//
// System.Data.Common.DbCommand
//
// Author:
//   Tim Coleman (tim@timcoleman.com)
//
// Copyright (C) Tim Coleman, 2003
//

//
// 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.ComponentModel;
using System.Data;

#if NET_4_5
using System.Threading;
using System.Threading.Tasks;
#endif

namespace System.Data.Common {
	public abstract class DbCommand : Component, IDbCommand, IDisposable
	{
		protected DbCommand ()
		{
		}

		#region Properties

		[DefaultValue ("")]
		[RefreshProperties (RefreshProperties.All)]
		public abstract string CommandText { get; set; }

		public abstract int CommandTimeout { get; set; }

		[DefaultValue (CommandType.Text)]
		[RefreshProperties (RefreshProperties.All)]
		public abstract CommandType CommandType { get; set; }

		[DefaultValue (null)]
		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
		public DbConnection Connection {
			get { return DbConnection; }
			set { DbConnection = value; }
		}

		protected abstract DbConnection DbConnection { get; set; }
		protected abstract DbParameterCollection DbParameterCollection { get; }
		protected abstract DbTransaction DbTransaction { get; set; }

		[EditorBrowsable (EditorBrowsableState.Never)]
		[Browsable (false)]
		[DefaultValue (true)]
		[DesignOnly (true)]
		public abstract bool DesignTimeVisible { get; set; }

		IDbConnection IDbCommand.Connection {
			get { return Connection; }
			set { Connection = (DbConnection) value; }
		}

		IDataParameterCollection IDbCommand.Parameters {
			get { return Parameters; }
		}

		IDbTransaction IDbCommand.Transaction {
			get { return Transaction; }
			set { Transaction = (DbTransaction) value; }
		}

		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
		public DbParameterCollection Parameters {
			get { return DbParameterCollection; }
		}

		[Browsable (false)]
		[DefaultValue (null)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
		public DbTransaction Transaction {
			get { return DbTransaction; }
			set { DbTransaction = value; }
		}

		[DefaultValue (UpdateRowSource.Both)]
		public abstract UpdateRowSource UpdatedRowSource { get; set; }

		#endregion // Properties

		#region Methods

		public abstract void Cancel ();
		protected abstract DbParameter CreateDbParameter ();

		public DbParameter CreateParameter ()
		{
			return CreateDbParameter ();
		}

		protected abstract DbDataReader ExecuteDbDataReader (CommandBehavior behavior);
		public abstract int ExecuteNonQuery ();
		
		public DbDataReader ExecuteReader ()
		{
			return ExecuteDbDataReader (CommandBehavior.Default);
		}

		public DbDataReader ExecuteReader (CommandBehavior behavior)
		{
                        return ExecuteDbDataReader (behavior);
		}

		public abstract object ExecuteScalar ();

		IDbDataParameter IDbCommand.CreateParameter ()
		{
			return CreateParameter ();
		}

		IDataReader IDbCommand.ExecuteReader ()
		{
			return ExecuteReader ();
		}

		IDataReader IDbCommand.ExecuteReader (CommandBehavior behavior)
		{
			return ExecuteReader (behavior);
		}

		public abstract void Prepare ();
		
#if NET_4_5
		protected virtual Task<DbDataReader> ExecuteDbDataReaderAsync (CommandBehavior behavior, CancellationToken cancellationToken)
		{
			if (cancellationToken.IsCancellationRequested) {
				return TaskHelper.CreateCanceledTask<DbDataReader> ();
			}
			
			try {
				return Task.FromResult (ExecuteDbDataReader (behavior));
			} catch (Exception e) {
				return TaskHelper.CreateExceptionTask<DbDataReader> (e);
			}
		}
		
		public Task<int> ExecuteNonQueryAsync ()
		{
			return ExecuteNonQueryAsync (CancellationToken.None);
		}
		
		public virtual Task<int> ExecuteNonQueryAsync (CancellationToken cancellationToken)
		{
			if (cancellationToken.IsCancellationRequested) {
				return TaskHelper.CreateCanceledTask<int> ();
			}
			
			try {
				return Task.FromResult (ExecuteNonQuery ());
			} catch (Exception e) {
				return TaskHelper.CreateExceptionTask<int> (e);
			}
		}
		
		public Task<Object> ExecuteScalarAsync ()
		{
			return ExecuteScalarAsync (CancellationToken.None);
		}
		
		public virtual Task<Object> ExecuteScalarAsync (CancellationToken cancellationToken)
		{
			if (cancellationToken.IsCancellationRequested) {
				return TaskHelper.CreateCanceledTask<Object> ();
			}
			
			try {
				return Task.FromResult (ExecuteScalar ());
			} catch (Exception e) {
				return TaskHelper.CreateExceptionTask<Object> (e);
			}
		}
		
		public Task<DbDataReader> ExecuteReaderAsync ()
		{
			return ExecuteReaderAsync (CancellationToken.None);
		}
		
		public Task<DbDataReader> ExecuteReaderAsync (CancellationToken cancellationToken)
		{
			if (cancellationToken.IsCancellationRequested) {
				return TaskHelper.CreateCanceledTask<DbDataReader> ();
			}
			
			try {
				return Task.FromResult (ExecuteReader ());
			} catch (Exception e) {
				return TaskHelper.CreateExceptionTask<DbDataReader> (e);
			}
		}
		
		public Task<DbDataReader> ExecuteReaderAsync (CommandBehavior behavior)
		{
			return ExecuteReaderAsync (behavior, CancellationToken.None);
		}
		
		public Task<DbDataReader> ExecuteReaderAsync (CommandBehavior behavior, CancellationToken cancellationToken)
		{
			if (cancellationToken.IsCancellationRequested) {
				return TaskHelper.CreateCanceledTask<DbDataReader> ();
			}
			
			try {
				return Task.FromResult (ExecuteReader (behavior));
			} catch (Exception e) {
				return TaskHelper.CreateExceptionTask<DbDataReader> (e);
			}
		}

#endif
		
		#endregion // Methods

	}
}