using DataLoader.Model;
using OSGeo.GDAL;
using OSGeo.OGR;
using OSGeo.OSR;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace DataLoader.CS
{
    public class GdalHelper
    {
        #region 成员变量+构造函数+初始化
        private static bool isInited = false;

        private static GdalHelper instance = null;

        private static readonly object obj = new object();

        public static SpatialReference sr4326 = null;

        public static SpatialReference sr4490 = null;

        public static SpatialReference sr104903 = null;

        public static string MOON200 = "GCS_Moon_2000";

        public static List<string> EPSGS = new List<string>() { "EPSG:4326", "EPSG:4490", "ESRI:104903" };

        /// <summary>
        /// 构造函数
        /// </summary>
        private GdalHelper()
        {
            lock (obj)
            {
                if (!isInited)
                {
                    RegisterGDal();

                    sr4326 = new SpatialReference(null);
                    sr4326.ImportFromEPSG(4326);

                    sr4490 = new SpatialReference(null);
                    sr4490.ImportFromEPSG(4490);

                    string wkt = "GEOGCS[\"GCS_Moon_2000\",\r\n" +
                        "    DATUM[\"D_Moon_2000\",\r\n" +
                        "        SPHEROID[\"Moon_2000_IAU_IAG\",1737400,0,\r\n" +
                        "            AUTHORITY[\"ESRI\",\"107903\"]],\r\n" +
                        "        AUTHORITY[\"ESRI\",\"106903\"]],\r\n" +
                        "    PRIMEM[\"Reference_Meridian\",0,\r\n" +
                        "        AUTHORITY[\"ESRI\",\"108900\"]],\r\n" +
                        "    UNIT[\"degree\",0.0174532925199433,\r\n" +
                        "        AUTHORITY[\"EPSG\",\"9122\"]],\r\n" +
                        "    AUTHORITY[\"ESRI\",\"104903\"]]";
                    sr104903 = new SpatialReference(wkt);
                    //sr104903.ImportFromWkt(ref wkt);

                    isInited = true;
                }
            }
        }

        /// <summary>
        /// 实例
        /// </summary>
        public static GdalHelper Instance
        {
            get
            {
                lock (obj)
                {
                    if (null == instance) instance = new GdalHelper();

                    return instance;
                }
            }
        }

        /// <summary>
        /// 注册GDAL
        /// </summary>
        public void RegisterGDal()
        {
            string gdalData = Path.Combine(Tools.BaseDir, "gdal-data");
            Environment.SetEnvironmentVariable("GDAL_DATA", gdalData);

            string proj7 = Path.Combine(Tools.BaseDir, "proj7\\share");
            Environment.SetEnvironmentVariable("PROJ_LIB", proj7);

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

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

        #region 读取栅格信息
        /// <summary>
        /// 读取栅格信息
        /// </summary>
        public void ReadRasterInfo(ViewData vd)
        {
            Dataset ds = null;
            try
            {
                ds = Gdal.Open(vd.FilePath, Access.GA_ReadOnly);
                if (null == ds || ds.RasterCount == 0) return;

                vd.Meta.gridsize = string.Format("{0},{1}", ds.RasterXSize, ds.RasterYSize); // 行列数

                SpatialReference sr = ds.GetSpatialRef();
                if (sr != null)
                {
                    vd.Meta.coor_sys = sr.GetName(); // 坐标系统
                    if (MOON200 == vd.Meta.coor_sys)
                    {
                        vd.Meta.epsg = "ESRI:104903"; // EPSG编码
                    }
                    else
                    {
                        string code = sr.GetAuthorityCode(null);
                        vd.Meta.epsg = string.IsNullOrEmpty(code) ? null : "EPSG:" + code; // EPSG编码
                    }
                }

                vd.Meta.bands = ds.RasterCount.ToString(); // 波段数
                vd.Meta.band_type = Enum.GetName(typeof(DataType), ds.GetRasterBand(1).DataType); // 数据类型
                ColorTable ct = ds.GetRasterBand(1).GetRasterColorTable();
                vd.Meta.ct = null == ct ? null : ct.ToString(); // 数据颜色表
                vd.Meta.h_datum = null; // 高程基准

                double[] transform = new double[6];
                ds.GetGeoTransform(transform);
                vd.Meta.resolution = string.Format("{0},{1}", transform[1], transform[5]); // 分辨率

                if (!EPSGS.Contains(vd.Meta.epsg)) return;

                Geometry minPoint = GetMinPoint(ds);
                Geometry maxPoint = GetMaxPoint(ds);
                double xmin = minPoint.GetX(0);
                double ymin = minPoint.GetY(0);
                double xmax = maxPoint.GetX(0);
                double ymax = maxPoint.GetY(0);
                string wkt = string.Format("POLYGON (({0} {1},{2} {3},{4} {5},{6} {7},{0} {1}))", xmin, ymax, xmax, ymax, xmax, ymin, xmin, ymin);

                vd.Meta.geom = wkt; // 四至范围
            }
            catch (Exception ex)
            {
                LogOut.Error(ex.StackTrace);
            }
            finally
            {
                if (ds != null) ds.Dispose();
            }
        }

        /// <summary>
        /// 获取Dataset的最小点
        /// </summary>
        private Geometry GetMinPoint(Dataset ds)
        {
            double[] transform = new double[6];
            ds.GetGeoTransform(transform);

            string epsg = ds.GetSpatialRef().GetAuthorityCode(null);
            double xMin = transform[0];
            double yMin = transform[3] - ds.RasterYSize * transform[1];

            Geometry point = new Geometry(wkbGeometryType.wkbPoint);
            point.AddPoint(xMin, yMin, 0);

            return Transform(ds, point, epsg);
        }

        /// <summary>
        /// 获取Dataset的最大点
        /// </summary>
        private Geometry GetMaxPoint(Dataset ds)
        {
            double[] transform = new double[6];
            ds.GetGeoTransform(transform);

            string epsg = ds.GetSpatialRef().GetAuthorityCode(null);
            double xMax = transform[0] + (ds.RasterXSize * transform[1]);
            double yMax = transform[3];

            Geometry point = new Geometry(wkbGeometryType.wkbPoint);
            point.AddPoint(xMax, yMax, 0);

            return Transform(ds, point, epsg);
        }

        /// <summary>
        /// 坐标转换
        /// </summary>
        private Geometry Transform(Dataset ds, Geometry point, string epsg)
        {
            if (string.IsNullOrEmpty(epsg))
            {
                point.AssignSpatialReference(sr104903);
                return point;
            }
            if ("4326" == epsg)
            {
                point.AssignSpatialReference(sr4326);
                return point;
            }
            if ("4490" == epsg)
            {
                point.AssignSpatialReference(sr4490);
                return point;
            }

            point.AssignSpatialReference(ds.GetSpatialRef());
            if (ds.GetSpatialRef().GetName().Contains("CGCS2000"))
            {
                point.TransformTo(sr4490);
            }
            else
            {
                point.TransformTo(sr4326);
            }

            return point;
        }

        /// <summary>
        /// 创建多边形
        /// </summary>
        public Geometry CreatePolygon(double xmin, double xmax, double ymin, double ymax, SpatialReference sr)
        {
            string kwt = string.Format("POLYGON (({0} {1},{2} {3},{4} {5},{6} {7},{0} {1}))", xmin, ymax, xmax, ymax, xmax, ymin, xmin, ymin);
            Geometry geo = Geometry.CreateFromWkt(kwt);
            geo.AssignSpatialReference(sr);

            return geo;
        }
        #endregion
    }
}