using System;
using System.Collections.Generic;
using System.Data;
using System.Xml;

namespace Xpace
{
    public interface IConverter
    {
        object Get(ref Result res);
    }

    public class TextConverter : IConverter
    {
        public TextConverter()
        {
            _reader = new TextResultReader();
        }

        public object Get(ref Result res)
        {
            _reader.read(ref res);
            return _reader.Get;
        }
        
        private TextResultReader _reader;
    }

    public class UInt64DoubleConverter : IConverter
    {
        public UInt64DoubleConverter()
        {
            _reader = new UInt64ResultReader();
        }

        public object Get(ref Result res)
        {
            _reader.read(ref res);
            double val = _reader.getUInt64;
            return val;
        }

        private UInt64ResultReader _reader;
    }

    public class Int32DateDateTimeConverter : IConverter
    {
        public Int32DateDateTimeConverter()
        {
            _reader = new Int32ResultReader();
        }

        public object Get(ref Result res)
        {
            _reader.read(ref res);
            Int32 val = _reader.getInt32;
            if (val == 0)
                return new DateTime(0);
            int y = val / 10000;
            int m = (val % 10000) / 100;
            int d = val % 100;
            return new DateTime(y, m, d);
        }

        private Int32ResultReader _reader;
    }

    public class Int32TimeDateTimeConverter : IConverter
    {
        public Int32TimeDateTimeConverter()
        {
            _reader = new Int32ResultReader();
        }

        public object Get(ref Result res)
        {
            _reader.read(ref res);
            Int32 val = _reader.getInt32;
            int h = val / 10000;
            int m = (val % 10000) / 100;
            int s = val % 100;
            if (s >= 60)
            {
                ++m;
                s -= 60;
            }
            if (m >= 60)
            {
                ++h;
                m -= 60;
            }
            return new DateTime(1, 1, 1, h, m, s);
        }

        private Int32ResultReader _reader;
    }

    public class ResultTable : DataTable
    {    
        public ResultTable(TableCursor tc)
        {
            _converters = new List<IConverter>();
        
            for (uint col = 0; col < tc.columnCount; ++col)
            {
                string config = tc.getColumnConfig(col);

                XmlDocument doc = new XmlDocument();
                doc.LoadXml(config);

                XmlElement node = doc["field"];

                // todo - a type mapper
                string type = node.GetAttribute("type");
                if (type == "text")
                {
                    _converters.Add(new TextConverter());
                    Columns.Add(node.GetAttribute("name"), typeof(string)); 
                }
                else if (type == "unsigned")
                {
                    _converters.Add(new UInt64DoubleConverter());
                    Columns.Add(node.GetAttribute("name"), typeof(double));
                }
                else if (type == "date")
                {
                    _converters.Add(new Int32DateDateTimeConverter());
                    Columns.Add(node.GetAttribute("name"), typeof(DateTime));
                }
                else if (type == "time")
                {
                    _converters.Add(new Int32TimeDateTimeConverter());
                    Columns.Add(node.GetAttribute("name"), typeof(DateTime));
                }
                else
                    throw new UnknownDataTypeException(type, "Quotes");
            }
        }

        public void set(Result res, uint maxRows)
        {
            Clear();
            for (uint r = 0; r < Math.Min(res.Count, maxRows); ++r)
            {
                DataRow row = NewRow();
                int col = 0;
                foreach (IConverter c in _converters)
                    row[col++] = c.Get(ref res);
                Rows.Add(row);
            }
        }

        private List <IConverter> _converters;
    }
}