using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace FastReport.Map.Import.Shp
{
    /// <summary>
    /// Represents loading map data from dbf-file.
    /// </summary>
    public class DbfFileImport
    {
        #region Fields

        private string filter;
        private Stream stream;
        private MapLayer layer;
        private List<DBaseFieldDescription> fields;
        private Encoding encoding;

        #endregion // Fields

        #region Properties

        /// <summary>
        /// Gets or sets the filter string used in an open file dialog.
        /// </summary>
        public string Filter
        {
            get { return filter; }
            protected set { filter = value; }
        }

        #endregion // Properties

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="DbfFileImport"/> class.
        /// </summary>
        public DbfFileImport()
        {
            filter = GetFilter();
            fields = new List<DBaseFieldDescription>();
            encoding = Encoding.ASCII;
        }

        #endregion // Constructors

        #region Private Methods

        private void LoadFieldsDescription()
        {
            byte[] buffer = new byte[11];
            string name = "";
            string type = "";
            int length = 0;

            stream.Seek(32, SeekOrigin.Begin);
            for (int i = 0; i < 128; i++)
            {
                stream.Read(buffer, 0, 11);
                name = encoding.GetString(buffer);
                name = name.Remove(name.IndexOf('\0'));

                stream.Read(buffer, 0, 1);
                type = encoding.GetString(buffer, 0, 1);

                stream.Seek(4, SeekOrigin.Current);
                stream.Read(buffer, 0, 1);
                length = (int)buffer[0];

                fields.Add(new DBaseFieldDescription(name, type, length));

                stream.Seek(15, SeekOrigin.Current);
                stream.Read(buffer, 0, 1);
                if (buffer[0] == 0x0D)
                {
                    break;
                }
                else
                {
                    stream.Seek(-1, SeekOrigin.Current);
                }
            }
        }

        private string LoadField(int length)
        {
            string field = "";
            byte[] buffer = new byte[length];
            stream.Read(buffer, 0, length);
            field = encoding.GetString(buffer);
            return field;
        }

        private string LoadChar(int length)
        {
            string field = LoadField(length);
            field = field.TrimEnd(null);
            return field;
        }

        private string LoadDate(int length)
        {
            string field = LoadField(length);
            char[] f = field.ToCharArray();
            field = f[6].ToString() + f[7].ToString() + "." + f[4].ToString() + f[5].ToString() + "." + f[0].ToString() + f[1].ToString() + f[2].ToString() + f[3].ToString();
            return field;
        }

        private string LoadNumeric(int length)
        {
            string field = LoadField(length);
            field = field.Trim();
            return field;
        }

        private string LoadLogical(int length)
        {
            string field = LoadField(length).ToUpper();
            if (field == "T" || field == "Y")
            {
                field = "true";
            }
            else if (field == "F" || field == "N")
            {
                field = "false";
            }
            else
            {
                field = "";
            }
            return field;
        }

        private void LoadRecords(int numRecords, int recordLength)
        {
            for (int i = 0; i < numRecords; i++)
            {
                stream.Seek(1, SeekOrigin.Current);
                foreach (DBaseFieldDescription f in fields)
                {
                    string value = "";
                    switch (f.Type)
                    {
                        case DBaseFieldType.Char:
                            value = LoadChar(f.Length);
                            break;
                        case DBaseFieldType.Date:
                            value = LoadDate(f.Length);
                            break;
                        case DBaseFieldType.Numeric:
                            value = LoadNumeric(f.Length);
                            break;
                        case DBaseFieldType.Logical:
                            value = LoadLogical(f.Length);
                            break;
                    }

                    if (i < layer.Shapes.Count)
                        layer.Shapes[i].SpatialData.SetValue(f.Name, value);
                }
            }
        }

        private Encoding GetEncoding(int id)
        {
            int codepage = 0;

            #region switch

            switch (id)
            {
                case 1:
                    codepage = 437;
                    break;
                case 2:
                    codepage = 850;
                    break;
                case 3:
                    codepage = 1252;
                    break;
                case 4:
                    codepage = 10000;
                    break;
                case 8:
                    codepage = 865;
                    break;
                case 9:
                    codepage = 437;
                    break;
                case 10:
                    codepage = 850;
                    break;
                case 11:
                    codepage = 437;
                    break;
                case 13:
                    codepage = 437;
                    break;
                case 14:
                    codepage = 850;
                    break;
                case 15:
                    codepage = 437;
                    break;
                case 16:
                    codepage = 850;
                    break;
                case 17:
                    codepage = 437;
                    break;
                case 18:
                    codepage = 850;
                    break;
                case 19:
                    codepage = 932;
                    break;
                case 20:
                    codepage = 850;
                    break;
                case 21:
                    codepage = 437;
                    break;
                case 22:
                    codepage = 850;
                    break;
                case 23:
                    codepage = 865;
                    break;
                case 24:
                    codepage = 437;
                    break;
                case 25:
                    codepage = 437;
                    break;
                case 26:
                    codepage = 850;
                    break;
                case 27:
                    codepage = 437;
                    break;
                case 28:
                    codepage = 863;
                    break;
                case 29:
                    codepage = 850;
                    break;
                case 31:
                    codepage = 852;
                    break;
                case 34:
                    codepage = 852;
                    break;
                case 35:
                    codepage = 852;
                    break;
                case 36:
                    codepage = 860;
                    break;
                case 37:
                    codepage = 850;
                    break;
                case 38:
                    codepage = 866;
                    break;
                case 55:
                    codepage = 850;
                    break;
                case 64:
                    codepage = 852;
                    break;
                case 77:
                    codepage = 936;
                    break;
                case 78:
                    codepage = 949;
                    break;
                case 79:
                    codepage = 950;
                    break;
                case 80:
                    codepage = 874;
                    break;
                case 87:
                    codepage = 0;
                    break;
                case 88:
                    codepage = 1252;
                    break;
                case 89:
                    codepage = 1252;
                    break;
                case 100:
                    codepage = 852;
                    break;
                case 101:
                    codepage = 866;
                    break;
                case 102:
                    codepage = 865;
                    break;
                case 103:
                    codepage = 861;
                    break;
                case 104:
                    codepage = 895;
                    break;
                case 105:
                    codepage = 620;
                    break;
                case 106:
                    codepage = 737;
                    break;
                case 107:
                    codepage = 857;
                    break;
                case 108:
                    codepage = 863;
                    break;
                case 120:
                    codepage = 950;
                    break;
                case 121:
                    codepage = 949;
                    break;
                case 122:
                    codepage = 936;
                    break;
                case 123:
                    codepage = 932;
                    break;
                case 124:
                    codepage = 874;
                    break;
                case 134:
                    codepage = 737;
                    break;
                case 135:
                    codepage = 852;
                    break;
                case 136:
                    codepage = 857;
                    break;
                case 150:
                    codepage = 10007;
                    break;
                case 151:
                    codepage = 10029;
                    break;
                case 152:
                    codepage = 10006;
                    break;
                case 200:
                    codepage = 1250;
                    break;
                case 201:
                    codepage = 1251;
                    break;
                case 202:
                    codepage = 1254;
                    break;
                case 203:
                    codepage = 1253;
                    break;
                case 204:
                    codepage = 1257;
                    break;
                default:
                    codepage = 0;
                    break;
            }

            #endregion // switch

            if (codepage == 0)
            {
                return Encoding.ASCII;
            }
            else
            {
                return Encoding.GetEncoding(codepage);
            }
        }

        private void LoadFileHeader()
        {
            byte[] buffer = new byte[4];

            stream.Seek(0, SeekOrigin.Begin);
            stream.Read(buffer, 0, 1);

            stream.Seek(4, SeekOrigin.Begin);
            stream.Read(buffer, 0, 4);
            if (!BitConverter.IsLittleEndian)
            {
                Array.Reverse(buffer, 0, 4);
            }
            int numRecords = BitConverter.ToInt32(buffer, 0);

            stream.Read(buffer, 0, 2);
            if (!BitConverter.IsLittleEndian)
            {
                Array.Reverse(buffer, 0, 2);
            }
            int headerLength = (int)BitConverter.ToInt16(buffer, 0);

            stream.Read(buffer, 0, 2);
            if (!BitConverter.IsLittleEndian)
            {
                Array.Reverse(buffer, 0, 2);
            }
            int recordLength = (int)BitConverter.ToInt16(buffer, 0);

            stream.Seek(29, SeekOrigin.Begin);
            stream.Read(buffer, 0, 1);
            encoding = GetEncoding((int)buffer[0]);

            LoadFieldsDescription();
            LoadRecords(numRecords, recordLength);
        }

        private void LoadFile(MapLayer layer, Stream stream)
        {
            this.stream = stream;
            this.layer = layer;
            LoadFileHeader();
        }

        #endregion // Private Methods

        #region Protected Methods

        /// <summary>
        /// Returns a file filter for an open file dialog.
        /// </summary>
        /// <returns>String that contains a file filter.</returns>
        protected string GetFilter()
        {
            return new FastReport.Utils.MyRes("FileFilters").Get("DbfFile");
        }

        #endregion // Protected Methods

        #region Public Methods

        /// <summary>
        /// Imports the map data from a specified file into a specfied layer.
        /// </summary>
        /// <param name="layer">The MapObject for an importing map.</param>
        /// <param name="filename">The name of a file that contains map.</param>
        public void ImportFile(MapLayer layer, string filename)
        {
            using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
            {
                LoadFile(layer, stream);
            }
        }

        #endregion // Public Methods
    }

    /// <summary>
    /// Represents the description of dBase field.
    /// </summary>
    public class DBaseFieldDescription
    {
        #region Fields

        private string name;
        private DBaseFieldType type;
        private int length;

        #endregion // Fields

        #region Properties

        /// <summary>
        /// Gets the field name.
        /// </summary>
        public string Name
        {
            get { return name; }
        }

        /// <summary>
        /// Gets the field type.
        /// </summary>
        public DBaseFieldType Type
        {
            get { return type; }
        }

        /// <summary>
        /// Gets the field length.
        /// </summary>
        public int Length
        {
            get { return length; }
        }

        #endregion // Properties

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="DBaseFieldDescription"/> class.
        /// </summary>
        public DBaseFieldDescription()
        {
            name = "";
            type = DBaseFieldType.Char;
            length = 0;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="DBaseFieldDescription"/> class with a specified parameters.
        /// </summary>
        /// <param name="name">The field name.</param>
        /// <param name="type">The field type.</param>
        /// <param name="length">The field length.</param>
        public DBaseFieldDescription(string name, DBaseFieldType type, int length)
        {
            this.name = name;
            this.type = type;
            this.length = length;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="DBaseFieldDescription"/> class with a specified parameters.
        /// </summary>
        /// <param name="name">The field name.</param>
        /// <param name="type">The field type.</param>
        /// <param name="length">The field length.</param>
        public DBaseFieldDescription(string name, string type, int length)
        {
            this.name = name;
            InitType(type);
            this.length = length;
        }

        #endregion // Constructors

        #region Private Methods

        private void InitType(string type)
        {
            if (type == "C")
            {
                this.type = DBaseFieldType.Char;
            }
            else if (type == "D")
            {
                this.type = DBaseFieldType.Date;
            }
            else if (type == "N")
            {
                this.type = DBaseFieldType.Numeric;
            }
            else if (type == "L")
            {
                this.type = DBaseFieldType.Logical;
            }
            else if (type == "M")
            {
                this.type = DBaseFieldType.Memo;
            }
            else
            {
                this.type = DBaseFieldType.Char;
            }
        }

        #endregion // Private Methods
    }

    /// <summary>
    /// The type of dBase field.
    /// </summary>
    public enum DBaseFieldType
    {
        /// <summary>
        /// Character field.
        /// </summary>
        Char,

        /// <summary>
        /// Date field.
        /// </summary>
        Date,

        /// <summary>
        /// Numeric field.
        /// </summary>
        Numeric,

        /// <summary>
        /// Logical field.
        /// </summary>
        Logical,

        /// <summary>
        /// Memo field.
        /// </summary>
        Memo
    }
}