using System;
using System.Collections.Generic;
using AlicizaX;
using UnityEngine;

namespace AlicizaX.Timer.Runtime
{
    public delegate void TimerHandler(params object[] args);

    [Serializable]
    public class Timer : IMemory
    {
        public int TimerId;
        public float TriggerTime;
        public float Interval;
        public TimerHandler Handler;
        public bool IsLoop;
        public bool IsRunning;
        public bool IsUnscaled;
        public bool IsActive; // 标记定时器是否有效
        public object[] Args;
        public LinkedListNode<Timer> Node; // 用于时间轮中的链表节点

        public void Clear()
        {
            Handler = null;
            Args = null;
            Node = null;
            IsActive = false;
        }
    }

    [UnityEngine.Scripting.Preserve]
    internal sealed class TimerModule : ITimerModule
    {
        private int _curTimerId;
        private TimeWheel _scaledTimeWheel;
        private TimeWheel _unscaledTimeWheel;
        private readonly Dictionary<int, Timer> _activeTimers = new Dictionary<int, Timer>();
        private readonly Action<Timer> _processTimerDelegate;
        private class TimeWheel
        {
            private readonly float _slotInterval; // 每个槽的时间间隔（秒）
            private readonly int _slotCount; // 槽的数量
            private readonly LinkedList<Timer>[] _slots;
            private float _currentTime;
            private int _currentSlotIndex;

            public TimeWheel(float slotInterval, int slotCount)
            {
                _slotInterval = slotInterval;
                _slotCount = slotCount;
                _slots = new LinkedList<Timer>[slotCount];
                for (int i = 0; i < slotCount; i++)
                    _slots[i] = new LinkedList<Timer>();
                _currentTime = 0f;
                _currentSlotIndex = 0;
            }

            public void AddTimer(Timer timer, float currentTime)
            {
                if (!timer.IsActive) return;

                float triggerTime = timer.TriggerTime;
                float delta = triggerTime - currentTime;

                if (delta < 0)
                {
                    // 立即触发
                    delta = 0;
                }

                int slotsToAdvance = Mathf.FloorToInt(delta / _slotInterval);
                int targetSlot = (_currentSlotIndex + slotsToAdvance) % _slotCount;

                timer.Node = _slots[targetSlot].AddLast(timer);
                timer.IsRunning = true;
            }

            public void Advance(float currentTime, Action<Timer> processTimer)
            {
                float timeDelta = currentTime - _currentTime;
                if (timeDelta <= 0) return;

                int steps = Mathf.FloorToInt(timeDelta / _slotInterval);
                for (int i = 0; i < steps; i++)
                {
                    _currentSlotIndex = (_currentSlotIndex + 1) % _slotCount;
                    _currentTime += _slotInterval;

                    LinkedList<Timer> currentSlot = _slots[_currentSlotIndex];
                    LinkedListNode<Timer> currentNode = currentSlot.First;
                    while (currentNode != null)
                    {
                        LinkedListNode<Timer> nextNode = currentNode.Next;
                        Timer timer = currentNode.Value;
                        currentSlot.Remove(currentNode);

                        if (timer.IsActive && timer.IsRunning)
                        {
                            processTimer(timer);
                        }

                        currentNode = nextNode;
                    }
                }
            }
        }

        public TimerModule()
        {
            _scaledTimeWheel = new TimeWheel(1f, 60);
            _unscaledTimeWheel = new TimeWheel(1f, 60);
            _processTimerDelegate = ProcessTimer; // 初始化时创建委托一次
        }


        public int AddTimer(TimerHandler callback, float time, bool isLoop = false,
            bool isUnscaled = false, params object[] args)
        {
            Timer timer = GetTimerFromPool();
            timer.TimerId = ++_curTimerId;
            timer.TriggerTime = (isUnscaled ? Time.unscaledTime : Time.time) + time;
            timer.Interval = isLoop ? time : 0f;
            timer.Handler = callback;
            timer.IsLoop = isLoop;
            timer.IsRunning = true;
            timer.IsUnscaled = isUnscaled;
            timer.Args = args;
            timer.IsActive = true;

            _activeTimers.Add(timer.TimerId, timer);
            TimeWheel targetWheel = isUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
            targetWheel.AddTimer(timer, isUnscaled ? Time.unscaledTime : Time.time);
            return timer.TimerId;
        }

        public void Stop(int timerId)
        {
            if (_activeTimers.TryGetValue(timerId, out Timer timer))
                timer.IsRunning = false;
        }

        public void Resume(int timerId)
        {
            if (_activeTimers.TryGetValue(timerId, out Timer timer))
                timer.IsRunning = true;
        }

        public bool IsRunning(int timerId) =>
            _activeTimers.TryGetValue(timerId, out Timer timer) && timer.IsRunning;

        public float GetLeftTime(int timerId) =>
            _activeTimers.TryGetValue(timerId, out Timer timer)
                ? Mathf.Max(timer.TriggerTime - (timer.IsUnscaled ? Time.unscaledTime : Time.time), 0)
                : 0;

        public void Restart(int timerId)
        {
            if (_activeTimers.TryGetValue(timerId, out Timer timer))
            {
                timer.TriggerTime = (timer.IsUnscaled ? Time.unscaledTime : Time.time) + timer.Interval;
                TimeWheel targetWheel = timer.IsUnscaled ? _unscaledTimeWheel : _scaledTimeWheel;
                targetWheel.AddTimer(timer, timer.IsUnscaled ? Time.unscaledTime : Time.time);
            }
        }

        public void RemoveTimer(int timerId)
        {
            if (_activeTimers.TryGetValue(timerId, out Timer timer))
            {
                timer.IsActive = false; // 标记为无效
                _activeTimers.Remove(timerId);
                ReturnTimerToPool(timer);
            }
        }

        public void RemoveAllTimer()
        {
            foreach (var timer in _activeTimers.Values)
            {
                timer.IsActive = false;
                ReturnTimerToPool(timer);
            }

            _activeTimers.Clear();
        }

        private Timer GetTimerFromPool() => MemoryPool.Acquire<Timer>();


        private void ReturnTimerToPool(Timer timer)
        {
            MemoryPool.Release(timer);
        }

        void IModuleUpdate.Update(float elapseSeconds, float realElapseSeconds)
        {
            float scaledTime = Time.time;
            _scaledTimeWheel.Advance(scaledTime, _processTimerDelegate);

            float unscaledTime = Time.unscaledTime;
            _unscaledTimeWheel.Advance(unscaledTime, _processTimerDelegate);
        }

        private void ProcessTimer(Timer timer)
        {
            if (!timer.IsActive || !timer.IsRunning) return;

            try
            {
                timer.Handler?.Invoke(timer.Args);
            }
            catch (Exception e)
            {
                Log.Error($"Timer callback error: {e}");
            }

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

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

        public int Priority => 0;
    }
}