/* author: YKMoon
 * 状态机
 * 初始化需要手动添加状态信息 AddState
 * Update里面来调用状态机运行StateMachineUpdate
 */
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace YKMoon
{
    public enum FSMUpdateMode
    {
        Normal,
        Unscaled,
    }

    public class UFSMState
    {
        public Action<float> onUpdate;
        public Action onEnterState;
        public Action onExitState;

        public int stateID = -1;

        public UFSMState() { }

        public UFSMState(int stateID, Action onEnterState, Action<float> onUpdate, Action onExitState)
        {
            this.stateID = stateID;
            this.onEnterState = onEnterState;
            this.onExitState = onExitState;
            this.onUpdate = onUpdate;
        }
    }
    public class UFSMCore
    {
        public UFSMState currentState = new UFSMState();
        public int lastState;
        /// <summary>
        /// 进入当前状态的时间点Time.time
        /// </summary>
        protected float timeEnteredState = 0;
        private Dictionary<int, UFSMState> stateDict = new Dictionary<int, UFSMState>();

        public int currentStateID {
            get {
                return currentState.stateID;
            }
            set {
                //UnityEngine.Debug.LogErrorFormat("当前状态 {0} 输入状态 {1}  == {2}", currentState.stateID, value, currentState.stateID == value);
                if (currentState.stateID == value)
                    return;
                if (!stateDict.ContainsKey(value)) {
#if UNITY_EDITOR
                    Debug.LogErrorFormat("StateMachine Does not contain ({0}) state!", value);
#endif
                    return;
                }
                lastState = currentState.stateID;
                timeEnteredState = Time.time;
                if (currentState.onExitState != null) {
                    currentState.onExitState.Invoke();
                }
                currentState = stateDict[value];
                if (currentState.onEnterState != null) {
                    currentState.onEnterState.Invoke();
                }

            }
        }

        public UFSMCore() : this(null, null) { }
        public UFSMCore(System.Action<float> EarlyGlobalUpdate, System.Action<float> LateGlobalUpdate)
        {
            this.EarlyGlobalUpdate = EarlyGlobalUpdate;
            this.LateGlobalUpdate = LateGlobalUpdate;
        }

        /// <summary>
        /// 添加状态
        /// </summary>
        /// <returns><c>true</c>, 如果添加成功, <c>false</c> 添加失败.</returns>
        /// <param name="stateID">状态ID.</param>
        /// <param name="onEnterState">进入状态时调用</param>
        /// <param name="onUpdate">更新时调用</param>
        /// <param name="onExitState">出状态时调用.</param>
        public bool AddState(int stateID, Action onEnterState, Action<float> onUpdate, Action onExitState)
        {
            if (stateDict.ContainsKey(stateID))
                return false;
            UFSMState newState = new UFSMState(stateID, onEnterState, onUpdate, onExitState);
            stateDict.Add(stateID, newState);
            return true;
        }

        public void Clear()
        {
            stateDict.Clear();
        }
        /// <summary>
        /// 状态机更新，这个默认在Update里面，如果不想这样就覆盖Update
        /// </summary>
        public void StateMachineUpdate(float deltaTime)
        {
            EarlyGlobalUpdate?.Invoke(deltaTime);
            currentState.onUpdate?.Invoke(deltaTime);
            LateGlobalUpdate?.Invoke(deltaTime);
        }
        /// <summary>
        /// (float deltaTime)
        /// </summary>
        public System.Action<float> EarlyGlobalUpdate;
        /// <summary>
        /// (float deltaTime)
        /// </summary>
        public System.Action<float> LateGlobalUpdate;
    }
}