using UnityEngine;

namespace Gameplay.Utils
{


    public class LTCombie : MonoBehaviour
    {

        private Mesh _CreateMeshFromSubMesh(Mesh sourceMesh, int subMeshIndex)
        {
            // 创建一个新的网格
            Mesh newMesh = new Mesh();
            
            var subMeshDescriptor = sourceMesh.GetSubMesh(subMeshIndex);

            // 获取来源网格的顶点、法线、切线和UV数组
            Vector3[] vertices = sourceMesh.vertices;
            Vector3[] normals = sourceMesh.normals;
            Vector4[] tangents = sourceMesh.tangents;
            Vector2[] uv = sourceMesh.uv;

            // 从来源网格中获取指定子网格的三角形索引数组
            int[] triangles = sourceMesh.GetTriangles(subMeshIndex);

            // 根据子网格描述符中的顶点数量，创建新网格的顶点、法线、切线和UV数组
            Vector3[] newVertices = new Vector3[subMeshDescriptor.vertexCount];
            Vector3[] newNormals = new Vector3[subMeshDescriptor.vertexCount];
            Vector4[] newTangents = new Vector4[subMeshDescriptor.vertexCount];
            Vector2[] newUV = new Vector2[subMeshDescriptor.vertexCount];

            // 根据子网格描述符中的三角形索引数量，创建新网格的三角形索引数组
            int[] newTriangles = new int[triangles.Length];

            // 从来源网格的数组中复制数据到新网格的数组
            for (int i = 0; i < subMeshDescriptor.vertexCount; i++)
            {
                newVertices[i] = vertices[subMeshDescriptor.firstVertex + i];
                newNormals[i] = normals[subMeshDescriptor.firstVertex + i];
                newTangents[i] = tangents[subMeshDescriptor.firstVertex + i];
                newUV[i] = uv[subMeshDescriptor.firstVertex + i];
            }

            for (int i = 0; i < subMeshDescriptor.indexCount; i++)
            {
                newTriangles[i] = triangles[i] - subMeshDescriptor.firstVertex;
            }

            // 设置新网格的顶点、法线、切线和UV数组，以及三角形索引数组
            newMesh.vertices = newVertices;
            newMesh.normals = newNormals;
            newMesh.tangents = newTangents;
            newMesh.uv = newUV;
            newMesh.triangles = newTriangles;
            
            return newMesh;
        }
        
        [ContextMenu("ManualCombine")]
        public void ManualCombine()
        {
            // combine branch
            {
                var allMeshRenders = GetComponentsInChildren<MeshRenderer>();
                var material = allMeshRenders[0].sharedMaterials[0];
                var combineInstanceArrays = new CombineInstance[allMeshRenders.Length];
                for (var i = 0; i < allMeshRenders.Length; i++)
                {
                    var meshFilter = allMeshRenders[i].GetComponent<MeshFilter>();
                    var getMesh = meshFilter.sharedMesh;
                    combineInstanceArrays[i].mesh = _CreateMeshFromSubMesh(getMesh, 0);
                    combineInstanceArrays[i].transform = meshFilter.transform.localToWorldMatrix;
                }

                var newMesh = new Mesh();
                newMesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32;
                newMesh.CombineMeshes(combineInstanceArrays, true, true);
                var newGameObject = new GameObject("CombinedMesh_branch");
                var newMeshFilter = newGameObject.AddComponent<MeshFilter>();
                newMeshFilter.sharedMesh = newMesh;
                var newMeshRenderer = newGameObject.AddComponent<MeshRenderer>();
                newMeshRenderer.sharedMaterial = material;
                newGameObject.transform.localPosition = Vector3.zero;
                newGameObject.transform.localRotation = Quaternion.identity;
                newGameObject.transform.localScale = Vector3.one;

                // transform.gameObject.SetActive(false);

            #if UNITY_EDITOR
                // save mesh to asset
                UnityEditor.AssetDatabase.CreateAsset(newMesh, "Assets/CombinedMesh_branch.asset");
                UnityEditor.AssetDatabase.SaveAssets();
                // save prefab to asset
                UnityEditor.PrefabUtility.SaveAsPrefabAsset(newGameObject, "Assets/CombinedMesh_branch.prefab");
            #endif
            }

            // combine trunk
            {
                var allMeshRenders = GetComponentsInChildren<MeshRenderer>();
                var material = allMeshRenders[0].sharedMaterials[1];
                var combineInstanceArrays = new CombineInstance[allMeshRenders.Length];
                for (var i = 0; i < allMeshRenders.Length; i++)
                {
                    var meshFilter = allMeshRenders[i].GetComponent<MeshFilter>();
                    var getMesh = meshFilter.sharedMesh;
                    combineInstanceArrays[i].mesh = _CreateMeshFromSubMesh(getMesh, 1);
                    combineInstanceArrays[i].transform = meshFilter.transform.localToWorldMatrix;
                }
            
                var newMesh = new Mesh();
                newMesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32;
                newMesh.CombineMeshes(combineInstanceArrays, true, true);
                var newGameObject = new GameObject("CombinedMesh_trunk");
                var newMeshFilter = newGameObject.AddComponent<MeshFilter>();
                newMeshFilter.sharedMesh = newMesh;
                var newMeshRenderer = newGameObject.AddComponent<MeshRenderer>();
                newMeshRenderer.sharedMaterial = material;
                newGameObject.transform.localPosition = Vector3.zero;
                newGameObject.transform.localRotation = Quaternion.identity;
                newGameObject.transform.localScale = Vector3.one;
            
            
            #if UNITY_EDITOR
                // save mesh to asset
                UnityEditor.AssetDatabase.CreateAsset(newMesh, "Assets/CombinedMesh_trunk.asset");
                UnityEditor.AssetDatabase.SaveAssets();
                // save prefab to asset
                UnityEditor.PrefabUtility.SaveAsPrefabAsset(newGameObject, "Assets/CombinedMesh_trunk.prefab");
            #endif
            }
            
            transform.gameObject.SetActive(false);


        }
    }
}