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

namespace BF
{
    public class BFEvent : BFEventBase
    {
        public BFEvent() : base(4) { }

        public BFEvent(int length = 4) : base(length) { }

        public static BFEvent operator +(BFEvent a, Action b)
        {
            a.AddListener(b);
            return a;
        }

        public static BFEvent operator -(BFEvent a, Action b)
        {
            a.RemoveListener(b);
            return a;
        }

        public void Invoke()
        {
            delegateLength = delegates.Count;
            for (int i = 0; i < delegateLength; i++)
            {
                var del = delegates[i] as Action;
                if (del != null)
                {
                    del();
                }
            }
        }
    }

    public class BFEvent<T> : BFEventBase
    {
        public BFEvent() : base(4) { }

        public BFEvent(int length = 4) : base(length) { }

        public static BFEvent<T> operator +(BFEvent<T> a, Action<T> b)
        {
            a.AddListener(b);
            return a;
        }

        public static BFEvent<T> operator -(BFEvent<T> a, Action<T> b)
        {
            a.RemoveListener(b);
            return a;
        }

        public void Invoke(T t)
        {
            delegateLength = delegates.Count;
            for (int i = 0; i < delegateLength; i++)
            {
                var del = delegates[i] as Action<T>;
                if (del != null)
                {
                    del(t);
                }
            }
        }
    }

    public class BFEvent<T1, T2> : BFEventBase
    {
        public BFEvent() : base(4) { }

        public BFEvent(int length = 4) : base(length) { }

        public static BFEvent<T1, T2> operator +(BFEvent<T1, T2> a, Action<T1, T2> b)
        {
            a.AddListener(b);
            return a;
        }

        public static BFEvent<T1, T2> operator -(BFEvent<T1, T2> a, Action<T1, T2> b)
        {
            a.RemoveListener(b);
            return a;
        }

        public void Invoke(T1 t1, T2 t2)
        {
            delegateLength = delegates.Count;
            for (int i = 0; i < delegateLength; i++)
            {
                var del = delegates[i] as Action<T1, T2>;
                if (del != null)
                {
                    del(t1, t2);
                }
            }
        }
    }

    public class BFEvent<T1, T2, T3> : BFEventBase
    {
        public BFEvent() : base(4) { }

        public BFEvent(int length = 4) : base(length) { }

        public static BFEvent<T1, T2, T3> operator +(BFEvent<T1, T2, T3> a, Action<T1, T2, T3> b)
        {
            a.AddListener(b);
            return a;
        }

        public static BFEvent<T1, T2, T3> operator -(BFEvent<T1, T2, T3> a, Action<T1, T2, T3> b)
        {
            a.RemoveListener(b);
            return a;
        }

        public void Invoke(T1 t1, T2 t2, T3 t3)
        {
            delegateLength = delegates.Count;
            for (int i = 0; i < delegateLength; i++)
            {
                var del = delegates[i] as Action<T1, T2, T3>;
                if (del != null)
                {
                    del(t1, t2, t3);
                }
            }
        }
    }

    public class BFEventBase
    {
        protected List<Delegate> delegates; //暂时用list。可以实现一个无GC得 LinkList 来代替
        private bool removed = false;
        protected int delegateLength;

        public int CallbackCount()
        {
            return delegates.Count;
        }

        public BFEventBase(int length)
        {
            delegates = new List<Delegate>(length);
        }

        public void AddListener(Delegate del)
        {
#if UNITY_EDITOR
            for (int i = 0; i < delegates.Count; i++)
            {
                if (delegates[i] == del)
                {
                    Debug.LogWarning("重复添加回调 :" + del.ToString());
                }
            }
#endif
            delegates.Add(del);
        }

        public void RemoveListener(Delegate del)
        {
            var length = delegates.Count;
            for (int i = 0; i < length; i++)
            {
                if (delegates[i] == del)
                {
                    removed = true;
                    delegates[i] = null;
                    BFMain.Instance.OneShotManager.AddOneShot(Execute);
                }
            }
        }

        public void Clear()
        {
            delegateLength = 0;
            delegates.Clear();
            removed = false;
        }

        private void Execute()
        {
            if (removed)
            {
                removed = false;
                var length = delegates.Count;
                for (int i = 0; i < length; i++)
                {
                    if (delegates[i] == null)
                    {
                        delegates.RemoveAt(i);
                        --i;
                        --length;
                    }
                }
            }

        }
    }
}