using UnityEngine;
using System.Collections.Generic;

public class TileInstancingManager : MonoBehaviour 
{
    public string jsonConfig = @"{
        ""mesh"": [
            {
                ""revertSeam"": 0,
                ""vertices"": [
                    0, 0, 0, 
                    1, 1, 0, 
                    1, 0, 0
                ],
                ""indices"": [
                    0, 1, 2
                ]
            },
            {
                ""revertSeam"": 0,
                ""vertices"": [
                    0, 0, 0, 
                    0, 1, 0, 
                    1, 1, 0
                ],
                ""indices"": [
                    0, 1, 2
                ]
                index++;
            }
        ],
        ""instances"": [
            {
                ""meshidx"": 0,
                ""uniforms"" : {
                    ""vTransform"" : [0, 0, 0],
                    ""vLocalTransform"": [""seamX / 2.0"", ""seamY / 2.0""],
                    ""vSeamOffset"": [0, 0],
                    ""vTextureSize"": [1, 1]
                },
                ""texture"": ""data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAAXNSR0IArs4c6QAAABRJREFUGFdj/M/A8J+BgYGBEcYAACwBA/9pGIu9AAAAAElFTkSuQmCC""
            },
            {
                ""meshidx"": 1,
                ""uniforms"" : {
                    ""vTransform"" : [0, 0, 0],
                    ""vLocalTransform"": [""seamX / 2.0"", ""seamY  + 0.2 * y + seamY / 2.0""],
                    ""vSeamOffset"": [0, 0],
                    ""vTextureSize"": [1, 1]
                },
                ""texture"": ""data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAAXNSR0IArs4c6QAAABRJREFUGFdjZPjP8J+BgYGBEcYAACoDA/9cU2MPAAAAAElFTkSuQmCC""
            },
             {
                ""meshidx"": 0,
                ""uniforms"" : {
                    ""vTransform"" : [0.5, 0, 0],
                    ""vLocalTransform"": [""seamX / 2.0"", ""y + seamY + seamY / 2.0""],
                    ""vSeamOffset"": [0, 0],
                    ""vTextureSize"": [1, 1]
                },
                ""texture"": ""data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAAXNSR0IArs4c6QAAABRJREFUGFdjZGD4/5+BgYGBEcYAACgFA/86LIEuAAAAAElFTkSuQmCC""
            },
            {
                ""meshidx"": 1,
                ""uniforms"" : {
                    ""vTransform"" : [0.5, 0, 0],
                    ""vLocalTransform"": [""seamX / 2.0"", ""seamY / 2.0""],
                    ""vSeamOffset"": [0, 0],
                    ""vTextureSize"": [1, 1]
                },
                 ""texture"": ""data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAAXNSR0IArs4c6QAAABRJREFUGFdjZPj//z8DAwMDI4wBAD7uBf32jHwdAAAAAElFTkSuQmCC""
            }
        ]
    }";

    private Material[] tileMaterials; 


    [System.Serializable]
    public class MeshData
    {
        public int revertSeam;
        public List<float> vertices;
        public List<int> indices;
    }

    [System.Serializable]
    public class InstanceData
    {
        public int meshidx;
        public Dictionary<string, object> uniforms;
        public string texture;
    }

    [System.Serializable]
    public class TileConfig
    {
        public List<MeshData> mesh;
        public List<InstanceData> instances;
    }

    public Mesh tileMesh;
    public Material tileMaterial;
    public TileConfig config;

    private const int BATCH_SIZE = 1023; // Unity的限制，每批最多1023个实例
    
    private List<Matrix4x4> matrices = new List<Matrix4x4>();
    private List<Vector4> colors = new List<Vector4>();
    private MaterialPropertyBlock propertyBlock;
    private ComputeBuffer colorBuffer;
    
    private void OnEnable()
    {
        propertyBlock = new MaterialPropertyBlock();
        SetupInstancing();
    }
    
    private void OnDisable()
    {
        if (colorBuffer != null)
        {
            colorBuffer.Release();
            colorBuffer = null;
        }
    }
    
    private void SetupInstancing()
    {
        // // 生成瓷砖变换矩阵
        // for (int index = 0; index < config.instances.Count; index++)
        // {
        //     Vector3 position = new Vector3(config.instances[index].uniforms.get("vTransform"), 0, z * config.tileSize);
        //     Matrix4x4 matrix = Matrix4x4.TRS(
        //         position,
        //         Quaternion.identity,
        //         Vector3.one
        //     );
        //     matrices.Add(matrix);
            
        //     // 可以根据瓷砖ID设置不同的颜色
        //     colors.Add(GetTileColor(x, z));
        // }

        // // 设置颜色缓冲区
        // colorBuffer = new ComputeBuffer(matrices.Count, 16);
        // colorBuffer.SetData(colors.ToArray());
        // propertyBlock.SetBuffer("_Colors", colorBuffer);
    }
    
    private void Update()
    {
        // 每帧渲染
        for (int i = 0; i < matrices.Count; i += BATCH_SIZE)
        {
            int batchCount = Mathf.Min(BATCH_SIZE, matrices.Count - i);
            Matrix4x4[] batchedMatrices = new Matrix4x4[batchCount];
            matrices.CopyTo(i, batchedMatrices, 0, batchCount);
            
            Graphics.DrawMeshInstanced(
                tileMesh, 
                0, 
                tileMaterial, 
                batchedMatrices,
                batchCount,
                propertyBlock
            );
        }
    }
}