using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;

public class MonsterMoveLine
{
    public static Dictionary<string, BezierCurveData> dic_BezierCurveDatas=new Dictionary<string, BezierCurveData>();
    public static List<BezierCurveData> curves = new List<BezierCurveData>();
    public class BezierCurveData
    {
        public string name;
        public Vector2 start;
        public List<Vector2> controlPoints = new List<Vector2>();
        public Vector2 end;
    }

    public static async void LoadBezier()
    {
        await LoadBezierTxtAsync("MoveLine");
    }
    /// <summary>
    /// 读取曲线数据 读取单个
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    public static async Task LoadSingleBezierTxtAsync(string path)
    {
        AsyncOperationHandle<TextAsset> handle = Addressables.LoadAssetAsync<TextAsset>(path);
        await handle.Task;
        var lines = handle.Result.text.Split('\n');


        foreach (var line in lines)
        {
            if (string.IsNullOrWhiteSpace(line)) continue;

            var parts = line.Split(';');
            BezierCurveData curve = new BezierCurveData();

            // 第一个是曲线名
            curve.name = parts[0];

            // 后面所有都是点
            List<Vector2> points = new List<Vector2>();
            for (int i = 1; i < parts.Length; i++)
            {
                points.Add(ParseVector(parts[i]));
            }

            // 第一个点是 start
            curve.start = points[0];
            if (points.Count > 1)
            {
                // 最后一个点是 end
                curve.end = points[points.Count - 1];
            }


            // 中间的都是 controlPoints
            for (int i = 1; i < points.Count - 1; i++)
            {
                curve.controlPoints.Add(points[i]);
            }

            curves.Add(curve);
            dic_BezierCurveDatas.Add(curve.name, curve);

        }
    }
    /// <summary>
    /// 读取曲线数据 游戏开始时在awake调用aa包
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    public static async Task LoadBezierTxtAsync(string path)
    {
        List<string> keys=new List<string>();
        keys.Add(path);
        keys.Add(GameManager.Instance.gameData.currGameType.ToString());
        AsyncOperationHandle<IList<TextAsset>> handles = Addressables.LoadAssetsAsync<TextAsset>(keys, null,Addressables.MergeMode.Intersection);
        await handles.Task;
        foreach (var text in handles.Result)
        {
           var lines = text.text.Split('\n');


            foreach (var line in lines)
            {
                if (string.IsNullOrWhiteSpace(line)) continue;

                var parts = line.Split(';');
                BezierCurveData curve = new BezierCurveData();

                // 第一个是曲线名
                curve.name = parts[0];

                // 后面所有都是点
                List<Vector2> points = new List<Vector2>();
                for (int i = 1; i < parts.Length; i++)
                {
                    points.Add(ParseVector(parts[i]));
                }

                // 第一个点是 start
                curve.start = points[0];
                if (points.Count > 1)
                {
                    // 最后一个点是 end
                    curve.end = points[points.Count - 1];
                }


                // 中间的都是 controlPoints
                for (int i = 1; i < points.Count - 1; i++)
                {
                    curve.controlPoints.Add(points[i]);
                }

                curves.Add(curve);
                dic_BezierCurveDatas.Add(curve.name, curve);

            }
        }
        
        Debug.Log("曲线读取完成共" + dic_BezierCurveDatas.Count + "条");

    }

    private static Vector2 ParseVector(string s)
    {
        var xy = s.Split(',');
        return new Vector2(float.Parse(xy[0]), float.Parse(xy[1]));
    }


    public BezierCurveData bezierCurveData;
    public float moveTime;
    public float moveSpeed;

    public void Init(BezierCurveData bezierCurveData, float Time)
    {
        this.bezierCurveData = bezierCurveData;
        this.moveTime = Time;
        Debug.Log($"初始化曲线 {this.bezierCurveData.name} ,移动时间 {moveTime}");
    }
    /// <summary>
    /// 获取曲线上的点
    /// </summary>
    /// <param name="t"></param>
    /// <returns></returns>
    public Vector2 GetBezierPoint(float t)
    {
        t = t / moveTime;
        BezierCurveData curve=bezierCurveData;
        List<Vector2> points = new List<Vector2>();
        points.Add(curve.start);
        points.AddRange(curve.controlPoints);
        points.Add(curve.end);

        return DeCasteljau_BY(points, t%1);
    }
   
    /// <summary>
    /// 贝塞尔
    /// </summary>
    /// <param name="points"></param>
    /// <param name="t"></param>
    /// <returns></returns>
    private Vector2 DeCasteljau_BSE(List<Vector2> points, float t)
    {
        while (points.Count > 1)
        {
            List<Vector2> next = new List<Vector2>();
            for (int i = 0; i < points.Count - 1; i++)
            {
                next.Add(Vector2.Lerp(points[i], points[i + 1], t));
            }
            points = next;
        }
        return CoordinateTransformation.CanvasToWorld( points[0],UIManager.Instance.uiRoot.GetComponent<RectTransform>(),Camera.main);
    }
    /// <summary>
    /// B样
    /// </summary>
    /// <param name="points"></param>
    /// <param name="t"></param>
    /// <returns></returns>
    private Vector2 DeCasteljau_BY(List<Vector2> points, float t)
    {
        // 方法A：保持德卡斯特里奥算法（推荐，数值更稳定）
        while (points.Count > 1)
        {
            List<Vector2> next = new List<Vector2>();
            for (int i = 0; i < points.Count - 1; i++)
            {
                next.Add(Vector2.Lerp(points[i], points[i + 1], t));
            }
            points = next;
        }
        return CoordinateTransformation.CanvasToWorld(points[0],
               UIManager.Instance.uiRoot.GetComponent<RectTransform>(), Camera.main);

        /* 方法B：伯恩斯坦多项式形式（标准贝塞尔公式）- 如果要用这个替换上面的循环
        int n = points.Count - 1;
        Vector2 result = Vector2.zero;
        for (int i = 0; i <= n; i++)
        {
            float bernstein = BinomialCoefficient(n, i) * Mathf.Pow(t, i) * Mathf.Pow(1 - t, n - i);
            result += points[i] * bernstein;
        }
        return CoordinateTransformation.CanvasToWorld(result, 
               UIManager.Instance.uiRoot.GetComponent<RectTransform>(), Camera.main);
        */
    }

    // 计算二项式系数
    private float BinomialCoefficient(int n, int k)
    {
        float result = 1f;
        for (int i = 1; i <= k; i++)
        {
            result *= (float)(n - k + i) / i;
        }
        return result;
    }


}