// Copyright © 2004, 2018, 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.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Security;
using System.Drawing;
#if !NETCOREAPP
using System.Security.Permissions;
#endif
using System.Transactions;
using Sog.Properties;

namespace MySql.Data.MySqlClient
{
#if NET452
  [ToolboxBitmap(typeof(MySqlConnection), "MySqlClient.resources.connection.bmp")]
#endif
    [DesignerCategory("Code")]
    [ToolboxItem(true)]
    public sealed partial class MySqlConnection : DbConnection, ICloneable
    {
        /// <summary>
        /// Returns schema information for the data source of this <see cref="DbConnection"/>. 
        /// </summary>
        /// <returns>A <see cref="DataTable"/> that contains schema information. </returns>
        public override DataTable GetSchema()
        {
            return this.GetSchema(null);
        }

        /// <summary>
        /// Returns schema information for the data source of this 
        /// <see cref="DbConnection"/> using the specified string for the schema name. 
        /// </summary>
        /// <param name="collectionName">Specifies the name of the schema to return. </param>
        /// <returns>A <see cref="DataTable"/> that contains schema information. </returns>
        public override DataTable GetSchema(string collectionName)
        {
            if (collectionName == null)
            {
                collectionName = SchemaProvider.MetaCollection;
            }

            return this.GetSchema(collectionName, null);
        }

        /// <summary>
        /// Returns schema information for the data source of this <see cref="DbConnection"/>
        /// using the specified string for the schema name and the specified string array 
        /// for the restriction values. 
        /// </summary>
        /// <param name="collectionName">Specifies the name of the schema to return.</param>
        /// <param name="restrictionValues">Specifies a set of restriction values for the requested schema.</param>
        /// <returns>A <see cref="DataTable"/> that contains schema information.</returns>
        public override DataTable GetSchema(string collectionName, string[] restrictionValues)
        {
            if (collectionName == null)
            {
                collectionName = SchemaProvider.MetaCollection;
            }

            string[] restrictions = this._schemaProvider.CleanRestrictions(restrictionValues);
            MySqlSchemaCollection c = this._schemaProvider.GetSchema(collectionName, restrictions);
            return c.AsDataTable();
        }

        /// <summary>
        /// Enlists in the specified transaction. 
        /// </summary>
        /// <param name="transaction">
        /// A reference to an existing <see cref="System.Transactions.Transaction"/> in which to enlist.
        /// </param>
        public override void EnlistTransaction(Transaction transaction)
        {
            // enlisting in the null transaction is a noop
            if (transaction == null)
            {
                return;
            }

            // guard against trying to enlist in more than one transaction
            if (this.driver.currentTransaction != null)
            {
                if (this.driver.currentTransaction.BaseTransaction == transaction)
                {
                    return;
                }

                this.Throw(new MySqlException("Already enlisted"));
            }

            // now see if we need to swap out drivers.  We would need to do this since
            // we have to make sure all ops for a given transaction are done on the
            // same physical connection.
            Driver existingDriver = DriverTransactionManager.GetDriverInTransaction(transaction);
            if (existingDriver != null)
            {
                // we can't allow more than one driver to contribute to the same connection
                if (existingDriver.IsInActiveUse)
                {
                    this.Throw(new NotSupportedException(Resources.MultipleConnectionsInTransactionNotSupported));
                }

                // there is an existing driver and it's not being currently used.
                // now we need to see if it is using the same connection string
                string text1 = existingDriver.Settings.ConnectionString;
                string text2 = this.Settings.ConnectionString;
                if (String.Compare(text1, text2, true) != 0)
                {
                    this.Throw(new NotSupportedException(Resources.MultipleConnectionsInTransactionNotSupported));
                }

                // close existing driver
                // set this new driver as our existing driver
                this.CloseFully();
                this.driver = existingDriver;
            }

            if (this.driver.currentTransaction == null)
            {
                MySqlPromotableTransaction t = new MySqlPromotableTransaction(this, transaction);
                if (!transaction.EnlistPromotableSinglePhase(t))
                {
                    this.Throw(new NotSupportedException(Resources.DistributedTxnNotSupported));
                }

                this.driver.currentTransaction = t;
                DriverTransactionManager.SetDriverInTransaction(this.driver);
                this.driver.IsInActiveUse = true;
            }
        }

        void AssertPermissions()
        {
            // Security Asserts can only be done when the assemblies 
            // are put in the GAC as documented in 
            // http://msdn.microsoft.com/en-us/library/ff648665.aspx
#if !NETCOREAPP
            if (this.Settings.IncludeSecurityAsserts)
            {
                PermissionSet set = new PermissionSet(PermissionState.None);
                set.AddPermission(new MySqlClientPermission(this.ConnectionString));
                set.Demand();
                MySqlSecurityPermission.CreatePermissionSet(true).Assert();
            }

#endif
        }

        /// <summary>
        /// Creates a new MySqlConnection object with the exact same ConnectionString value
        /// </summary>
        /// <returns>A cloned MySqlConnection object</returns>
        public object Clone()
        {
            MySqlConnection clone = new MySqlConnection();
            clone.IsClone = true;
            clone.ParentHasbeenOpen = this.hasBeenOpen;
            string connectionString = this.Settings.ConnectionString;
            if (connectionString != null)
            {
                clone.ConnectionString = connectionString;
            }

            return clone;
        }
    }
}