using CalcVolServe.Models;
using OSGeo.GDAL;
using OSGeo.OGR;
using OSGeo.OSR;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Web;

namespace CalcVolServe.cs
{
    public class GdalOp
    {
        private static bool isInited = false;

        private static object obj = new object();

        private static readonly char[] c1 = new char[] { ',' };

        private static readonly char[] c2 = new char[] { ' ' };

        public GdalOp()
        {
            lock (obj)
            {
                if (!isInited)
                {
                    RegisterGDal();
                    isInited = true;
                }
            }
        }

        public void RegisterGDal()
        {
            string path = Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, "GDAL");

            string dir = Environment.GetEnvironmentVariable("PATH");
            //if (dir.IndexOf(path) == -1)
            //{
            //    string gPath = dir + path + ";" + Path.Combine(path, "plugins") + ";";
            //    Environment.SetEnvironmentVariable("PATH", gPath);
            //}

            //string gdalData = Path.Combine(path, "gdal-data");
            //Environment.SetEnvironmentVariable("GDAL_DATA", gdalData);
            //Gdal.SetConfigOption("GDAL_DATA", gdalData);

            //Environment.SetEnvironmentVariable("GEOTIFF_CSV", gdalData);
            //Gdal.SetConfigOption("GEOTIFF_CSV", gdalData);

            //string driverPath = Path.Combine(path, "plugins");
            //Environment.SetEnvironmentVariable("GDAL_DRIVER_PATH", driverPath);
            //Gdal.SetConfigOption("GDAL_DRIVER_PATH", driverPath);

            //string projSharePath = Path.Combine(path, "share");
            //Environment.SetEnvironmentVariable("PROJ_LIB", projSharePath);
            //Gdal.SetConfigOption("PROJ_LIB", projSharePath);

            Gdal.SetConfigOption("GDAL_FILENAME_IS_UTF8", "YES"); // NO
            Gdal.SetConfigOption("SHAPE_ENCODING", "CP936"); // 空,gb2312,CP936

            Ogr.RegisterAll();
            Gdal.AllRegister();
        }

        #region 读取shp
        public List<Triangle> ReadShp(string file, string wkt)
        {
            OSGeo.OGR.Driver driver = Ogr.GetDriverByName("ESRI Shapefile");
            DataSource shpDS = driver.Open(file, 0);
            if (shpDS == null)
            {
                driver.Dispose();
                return null;
            }

            Layer fLayer = shpDS.GetLayerByIndex(0);
            SpatialReference sr = fLayer.GetSpatialRef();
            Geometry ring = CreateRing(wkt, sr);
            string layerName = fLayer.GetName();
            fLayer.Dispose();

            //string name = Path.GetFileNameWithoutExtension(shpFile);
            string sql = string.Format("select FID from {0}", layerName);

            Layer layer = shpDS.ExecuteSQL(sql, ring, null);
            if (layer == null)
            {
                Dispose(null, driver, shpDS, null);
                return null;
            }

            List<Triangle> list = new List<Triangle>();
            Feature f = layer.GetNextFeature();
            while (f != null)
            {
                Geometry g = f.GetGeometryRef();
                if (g != null && g.GetGeometryName() == "POLYGON" && g.GetGeometryCount() > 0)
                {
                    Triangle t = new Triangle();
                    Geometry r = g.GetGeometryRef(0);
                    for (int i = 0, c = r.GetPointCount() - 1; i < c; i++)
                    {
                        double[] arr = new double[] { 0, 0, 0 };
                        r.GetPoint(i, arr);

                        Point p = new Point(arr[0], arr[1], arr[2]);
                        t.Points.Add(p);
                    }
                    list.Add(t);
                }

                f = layer.GetNextFeature();
            }

            Dispose(null, driver, shpDS, layer);

            return list;
        }

        public Geometry CreateRing(string wkt, SpatialReference sr)
        {
            string str = wkt.Replace("LINEARRING Z (", "").Replace(")", "");
            string[] strs = str.Split(c1);

            Geometry ring = new Geometry(wkbGeometryType.wkbLinearRing);
            foreach (string s in strs)
            {
                string[] arr = s.Trim().Split(c2);
                ring.AddPoint_2D(double.Parse(arr[0]), double.Parse(arr[1]));
            }

            Geometry polygon = new Geometry(wkbGeometryType.wkbPolygon);
            polygon.AssignSpatialReference(sr);
            polygon.AddGeometry(ring);

            return polygon;
        }

        private void Dispose(Dataset ds, OSGeo.OGR.Driver driver, DataSource dS, Layer layer)
        {
            if (layer != null)
            {
                layer.Dispose();
            }
            if (dS != null)
            {
                dS.Dispose();
            }
            if (driver != null)
            {
                driver.Dispose();
            }
            if (ds != null)
            {
                ds.Dispose();
            }
        }
        #endregion

        #region 读取tif
        public void ReadTif(string file, List<Triangle> list, string prop)
        {
            Type type = typeof(Point);
            PropertyInfo pi = type.GetProperty(prop);
            if (pi == null) return;

            Dataset ds = Gdal.Open(file, Access.GA_ReadOnly);
            if (ds == null) return;

            Band band = ds.GetRasterBand(1);
            foreach (Triangle t in list)
            {
                foreach (Point p in t.Points)
                {
                    int[] xy = Geo2ImageSpace(ds, p.X, p.Y);
                    if (xy[0] < 1 || xy[1] < 1 || xy[0] > ds.RasterXSize || xy[1] > ds.RasterYSize)
                    {
                        continue;
                    }

                    double val = ReadBand(band, xy[0], xy[1]);
                    pi.SetValue(p, val);
                }
            }

            band.Dispose();
            ds.Dispose();
        }

        private double ReadBand(Band band, int row, int col)
        {
            double val = 0;
            switch (band.DataType)
            {
                case DataType.GDT_Byte:
                    //public CPLErr ReadRaster(int xOff, int yOff, int xSize, int ySize, byte[] buffer, int buf_xSize, int buf_ySize, int pixelSpace, int lineSpace);
                    //byte[] byteBuffer = new byte[band.XSize * band.YSize];

                    short[] byteBuffer = new short[1];
                    band.ReadRaster(row, col, 1, 1, byteBuffer, 1, 1, 1, 1);
                    val = byteBuffer[0];
                    break;
                case DataType.GDT_Int16:
                case DataType.GDT_CInt16:
                case DataType.GDT_UInt16:
                    //short[] shortBuffer = new short[band.XSize * band.YSize];
                    //public CPLErr ReadRaster(int xOff, int yOff, int xSize, int ySize, short[] buffer, int buf_xSize, int buf_ySize, int pixelSpace, int lineSpace);

                    //short[] shortBuffer = new short[band.XSize * band.YSize];
                    //band.ReadRaster(0, 0, band.XSize, band.YSize, shortBuffer, band.XSize, band.YSize, row, col);

                    short[] shortBuffer = new short[1];
                    band.ReadRaster(row, col, 1, 1, shortBuffer, 1, 1, 1, 1);
                    val = shortBuffer[0];
                    break;
                case DataType.GDT_Int32:
                case DataType.GDT_CInt32:
                case DataType.GDT_UInt32:
                    //public CPLErr ReadRaster(int xOff, int yOff, int xSize, int ySize, int[] buffer, int buf_xSize, int buf_ySize, int pixelSpace, int lineSpace);

                    int[] intBuffer = new int[1];
                    band.ReadRaster(row, col, 1, 1, intBuffer, 1, 1, 1, 1);
                    val = intBuffer[0];
                    break;
                case DataType.GDT_Float32:
                case DataType.GDT_CFloat32:
                    //public CPLErr ReadRaster(int xOff, int yOff, int xSize, int ySize, float[] buffer, int buf_xSize, int buf_ySize, int pixelSpace, int lineSpace);

                    float[] floatBuffer = new float[1];
                    band.ReadRaster(row, col, 1, 1, floatBuffer, 1, 1, 1, 1);
                    val = floatBuffer[0];
                    break;
                case DataType.GDT_Float64:
                case DataType.GDT_CFloat64:
                    //public CPLErr ReadRaster(int xOff, int yOff, int xSize, int ySize, double[] buffer, int buf_xSize, int buf_ySize, int pixelSpace, int lineSpace);

                    double[] doubleBuffer = new double[1];
                    band.ReadRaster(row, col, 1, 1, doubleBuffer, 1, 1, 1, 1);
                    val = doubleBuffer[0];
                    break;
            }

            return val;
        }

        private int[] Geo2ImageSpace(Dataset ds, double x, double y)
        {
            double[] transform = new double[6];
            ds.GetGeoTransform(transform); // 影像坐标变换参数
            //string prj = ds.GetProjection(); // 影像坐标系信息（WKT格式字符串）

            int col = (int)((y * transform[1] - x * transform[4] + transform[0] * transform[4] - transform[3] * transform[1]) / (transform[5] * transform[1] - transform[2] * transform[4])); // 像素所在列
            int row = (int)((x - transform[0] - col * transform[2]) / transform[1]); // 像素所在行

            return new int[] { row, col };
        }
        #endregion
    }
}