//
// System.Data.Odbc.OdbcParameter
//
// Authors:
//   Brian Ritchie (brianlritchie@hotmail.com)
//
// Copyright (C) Brian Ritchie, 2002
//

using System;
using System.Data;
using System.Data.Common;

namespace System.Data.Odbc
{
	public sealed class OdbcParameter : MarshalByRefObject, IDbDataParameter, IDataParameter, ICloneable
	{
		#region Fields

		string name;
		object ParamValue;
		int size;
		bool isNullable;
		byte precision;
		byte scale;
		DataRowVersion sourceVersion;
		string sourceColumn;
		ParameterDirection direction;
		OdbcType odbcType;
		DbType dbType;
		OdbcParameterCollection container = null;	
		
		// Buffers for parameter value based on type. Currently I've only optimized 
		// for int parameters and everything else is just converted to a string.
		private bool bufferIsSet;
		int intbuf;
		byte[] buffer;

		#endregion

		#region Constructors
		
		public OdbcParameter ()
		{
			name = String.Empty;
			ParamValue = null;
			size = 0;
			isNullable = true;
			precision = 0;
			scale = 0;
			sourceColumn = String.Empty;
		}

		public OdbcParameter (string name, object value) 
			: this ()
		{
			this.name = name;
			this.ParamValue = value;
		}

		public OdbcParameter (string name, OdbcType dataType) 
			: this ()
		{
			this.name = name;
			OdbcType = dataType;
		}

		public OdbcParameter (string name, OdbcType dataType, int size)
			: this (name, dataType)
		{
			this.size = size;
		}

		public OdbcParameter (string name, OdbcType dataType, int size, string srcColumn)
			: this (name, dataType, size)
		{
			this.sourceColumn = srcColumn;
		}

		public OdbcParameter(string name, OdbcType dataType, int size, ParameterDirection direction, bool isNullable, byte precision, byte scale, string srcColumn, DataRowVersion srcVersion, object value)
			: this (name, dataType, size, srcColumn)
		{
			this.direction = direction;
			this.isNullable = isNullable;
			this.precision = precision;
			this.scale = scale;
			this.sourceVersion = srcVersion;
			this.ParamValue = value;
		}

		#endregion

		#region Properties

		// Used to ensure that only one collection can contain this
                // parameter
                internal OdbcParameterCollection Container {
                        get { return container; }
                        set { container = value; }
                }

		public DbType DbType {
			get { return dbType; }
			set { 
				dbType = value;
			}
		}
		
		public ParameterDirection Direction {
			get { return direction; }
			set { direction = value; }
		}
		
		public bool IsNullable {
			get { return isNullable; }
			set { isNullable = value; }
		}

		public OdbcType OdbcType {
			get { return odbcType; }
			set {
				odbcType = value;
			}
		}
		
		public string ParameterName {
			get { return name; }
			set { name = value; }
		}

		public byte Precision {
			get { return precision; }
			set { precision = value; }
		}
		
		public byte Scale {
			get { return scale; }
			set { scale = value; }
		}
		
		public int Size {
			get { return size; }
			set { size = value; }
		}

		public string SourceColumn {
			get { return sourceColumn; }
			set { sourceColumn = value; }
		}
		
		public DataRowVersion SourceVersion {
			get { return sourceVersion; }
			set { sourceVersion = value; }
		}
		
		public object Value {
			get { 
				return ParamValue;
			}
			set { 
				this.ParamValue = value;
				bufferIsSet = false;
			}
		}

		#endregion // Properties

		#region Methods

		internal void Bind(IntPtr hstmt, int ParamNum) {
			OdbcReturn ret;
			// Set up the buffer if we haven't done so yet
			if (!bufferIsSet)
				setBuffer();

			// Convert System.Data.ParameterDirection into odbc enum
			OdbcInputOutputDirection paramdir = libodbc.ConvertParameterDirection(this.direction);
			// Bind parameter based on type
			if (odbcType == OdbcType.Int)
				ret = libodbc.SQLBindParameter(hstmt, (ushort)ParamNum, (short)paramdir,
					(short)odbcType, (short)odbcType, Convert.ToUInt32(size),
					0, ref intbuf, 0, 0);
			else
				ret = libodbc.SQLBindParameter(hstmt, (ushort)ParamNum, (short)paramdir,
					(short)OdbcType.Char, (short)odbcType, Convert.ToUInt32(size),
					0, buffer, 0, 0);
			// Check for error condition
			if ((ret != OdbcReturn.Success) && (ret != OdbcReturn.SuccessWithInfo))
				throw new OdbcException(new OdbcError("SQLBindParam", OdbcHandleType.Stmt, hstmt));
		}

		private void setBuffer() {
			// Load buffer with new value
			if (odbcType == OdbcType.Int)
				intbuf = (int)ParamValue;
			else {
				string paramValueString = ParamValue.ToString();
				// Treat everything else as a string
				// Init string buffer
				if (buffer == null || buffer.Length < ((size > 20) ? size : 20))
					buffer = new byte[(size > 20) ? size : 20];
				else
					buffer.Initialize();
				// Convert value into string and store into buffer
				System.Text.Encoding.ASCII.GetBytes(paramValueString, 0, paramValueString.Length, buffer, 0);
			}
			bufferIsSet = true;
		}

		[MonoTODO]
		object ICloneable.Clone ()
		{
			throw new NotImplementedException ();
		}

		public override string ToString ()
		{
			return ParameterName;
		}
		#endregion
	}
}