using System;

namespace GisSharpBlog.NetTopologySuite.IO
{
    /// <summary>
    /// Class for holding the information assicated with a dbase field.
    /// </summary>
    public class DbaseFieldDescriptor
    {
        // Field Name

        // Field Type (C N L D or M)

        // Field Data Address offset from the start of the record.

        // Length of the data in bytes

        // Field decimal count in Binary, indicating where the decimal is

        /// <summary>
        /// Field Name.
        /// </summary>
        public string Name { get; set; }

        /// <summary>
        /// Field Type (C N L D or M).
        /// </summary>
        public char DbaseType { get; set; }

        /// <summary>
        /// Field Data Address offset from the start of the record.
        /// </summary>
        public int DataAddress { get; set; }

        /// <summary>
        /// Length of the data in bytes.
        /// </summary>
        public int Length { get; set; }

        /// <summary>
        /// Field decimal count in Binary, indicating where the decimal is.
        /// </summary>
        public int DecimalCount { get; set; }

        /// <summary>
        /// Returns the equivalent CLR type for this field.
        /// </summary>
        public Type Type
        {
            get
            {
                Type type;
                switch (DbaseType)
                {
                    case 'L': // logical data type, one character (T,t,F,f,Y,y,N,n)
                        type = typeof(bool);
                        break;
                    case 'C': // char or string
                        type = typeof(string);
                        break;
                    case 'D': // date
                        type = typeof(DateTime);
                        break;
                    case 'N': // numeric
                        type = typeof(double);
                        break;
                    case 'F': // double
                        type = typeof(float);
                        break;
                    case 'B': // BLOB - not a dbase but this will hold the WKB for a geometry object.
                        type = typeof(byte[]);
                        break;
                    default:
                        throw new NotSupportedException("Do not know how to parse Field type " + DbaseType);
                }
                return type;
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="type"></param>
        /// <returns></returns>
        public static char GetDbaseType(Type type)
        {
            DbaseFieldDescriptor dbaseColumn = new DbaseFieldDescriptor();
            if (type == typeof(Char))
            {
                return 'C';
            }
            if (type == typeof(string))
            {
                return 'C';
            }
            else if (type == typeof(Double))
            {
                return 'N';
            }
            else if (type == typeof(Single))
            {
                return 'N';
            }
            else if (type == typeof(Int16))
            {
                return 'N';
            }
            else if (type == typeof(Int32))
            {
                return 'N';
            }
            else if (type == typeof(Int64))
            {
                return 'N';
            }
            else if (type == typeof(UInt16))
            {
                return 'N';
            }
            else if (type == typeof(UInt32))
            {
                return 'N';
            }
            else if (type == typeof(UInt64))
            {
                return 'N';
            }
            else if (type == typeof(Decimal))
            {
                return 'N';
            }
            else if (type == typeof(Boolean))
            {
                return 'L';
            }
            else if (type == typeof(DateTime))
            {
                return 'D';
            }

            throw new NotSupportedException(String.Format("{0} does not have a corresponding dbase type.", type.Name));
        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public static DbaseFieldDescriptor ShapeField()
        {
            DbaseFieldDescriptor shpfield = new DbaseFieldDescriptor();
            shpfield.Name = "Geometry";
            shpfield.DbaseType = 'B';
            return shpfield;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public static DbaseFieldDescriptor IdField()
        {
            DbaseFieldDescriptor shpfield = new DbaseFieldDescriptor();
            shpfield.Name = "Row";
            shpfield.DbaseType = 'I';
            return shpfield;
        }
    }
}