//
// Mono.Data.SqliteClient.SqliteDataReader.cs
//
// Provides a means of reading a forward-only stream of rows from a Sqlite 
// database file.
//
// Author(s): Vladimir Vukicevic  <vladimir@pobox.com>
//            Everaldo Canuto  <everaldo_canuto@yahoo.com.br>
//
// Copyright (C) 2002  Vladimir Vukicevic
//
// 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.Runtime.InteropServices;
using System.Collections;
using System.Data;
using System.Data.Common;

namespace Mono.Data.SqliteClient
{
	public class SqliteDataReader : MarshalByRefObject, IEnumerable, IDataReader, IDisposable, IDataRecord
	{

		#region Fields
		
		private SqliteCommand command;
		private ArrayList rows;
		private ArrayList columns;
		private Hashtable column_names;
		private int current_row;
		private bool closed;
		private bool reading;
		private int records_affected;
		
		#endregion

		#region Constructors and destructors
		
		internal SqliteDataReader (SqliteCommand cmd)
		{
			command = cmd;
			rows = new ArrayList ();
			columns = new ArrayList ();
			column_names = new Hashtable ();
			closed = false;
			current_row = -1;
			reading = true;
		}
		
		#endregion

		#region Properties
		
		public int Depth {
			get { return 0; }
		}
		
		public int FieldCount {
			get { return columns.Count; }
		}
		
		public object this[string name] {
			get { return ((ArrayList) rows[current_row])[(int) column_names[name]]; }
		}
		
		public object this[int i] {
			get { return ((ArrayList) rows[current_row])[i]; }
		}
		
		public bool IsClosed {
			get { return closed; }
		}
		
		public int RecordsAffected {
			get { return records_affected; }
		}
		
		#endregion

		#region Internal Methods
		
		internal unsafe int SqliteCallback (ref object o, int argc, sbyte **argv, sbyte **colnames)
		{
			// cache names of columns if we need to
			if (column_names.Count == 0) {
				for (int i = 0; i < argc; i++) {
					string col = new String (colnames[i]);
					columns.Add (col);
					column_names[col.ToLower ()] = i;
				}
			}
			
			ArrayList data_row = new ArrayList (argc);
 			for (int i = 0; i < argc; i++) {
				if (argv[i] != ((sbyte *)0)) {
					data_row.Add(new String (argv[i]));
				} else {
					data_row.Add(null);
				}
			}
			rows.Add (data_row);
			return 0;
		}
		
		internal void ReadingDone ()
		{
			records_affected = command.NumChanges ();
			reading = false;
		}
		
		#endregion

		#region  Public Methods
		
		public void Close ()
		{
			closed = true;
		}
		
		public void Dispose ()
		{
			Close ();
		}
		
		IEnumerator IEnumerable.GetEnumerator () 
		{
			return new DbEnumerator (this);
		}
		
		public DataTable GetSchemaTable () 
		{
			DataTable dataTableSchema = new DataTable ();
			
			dataTableSchema.Columns.Add ("ColumnName", typeof (String));
			dataTableSchema.Columns.Add ("ColumnOrdinal", typeof (Int32));
			dataTableSchema.Columns.Add ("ColumnSize", typeof (Int32));
			dataTableSchema.Columns.Add ("NumericPrecision", typeof (Int32));
			dataTableSchema.Columns.Add ("NumericScale", typeof (Int32));
			dataTableSchema.Columns.Add ("IsUnique", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsKey", typeof (Boolean));
			dataTableSchema.Columns.Add ("BaseCatalogName", typeof (String));
			dataTableSchema.Columns.Add ("BaseColumnName", typeof (String));
			dataTableSchema.Columns.Add ("BaseSchemaName", typeof (String));
			dataTableSchema.Columns.Add ("BaseTableName", typeof (String));
			dataTableSchema.Columns.Add ("DataType", typeof(Type));
			dataTableSchema.Columns.Add ("AllowDBNull", typeof (Boolean));
			dataTableSchema.Columns.Add ("ProviderType", typeof (Int32));
			dataTableSchema.Columns.Add ("IsAliased", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsExpression", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsIdentity", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsAutoIncrement", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsRowVersion", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsHidden", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsLong", typeof (Boolean));
			dataTableSchema.Columns.Add ("IsReadOnly", typeof (Boolean));
			
			dataTableSchema.BeginLoadData();
			for (int i = 0; i < this.FieldCount; i += 1 ) {
				
				DataRow schemaRow = dataTableSchema.NewRow ();
				
				schemaRow["ColumnName"] = columns[i];
				schemaRow["ColumnOrdinal"] = i;
				schemaRow["ColumnSize"] = 0;
				schemaRow["NumericPrecision"] = 0;
				schemaRow["NumericScale"] = 0;
				schemaRow["IsUnique"] = false;
				schemaRow["IsKey"] = false;
				schemaRow["BaseCatalogName"] = "";
				schemaRow["BaseColumnName"] = columns[i];
				schemaRow["BaseSchemaName"] = "";
				schemaRow["BaseTableName"] = "";
				schemaRow["DataType"] = typeof(string);
				schemaRow["AllowDBNull"] = true;
				schemaRow["ProviderType"] = 0;
				schemaRow["IsAliased"] = false;
				schemaRow["IsExpression"] = false;
				schemaRow["IsIdentity"] = false;
				schemaRow["IsAutoIncrement"] = false;
				schemaRow["IsRowVersion"] = false;
				schemaRow["IsHidden"] = false;
				schemaRow["IsLong"] = false;
				schemaRow["IsReadOnly"] = false;
				
				dataTableSchema.Rows.Add (schemaRow);
				schemaRow.AcceptChanges();
			}
			dataTableSchema.EndLoadData();
			
			return dataTableSchema;
		}
		
		public bool NextResult ()
		{
			current_row++;
			
			return (current_row < rows.Count);
		}
		
		public bool Read ()
		{
			return NextResult ();
		}

		#endregion
		
		#region IDataRecord getters
		
		public bool GetBoolean (int i)
		{
			return Convert.ToBoolean ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public byte GetByte (int i)
		{
			return Convert.ToByte ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public long GetBytes (int i, long fieldOffset, byte[] buffer, int bufferOffset, int length)
		{
			throw new NotImplementedException ();
		}
		
		public char GetChar (int i)
		{
			return Convert.ToChar ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public long GetChars (int i, long fieldOffset, char[] buffer, int bufferOffset, int length)
		{
			throw new NotImplementedException ();
		}
		
		public IDataReader GetData (int i)
		{
			throw new NotImplementedException ();
		}
		
		public string GetDataTypeName (int i)
		{
			return "text"; // SQL Lite data type
		}
		
		public DateTime GetDateTime (int i)
		{
			return Convert.ToDateTime ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public decimal GetDecimal (int i)
		{
			return Convert.ToDecimal ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public double GetDouble (int i)
		{
			return Convert.ToDouble ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public Type GetFieldType (int i)
		{
			return System.Type.GetType ("System.String"); // .NET data type
		}
		
		public float GetFloat (int i)
		{
			return Convert.ToSingle ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public Guid GetGuid (int i)
		{
			throw new NotImplementedException ();
		}
		
		public short GetInt16 (int i)
		{
			return Convert.ToInt16 ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public int GetInt32 (int i)
		{
			return Convert.ToInt32 ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public long GetInt64 (int i)
		{
			return Convert.ToInt64 ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public string GetName (int i)
		{
			return (string) columns[i];
		}
		
		public int GetOrdinal (string name)
		{
			return (int) column_names[name];
		}
		
		public string GetString (int i)
		{
			return ((string) ((ArrayList) rows[current_row])[i]);
		}
		
		public object GetValue (int i)
		{
			return ((ArrayList) rows[current_row])[i];
		}
		
		public int GetValues (object[] values)
		{
			int num_to_fill = System.Math.Min (values.Length, columns.Count);
			for (int i = 0; i < num_to_fill; i++) {
				if (((ArrayList) rows[current_row])[i] != null) {
					values[i] = ((ArrayList) rows[current_row])[i];
				} else {
					values[i] = DBNull.Value;
				}
			}
			return num_to_fill;
		}
		
		public bool IsDBNull (int i)
		{
			return (((ArrayList) rows[current_row])[i] == null);
		}
		        
		#endregion
	}
}