using System.Collections.Generic;
using TH1_Renderer.UnitAtomAnim;
using TH1Renderer;
using UnityEngine;

namespace TH1_Anim.UnitAtomAnim
{
    public class UnitAtomAnimMove : IUnitAtomAnim
    {
        private UnitAtomAnimMoveData _data;
        private Vector3 _originPos;
        private Vector3 _targetPos;

        public UnitAtomAnimMove(IUnitAtomAnimData data) : base()
        {
            _data = data as UnitAtomAnimMoveData;
            State = UnitAtomAnimState.Prepare;
        }
        public override bool OnStart(UnitMono unitMono)
        {
            if (_data == null)
            {
                return false;
            }
            Duration = Table.Instance.AnimDataAssets.AttackAnimTime;
            if(_data.Path != null)
                Duration = Table.Instance.AnimDataAssets.AttackAnimTime / 2f * _data.Path.Count;
                
            _originPos = Table.Instance.GridPosToWorld(_data.OriginGridPos, "isUnit");
            _targetPos = Table.Instance.GridPosToWorld(_data.TargetGridPos, "isUnit");

            UpdateDirection(unitMono,_data.OriginGridPos,_data.TargetGridPos);
            return true;
        }

        public Vector3 GetPositionOnPath(List<Vector2Int> path2, float t)
        {
            if (path2 == null || path2.Count == 0) return Vector3.zero;
            var path = new List<Vector3>();
            foreach (var p in path2)
                path.Add(Table.Instance.GridPosToWorld(p, "isUnit"));
            // 边界情况
            if (path.Count == 1) return path[0];
    
            // 计算总路程
            float totalLength = 0;
            for (int i = 0; i < path.Count - 1; i++)
            {
                totalLength += Vector3.Distance(path[i], path[i+1]);
            }
            if (totalLength <= 0) return path[0];
            // 确定目标移动距离
            float targetDistance = totalLength * Mathf.Clamp01(t);
            float distanceCovered = 0;
            // 找到目标点所在的线段
            for (int i = 0; i < path.Count - 1; i++)
            {
                float segmentLength = Vector2.Distance(path[i], path[i + 1]);
                if (distanceCovered + segmentLength >= targetDistance)
                {
                    // 在此线段内进行插值
                    float distanceIntoSegment = targetDistance - distanceCovered;
                    float segmentT = distanceIntoSegment / segmentLength;
                    return Vector2.Lerp(path[i], path[i + 1], segmentT);
                }
                distanceCovered += segmentLength;
            }
            // 如果 t >= 1，直接返回终点
            return path[path.Count - 1];
        }
        
        
        public override void OnUpdate(UnitMono unitMono,float progressTime)
        {
            if (unitMono == null) return;
            float t = Mathf.Clamp(progressTime / Duration,0f,1f);
            //如果是直接移动过去
            if(_data.Path == null)
                unitMono.gameObject.transform.position = Vector3.Lerp(_originPos, _targetPos, t);
            else
            {
                unitMono.gameObject.transform.position = GetPositionOnPath(_data.Path,t);
            }
            //Debug.Log($"{Time.time} / {progressTime} : {_originPos} -> {_targetPos}  now @ {unitMono.gameObject.transform.position}");
        }

    }
    
    
    
}