// Copyright (c) 2004, 2019, 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.Collections.Generic;
using System.Data;
using Sog.Properties;

namespace MySql.Data.MySqlClient
{
    /// <summary>
    /// BaseCommandInterceptor is the base class that should be used for all userland 
    /// command interceptors
    /// </summary>
    public abstract class BaseCommandInterceptor
    {
        /// <summary>
        /// Gets the active connection.
        /// </summary>
        protected MySqlConnection ActiveConnection { get; private set; }

        /// <summary>
        /// Executes an SQL statements that returns a scalar value such as a calculation.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="returnValue">A scalar value that represents the result returned by the execution of the SQL statement.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteScalar(string sql, ref object returnValue)
        {
            return false;
        }

        /// <summary>
        /// Executes an SQL statement that returns the number of affected rows.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="returnValue">The number of affected rows.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteNonQuery(string sql, ref int returnValue)
        {
            return false;
        }

        /// <summary>
        /// Executes an SQL statement that will return a resultset.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="behavior">A value that describes the results of the query and its effect on the database.</param>
        /// <param name="returnValue">A <see cref="MySqlDataReader"/> object containing the result of the statement execution.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
        {
            return false;
        }

        /// <summary>
        /// Sets the active connection.
        /// </summary>
        /// <param name="connection">The active connection.</param>
        public virtual void Init(MySqlConnection connection)
        {
            this.ActiveConnection = connection;
        }
    }

    /// <summary>
    /// CommandInterceptor is the "manager" class that keeps the list of registered interceptors
    /// for the given connection.
    /// </summary>
    internal sealed partial class CommandInterceptor : Interceptor
    {
        bool _insideInterceptor = false;
        readonly List<BaseCommandInterceptor> _interceptors = new List<BaseCommandInterceptor>();

        public CommandInterceptor(MySqlConnection connection)
        {
            this.Connection = connection;

            this.LoadInterceptors(connection.Settings.CommandInterceptors);
        }

        public bool ExecuteScalar(string sql, ref object returnValue)
        {
            if (this._insideInterceptor)
            {
                return false;
            }

            this._insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in this._interceptors)
            {
                handled |= bci.ExecuteScalar(sql, ref returnValue);
            }

            this._insideInterceptor = false;
            return handled;
        }

        public bool ExecuteNonQuery(string sql, ref int returnValue)
        {
            if (this._insideInterceptor)
            {
                return false;
            }

            this._insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in this._interceptors)
            {
                handled |= bci.ExecuteNonQuery(sql, ref returnValue);
            }

            this._insideInterceptor = false;
            return handled;
        }

        public bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
        {
            if (this._insideInterceptor)
            {
                return false;
            }

            this._insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in this._interceptors)
            {
                handled |= bci.ExecuteReader(sql, behavior, ref returnValue);
            }

            this._insideInterceptor = false;
            return handled;
        }

        protected override void AddInterceptor(object o)
        {
            if (o == null)
            {
                throw new ArgumentException("Unable to instantiate CommandInterceptor");
            }

            if (!(o is BaseCommandInterceptor))
            {
                throw new InvalidOperationException(string.Format(
                    Resources.TypeIsNotCommandInterceptor,
                    o.GetType()));
            }

            BaseCommandInterceptor ie = (BaseCommandInterceptor)o;
            ie.Init(this.Connection);
            this._interceptors.Insert(0, (BaseCommandInterceptor)o);
        }


#if !NETCOREAPP
        protected override string ResolveType(string nameOrType)
    {
      if (MySqlConfiguration.Settings == null || MySqlConfiguration.Settings.CommandInterceptors == null)
        return base.ResolveType(nameOrType);
      foreach (InterceptorConfigurationElement e in MySqlConfiguration.Settings.CommandInterceptors)
        if (String.Compare(e.Name, nameOrType, true) == 0)
          return e.Type;
      return base.ResolveType(nameOrType);
    }
#endif

    }
}