using ProjNet.CoordinateSystems.Transformations;
using ProjNet.CoordinateSystems;
using ProjNet;
using System.Collections.Generic;
using System.Linq;
using NetTopologySuite.Geometries;

namespace gehGassi.Common.Data
{
    /// <summary>
    /// Erweiterungen
    /// </summary>
    public static class Extensions
    {
        public static string ToPascalCase(this string value)
        {
            // If there are 0 or 1 characters, just return the string.
            if (value == null) return value;
            if (value.Length < 2) return value.ToUpper();

            var delimiter = new[] { ' ', '-', '_', '.' };

            var charArray = new char[value.Length];
            var newWord = true;
            for (var i = 0; i < value.Length; ++i)
            {
                var currentChar = value[i];
                if (char.IsLetter(currentChar))
                {
                    if (newWord || char.IsUpper(currentChar))
                    {
                        newWord = false;
                        currentChar = char.ToUpper(currentChar);
                    }
                    else
                    {
                        currentChar = char.ToLower(currentChar);
                    }
                }
                else if (delimiter.Contains(currentChar))
                {
                    newWord = true;
                }
                charArray[i] = currentChar;
            }
            return new string(charArray);
        }

        /// <summary>
        /// Gibt einen Text gekürzt auf eine max. Zeichenzahl zurück.
        /// Wenn der Text länger als maxLength war, wird "..." angehängt.
        /// </summary>
        /// <param name="text">Text</param>
        /// <param name="maxLength">max. Länge</param>
        /// <returns>Text gekürzt</returns>
        public static string Ellipsis(this string text, int maxLength)
        {
            if (string.IsNullOrWhiteSpace(text))
                return "";
            if (maxLength > 0 && text.Length > maxLength)
            {
                return text.Substring(0, maxLength) + "...";
            }
            return text;
        }

        /// <summary>
        /// Hilfsfunktion die aus einem String "gefährlichen" Text für SQL-Injection Attacken entfernt
        /// </summary>
        /// <param name="text">Text</param>
        /// <param name="maxLength">Max. Länge des Textes</param>
        /// <returns>Bereinigter Text</returns>
        public static string SanitizeSqlInjection(this string text, int maxLength)
        {
            if (string.IsNullOrWhiteSpace(text))
                return "";

            if (text.Length > maxLength)
                text = text.Substring(0, maxLength);

            var result = text.Trim().Replace(";", "");
            result = result.Replace("'", "");
            result = result.Replace("--", "");
            result = result.Replace("/*", "");
            result = result.Replace("*/", "");
            result = result.Replace("xp_", "");

            return result;
        }

        /// <summary>
        /// Hilfsfunktion die aus einem Text einen filter-Text für felxible Like-Abfragen erstellt.
        /// * wird mit SQL-Wildcard % ersetzt
        /// - wird mit SQL-Wildcard % ersetzt
        /// " " wird mit SQL-Wildcard % ersetzt
        /// </summary>
        /// <param name="text">Text der bearbeitet werden soll</param>
        /// <returns>SQL-Like angepasster Text</returns>
        public static string SqlFilter(this string text)
        {
            if (string.IsNullOrWhiteSpace(text))
                return "";

            var result = text.Trim().Replace("*", "%");
            result = result.Replace("-", "%");
            result = result.Replace(" ", "%");

            return $"%{result}%";
        }

        private static readonly CoordinateSystemServices _coordinateSystemServices
        = new CoordinateSystemServices(
            new Dictionary<int, string>
            {
                // Coordinate systems:

                [4326] = GeographicCoordinateSystem.WGS84.WKT,

                // This coordinate system covers the area of our data.
                // Different data requires a different coordinate system.
                [2855] =
                    @"
                        PROJCS[""NAD83(HARN) / Washington North"",
                            GEOGCS[""NAD83(HARN)"",
                                DATUM[""NAD83_High_Accuracy_Regional_Network"",
                                    SPHEROID[""GRS 1980"",6378137,298.257222101,
                                        AUTHORITY[""EPSG"",""7019""]],
                                    AUTHORITY[""EPSG"",""6152""]],
                                PRIMEM[""Greenwich"",0,
                                    AUTHORITY[""EPSG"",""8901""]],
                                UNIT[""degree"",0.01745329251994328,
                                    AUTHORITY[""EPSG"",""9122""]],
                                AUTHORITY[""EPSG"",""4152""]],
                            PROJECTION[""Lambert_Conformal_Conic_2SP""],
                            PARAMETER[""standard_parallel_1"",48.73333333333333],
                            PARAMETER[""standard_parallel_2"",47.5],
                            PARAMETER[""latitude_of_origin"",47],
                            PARAMETER[""central_meridian"",-120.8333333333333],
                            PARAMETER[""false_easting"",500000],
                            PARAMETER[""false_northing"",0],
                            UNIT[""metre"",1,
                                AUTHORITY[""EPSG"",""9001""]],
                            AUTHORITY[""EPSG"",""2855""]]
                    ",
                [3035] =
                    @"
                        PROJCS[""ETRS89-extended / LAEA Europe"",
                            GEOGCS[""ETRS89"",
                                DATUM[""European_Terrestrial_Reference_System_1989"",
                                    SPHEROID[""GRS 1980"",6378137,298.257222101],
                                    TOWGS84[0,0,0,0,0,0,0]],
                                PRIMEM[""Greenwich"",0],
                                UNIT[""degree"",0.0174532925199433,
                                    AUTHORITY[""EPSG"",""9122""]],
                                AUTHORITY[""EPSG"",""4258""]],
                            PROJECTION[""Lambert_Azimuthal_Equal_Area""],
                            PARAMETER[""latitude_of_center"",52],
                            PARAMETER[""longitude_of_center"",10],
                            PARAMETER[""false_easting"",4321000],
                            PARAMETER[""false_northing"",3210000],
                            UNIT[""metre"",1],
                            AUTHORITY[""EPSG"",""3035""]]
                        "
            });

        public static Geometry ProjectTo(this Geometry geometry, int srid)
        {
            var transformation = _coordinateSystemServices.CreateTransformation(geometry.SRID, srid);

            var result = geometry.Copy();
            result.Apply(new MathTransformFilter(transformation.MathTransform));

            return result;
        }

        private class MathTransformFilter : ICoordinateSequenceFilter
        {
            private readonly MathTransform _transform;

            public MathTransformFilter(MathTransform transform)
                => _transform = transform;

            public bool Done => false;
            public bool GeometryChanged => true;

            public void Filter(CoordinateSequence seq, int i)
            {
                var x = seq.GetX(i);
                var y = seq.GetY(i);
                var z = seq.GetZ(i);
                _transform.Transform(ref x, ref y, ref z);
                seq.SetX(i, x);
                seq.SetY(i, y);
                seq.SetZ(i, z);
            }
        }
    }
}