using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace YKMoon.Math
{
    /// <summary>
    /// 整理的数学公式等等
    /// </summary>
    public partial class YKMath
    {
        public class Line
        {
            public Vector3 p1 = Vector3.zero;
            public Vector3 p2 = Vector3.zero;
            public Vector3 dir = Vector3.back;

            public Line() { }
            public Line(Vector3 p1, Vector3 p2)
            {
                this.p1 = p1;
                this.p2 = p2;
                dir = (p2 - p1).normalized;
            }
        }

        public class Plane
        {
            public Vector3 normal = Vector3.up;
            public Vector3 pos = Vector3.zero;
        }

        //linePnt - point the line passes through
        //lineDir - unit vector in direction of line, either direction works
        //pnt - the point to find nearest on line for
        public static Vector3 NearestPointOnLine(Vector3 linePnt, Vector3 lineDir, Vector3 pnt)
        {
            lineDir.Normalize();//this needs to be a unit vector
            var v = pnt - linePnt;
            var d = Vector3.Dot(v, lineDir);
            return linePnt + lineDir * d;
        }

        /// <summary>
        /// 平行于x轴的直线们
        /// </summary>
        /// <returns></returns>
        public static List<Line> GetTransformHorizontalLines(Transform box)
        {
            List<Line> result = new List<Line>();
            BoxCollider col = box.GetComponent<BoxCollider>();
            Vector3 rt = box.TransformPoint(new Vector3(0.5f, 0, 0.5f));
            Vector3 rb = box.TransformPoint(new Vector3(0.5f, 0, -0.5f));
            Vector3 lb = box.TransformPoint(new Vector3(-0.5f, 0, -0.5f));
            Vector3 lt = box.TransformPoint(new Vector3(-0.5f, 0, 0.5f));

            result.Add(new Line(lt, rt));
            result.Add(new Line(lb, rb));
            return result;
        }
        /// <summary>
        /// zx平面的直线们
        /// </summary>
        /// <param name="box"></param>
        /// <returns></returns>
        public static List<Line> GetTransformLines(Transform box)
        {
            List<Line> result = new List<Line>();
            BoxCollider col = box.GetComponent<BoxCollider>();
            Vector3 rt = box.TransformPoint(new Vector3(0.5f, 0, 0.5f));
            Vector3 rb = box.TransformPoint(new Vector3(0.5f, 0, -0.5f));
            Vector3 lb = box.TransformPoint(new Vector3(-0.5f, 0, -0.5f));
            Vector3 lt = box.TransformPoint(new Vector3(-0.5f, 0, 0.5f));

            Vector3[] ps = new Vector3[] { rt, rb, lb, lt };
            for(int i = 0; i < ps.Length; i++) {
                GameObject obj = new GameObject(i.ToString());
                obj.transform.position = ps[i];
                obj.transform.SetParent(box);

                result.Add(new Line(ps[i], ps[(i + 1) % ps.Length]));
            }
            return result;
        }
        /// <summary>
        /// 获得zx平面内的transform的四个顶点
        /// </summary>
        public static List<Vector3> GetTransformPoints(Transform box)
        {
            BoxCollider col = box.GetComponent<BoxCollider>();
            Vector3 rt = box.TransformPoint(new Vector3(0.5f, 0, 0.5f));
            Vector3 rb = box.TransformPoint(new Vector3(0.5f, 0, -0.5f));
            Vector3 lb = box.TransformPoint(new Vector3(-0.5f, 0, -0.5f));
            Vector3 lt = box.TransformPoint(new Vector3(-0.5f, 0, 0.5f));
            List<Vector3> result = new List<Vector3>() { rt, rb, lb, lt };
            for(int i = 0; i < result.Count; i++) {
                var t = result[i];
                t.y = 0;
                result[i] = t;
            }
            return result;
        }
        /// <summary>
        /// 获得zx平面内最接近的transform顶点
        /// </summary>
        public static Vector3 GetClosetPositionInRect(Transform trans, Vector3 position, Vector3 dir)
        {
            Vector3 result = Vector3.zero;
            var points = GetTransformPoints(trans);
            float minDis = float.MaxValue;

            for(int i = 0; i < points.Count; i++) {
                var point = points[i];
                float dis = Vector3.Cross(dir, point - position).magnitude;
                if(dis < minDis) {
                    minDis = dis;
                    result = point;
                }
            }
            return result;
        }
        /// <summary>
        /// 是否在扇形范围
        /// </summary>
        /// <param name="sectorOrigin">圆心</param>
        /// <param name="sectorForward">扇形正方向</param>
        /// <param name="sectorRadius">半径</param>
        /// <param name="sectorAngle">左右角度</param>
        /// <param name="targetPos">目标点</param>
        /// <returns></returns>
        public static bool IsInSectorYPlane(Vector3 sectorOrigin, Vector3 sectorForward, float sectorRadius, float sectorAngle, Vector3 targetPos)
        {
            sectorAngle = MinMaxClamp(sectorAngle, 0, 180);
            Vector3 dir = GetDirIgnoreYAxis(sectorOrigin, targetPos);
            Vector3 forward = GetVector3IgnoreYAxis(sectorForward);
            float dis = GetDistanceIgnoreYAxis(sectorOrigin, targetPos);
            if(dis > sectorRadius) {
                return false;
            }
            float angle = Vector3.Angle(forward, dir);
            if(angle <= sectorAngle) {
                return true;
            }
            return false;
        }
    }
}