// created on 12/6/2002 at 20:29

// Npgsql.NpgsqlRowDescription.cs
//
// Author:
//	Francisco Jr. (fxjrlists@yahoo.com.br)
//
//	Copyright (C) 2002 The Npgsql Development Team
//	npgsql-general@gborg.postgresql.org
//	http://gborg.postgresql.org/project/npgsql/projdisplay.php
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



using System;
using System.Collections;
using System.IO;
using System.Text;
using System.Net;

namespace Npgsql
{


    /// <summary>
    /// This struct represents the internal data of the RowDescription message.
    /// </summary>
    ///
    // [FIXME] Is this name OK? Does it represent well the struct intent?
    // Should it be a struct or a class?
    internal struct NpgsqlRowDescriptionFieldData
    {
        public String 	name;                      // Protocol 2/3
        public Int32    table_oid;                 // Protocol 3
        public Int16    column_attribute_number;   // Protocol 3
        public Int32		type_oid;                  // Protocol 2/3
        public Int16		type_size;                 // Protocol 2/3
        public Int32		type_modifier;		         // Protocol 2/3
        public FormatCode    format_code;               // Protocol 3. 0 text, 1 binary
    }

    /// <summary>
    /// This class represents a RowDescription message sent from
    /// the PostgreSQL.
    /// </summary>
    ///
    internal sealed class NpgsqlRowDescription
    {
        // Logging related values
        private static readonly String CLASSNAME = "NpgsqlRowDescription";


        private ArrayList	fields_data = new ArrayList();

        private ArrayList   fields_index = new ArrayList();

        private Int32 protocol_version;

        public NpgsqlRowDescription(Int32 protocolVersion)
        {
            protocol_version = protocolVersion;
        }

        public void ReadFromStream(Stream input_stream, Encoding encoding)
        {
            NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "ReadFromStream");


            if (protocol_version == ProtocolVersion.Version2)
            {
                Byte[] input_buffer = new Byte[10]; // Max read will be 4 + 2 + 4

                // Read the number of fields.
                input_stream.Read(input_buffer, 0, 2);
                Int16 num_fields = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(input_buffer, 0));


                // Temporary FieldData object to get data from stream and put in array.
                NpgsqlRowDescriptionFieldData fd;

                // Now, iterate through each field getting its data.
                for (Int16 i = 0; i < num_fields; i++)
                {
                    fd = new NpgsqlRowDescriptionFieldData();

                    // Set field name.
                    fd.name = PGUtil.ReadString(input_stream, encoding);

                    // Read type_oid(Int32), type_size(Int16), type_modifier(Int32)
                    input_stream.Read(input_buffer, 0, 4 + 2 + 4);

                    fd.type_oid = IPAddress.NetworkToHostOrder(BitConverter.ToInt32(input_buffer, 0));
                    fd.type_size = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(input_buffer, 4));
                    fd.type_modifier = IPAddress.NetworkToHostOrder(BitConverter.ToInt32(input_buffer, 6));

                    // Add field data to array.
                    fields_data.Add(fd);

                    fields_index.Add(fd.name);
                }
            }
            else
            {
                Byte[] input_buffer = new Byte[4]; // Max read will be 4 + 2 + 4 + 2 + 4 + 2

                // Read the length of message.
                // [TODO] Any use for now?
                PGUtil.ReadInt32(input_stream, input_buffer);
                Int16 num_fields = PGUtil.ReadInt16(input_stream, input_buffer);

                // Temporary FieldData object to get data from stream and put in array.
                NpgsqlRowDescriptionFieldData fd;

                for (Int16 i = 0; i < num_fields; i++)
                {
                    fd = new NpgsqlRowDescriptionFieldData();

                    fd.name = PGUtil.ReadString(input_stream, encoding);
                    fd.table_oid = PGUtil.ReadInt32(input_stream, input_buffer);
                    fd.column_attribute_number = PGUtil.ReadInt16(input_stream, input_buffer);
                    fd.type_oid = PGUtil.ReadInt32(input_stream, input_buffer);
                    fd.type_size = PGUtil.ReadInt16(input_stream, input_buffer);
                    fd.type_modifier = PGUtil.ReadInt32(input_stream, input_buffer);
                    fd.format_code = (FormatCode)PGUtil.ReadInt16(input_stream, input_buffer);

                    fields_data.Add(fd);
                    fields_index.Add(fd.name);
                }

            }


        }

        public NpgsqlRowDescriptionFieldData this[Int32 index]
        {
            get
            {
                return (NpgsqlRowDescriptionFieldData)fields_data[index];
            }

        }

        public Int16 NumFields
        {
            get
            {
                return (Int16)fields_data.Count;
            }
        }

        public Int16 FieldIndex(String fieldName)
        {
            Int16 result = 0;
                       
            foreach (String name in fields_index)
            {
                
                if (name.Equals(fieldName))
                {
                    return result;
                }
                result++;
            }
            
            return -1;            
            
        }

    }

}