using System.Collections.Generic;
using System.Diagnostics.Tracing;

namespace WK
{

    /// <summary>
    /// 事件发生后检测条件的被动触发器
    /// </summary>
    public class GlobalPassiveTrigger
    {
        public class ConditionBase
        {
            public virtual bool Evaluate(params object[] args) { return false; }

            public static ConditionBase Always = new ConditionAlways();
            public static ConditionBase AlwaysNot = new ConditionAlwaysNot();
        }

        public class ConditionAlways : ConditionBase
        {
            public override bool Evaluate(params object[] args)
            {
                return true;
            }
        }

        public class ConditionAlwaysNot : ConditionBase
        {
            public override bool Evaluate(params object[] args)
            {
                return false;
            }
        }

        public class ConditionAnd : ConditionBase
        {
            private ConditionBase m_Left;
            private ConditionBase m_Right;
            public ConditionAnd(ConditionBase left, ConditionBase right)
            {
                m_Left = left;
                m_Right = right;
            }
            public override bool Evaluate(params object[] args)
            {
                return m_Left.Evaluate(args) && m_Right.Evaluate(args);
            }
        }

        public class ConditionOr : ConditionBase
        {
            private ConditionBase m_Left;
            private ConditionBase m_Right;
            public ConditionOr(ConditionBase left, ConditionBase right)
            {
                m_Left = left;
                m_Right = right;
            }
            public override bool Evaluate(params object[] args)
            {
                return m_Left.Evaluate(args) || m_Right.Evaluate(args);
            }
        }

        public delegate void Action(params object[] args);

        // 触发事件
        private string m_Event;
        // 触发条件
        private ConditionBase m_Condition;
        // 触发操作
        private List<Action> m_Actions = new List<Action>();

        public void SetEvent(string eventType)
        {
            if (m_Event != string.Empty || m_Event != null)
            {
                GlobalEventManager.Instance.UnRegister(m_Event, OnEvent);
            }
            m_Event = eventType;
            GlobalEventManager.Instance.Register(eventType, OnEvent);
        }

        public void AddAction(Action action)
        {
            m_Actions.Add(action);
        }

        public void SetCondition(ConditionBase condition)
        {
            m_Condition = condition;
        }

        public void OnEvent(params object[] args)
        {
            if (m_Condition == null)
                return;
            if (m_Condition.Evaluate())
            {
                foreach (Action action in m_Actions)
                {
                    action.Invoke(args);
                }
            }
        }

    }

}