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

public class MeshSelection : MonoBehaviour
{

    private GameObject ToolSelectObj;

    public List<int> SelectedTrianglesIndex = new List<int>();

    public HashSet<Vector3> TrianglesVector3s = new HashSet<Vector3>();


    public void GetBoundaryVertices(Mesh mesh)
    {
        Vector3[] vertices = mesh.vertices;
        int[] triangles = mesh.triangles;

        Dictionary<(int, int), int> edgeFaces = new Dictionary<(int, int), int>();

        foreach (var i in SelectedTrianglesIndex)
        {
            int a = triangles[i];
            int b = triangles[i + 1];
            int c = triangles[i + 2];

            RegisterEdge(a, b, edgeFaces);
            RegisterEdge(b, c, edgeFaces);
            RegisterEdge(c, a, edgeFaces);

            
        }

        foreach (var edge in edgeFaces)
        {
            if (edge.Value == 1)
            {
                TrianglesVector3s.Add(ToolSelectObj.transform.TransformPoint(vertices[edge.Key.Item1]));
                TrianglesVector3s.Add(ToolSelectObj.transform.TransformPoint(vertices[edge.Key.Item2]));

            }
        }

    }
    private static void RegisterEdge(int a, int b, Dictionary<(int, int), int> edgeFaces)
    {
        var edge = a < b ? (a, b) : (b, a);
        edgeFaces.TryGetValue(edge, out int count);
        edgeFaces[edge] = count + 1;
    }

    public void CreateCenter()
    {
        Vector3 v3 = Vector3.zero;
        foreach(Vector3 vector3 in TrianglesVector3s)
        {
            GameObject gameObject = new GameObject();
            gameObject.transform.position = vector3;
            v3 += vector3;
        }

        GameObject obj = new GameObject();
        obj.transform.SetParent(ToolSelectObj.transform.parent, true);
        obj.transform.localPosition = v3 / TrianglesVector3s.Count ;
        obj.name = ToolSelectObj.name+"---生成点";
        //ToolSelectObj.transform.SetParent(obj.transform,true);

        TrianglesVector3s.Clear();
    }

    public void setObj(GameObject obj)
    {
        ToolSelectObj = obj;
    }

}