using System.Collections.Generic;
using UnityEngine;

namespace LTGame
{

    public class NStateMachine<T> where T : NBaseState
    {

        private Dictionary<int, T> _state;

        public NStateMachine()
        {
            _state = new Dictionary<int, T>();
        }

        public T currentState { get; private set; }
        public T lastState { get; private set; }

        private int _forceChangeStateId = 0;
        private object _forceChangeParam = null;

        public bool Add(T state)
        {
            if (_state.ContainsKey(state.id))
            {
                return false;
            }
            _state.Add(state.id, state);
            return true;
        }

        public bool Remove(int id)
        {
            return _state.Remove(id);
        }

        public T Find(int id)
        {
            if (_state.TryGetValue(id, out T find))
            {
                return find;
            }
            return null;
        }

        public bool ChangeState(int id,
            object param = null)
        {
            var state = Find(id);
            if (state == null)
            {
                DebugUtil.LogError("NStateMachine.ChangeState: {0} not found", id);
                return false;
            }

            var canChange = true;
            if (null != currentState)
            {
                if (currentState.id == state.id && !state.canReEnter)
                {
                    canChange = false;
                }
            }
            if (!canChange)
            {
                return false;
            }

            if (null != currentState)
            {
                currentState.Exit(state, param);
            }
            lastState = currentState;
            currentState = state;
            state.Enter(lastState, param);

            return true;

        }

        public void SetForceChangeState(int id,
            object param = null)
        {
            _forceChangeStateId = id;
            _forceChangeParam = param;
        }

        public void LogicUpdate(float dt)
        {
            if (currentState == null)
            {
                if (_forceChangeStateId != 0)
                {
                    ChangeState(_forceChangeStateId, _forceChangeParam);
                    _forceChangeStateId = 0;
                    _forceChangeParam = null;
                    OnRunning(dt);
                }
                return;
            }

            if (_forceChangeStateId != 0)
            {
                if (_forceChangeStateId == currentState.id)
                {
                    if (currentState.canReEnter)
                    {
                        ChangeState(_forceChangeStateId, _forceChangeParam);
                    }
                }
                else
                {
                    ChangeState(_forceChangeStateId, _forceChangeParam);
                }
                _forceChangeStateId = 0;
                _forceChangeParam = null;
                OnRunning(dt);
                return;
            }

            var nextState = currentState.GetNextState();
            if (nextState != 0)
            {
                ChangeState(nextState);
            }
            OnRunning(dt);
        }

        public void OnRunning(float dt)
        {
            if (null == currentState)
            {
                return;
            }
            currentState.Run(dt);
        }

    }

}