using System;
using System.Collections.Generic;
using Gameplay.Character;
using Gameplay.Level;
using Gameplay.Vehicle.Impl;
using LTGame;
using UnityEngine;
namespace Gameplay.Vehicle.State
{
    public class VehicleStateMove : BaseVehicleState
    {

        private List<int> _tgsPath;
        private int _currentPathIndex;
        private Map _map;
        private Vector3 _targetPosition;
        private int _lastTargetCellIndex;
        private readonly List<Vector3> _roadPointList;

        private float _lastMoveSpeed;


        public VehicleStateMove(NormalVehicle owner) : base(owner, EVehicleState.Move)
        {
            _tgsPath = new List<int>();
            _roadPointList = new List<Vector3>();
        }

        protected override void _OnEnter(NBaseState exitState,
            object param)
        {
            base._OnEnter(exitState, param);

            if (owner.controlData.followUnit != null
                && owner.controlData.targetEnemy != owner.controlData.followUnit)
            {
                owner.controlData.targetCellIndex = owner.controlData.followUnit.transData.cellIndex;
            }
            _lastTargetCellIndex = owner.controlData.targetCellIndex;

            _map = LevelManager.Instance.CurrentLevel.Map;

            // 初始化路径
            _FindPath();

            if (isFinished) return;

            owner.statusData.isMoveing = true;
            
            owner.vAnim.targetAnim = "move";
        }


        protected override void _OnRunning()
        {
            base._OnRunning();
            
            owner.fightData.lastMoveTime = LevelManager.Instance.CurrentLevel.LevelTime;
            
            if (owner.aliveData.currentHp <= 0)
            {
                isFinished = true;
                nextState = EVehicleState.Destroy;
                return;
            }

            // 如果目标改变,则重新寻路
            if (_lastTargetCellIndex != owner.controlData.targetCellIndex)
            {
                isFinished = true;
                nextState = EVehicleState.Move;
                return;
            }

            // 持续判断当前索引格子是否可移动
            var currentMoveCellIndex = _tgsPath[_currentPathIndex];
            var islocalMove = currentMoveCellIndex == owner.transData.cellIndex;
            if (!islocalMove)
            {
                // 同方格移动,不处理
                _map.GetRuntimeBlockProperty(currentMoveCellIndex, out var blockData);
                var canMove = MapUtils.CanPass(owner.commonData.crossLevel, blockData);
                if (!canMove)
                {
                    isFinished = true;
                    nextState = EVehicleState.Move;
                    return;
                }
            }

            _DoMove();
        }

        protected override void _OnExit(NBaseState exitState,
            object param)
        {
            base._OnExit(exitState, param);

            owner.statusData.isMoveing = false;
        }

        private void _DoMove()
        {

            if (!_DirectMoveTo(_targetPosition, deltaTime))
            {
                var followUnit = owner.controlData.followUnit;
                if (followUnit != null) // 有追踪对象
                {
                    if (followUnit == owner.controlData.targetEnemy)
                    {
                        // 目标一致,则停下
                        owner.controlData.targetCellIndex = owner.transData.cellIndex;
                        // 重算路径
                        _FindPath();
                        return;
                    }
                    else
                    {
                        // 目标不一致,继续向目标移动
                        var followCellIndex = followUnit.transData.cellIndex;
                        if (followCellIndex != owner.controlData.targetCellIndex)
                        {
                            // 重算路径
                            isFinished = true;
                            nextState = EVehicleState.Move;
                            return;
                        }
                    }
                }

                // 还在走,就继续走
                return;
            }


            // 到达转折点
            _currentPathIndex++;
            if (_currentPathIndex >= _tgsPath.Count)
            {
                // 到达终点
                isFinished = true;
                nextState = EVehicleState.Stop;
                owner.controlData.targetCellIndex = -1;
                if (LevelManager.Instance.CurrentLevel.selectUnit == owner)
                {
                    SelecterView.Instance.SetSelectAndTarget(owner.Node, null);
                }
                Framework.EventManager.Instance.Send(Framework.EventManager.EventName.LevelCharacterArriveBlock, new EDArriveBlock()
                {
                    characterId = owner.GetID(),
                    cellIndex = owner.transData.cellIndex
                });
            }
            else
            {
                var newCellIndex = _tgsPath[_currentPathIndex];
                // 更新目标点
                _targetPosition = _map.TGSCellIndex2WorldPosition(newCellIndex);
            }
        }

        private bool _DirectMoveTo(Vector3 pos,
            float dt)
        {
            var currentPos = owner.transData.pos;
            var toTarget = pos - currentPos;
            toTarget.y = 0;

            _RotateToBlock(toTarget, dt);

            var requireDistance = toTarget.magnitude;

            var moveSpeed = owner.fightData.GetMoveSpeed();
            var moveDt = dt * moveSpeed;

            if (moveDt < requireDistance)
            {
                var moveDir = toTarget.normalized;
                var moveDistance = moveDt * moveDir;
                var newPos = currentPos + moveDistance;
                owner.transData.pos = newPos;
                return false;
            }
            else
            {
                // 直接到达目标点
                owner.transData.pos = pos;
                return true;
            }
        }

        private void _RotateToBlock(Vector3 toTarget,
            float dt)
        {
            var toAngle = Vector3.SignedAngle(Vector3.forward, toTarget, Vector3.up);
            var currentAngle = owner.transData.yaw;
            if (Math.Abs(toAngle - currentAngle) > 0.1f)
            {
                var turnSpeed = owner.fightData.turnSpeed;
                var turnDt = dt * turnSpeed;
                var newAngle = Mathf.MoveTowardsAngle(currentAngle, toAngle, turnDt);
                owner.transData.yaw = newAngle;
            }

        }

        private bool _IsFathExist()
        {
            return !(_tgsPath == null || _tgsPath.Count <= 0);
        }

        private void _FindPath()
        {
            if (_map == null) return;

            _roadPointList.Clear();
            _currentPathIndex = 0;
            var to = owner.controlData.targetCellIndex;
            var from = owner.transData.cellIndex;

            _tgsPath = PathFinder.FindPath(_map, from, to, owner.commonData.crossLevel);

            // 再次判定是否可以直接走通
            if (_IsFathExist())
            {
                _targetPosition = _map.TGSCellIndex2WorldPosition(_tgsPath[_currentPathIndex]);
            }
            else
            {
                owner.Log(string.Format("无有效路径: from:{0} to:{1}", from, to));
                isFinished = true;
                nextState = EDownState.Idle;

                // 停止到当前节点
                owner.StopToCurrentCell();
            }

            for (var i = _tgsPath.Count - 1; i >= 0; --i)
            {
                var tgsIndex = _tgsPath[i];
                var worldPos = _map.TGSCellIndex2WorldPosition(tgsIndex);
                _roadPointList.Add(worldPos);
            }
        }

        public List<Vector3> CalcRoadLine()
        {
            return _roadPointList;
        }

        public int GetCurrentIndex()
        {
            return _currentPathIndex;
        }

    }
}