using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

using Sog;
namespace Operation
{
    public class Transition<T, V>
    {
        public T current;
        public V msg;
        public T next;
    };

    public delegate void ActionHandler(Object obj);
    //public delegate void ActionHandler(long, long);

    //T 状态类型
    //V 消息类型
    //使用方法 
    //构造函数传入 初始状态 状态迁移表 和 状态处理表
    //然后调用ChangeState
    public class FiniteStateMachine<T, V>
    {
        public Dictionary<T, ActionHandler> StateHandlerTable;
        public List<Transition<T, V>> TransMachine;
        public T State;

        public FiniteStateMachine(T initState, Dictionary<T, ActionHandler> handlerTable, List<Transition<T, V>> transMachine)
        {
            State = initState;
            StateHandlerTable = handlerTable;
            TransMachine = transMachine;
        }

        public void ChangeState(V m, Object obj)
        {
            ActionHandler actHandler = FindAction(m);
            if (actHandler == null)
            {
                TraceLog.Error("FiniteStateMachine.ChangeState error  not find action current = {0} message = {1}", State, m);
                return;
            }

            actHandler(obj);
        }

        private ActionHandler FindAction(V m)
        {
            Transition<T, V> trans = FindTransition(m);
            if (trans == null)
            {
                TraceLog.Error("FiniteStateMachine.FindAction error not find trans current = {0} message = {1}", State, m);
                return null;
            }

            State = trans.next;
            ActionHandler actHandler = null;
            StateHandlerTable.TryGetValue(State, out actHandler);

            if (actHandler == null)
            {
                TraceLog.Error("FiniteStateMachine.FindAction error not find handler state = {0} message={1}", State, m);
                return null;
            }

            return actHandler;
        }

        private Transition<T, V> FindTransition(V m)
        {
            Transition<T, V> ret = null;
            foreach (Transition<T, V> trans in TransMachine)
            {
                if (trans.current.Equals(State) && trans.msg.Equals(m))
                {
                    ret = trans;
                    break;
                }
            }

            return ret;
        }
    }
}