/*
 *	Firebird ADO.NET Data provider for .NET and Mono 
 * 
 *	   The contents of this file are subject to the Initial 
 *	   Developer's Public License Version 1.0 (the "License"); 
 *	   you may not use this file except in compliance with the 
 *	   License. You may obtain a copy of the License at 
 *	   http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *	   Software distributed under the License is distributed on 
 *	   an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either 
 *	   express or implied. See the License for the specific 
 *	   language governing rights and limitations under the License.
 * 
 *	Copyright (c) 2002, 2005 Carlos Guzman Alvarez
 *	All Rights Reserved.
 */

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

using FirebirdSql.Data.Common;

namespace FirebirdSql.Data.Gds
{
	internal class XdrStream : Stream
	{
		#region Static Fields

		private static byte[] fill;
		private static byte[] pad;

		#endregion

		#region Static Properties

		internal static byte[] Fill
		{
			get
			{
				if (fill == null)
				{
					fill = new byte[32767];
					for (int i = 0; i < fill.Length; i++)
					{
						fill[i] = 32;
					}
				}

				return fill;
			}
		}

		private static byte[] Pad
		{
			get
			{
				if (pad == null)
				{
					pad = new byte[] { 0, 0, 0, 0 };
				}

				return pad;
			}
		}

		#endregion

		#region Fields

		private byte[]	buffer;
		private Charset charset;
		private Stream	innerStream;

		#endregion

		#region Stream Properties

		public override bool CanWrite
		{
			get { return this.innerStream.CanWrite; }
		}

		public override bool CanRead
		{
			get { return this.innerStream.CanRead; }
		}

		public override bool CanSeek
		{
			get { return this.innerStream.CanSeek; }
		}

		public override long Position
		{
			get { return this.innerStream.Position; }
			set { this.innerStream.Position = value; }
		}

		public override long Length
		{
			get { return this.innerStream.Length; }
		}

		#endregion

		#region Constructors

		public XdrStream() : this(Charset.DefaultCharset)
		{
		}

		public XdrStream(Charset charset) : this(new MemoryStream(), charset)
		{
		}

		public XdrStream(byte[] buffer, Charset charset) : this(new MemoryStream(buffer), charset)
		{
		}

		public XdrStream(Stream innerStream, Charset charset) : base()
		{
			this.buffer			= new byte[8] { 0, 0, 0, 0, 0, 0, 0, 0 };
			this.innerStream	= innerStream;
			this.charset		= charset;
		}

		#endregion

		#region Stream methods

		public override void Close()
		{
			if (this.innerStream != null)
			{
				this.innerStream.Close();
			}

			this.buffer			= null;
			this.charset		= null;
			this.innerStream	= null;
		}

		public override void Flush()
		{
			this.CheckDisposed();

			this.innerStream.Flush();
		}

		public override void SetLength(long length)
		{
			this.CheckDisposed();

			this.innerStream.SetLength(length);
		}

		public override long Seek(long offset, System.IO.SeekOrigin loc)
		{
			this.CheckDisposed();

			return this.innerStream.Seek(offset, loc);
		}

		public override int Read(byte[] buffer, int offset, int count)
		{
			this.CheckDisposed();

			if (this.CanRead)
			{
				return this.innerStream.Read(buffer, offset, count);
			}

			throw new InvalidOperationException("Read operations are not allowed by this stream");
		}

		public override void WriteByte(byte value)
		{
			this.CheckDisposed();

			this.innerStream.WriteByte(value);
		}

		public override void Write(byte[] buffer, int offset, int count)
		{
			this.CheckDisposed();

			if (this.CanWrite)
			{
				this.innerStream.Write(buffer, offset, count);
			}
			else
			{
				throw new InvalidOperationException("Write operations are not allowed by this stream");
			}
		}

		public byte[] ToArray()
		{
			this.CheckDisposed();

			if (this.innerStream is MemoryStream)
			{
				return ((MemoryStream)this.innerStream).ToArray();
			}

			throw new InvalidOperationException();
		}

		#endregion

		#region Xdr	Read Methods

		public byte[] ReadBytes(int count)
		{
			byte[] buffer = new byte[count];
			this.Read(buffer, 0, buffer.Length);

			return buffer;
		}

		public byte[] ReadOpaque(int length)
		{
			byte[] buffer = new byte[length];
			int readed = 0;

			if (length > 0)
			{
				while (readed < length)
				{
					readed += this.Read(buffer, readed, length - readed);
				}

				int padLength = ((4 - length) & 3);
				if (padLength > 0)
				{
					this.Read(Pad, 0, padLength);
				}
			}

			return buffer;
		}

		public byte[] ReadBuffer()
		{
			return this.ReadOpaque(this.ReadInt32());
		}

		public string ReadString()
		{
			return this.ReadString(this.charset);
		}

		public string ReadString(int length)
		{
			return this.ReadString(this.charset, length);
		}

		public string ReadString(Charset charset)
		{
			return this.ReadString(charset, this.ReadInt32());
		}

		public string ReadString(Charset charset, int length)
		{
			byte[] buffer = this.ReadOpaque(length);

			return charset.GetString(buffer, 0, buffer.Length);
		}

		public short ReadInt16()
		{
			return Convert.ToInt16(this.ReadInt32());
		}

		public int ReadInt32()
		{
			this.Read(buffer, 0, 4);

			return IPAddress.HostToNetworkOrder(BitConverter.ToInt32(buffer, 0));
		}

		public long ReadInt64()
		{
			this.Read(buffer, 0, 8);

			return IPAddress.HostToNetworkOrder(BitConverter.ToInt64(buffer, 0));
		}

		public Guid ReadGuid(int length)
		{
			return new Guid(this.ReadOpaque(length));
		}

		public float ReadSingle()
		{
			return BitConverter.ToSingle(BitConverter.GetBytes(this.ReadInt32()), 0);
		}

		public double ReadDouble()
		{
			return BitConverter.ToDouble(BitConverter.GetBytes(this.ReadInt64()), 0);
		}

		public DateTime ReadDateTime()
		{
			DateTime date = this.ReadDate();
			DateTime time = this.ReadTime();

			return new System.DateTime(
				date.Year, date.Month, date.Day,
				time.Hour, time.Minute, time.Second, time.Millisecond);
		}

		public DateTime ReadDate()
		{
			return TypeDecoder.DecodeDate(this.ReadInt32());
		}

		public DateTime ReadTime()
		{
			return TypeDecoder.DecodeTime(this.ReadInt32());
		}

		public decimal ReadDecimal(int type, int scale)
		{
			decimal value = 0;

			switch (type & ~1)
			{
				case IscCodes.SQL_SHORT:
					value = TypeDecoder.DecodeDecimal(this.ReadInt16(), scale, type);
					break;

				case IscCodes.SQL_LONG:
					value = TypeDecoder.DecodeDecimal(this.ReadInt32(), scale, type);
					break;

				case IscCodes.SQL_QUAD:
				case IscCodes.SQL_INT64:
					value = TypeDecoder.DecodeDecimal(this.ReadInt64(), scale, type);
					break;

				case IscCodes.SQL_DOUBLE:
				case IscCodes.SQL_D_FLOAT:
					value = Convert.ToDecimal(this.ReadDouble());
					break;
			}

			return value;
		}

		public object ReadValue(DbField field)
		{
			object fieldValue = null;
			Charset innerCharset = (this.charset.Name != "NONE") ? this.charset : field.Charset;

			switch (field.DbDataType)
			{
				case DbDataType.Char:
					{
						string s = this.ReadString(innerCharset, field.Length);

						if ((field.Length % field.Charset.BytesPerCharacter) == 0 &&
							s.Length > field.CharCount)
						{
							fieldValue = s.Substring(0, field.CharCount);
						}
						else
						{
							fieldValue = s;
						}
					}
					break;

				case DbDataType.VarChar:
					fieldValue = this.ReadString(innerCharset).TrimEnd();
					break;

				case DbDataType.SmallInt:
					fieldValue = this.ReadInt16();
					break;

				case DbDataType.Integer:
					fieldValue = this.ReadInt32();
					break;

				case DbDataType.Array:
				case DbDataType.Binary:
				case DbDataType.Text:
				case DbDataType.BigInt:
					fieldValue = this.ReadInt64();
					break;

				case DbDataType.Decimal:
				case DbDataType.Numeric:
					fieldValue = this.ReadDecimal(
						field.DataType,
						field.NumericScale);
					break;

				case DbDataType.Float:
					fieldValue = this.ReadSingle();
					break;

				case DbDataType.Guid:
					fieldValue = this.ReadGuid(field.Length);
					break;

				case DbDataType.Double:
					fieldValue = this.ReadDouble();
					break;

				case DbDataType.Date:
					fieldValue = this.ReadDate();
					break;

				case DbDataType.Time:
					fieldValue = this.ReadTime();
					break;

				case DbDataType.TimeStamp:
					fieldValue = this.ReadDateTime();
					break;
			}

			int sqlInd = this.ReadInt32();

			if (sqlInd == 0)
			{
				return fieldValue;
			}
			else if (sqlInd == -1)
			{
				return null;
			}
			else
			{
				throw new IscException("invalid sqlind value: " + sqlInd);
			}
		}

		#endregion

		#region Xdr	Write Methods

		public void WriteOpaque(byte[] buffer)
		{
			this.WriteOpaque(buffer, buffer.Length);
		}

		public void WriteOpaque(byte[] buffer, int length)
		{
			if (buffer != null && length > 0)
			{
				this.Write(buffer, 0, buffer.Length);
				this.Write(Fill, 0, length - buffer.Length);
				this.Write(Pad, 0, ((4 - length) & 3));
			}
		}

		public void WriteBuffer(byte[] buffer)
		{
			this.WriteBuffer(buffer, buffer == null ? 0 : buffer.Length);
		}

		public void WriteBuffer(byte[] buffer, int length)
		{
			this.Write(length);
			if (buffer != null && length > 0)
			{
				this.Write(buffer, 0, length);
				this.Write(Pad, 0, ((4 - length) & 3));
			}
		}

		public void WriteBlobBuffer(byte[] buffer)
		{
			int length = buffer.Length;	// 2 for short for buffer length

			if (length > short.MaxValue)
			{
				throw (new IOException()); //Need a	value???
			}

			this.Write(length + 2);
			this.Write(length + 2);	//bizarre but true!	three copies of	the	length
			this.WriteByte((byte)((length >> 0) & 0xff));
			this.WriteByte((byte)((length >> 8) & 0xff));
			this.Write(buffer, 0, length);

			this.Write(Pad, 0, ((4 - length + 2) & 3));
		}

		public void WriteTyped(int type, byte[] buffer)
		{
			int length;

			if (buffer == null)
			{
				this.Write(1);
				this.WriteByte((byte)type);
				length = 1;
			}
			else
			{
				length = buffer.Length + 1;
				this.Write(length);
				this.WriteByte((byte)type);
				this.Write(buffer, 0, buffer.Length);
			}
			this.Write(Pad, 0, ((4 - length) & 3));
		}

		public void Write(string value)
		{
			byte[] buffer = this.charset.GetBytes(value);

			this.WriteBuffer(buffer, buffer.Length);
		}

		public void Write(short value)
		{
			this.Write((int)value);
		}

		public void Write(int value)
		{
			this.Write(BitConverter.GetBytes(IPAddress.NetworkToHostOrder(value)), 0, 4);
		}

		public void Write(long value)
		{
			this.Write(BitConverter.GetBytes(IPAddress.NetworkToHostOrder(value)), 0, 8);
		}

		public void Write(float value)
		{
			byte[] buffer = BitConverter.GetBytes(value);

			this.Write(BitConverter.ToInt32(buffer, 0));
		}

		public void Write(double value)
		{
			byte[] buffer = BitConverter.GetBytes(value);

			this.Write(BitConverter.ToInt64(buffer, 0));
		}

		public void Write(decimal value, int type, int scale)
		{
			object numeric = TypeEncoder.EncodeDecimal(value, scale, type);

			switch (type & ~1)
			{
				case IscCodes.SQL_SHORT:
					this.Write((short)numeric);
					break;

				case IscCodes.SQL_LONG:
					this.Write((int)numeric);
					break;

				case IscCodes.SQL_QUAD:
				case IscCodes.SQL_INT64:
					this.Write((long)numeric);
					break;

				case IscCodes.SQL_DOUBLE:
				case IscCodes.SQL_D_FLOAT:
					this.Write((double)value);
					break;
			}
		}

		public void Write(DateTime value)
		{
			this.WriteDate(value);
			this.WriteTime(value);
		}

		public void WriteDate(DateTime value)
		{
			this.Write(TypeEncoder.EncodeDate(Convert.ToDateTime(value)));
		}

		public void WriteTime(DateTime value)
		{
			this.Write(TypeEncoder.EncodeTime(Convert.ToDateTime(value)));
		}

		public void Write(Descriptor descriptor)
		{
			for (int i = 0; i < descriptor.Count; i++)
			{
				this.Write(descriptor[i]);
			}
		}

		public void Write(DbField param)
		{
			Charset innerCharset = (this.charset.Name != "NONE") ? this.charset : param.Charset;

			param.FixNull();

			try
			{
				switch (param.DbDataType)
				{
					case DbDataType.Char:
						{
							string svalue = param.DbValue.GetString();

							if ((param.Length % param.Charset.BytesPerCharacter) == 0 &&
								svalue.Length > param.CharCount)
							{
								throw new IscException(335544321);
							}

							this.WriteOpaque(innerCharset.GetBytes(svalue), param.Length);
						}
						break;

					case DbDataType.VarChar:
						{
							string svalue = param.DbValue.GetString().TrimEnd();

							if ((param.Length % param.Charset.BytesPerCharacter) == 0 &&
								svalue.Length > param.CharCount)
							{
								throw new IscException(335544321);
							}

							byte[] data = innerCharset.GetBytes(svalue);

							this.WriteBuffer(data, data.Length);
						}
						break;

					case DbDataType.SmallInt:
						this.Write(param.DbValue.GetInt16());
						break;

					case DbDataType.Integer:
						this.Write(param.DbValue.GetInt32());
						break;

					case DbDataType.BigInt:
					case DbDataType.Array:
					case DbDataType.Binary:
					case DbDataType.Text:
						this.Write(param.DbValue.GetInt64());
						break;

					case DbDataType.Decimal:
					case DbDataType.Numeric:
						this.Write(
							param.DbValue.GetDecimal(),
							param.DataType,
							param.NumericScale);
						break;

					case DbDataType.Float:
						this.Write(param.DbValue.GetFloat());
						break;

					case DbDataType.Guid:
						this.WriteOpaque(param.DbValue.GetGuid().ToByteArray());
						break;

					case DbDataType.Double:
						this.Write(param.DbValue.GetDouble());
						break;

					case DbDataType.Date:
						this.Write(param.DbValue.EncodeDate());
						break;

					case DbDataType.Time:
						this.Write(param.DbValue.EncodeTime());
						break;

					case DbDataType.TimeStamp:
						this.Write(param.DbValue.EncodeDate());
						this.Write(param.DbValue.EncodeTime());
						break;

					default:
						throw new IscException("Unknown sql data type: " + param.DataType);
				}

				this.Write(param.NullFlag);
			}
			catch (IOException)
			{
				throw new IscException(IscCodes.isc_net_write_err);
			}
		}

		#endregion

		#region Private	Methods

		private void CheckDisposed()
		{
			if (this.innerStream == null)
			{
				throw new ObjectDisposedException("The XdrStream is closed.");
			}
		}

		#endregion
	}
}