// Copyright (c) 2004, 2016, Oracle and/or its affiliates. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation.  The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

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

namespace MySql.Data.MySqlClient
{
    /// <include file='docs/MySqlTransaction.xml' path='docs/Class/*'/>
    public sealed class MySqlTransaction : DbTransaction
    {
        private bool open;
        private bool disposed = false;

        internal MySqlTransaction(MySqlConnection c, IsolationLevel il)
        {
            this.Connection = c;
            this.IsolationLevel = il;
            this.open = true;
        }

        #region Destructor
        ~MySqlTransaction()
        {
            this.Dispose(false);
        }
        #endregion

        #region Properties

        /// <summary>
        /// Gets the <see cref="MySqlConnection"/> object associated with the transaction, or a null reference (Nothing in Visual Basic) if the transaction is no longer valid.
        /// </summary>
        /// <value>The <see cref="MySqlConnection"/> object associated with this transaction.</value>
        /// <remarks>
        /// A single application may have multiple database connections, each 
        /// with zero or more transactions. This property enables you to 
        /// determine the connection object associated with a particular 
        /// transaction created by <see cref="MySqlConnection.BeginTransaction()"/>.
        /// </remarks>
        public new MySqlConnection Connection { get; }

        /// <summary>
        /// Specifies the <see cref="IsolationLevel"/> for this transaction.
        /// </summary>
        /// <value>
        /// The <see cref="IsolationLevel"/> for this transaction. The default is <b>ReadCommitted</b>.
        /// </value>
        /// <remarks>
        /// Parallel transactions are not supported. Therefore, the IsolationLevel 
        /// applies to the entire transaction.
        /// </remarks>
        public override IsolationLevel IsolationLevel { get; }

        protected override DbConnection DbConnection
        {
            get { return this.Connection; }
        }

        #endregion


        protected override void Dispose(bool disposing)
        {
            if (this.disposed)
            {
                return;
            }

            base.Dispose(disposing);
            if (disposing)
            {
                if ((this.Connection != null && this.Connection.State == ConnectionState.Open || this.Connection.SoftClosed) && this.open)
                {
                    this.Rollback();
                }
            }

            this.disposed = true;
        }

        /// <include file='docs/MySqlTransaction.xml' path='docs/Commit/*'/>
        public override void Commit()
        {
            if (this.Connection == null || (this.Connection.State != ConnectionState.Open && !this.Connection.SoftClosed))
            {
                throw new InvalidOperationException("Connection must be valid and open to commit transaction");
            }

            if (!this.open)
            {
                throw new InvalidOperationException("Transaction has already been committed or is not pending");
            }

            MySqlCommand cmd = new MySqlCommand("COMMIT", this.Connection);
            cmd.ExecuteNonQuery();
            this.open = false;
        }

        /// <include file='docs/MySqlTransaction.xml' path='docs/Rollback/*'/>
        public override void Rollback()
        {
            if (this.Connection == null || (this.Connection.State != ConnectionState.Open && !this.Connection.SoftClosed))
            {
                throw new InvalidOperationException("Connection must be valid and open to rollback transaction");
            }

            if (!this.open)
            {
                throw new InvalidOperationException("Transaction has already been rolled back or is not pending");
            }

            MySqlCommand cmd = new MySqlCommand("ROLLBACK", this.Connection);
            cmd.ExecuteNonQuery();
            this.open = false;
        }

    }
}