using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using Unity.IL2CPP.CompilerServices;
using UnityEngine;

namespace AlicizaX
{
    public delegate void TimerHandler(params object[] args);
    public delegate void TimerHandlerNoArgs();

    [Il2CppSetOption(Option.NullChecks, false)]
    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
    [StructLayout(LayoutKind.Sequential, Pack = 4)]
    internal struct TimerInfo : IMemory
    {
        public int TimerId;
        public float TriggerTime;
        public float Interval;

        public TimerHandler Handler;
        public TimerHandlerNoArgs HandlerNoArgs;
        public Delegate HandlerGeneric;

        public bool IsLoop;
        public bool IsRunning;
        public bool IsUnscaled;
        public bool IsActive;
        public byte HandlerType;

        public object[] Args;
        public object GenericArg;


        public int Level;
        public int SlotIndex;
        public int NextTimerIndex;
        public int PrevTimerIndex;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void Clear()
        {
            Handler = null;
            HandlerNoArgs = null;
            HandlerGeneric = null;
            Args = null;
            GenericArg = null;
            IsActive = false;
            Level = -1;
            SlotIndex = -1;
            NextTimerIndex = -1;
            PrevTimerIndex = -1;
        }
    }

    [UnityEngine.Scripting.Preserve]
    [Il2CppSetOption(Option.NullChecks, false)]
    [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
    internal sealed class TimerModule : ITimerModule
    {
        private int _curTimerId;
        private HierarchicalTimeWheel _scaledTimeWheel;
        private HierarchicalTimeWheel _unscaledTimeWheel;

        private TimerInfo[] _timerPool;
        private int[] _timerIdToPoolIndex;
        private int _timerPoolCapacity;
        private int[] _freeIndices;
        private int _freeCount;

        private int[] _pendingRemoveTimers;
        private int _pendingRemoveCount;

        private class HierarchicalTimeWheel
        {
            private const int SLOT_COUNT_LEVEL0 = 256;
            private const int SLOT_COUNT_LEVEL1 = 64;
            private const int SLOT_COUNT_LEVEL2 = 64;

            private readonly float _slotInterval;
            private readonly TimeWheelLevel[] _levels;
            private float _currentTime;

            private class TimeWheelLevel
            {
                public readonly int[] SlotHeads;
                public readonly int SlotCount;
                public int CurrentSlot;

                public TimeWheelLevel(int slotCount)
                {
                    SlotCount = slotCount;
                    SlotHeads = new int[slotCount];
                    for (int i = 0; i < slotCount; i++)
                        SlotHeads[i] = -1;
                }
            }

            public HierarchicalTimeWheel(float slotInterval)
            {
                _slotInterval = slotInterval;
                _levels = new TimeWheelLevel[3];
                _levels[0] = new TimeWheelLevel(SLOT_COUNT_LEVEL0);
                _levels[1] = new TimeWheelLevel(SLOT_COUNT_LEVEL1);
                _levels[2] = new TimeWheelLevel(SLOT_COUNT_LEVEL2);
            }

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public void AddTimer(int poolIndex, TimerInfo[] pool, float currentTime)
            {
                ref TimerInfo timer = ref pool[poolIndex];
                if (!timer.IsActive) return;

                float delta = timer.TriggerTime - currentTime;
                if (delta < 0) delta = 0;

                int totalSlots = Mathf.FloorToInt(delta / _slotInterval);
                int level = 0;
                int slotIndex = 0;

                if (totalSlots < SLOT_COUNT_LEVEL0)
                {
                    level = 0;
                    slotIndex = (_levels[0].CurrentSlot + totalSlots) % SLOT_COUNT_LEVEL0;
                }
                else if (totalSlots < SLOT_COUNT_LEVEL0 * SLOT_COUNT_LEVEL1)
                {
                    level = 1;
                    int level1Slots = totalSlots / SLOT_COUNT_LEVEL0;
                    slotIndex = (_levels[1].CurrentSlot + level1Slots) % SLOT_COUNT_LEVEL1;
                }
                else
                {
                    level = 2;
                    int level2Slots = totalSlots / (SLOT_COUNT_LEVEL0 * SLOT_COUNT_LEVEL1);
                    slotIndex = (_levels[2].CurrentSlot + level2Slots) % SLOT_COUNT_LEVEL2;
                }

                timer.Level = level;
                timer.SlotIndex = slotIndex;
                timer.NextTimerIndex = _levels[level].SlotHeads[slotIndex];
                timer.PrevTimerIndex = -1;

                if (_levels[level].SlotHeads[slotIndex] != -1)
                {
                    pool[_levels[level].SlotHeads[slotIndex]].PrevTimerIndex = poolIndex;
                }

                _levels[level].SlotHeads[slotIndex] = poolIndex;
                timer.IsRunning = true;
            }

            public void Advance(float currentTime, TimerInfo[] pool, Action<int> processTimer)
            {
                float timeDelta = currentTime - _currentTime;
                if (timeDelta <= 0) return;

                int steps = Mathf.FloorToInt(timeDelta / _slotInterval);

                for (int step = 0; step < steps; step++)
                {
                    _currentTime += _slotInterval;
                    ProcessLevel(0, pool, processTimer);

                    if ((_levels[0].CurrentSlot % SLOT_COUNT_LEVEL0) == 0)
                    {
                        ProcessLevel(1, pool, processTimer);
                    }

                    if ((_levels[0].CurrentSlot % (SLOT_COUNT_LEVEL0 * SLOT_COUNT_LEVEL1)) == 0)
                    {
                        ProcessLevel(2, pool, processTimer);
                    }
                }
            }

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            private void ProcessLevel(int level, TimerInfo[] pool, Action<int> processTimer)
            {
                TimeWheelLevel wheelLevel = _levels[level];
                wheelLevel.CurrentSlot = (wheelLevel.CurrentSlot + 1) % wheelLevel.SlotCount;

                int currentHead = wheelLevel.SlotHeads[wheelLevel.CurrentSlot];
                wheelLevel.SlotHeads[wheelLevel.CurrentSlot] = -1;

                int currentIndex = currentHead;
                while (currentIndex != -1)
                {
                    ref TimerInfo timer = ref pool[currentIndex];
                    int nextIndex = timer.NextTimerIndex;

                    timer.NextTimerIndex = -1;
                    timer.PrevTimerIndex = -1;
                    timer.Level = -1;

                    if (timer.IsActive && timer.IsRunning)
                    {
                        if (level == 0)
                        {
                            processTimer(currentIndex);
                        }
                        else
                        {
                            AddTimer(currentIndex, pool, _currentTime);
                        }
                    }

                    currentIndex = nextIndex;
                }
            }

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public void RemoveTimer(int poolIndex, TimerInfo[] pool)
            {
                if (poolIndex < 0 || poolIndex >= pool.Length)
                    return;

                ref TimerInfo timer = ref pool[poolIndex];

                if (timer.Level < 0 || timer.Level >= _levels.Length)
                    return;

                int level = timer.Level;
                int slotIndex = timer.SlotIndex;

                if (slotIndex < 0 || slotIndex >= _levels[level].SlotCount)
                    return;

                if (timer.PrevTimerIndex != -1)
                {
                    if (timer.PrevTimerIndex < pool.Length)
                    {
                        pool[timer.PrevTimerIndex].NextTimerIndex = timer.NextTimerIndex;
                    }
                }
                else
                {
                    _levels[level].SlotHeads[slotIndex] = timer.NextTimerIndex;
                }

                if (timer.NextTimerIndex != -1)
                {
                    if (timer.NextTimerIndex < pool.Length)
                    {
                        pool[timer.NextTimerIndex].PrevTimerIndex = timer.PrevTimerIndex;
                    }
                }

                timer.Level = -1;
                timer.SlotIndex = -1;
                timer.NextTimerIndex = -1;
                timer.PrevTimerIndex = -1;
            }
        }

        public TimerModule()
        {
            _timerPoolCapacity = 64;
            _timerPool = new TimerInfo[_timerPoolCapacity];
            _timerIdToPoolIndex = new int[1024];
            _freeIndices = new int[_timerPoolCapacity];
            _freeCount = _timerPoolCapacity;
            _pendingRemoveTimers = new int[64];
            _pendingRemoveCount = 0;

            for (int i = 0; i < _timerPoolCapacity; i++)
            {
                _freeIndices[i] = i;
                _timerPool[i].NextTimerIndex = -1;
                _timerPool[i].PrevTimerIndex = -1;
                _timerPool[i].Level = -1;
                _timerPool[i].SlotIndex = -1;
            }

            _scaledTimeWheel = new HierarchicalTimeWheel(0.001f);
            _unscaledTimeWheel = new HierarchicalTimeWheel(0.001f);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public int AddTimer(TimerHandlerNoArgs callback, float time, bool isLoop = false, bool isUnscaled = false)
        {
            int poolIndex = AcquireTimerFromPool();
            ref TimerInfo timer = ref _timerPool[poolIndex];

            timer.TimerId = ++_curTimerId;
            timer.TriggerTime = (isUnscaled ? Time.unscaledTime : Time.time) + time;
            timer.Interval = isLoop ? time : 0f;
            timer.HandlerNoArgs = callback;
            timer.HandlerType = 1;
            timer.IsLoop = isLoop;
            timer.IsRunning = true;
            timer.IsUnscaled = isUnscaled;
            timer.IsActive = true;
            timer.Args = null;
            timer.GenericArg = null;

            RegisterTimer(timer.TimerId, poolIndex);

            HierarchicalTimeWheel targetWheel = isUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
            targetWheel.AddTimer(poolIndex, _timerPool, isUnscaled ? Time.unscaledTime : Time.time);

            return timer.TimerId;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public int AddTimer<T>(Action<T> callback, T arg, float time, bool isLoop = false, bool isUnscaled = false)
        {
            int poolIndex = AcquireTimerFromPool();
            ref TimerInfo timer = ref _timerPool[poolIndex];

            timer.TimerId = ++_curTimerId;
            timer.TriggerTime = (isUnscaled ? Time.unscaledTime : Time.time) + time;
            timer.Interval = isLoop ? time : 0f;
            timer.HandlerGeneric = callback;
            timer.GenericArg = arg;
            timer.HandlerType = 2;
            timer.IsLoop = isLoop;
            timer.IsRunning = true;
            timer.IsUnscaled = isUnscaled;
            timer.IsActive = true;
            timer.Args = null;

            RegisterTimer(timer.TimerId, poolIndex);

            HierarchicalTimeWheel targetWheel = isUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
            targetWheel.AddTimer(poolIndex, _timerPool, isUnscaled ? Time.unscaledTime : Time.time);

            return timer.TimerId;
        }

        public int AddTimer(TimerHandler callback, float time, bool isLoop = false, bool isUnscaled = false, params object[] args)
        {
            int poolIndex = AcquireTimerFromPool();
            ref TimerInfo timer = ref _timerPool[poolIndex];

            timer.TimerId = ++_curTimerId;
            timer.TriggerTime = (isUnscaled ? Time.unscaledTime : Time.time) + time;
            timer.Interval = isLoop ? time : 0f;
            timer.Handler = callback;
            timer.HandlerType = 0;
            timer.IsLoop = isLoop;
            timer.IsRunning = true;
            timer.IsUnscaled = isUnscaled;
            timer.IsActive = true;
            timer.Args = args;
            timer.GenericArg = null;

            RegisterTimer(timer.TimerId, poolIndex);

            HierarchicalTimeWheel targetWheel = isUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
            targetWheel.AddTimer(poolIndex, _timerPool, isUnscaled ? Time.unscaledTime : Time.time);

            return timer.TimerId;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private int AcquireTimerFromPool()
        {
            if (_freeCount > 0)
            {
                return _freeIndices[--_freeCount];
            }

            int oldCapacity = _timerPoolCapacity;
            _timerPoolCapacity *= 2;
            Array.Resize(ref _timerPool, _timerPoolCapacity);
            Array.Resize(ref _freeIndices, _timerPoolCapacity);

            for (int i = _timerPoolCapacity - 1; i >= oldCapacity; i--)
            {
                _freeIndices[_freeCount++] = i;
                _timerPool[i].NextTimerIndex = -1;
                _timerPool[i].PrevTimerIndex = -1;
                _timerPool[i].Level = -1;
                _timerPool[i].SlotIndex = -1;
            }

            return _freeIndices[--_freeCount];
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void RegisterTimer(int timerId, int poolIndex)
        {
            if (timerId >= _timerIdToPoolIndex.Length)
            {
                Array.Resize(ref _timerIdToPoolIndex, _timerIdToPoolIndex.Length * 2);
            }

            _timerIdToPoolIndex[timerId] = poolIndex;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private int GetPoolIndex(int timerId)
        {
            return timerId > 0 && timerId < _timerIdToPoolIndex.Length ? _timerIdToPoolIndex[timerId] : -1;
        }

        public void Stop(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            if (poolIndex >= 0 && poolIndex < _timerPool.Length && _timerPool[poolIndex].IsActive)
                _timerPool[poolIndex].IsRunning = false;
        }

        public void Resume(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            if (poolIndex >= 0 && poolIndex < _timerPool.Length && _timerPool[poolIndex].IsActive)
                _timerPool[poolIndex].IsRunning = true;
        }

        public bool IsRunning(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            return poolIndex >= 0 && poolIndex < _timerPool.Length &&
                   _timerPool[poolIndex].IsActive && _timerPool[poolIndex].IsRunning;
        }

        public float GetLeftTime(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            if (poolIndex < 0 || poolIndex >= _timerPool.Length || !_timerPool[poolIndex].IsActive)
                return 0;

            ref TimerInfo timer = ref _timerPool[poolIndex];
            return Mathf.Max(timer.TriggerTime - (timer.IsUnscaled ? Time.unscaledTime : Time.time), 0);
        }

        public void Restart(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            if (poolIndex < 0 || poolIndex >= _timerPool.Length || !_timerPool[poolIndex].IsActive)
                return;

            ref TimerInfo timer = ref _timerPool[poolIndex];

            HierarchicalTimeWheel targetWheel = timer.IsUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
            targetWheel.RemoveTimer(poolIndex, _timerPool);

            timer.TriggerTime = (timer.IsUnscaled ? Time.unscaledTime : Time.time) + timer.Interval;
            targetWheel.AddTimer(poolIndex, _timerPool, timer.IsUnscaled ? Time.unscaledTime : Time.time);
        }

        public void RemoveTimer(int timerId)
        {
            int poolIndex = GetPoolIndex(timerId);
            if (poolIndex < 0 || poolIndex >= _timerPool.Length || !_timerPool[poolIndex].IsActive)
                return;

            ref TimerInfo timer = ref _timerPool[poolIndex];
            timer.IsActive = false;

            if (timer.Level >= 0)
            {
                HierarchicalTimeWheel targetWheel = timer.IsUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
                targetWheel.RemoveTimer(poolIndex, _timerPool);
            }

            ReleaseTimerToPool(poolIndex);
        }

        public void RemoveAllTimer()
        {
            for (int i = 0; i < _timerPoolCapacity; i++)
            {
                if (_timerPool[i].IsActive)
                {
                    _timerPool[i].Clear();
                    _freeIndices[_freeCount++] = i;
                }
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void ReleaseTimerToPool(int poolIndex)
        {
            if (poolIndex >= 0 && poolIndex < _timerPool.Length)
            {
                _timerPool[poolIndex].Clear();

                if (_freeCount >= _freeIndices.Length)
                {
                    Array.Resize(ref _freeIndices, _freeIndices.Length * 2);
                }

                _freeIndices[_freeCount++] = poolIndex;
            }
        }

        void IModuleUpdate.Update(float elapseSeconds, float realElapseSeconds)
        {
            _scaledTimeWheel.Advance(Time.time, _timerPool, ProcessTimer);
            _unscaledTimeWheel.Advance(Time.unscaledTime, _timerPool, ProcessTimer);

            ProcessPendingRemovals();
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void ProcessTimer(int poolIndex)
        {
            if (poolIndex < 0 || poolIndex >= _timerPool.Length)
                return;

            ref TimerInfo timer = ref _timerPool[poolIndex];
            if (!timer.IsActive || !timer.IsRunning)
                return;

            try
            {
                switch (timer.HandlerType)
                {
                    case 0: // TimerHandler
                        timer.Handler?.Invoke(timer.Args);
                        break;
                    case 1: // NoArgs
                        timer.HandlerNoArgs?.Invoke();
                        break;
                    case 2: // Generic
                        ((dynamic)timer.HandlerGeneric)?.Invoke((dynamic)timer.GenericArg);
                        break;
                }
            }
            catch (Exception e)
            {
                Log.Error($"Timer callback error: {e}");
            }

            if (!timer.IsActive)
                return;

            if (timer.IsLoop)
            {
                timer.TriggerTime += timer.Interval;
                HierarchicalTimeWheel targetWheel = timer.IsUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
                targetWheel.AddTimer(poolIndex, _timerPool, timer.IsUnscaled ? Time.unscaledTime : Time.time);
            }
            else
            {
                AddPendingRemoval(timer.TimerId);
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void AddPendingRemoval(int timerId)
        {
            if (_pendingRemoveCount >= _pendingRemoveTimers.Length)
            {
                Array.Resize(ref _pendingRemoveTimers, _pendingRemoveTimers.Length * 2);
            }
            _pendingRemoveTimers[_pendingRemoveCount++] = timerId;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void ProcessPendingRemovals()
        {
            for (int i = 0; i < _pendingRemoveCount; i++)
            {
                RemoveTimer(_pendingRemoveTimers[i]);
            }
            _pendingRemoveCount = 0;
        }

        void IModule.Dispose() => RemoveAllTimer();

        public int Priority => 0;
    }
}