//
// System.Data.SqlClient.DbEnumerator.cs
//
// Author:
//   Tim Coleman (tim@timcoleman.com)
//
// Copyright (C) Tim Coleman, 2002
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;

namespace System.Data.Common {
	public class DbEnumerator : IEnumerator
	{
		#region Fields

		IDataReader reader;
		bool closeReader;
		SchemaInfo[] schema;
		FieldNameLookup lookup;
		int fieldCount;
	
		#endregion // Fields

		#region Constructors

		public DbEnumerator (IDataReader reader) 
			: this (reader, false)
		{
		}

		public DbEnumerator (IDataReader reader, bool closeReader)
		{
			this.reader = reader;
			this.closeReader = closeReader;
			this.lookup = new FieldNameLookup ();
			this.fieldCount = reader.FieldCount;
			LoadSchema (reader.GetSchemaTable ());
		}

		#endregion // Constructors

		#region Properties

		public object Current {
			get { 
				object[] values = new object[fieldCount];
				reader.GetValues (values);
				return new DbDataRecord (schema, values, lookup); 
			}
		}

		#endregion // Properties

		#region Methods

		private void LoadSchema (DataTable schemaTable)
		{
			schema = new SchemaInfo [fieldCount];
			int index = 0;
			foreach (DataRow row in schemaTable.Rows) {
				SchemaInfo columnSchema = new SchemaInfo ();

				lookup.Add ((string) row["ColumnName"]);

				columnSchema.AllowDBNull = (bool) row ["AllowDBNull"];
				columnSchema.ColumnName = row ["ColumnName"].ToString ();
				columnSchema.ColumnOrdinal = (int) row ["ColumnOrdinal"];
				columnSchema.ColumnSize = (int) row ["ColumnSize"];
				columnSchema.DataTypeName = reader.GetDataTypeName (index);
				columnSchema.FieldType = reader.GetFieldType (index);
				columnSchema.IsReadOnly = (bool) row ["IsReadOnly"];
				columnSchema.TableName = row ["BaseTableName"].ToString ();

				if (row ["NumericPrecision"] != DBNull.Value)
					columnSchema.NumericPrecision = Convert.ToByte (row ["NumericPrecision"]);
				else
					columnSchema.NumericPrecision = Convert.ToByte (0);

				if (row ["NumericScale"] != DBNull.Value)
					columnSchema.NumericScale = Convert.ToByte (row ["NumericScale"]);
				else
					columnSchema.NumericScale = Convert.ToByte (0);

				schema [index] = columnSchema;
				index += 1;
			}
		}

		public bool MoveNext ()
		{
			if (reader.Read ()) 
				return true;
			if (closeReader)
				reader.Close ();
			return false;
		}

		[EditorBrowsable (EditorBrowsableState.Never)]
		public void Reset ()
		{
			throw new NotSupportedException ();
		}
		
		#endregion // Methods
	}
}