action<InteractableStateChangeArgs> WhenStateChanged;

        int MaxInteractors { get; }
        int MaxSelectingInteractors { get; }

        IEnumerable<IInteractorView> InteractorViews { get; }
        IEnumerable<IInteractorView> SelectingInteractorViews { get; }

        event Action<IInteractorView> WhenInteractorViewAdded;
        event Action<IInteractorView> WhenInteractorViewRemoved;
        event Action<IInteractorView> WhenSelectingInteractorViewAdded;
        event Action<IInteractorView> WhenSelectingInteractorViewRemoved;
    }

    public interface IInteractable : IInteractableView
    {
        void Enable();
        void Disable();
        new int MaxInteractors { get; set; }
        new int MaxSelectingInteractors { get; set; }
        void RemoveInteractorByIdentifier(int id);
    }

    public class InteractableRegistry<interactor, interactable>
                                     where interactor : Interactor<interactor, interactable>
                                     where interactable : Interactable<interactor, interactable>
    {
        public struct InteractableSet
        {
            private readonly IReadOnlyList<interactable> _data;
            private readonly ISet<interactable> _onlyInclude;
            private readonly interactor _testAgainst;

            public InteractableSet( ISet<interactable> onlyInclude, interactor testAgainst)
            {
                _data = _interactables;
                _onlyInclude = onlyInclude;
                _testAgainst = testAgainst;
            }

            public Enumerator GetEnumerator()
            {
                return new Enumerator(this);
            }


            private bool Include(interactable interactable)
            {
                if (_onlyInclude != null && !_onlyInclude.Contains(interactable))
                {
                    return false;
                }

                if (_testAgainst != null && !interactable.CanBeSelectedBy(_testAgainst))
                {
                    return false;
                }

                return true;
            }

            public struct Enumerator
            {
                private readonly InteractableSet _set;
                private int _position;

                private IReadOnlyList<interactable> Data => _set._data;

                public Enumerator(in InteractableSet set)
                {
                    _set = set;
                    _position = -1;
                }

                public interactable Current
                {
                    get
                    {
                        if (Data == null || _position < 0)
                        {
                            throw new System.InvalidOperationException();
                        }
                        return Data[_position];
                    }
                }

                public bool MoveNext()
                {
                    if (Data == null)
                    {
                        return false;
                    }

                    do
                    {
                        _position++;
                    } while (_position < Data.Count &&
                        !_set.Include(Data[_position]));

                    return _position < Data.Count;
                }

            }
        }

        private static List<interactable> _interactables;

        public InteractableRegistry()
        {
            _interactables = new List<interactable>();
        }

        public virtual void Register(interactable interactable)
        {
            _interactables.Add(interactable);
        }

        public virtual void Unregister(interactable interactable)
        {
            _interactables.Remove(interactable);
        }

        public virtual InteractableSet List(interactor interactor)
        {
            return new InteractableSet(null, interactor);
        }

        public virtual InteractableSet List()
        {
            return new InteractableSet(null, null);
        }
    }
    public abstract class Interactable<interactor, interactable> : MonoBehaviour, IInteractable
                                        where interactor : Interactor<interactor, interactable>
                                        where interactable : Interactable<interactor, interactable>
    {

        private List<UnityEngine.Object> _interactorFilters = new();
        private List<IGameObjectFilter> InteractorFilters = null;
        private int _maxInteractors = -1;
        private int _maxSelectingInteractors = -1;
        private UnityEngine.Object _data = null;
        public object Data { get; protected set; } = null;
        protected bool _started = false;

        #region Properties
        public int MaxInteractors
        {
            get
            {
                return _maxInteractors;
            }
            set
            {
                _maxInteractors = value;
            }
        }

        public int MaxSelectingInteractors
        {
            get
            {
                return _maxSelectingInteractors;
            }
            set
            {
                _maxSelectingInteractors = value;
            }
        }
        #endregion


        public IEnumerable<IInteractorView> InteractorViews => _interactors.Cast<IInteractorView>();
        public IEnumerable<IInteractorView> SelectingInteractorViews => _selectingInteractors.Cast<IInteractorView>();

        private EnumerableHashSet<interactor> _interactors = new();
        private EnumerableHashSet<interactor> _selectingInteractors = new();

        private InteractableState _state = InteractableState.Disabled;
        public event Action<InteractableStateChangeArgs> WhenStateChanged = delegate { };

        public event Action<IInteractorView> WhenInteractorViewAdded = delegate { };
        public event Action<IInteractorView> WhenInteractorViewRemoved = delegate { };
        public event Action<IInteractorView> WhenSelectingInteractorViewAdded = delegate { };
        public event Action<IInteractorView> WhenSelectingInteractorViewRemoved = delegate { };

        private MultiAction<interactor> _whenInteractorAdded = new();
        private MultiAction<interactor> _whenInteractorRemoved = new();
        private MultiAction<interactor> _whenSelectingInteractorAdded = new();
        private MultiAction<interactor> _whenSelectingInteractorRemoved = new();
        public MAction<interactor> WhenInteractorAdded => _whenInteractorAdded;
        public MAction<interactor> WhenInteractorRemoved => _whenInteractorRemoved;

        public InteractableState State
        {
            get
            {
                return _state;
            }
            private set
            {
                if (_state == value) return;
                InteractableState previousState = _state;
                _state = value;
                WhenStateChanged(new InteractableStateChangeArgs(previousState, _state));
            }
        }

        private static InteractableRegistry<interactor, interactable> _registry = new();

        public static InteractableRegistry<interactor, interactable> Registry => _registry;

        protected virtual void InteractorAdded(interactor interactor)
        {
            WhenInteractorViewAdded(interactor);
            _whenInteractorAdded.Invoke(interactor);
        }
        protected virtual void InteractorRemoved(interactor interactor)
        {
            WhenInteractorViewRemoved(interactor);
            _whenInteractorRemoved.Invoke(interactor);
        }

        protected virtual void SelectingInteractorAdded(interactor interactor)
        {
            WhenSelectingInteractorViewAdded(interactor);
            _whenSelectingInteractorAdded.Invoke(interactor);
        }
        protected virtual void SelectingInteractorRemoved(interactor interactor)
        {
            WhenSelectingInteractorViewRemoved(interactor);
            _whenSelectingInteractorRemoved.Invoke(interactor);
        }

        public IEnumerableHashSet<interactor> Interactors => _interactors;


        public void AddInteractor(interactor interactor)
        {
            _interactors.Add(interactor);
            InteractorAdded(interactor);
            UpdateInteractableState();
        }

        public void RemoveInteractor(interactor interactor)
        {
            if (!_interactors.Remove(interactor))
            {
                return;
            }
            interactor.InteractableChangesUpdate();
            InteractorRemoved(interactor);
            UpdateInteractableState();
        }

        public void AddSelectingInteractor(interactor interactor)
        {
            _selectingInteractors.Add(interactor);
            SelectingInteractorAdded(interactor);
            UpdateInteractableState();
        }

        public void RemoveSelectingInteractor(interactor interactor)
        {
            if (!_selectingInteractors.Remove(interactor))
            {
                return;
            }
            interactor.InteractableChangesUpdate();
            SelectingInteractorRemoved(interactor);
            UpdateInteractableState();
        }

        private void UpdateInteractableState()
        {
            if (State == InteractableState.Disabled) return;

            if (_selectingInteractors.Count > 0)
            {
                State = InteractableState.Select;
            }
            else if (_interactors.Count > 0)
            {
                State = InteractableState.Hover;
            }
            else
            {
                State = InteractableState.Normal;
            }
        }

        public bool CanBeSelectedBy(interactor interactor)
        {
            if (State == InteractableState.Disabled)
            {
                return false;
            }

            if (MaxSelectingInteractors >= 0 &&
                _selectingInteractors.Count == MaxSelectingInteractors)
            {
                return false;
            }

            if (MaxInteractors >= 0 &&
                _interactors.Count == MaxInteractors &&
                !_interactors.Contains(interactor))
            {
                return false;
            }

            if (InteractorFilters == null)
            {
                return true;
            }

            foreach (IGameObjectFilter interactorFilter in InteractorFilters)
            {
                if (!interactorFilter.Filter(interactor.gameObject))
                {
                    return false;
                }
            }

            return true;
        }

        public bool HasInteractor(interactor interactor)
        {
            return _interactors.Contains(interactor);
        }

        public bool HasSelectingInteractor(interactor interactor)
        {
            return _selectingInteractors.Contains(interactor);
        }

        public void Enable()
        {
            if (State != InteractableState.Disabled)
            {
                return;
            }

            if (_started)
            {
                _registry.Register((interactable)this);
                State = InteractableState.Normal;
            }

        }

        public void Disable()
        {
            if (State == InteractableState.Disabled)
            {
                return;
            }

            if (_started)
            {
                List<interactor> selectingInteractorsCopy = new List<interactor>(_selectingInteractors);
                foreach (interactor selectingInteractor in selectingInteractorsCopy)
                {
                    RemoveSelectingInteractor(selectingInteractor);
                }

                List<interactor> interactorsCopy = new List<interactor>(_interactors);
                foreach (interactor interactor in interactorsCopy)
                {
                    RemoveInteractor(interactor);
                }

                _registry.Unregister((interactable)this);
                State = InteractableState.Disabled;
            }
        }

        public void RemoveInteractorByIdentifier(int id)
        {
            interactor foundInteractor = null;
            foreach (interactor selectingInteractor in _selectingInteractors)
            {
                if (selectingInteractor.Identifier == id)
                {
                    foundInteractor = selectingInteractor;
                    break;
                }
            }

            if (foundInteractor != null)
            {
                RemoveSelectingInteractor(foundInteractor);
            }

            foundInteractor = null;

            foreach (interactor interactor in _interactors)
            {
                if (interactor.Identifier == id)
                {
                    foundInteractor = interactor;
                    break;
                }
            }

            if (foundInteractor == null)
            {
                return;
            }

            RemoveInteractor(foundInteractor);
        }

        protected virtual void Awake()
        {
            InteractorFilters = _interactorFilters.ConvertAll(mono => mono as IGameObjectFilter);
        }

        protected virtual void Start()
        {
            this.BeginStart(ref _started);

            if (Data == null)
            {
                _data = this;
                Data = _data;
            }
            this.EndStart(ref _started);
        }

        protected virtual void OnEnable()
        {
            Enable();
        }

        protected virtual void OnDisable()
        {
            Disable();
        }

    }

    public interface IEnumerableHashSet<T> : IEnumerable<T>
    {
        new HashSet<T>.Enumerator GetEnumerator();
    }

    public class EnumerableHashSet<T> : HashSet<T>, IEnumerableHashSet<T>
    {
        public EnumerableHashSet() : base() { }
        public EnumerableHashSet(IEnumerable<T> values) : base(values) { }
    }

    public static class MonoBehaviourStartExtensions
    {
        public static void BeginStart(this MonoBehaviour monoBehaviour, ref bool started, Action baseStart = null)
        {
            if (!started)
            {
                monoBehaviour.enabled = false;
                started = true;
                baseStart?.Invoke();
                started = false;
            }
            else
            {
                baseStart?.Invoke();
            }
        }

        public static void EndStart(this MonoBehaviour monoBehaviour, ref bool started)
        {
            if (!started)
            {
                started = true;
                monoBehaviour.enabled = true;
            }
        }
    }

    [Serializable]
    public class ProgressCurve
    {
        [SerializeField]
        private AnimationCurve _animationCurve;

        [SerializeField]
        private float _animationLength;

        private Func<float> _timeProvider = () => Time.time;

        private float _animationStartTime;

        public ProgressCurve()
        {
            _animationCurve = AnimationCurve.EaseInOut(0f, 0f, 1f, 1f);
            _animationLength = 1.0f;
        }

        public ProgressCurve(AnimationCurve animationCurve, float animationLength)
        {
            _animationCurve = animationCurve;
            _animationLength = animationLength;
        }

        public void Copy(ProgressCurve other)
        {
            _animationCurve = other._animationCurve;
            _animationLength = other._animationLength;
            _animationStartTime = other._animationStartTime;
            _timeProvider = other._timeProvider;
        }

        public void Start()
        {
            _animationStartTime = _timeProvider();
        }

        public float Progress()
        {
            if (_animationLength <= 0f)
            {
                return _animationCurve.Evaluate(1.0f);
            }

            float normalizedTimeProgress = Mathf.Clamp01(ProgressTime() / _animationLength);
            return _animationCurve.Evaluate(normalizedTimeProgress);
        }

        public float ProgressTime()
        {
            return Mathf.Clamp(_timeProvider() - _animationStartTime, 0f, _animationLength);
        }
    }

    [AttributeUsage(AttributeTargets.Field, AllowMultiple = false)]
    public class InterfaceAttribute : PropertyAttribute
    {
        public Type[] Types = null;
        public string TypeFromFieldName;

        public InterfaceAttribute(Type type, params Type[] types)
        {
            Debug.Assert(type.IsInterface, $"{type.Name} needs to be an interface.");

            Types = new Type[types.Length + 1];
            Types[0] = type;
            for (int i = 0; i < types.Length; i++)
            {
                Debug.Assert(types[i].IsInterface, $"{types[i].Name} needs to be an interface.");
                Types[i + 1] = types[i];
            }
        }

    }
}