// 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.Collections.Generic;
using System.Linq;
using MySql.Data.MySqlClient;
using Sog.Properties;

namespace MySql.Data.MySqlClient.Interceptors
{
    /// <summary>
    /// BaseExceptionInterceptor is the base class that should be used for all userland 
    /// exception interceptors.
    /// </summary>
    public abstract class BaseExceptionInterceptor
    {
        /// <summary>
        /// Returns the received exception.
        /// </summary>
        /// <param name="exception">The exception to be returned.</param>
        /// <returns>The exception originally received.</returns>
        public abstract Exception InterceptException(Exception exception);

        /// <summary>
        /// Gets the active connection.
        /// </summary>
        protected MySqlConnection ActiveConnection { get; private set; }

        /// <summary>
        /// Initilizes this object by setting the active connection.
        /// </summary>
        /// <param name="connection">The connection to become active.</param>
        public virtual void Init(MySqlConnection connection)
        {
            this.ActiveConnection = connection;
        }
    }

    /// <summary>
    /// StandardExceptionInterceptor is the standard interceptor that simply returns the exception.
    /// It is the default action.
    /// </summary>
    internal sealed class StandardExceptionInterceptor : BaseExceptionInterceptor
    {
        /// <summary>
        /// Returns the received exception, which is the default action
        /// </summary>
        /// <param name="exception">The exception to be returned.</param>
        /// <returns>The exception originally received.</returns>
        public override Exception InterceptException(Exception exception)
        {
            return exception;
        }
    }

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

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

            this.LoadInterceptors(connection.Settings.ExceptionInterceptors);

            // we always have the standard interceptor
            this._interceptors.Add(new StandardExceptionInterceptor());

        }

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

            if (!(o is BaseExceptionInterceptor))
            {
                throw new InvalidOperationException(String.Format(
                    Resources.TypeIsNotExceptionInterceptor,
                  o.GetType()));
            }

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

        public void Throw(Exception exception)
        {
            Exception e = this._interceptors.Aggregate(exception, (current, ie) => ie.InterceptException(current));
            throw e;
        }

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

    }
}