using System.IO;
using System.Text;
using SharpDX;
using SparkClient.Views.UserControl.ViewportData.Entity;
using SparkClient.Views.UserControl.ViewportData.Enum;

namespace SparkClient.Views.UserControl.ViewportData.Helper;

public class ObjExporter
{

    public static void ExportToObj2(List<Viewport3DTriangleEntity> entities, string outputPath)
    {
        //分组
        Dictionary<string, List<Viewport3DTriangleEntity>> feactList = entities
            .Where(entity => entity.PlaneType != PlaneType.Girdle)
            .GroupBy(entity => entity.PlaneCode)
            .ToDictionary(group => group.Key, group => group.ToList());
        //腰 单组
        List<Viewport3DTriangleEntity> waistList = entities
            .Where(entity => entity.PlaneType == PlaneType.Girdle)
            .ToList();
        
        //同一个面只保留外边框(除了腰)
        Dictionary<string, List<Vector3>> resultPoints = new Dictionary<string, List<Vector3>>();
        
        foreach (var dic in feactList)
        {
            List<Vector3> tempPoints = new List<Vector3>();
            foreach (var entity in dic.Value)
            {
                tempPoints.Add(entity.Point1);
                tempPoints.Add(entity.Point2);
                tempPoints.Add(entity.Point3);
            }
            resultPoints.Add(dic.Key, ViewportHelperPro.VectorClockwiseSort(new HashSet<Vector3>(tempPoints).ToList()));
        }
        List<Vector3> selFaceVector = new List<Vector3>();
        if (waistList.Count > 0)
        {
            foreach (var entity in waistList)
            {
                selFaceVector.Add(entity.Point1);
                selFaceVector.Add(entity.Point2);
                selFaceVector.Add(entity.Point3);
            }
        }
        resultPoints.Add("yao", selFaceVector);
        
        StringBuilder sb = new StringBuilder();

        // 顶点列表
        List<Vector3> uniqueVertices = new List<Vector3>();
        Dictionary<Vector3, int> vertexIndexMap = new Dictionary<Vector3, int>();

        // 1. 对每个面生成顶点和面
        foreach (var face in resultPoints)
        {
            // 对每个面，获取它的顶点列表
            List<Vector3> faceVertices = face.Value;

            // 去重顶点
            foreach (var vertex in faceVertices)
            {
                if (!vertexIndexMap.ContainsKey(vertex))
                {
                    vertexIndexMap[vertex] = uniqueVertices.Count;
                    uniqueVertices.Add(vertex);
                }
            }
        }

        // 2. 写入顶点数据
        foreach (var vertex in uniqueVertices)
        {
            sb.AppendLine($"v {vertex.X} {vertex.Y} {vertex.Z}");
        }

        // 3. 写入每个面（f行），包括正面和反面
        foreach (var face in resultPoints)
        {
            sb.AppendLine($"# Face: {face.Key}");

            // 获取面上的所有顶点并排序
            List<Vector3> faceVertices = face.Value;
            // Vector3 center = GetCenterOfVertices(faceVertices);
            // faceVertices.Sort((v1, v2) => GetAngle(v1, center).CompareTo(GetAngle(v2, center)));

            // 正面：按顺时针顺序输出
            sb.Append("f");
            foreach (var vertex in faceVertices)
            {
                sb.Append($" {vertexIndexMap[vertex] + 1}");
            }
            sb.AppendLine();

            // 反面：按逆时针顺序输出（反转顶点顺序）
            sb.Append("f");
            for (int i = faceVertices.Count - 1; i >= 0; i--)
            {
                sb.Append($" {vertexIndexMap[faceVertices[i]] + 1}");
            }
            sb.AppendLine();
        }

        // 4. 写入文件
        File.WriteAllText(outputPath, sb.ToString());
        
    }
    
    // 计算一组顶点的中心点（用于排序）
    private static Vector3 GetCenterOfVertices(List<Vector3> vertices)
    {
        float centerX = 0, centerY = 0, centerZ = 0;
        foreach (var vertex in vertices)
        {
            centerX += vertex.X;
            centerY += vertex.Y;
            centerZ += vertex.Z;
        }
        return new Vector3(centerX / vertices.Count, centerY / vertices.Count, centerZ / vertices.Count);
    }
    
    private static float GetAngle(Vector3 vertex, Vector3 center)
    {
        // 计算顶点与中心的方向向量
        Vector3 direction = vertex - center;

        // 在XY平面上计算角度
        float angle = (float)Math.Atan2(direction.Y, direction.X); // 返回的是弧度，[-π, π]

        // 如果你想要角度范围 [0, 2π]，可以做如下处理
        if (angle < 0)
        {
            angle += MathF.PI * 2;
        }

        return angle;
    }
}