using UnityEngine;
using System.Collections;
using com.rfilkov.kinect;


namespace com.rfilkov.components
{
    /// <summary>
    /// SceneMeshRenderer renders virtual mesh of the environment in the scene, as detected by the given sensor. 
    /// </summary>
    public class SceneMeshRenderer : MonoBehaviour
    {
        [Tooltip("Depth sensor index - 0 is the 1st one, 1 - the 2nd one, etc.")]
        public int sensorIndex = 0;

        [Tooltip("Resolution of the images used to generate the scene.")]
        private DepthSensorBase.PointCloudResolution sourceImageResolution = DepthSensorBase.PointCloudResolution.DepthCameraResolution;

        [Tooltip("Whether to show the mesh as point cloud, or as solid mesh.")]
        public bool showAsPointCloud = true;

        [Tooltip("Horizontal limit - minimum, in meters.")]
        [Range(-5f, 5f)]
        public float xMin = -2f;

        [Tooltip("Horizontal limit - maximum, in meters.")]
        [Range(-5f, 5f)]
        public float xMax = 2f;

        [Tooltip("Vertical limit - minimum, in meters.")]
        [Range(-5f, 5f)]
        public float yMin = -2f;

        [Tooltip("Vertical limit - maximum, in meters.")]
        [Range(-5f, 5f)]
        public float yMax = 2f;

        [Tooltip("Distance limit - minimum, in meters.")]
        [Range(0.5f, 10f)]
        public float zMin = 1f;

        [Tooltip("Distance limit - maximum, in meters.")]
        [Range(0.5f, 10f)]
        public float zMax = 3f;

        [Tooltip("Time interval between scene mesh updates, in seconds. 0 means no wait.")]
        public float updateMeshInterval = 0f;

        [Tooltip("Whether to include the detected players to the scene mesh or not.")]
        private bool includePlayers = true;

        [Tooltip("Whether to update the mesh, only when there are no players detected.")]
        private bool updateWhenNoPlayers = false;

        //[Tooltip("Whether to update the mesh collider as well, when the user mesh changes.")]
        //public bool updateMeshCollider = false;

        [Tooltip("Time interval between mesh-collider updates, in seconds. 0 means no mesh-collider updates.")]
        public float updateColliderInterval = 0f;


        // reference to object's mesh
        private Mesh mesh = null;

        // references to KM and data
        private KinectManager kinectManager = null;
        private KinectInterop.SensorData sensorData = null;
        private DepthSensorBase sensorInt = null;
        private Vector3 spaceScale = Vector3.zero;

        // render textures 
        private RenderTexture colorTexture = null;
        private RenderTexture colorTextureCopy = null;
        private bool colorTextureCreated = false;

        // times
        private ulong lastSpaceCoordsTime = 0;
        private float lastMeshUpdateTime = 0f;
        private float lastColliderUpdateTime = 0f;

        private int minDepth = 0;
        private int maxDepth = 0;

        // image parameters
        private int imageWidth = 0;
        private int imageHeight = 0;

        // mesh parameters
        private Vector3[] spaceTable = null;
        private Vector3[] meshVertices = null;
        private int[] meshIndices = null;
        private byte[] meshVertUsed = null;
        private bool bMeshInited = false;


        void Start()
        {
            // get sensor data
            kinectManager = KinectManager.Instance;
            sensorData = (kinectManager != null && kinectManager.IsInitialized()) ? kinectManager.GetSensorData(sensorIndex) : null;
        }


        void OnDestroy()
        {
            if(bMeshInited)
            {
                // release the mesh-related resources
                FinishMesh();
            }
        }


        void LateUpdate()
        {
            if(mesh == null && sensorData != null && sensorData.depthCamIntr != null)
            {
                // init mesh and its related data
                InitMesh();
            }

            if (bMeshInited)
            {
                // min & max depth
                minDepth = Mathf.RoundToInt(zMin * 1000f);
                maxDepth = Mathf.RoundToInt(zMax * 1000f);

                // update the mesh
                UpdateMesh();
            }
        }


        // inits the mesh and related data
        private void InitMesh()
        {
            // create mesh
            mesh = new Mesh
            {
                name = "SceneMesh-Sensor" + sensorIndex,
                indexFormat = UnityEngine.Rendering.IndexFormat.UInt32
            };

            MeshFilter meshFilter = GetComponent<MeshFilter>();
            if(meshFilter != null)
            {
                meshFilter.mesh = mesh;
            }
            else
            {
                Debug.LogWarning("MeshFilter not found! You may not see the mesh on screen");
            }

            if (sensorData != null && sensorData.sensorInterface != null)
            {
                sensorInt = (DepthSensorBase)sensorData.sensorInterface;

                Vector2Int imageRes = Vector2Int.zero;
                if (sensorInt.pointCloudColorTexture == null)
                {
                    sensorInt.pointCloudResolution = sourceImageResolution;
                    imageRes = sensorInt.GetPointCloudTexResolution(sensorData);

                    colorTexture = KinectInterop.CreateRenderTexture(colorTexture, imageRes.x, imageRes.y, RenderTextureFormat.ARGB32);
                    sensorInt.pointCloudColorTexture = colorTexture;
                    colorTextureCreated = true;
                }
                else
                {
                    imageRes = sensorInt.GetPointCloudTexResolution(sensorData);
                    colorTexture = sensorInt.pointCloudColorTexture;
                    colorTextureCreated = false;
                }

                // create copy texture
                colorTextureCopy = KinectInterop.CreateRenderTexture(colorTextureCopy, imageRes.x, imageRes.y, RenderTextureFormat.ARGB32);

                // set the color texture
                Renderer meshRenderer = GetComponent<Renderer>();
                if (meshRenderer && meshRenderer.material && meshRenderer.material.mainTexture == null)
                {
                    meshRenderer.material.mainTexture = colorTextureCopy; // sensorInt.pointCloudColorTexture;
                    //meshRenderer.material.SetTextureScale("_MainTex", kinectManager.GetColorImageScale(sensorIndex));
                }

                // image width & height
                imageWidth = imageRes.x;
                imageHeight = imageRes.y;
                int pointCount = imageWidth * imageHeight;

                // mesh arrays
                meshVertices = new Vector3[pointCount];
                meshIndices = new int[6 * pointCount];  // 2 triangles per vertex, last row and column excluded
                meshVertUsed = new byte[pointCount];
                spaceScale = kinectManager.GetSensorSpaceScale(sensorIndex);

                // create space table
                spaceTable = sensorInt.pointCloudResolution == DepthSensorBase.PointCloudResolution.DepthCameraResolution ?
                    sensorInt.GetDepthCameraSpaceTable(sensorData) : sensorInt.GetColorCameraSpaceTable(sensorData);

                // init mesh uv array
                //spaceTable = new Vector3[pointCount];
                Vector2[] meshUv = new Vector2[pointCount];

                for (int y = 0, i = 0; y < imageHeight; y++)
                {
                    for (int x = 0; x < imageWidth; x++, i++)
                    {
                        Vector2 imagePos = new Vector2(x, y);

                        //spaceTable[i] = sensorInt.MapDepthPointToSpaceCoords(sensorData, imagePos, 1000);
                        //sourceImageResolution == DepthSensorBase.PointCloudResolution.ColorCameraResolution ?
                        //sensorInt.MapColorPointToSpaceCoords(sensorData, imagePos, 1000) :
                        //sensorInt.MapDepthPointToSpaceCoords(sensorData, imagePos, 1000);

                        meshUv[i] = new Vector2(imagePos.x / imageWidth, imagePos.y / imageHeight);
                    }
                }

                mesh.vertices = meshVertices;
                mesh.SetIndices(meshIndices, MeshTopology.Triangles, 0);
                mesh.uv = meshUv;

                if(showAsPointCloud)
                {
                    meshIndices = new int[pointCount];
                    for (int i = 0; i < pointCount; i++)
                        meshIndices[i] = i;
                    mesh.SetIndices(meshIndices, MeshTopology.Points, 0);
                }

                bMeshInited = true;
            }
        }


        // releases mesh-related resources
        private void FinishMesh()
        {
            if (sensorInt)
            {
                sensorInt.pointCloudColorTexture = null;
            }

            if (colorTexture && colorTextureCreated)
            {
                colorTexture.Release();
                colorTexture = null;
            }

            if (colorTextureCopy)
            {
                colorTextureCopy.Release();
                colorTextureCopy = null;
            }

            spaceTable = null;
            meshVertices = null;
            meshIndices = null;
            meshVertUsed = null;

            bMeshInited = false;
        }


        // updates the mesh according to current depth frame
        private void UpdateMesh()
        {
            if (bMeshInited && sensorData.depthImage != null && lastSpaceCoordsTime != sensorData.lastDepthFrameTime)
            {
                // check for players
                bool bHavePlayers = kinectManager.GetUsersCount() != 0;

                if ((Time.time - lastMeshUpdateTime) >= updateMeshInterval && (!updateWhenNoPlayers || !bHavePlayers))
                {
                    lastSpaceCoordsTime = sensorData.lastDepthFrameTime;
                    lastMeshUpdateTime = Time.time;

                    int imageWidth1 = imageWidth - 1, imageHeight1 = imageHeight - 1;
                    const int maxDistMm = 200; // max distance between vertices in a triangle, in mm

                    // copy the texture
                    Graphics.CopyTexture(colorTexture, colorTextureCopy);

                    for (int y = 0, di = 0, ti = 0; y < imageHeight; y++)
                    {
                        for (int x = 0; x < imageWidth; x++, di++, ti += 6)
                        {
                            ushort depth = sensorData.depthImage[di];
                            bool isValidBodyPixel = !includePlayers && bHavePlayers ? sensorData.bodyIndexImage[di] == 255 : true;

                            bool bVertexSet = false;
                            if (depth >= minDepth && depth <= maxDepth && isValidBodyPixel)
                            {
                                float fDepth = (float)depth * 0.001f;
                                Vector3 vVertex = new Vector3(spaceTable[di].x * fDepth * spaceScale.x, spaceTable[di].y * fDepth * spaceScale.y, fDepth);

                                bool bUsedVertex = !showAsPointCloud && meshVertUsed[di] != 0;
                                if (bUsedVertex || (vVertex.x >= xMin && vVertex.x <= xMax && vVertex.y >= yMin && vVertex.y <= yMax))
                                {
                                    meshVertices[di] = vVertex;

                                    if (!showAsPointCloud)
                                    {
                                        meshVertUsed[di] = 1;

                                        if (x < imageWidth1 && y < imageHeight1)
                                        {
                                            int tl = di; ushort tld = depth;
                                            int tr = tl + 1; ushort trd = sensorData.depthImage[tr];
                                            int bl = tl + imageWidth; ushort bld = sensorData.depthImage[bl];
                                            int br = bl + 1; ushort brd = sensorData.depthImage[br];

                                            float fBrDepth = (float)brd * 0.001f;
                                            Vector3 vVertex2 = new Vector3(spaceTable[br].x * fBrDepth * spaceScale.x, spaceTable[di].y * fBrDepth * spaceScale.y, fBrDepth);

                                            // 1st triangle
                                            if (tld >= minDepth && tld <= maxDepth && 
                                                trd >= minDepth && trd <= maxDepth && 
                                                bld >= minDepth && bld <= maxDepth &&
                                                vVertex2.x >= xMin && vVertex2.x <= xMax && vVertex2.y >= yMin && vVertex2.y <= yMax &&
                                                Mathf.Abs(trd - tld) < maxDistMm && Mathf.Abs(bld - tld) < maxDistMm)
                                            {
                                                meshIndices[ti] = bl;
                                                meshIndices[ti + 1] = tr;
                                                meshIndices[ti + 2] = tl;
                                                meshVertUsed[trd] = meshVertUsed[bld] = 1;
                                            }
                                            else
                                            {
                                                meshIndices[ti] = meshIndices[ti + 1] = meshIndices[ti + 2] = 0;
                                                meshVertUsed[trd] = meshVertUsed[bld] = 0;
                                            }

                                            // 2nd triangle
                                            if (bld >= minDepth && bld <= maxDepth && 
                                                trd >= minDepth && trd <= maxDepth && 
                                                brd >= minDepth && brd <= maxDepth &&
                                                vVertex2.x >= xMin && vVertex2.x <= xMax && vVertex2.y >= yMin && vVertex2.y <= yMax &&
                                                Mathf.Abs(trd - bld) < maxDistMm && Mathf.Abs(brd - bld) < maxDistMm)
                                            {
                                                meshIndices[ti + 3] = br;
                                                meshIndices[ti + 4] = tr;
                                                meshIndices[ti + 5] = bl;
                                                meshVertUsed[bld] = meshVertUsed[trd] = meshVertUsed[brd] = 1;
                                            }
                                            else
                                            {
                                                meshIndices[ti + 3] = meshIndices[ti + 4] = meshIndices[ti + 5] = 0;
                                                meshVertUsed[bld] = meshVertUsed[trd] = meshVertUsed[brd] = 0;
                                            }
                                        }
                                        else
                                        {
                                            meshIndices[ti] = meshIndices[ti + 1] = meshIndices[ti + 2] = 0;
                                            meshIndices[ti + 3] = meshIndices[ti + 4] = meshIndices[ti + 5] = 0;
                                        }
                                    }

                                    bVertexSet = true;
                                }
                            }

                            if (!bVertexSet)
                            {
                                meshVertices[di] = Vector3.zero;

                                if (!showAsPointCloud)
                                {
                                    meshIndices[ti] = meshIndices[ti + 1] = meshIndices[ti + 2] = 0;
                                    meshIndices[ti + 3] = meshIndices[ti + 4] = meshIndices[ti + 5] = 0;
                                }
                            }
                        }
                    }

                    mesh.vertices = meshVertices;

                    if(!showAsPointCloud)
                    {
                        mesh.SetIndices(meshIndices, MeshTopology.Triangles, 0);
                    }

                    mesh.RecalculateBounds();

                    if (updateColliderInterval > 0 && (Time.time - lastColliderUpdateTime) >= updateColliderInterval)
                    {
                        lastColliderUpdateTime = Time.time;
                        MeshCollider meshCollider = GetComponent<MeshCollider>();

                        if (meshCollider)
                        {
                            meshCollider.sharedMesh = null;
                            meshCollider.sharedMesh = mesh;
                        }
                    }

                }
            }
        }

    }
}