// Copyright ?2009, 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.Diagnostics;
using System.Linq;
using System.Reflection;
using Sog.Properties;

namespace MySql.Data.MySqlClient
{
    /// <summary>
    /// Traces information about the client execution.
    /// </summary>
    public class MySqlTrace
    {
        private static TraceSource source = new TraceSource("mysql");

        static MySqlTrace()
        {
            foreach (TraceListener listener in source.Listeners.Cast<TraceListener>().Where(listener => listener.GetType().ToString().Contains("MySql.EMTrace.EMTraceListener")))
            {
                QueryAnalysisEnabled = true;
                break;
            }
        }

        /// <summary>
        /// Gets the list of trace listeners.
        /// </summary>
        public static TraceListenerCollection Listeners { get; } = source.Listeners;

        /// <summary>
        /// Gets or sets the switch to control tracing and debugging.
        /// </summary>
        public static SourceSwitch Switch
        {
            get { return source.Switch; }
            set { source.Switch = value; }
        }

        /// <summary>
        /// Gets or sets a flag indicating if query analysis is enabled.
        /// </summary>
        public static bool QueryAnalysisEnabled { get; set; }

        /// <summary>
        /// Enables query analysis.
        /// </summary>
        /// <param name="host">The host on which to enable query analysis.</param>
        /// <param name="postInterval">The interval of time for logging trace information.</param>
        public static void EnableQueryAnalyzer(string host, int postInterval)
        {
            if (QueryAnalysisEnabled)
            {
                return;
            }

            // create a EMTraceListener and add it to our source
            TraceListener l = (TraceListener)Activator.CreateInstance(Type.GetType("MySql.EMTrace.EMTraceListener"), host, postInterval);

            if (l == null)
            {
                throw new MySqlException(Resources.UnableToEnableQueryAnalysis);
            }

            source.Listeners.Add(l);
            Switch.Level = SourceLevels.All;
        }

        /// <summary>
        /// Disables query analysis.
        /// </summary>
        public static void DisableQueryAnalyzer()
        {
            QueryAnalysisEnabled = false;
            foreach (TraceListener l in from TraceListener l in Source.Listeners where l.GetType().ToString().Contains("EMTraceListener") select l)
            {
                source.Listeners.Remove(l);
                break;
            }
        }

        internal static TraceSource Source
        {
            get
            {
                return source;
            }
        }

        internal static void LogInformation(int id, string msg)
        {
            Source.TraceEvent(TraceEventType.Information, id, msg, MySqlTraceEventType.NonQuery, -1);
            Trace.TraceInformation(msg);
        }

        internal static void LogWarning(int id, string msg)
        {
            Source.TraceEvent(TraceEventType.Warning, id, msg, MySqlTraceEventType.NonQuery, -1);
            Trace.TraceWarning(msg);
        }

        internal static void LogError(int id, string msg)
        {
            Source.TraceEvent(TraceEventType.Error, id, msg, MySqlTraceEventType.NonQuery, -1);
            Trace.TraceError(msg);
        }

        internal static void TraceEvent(
            TraceEventType eventType,
            MySqlTraceEventType mysqlEventType, string msgFormat, params object[] args)
        {
            Source.TraceEvent(eventType, (int)mysqlEventType, msgFormat, args);
        }
    }

    /// <summary>
    /// Specifies the types of warning flags.
    /// </summary>
    public enum UsageAdvisorWarningFlags
    {
        /// <summary>
        /// No index exists.
        /// </summary>
        NoIndex = 1,

        /// <summary>
        /// Bad index exists.
        /// </summary>
        BadIndex,

        /// <summary>
        /// Rows have been excluded from the result.
        /// </summary>
        SkippedRows,

        /// <summary>
        /// Columns have been excluded from the result.
        /// </summary>
        SkippedColumns,

        /// <summary>
        /// Type conversions took place.
        /// </summary>
        FieldConversion
    }

    /// <summary>
    /// Specifies the event that triggered the trace.
    /// </summary>
    public enum MySqlTraceEventType : int
    {
        /// <summary>
        /// A connection has been opened.
        /// </summary>
        ConnectionOpened = 1,

        /// <summary>
        /// A connection has been closed.
        /// </summary>
        ConnectionClosed,

        /// <summary>
        /// A query has been executed.
        /// </summary>
        QueryOpened,

        /// <summary>
        /// Data has been retrieved from the resultset.
        /// </summary>
        ResultOpened,

        /// <summary>
        /// Data retrieval has ended.
        /// </summary>
        ResultClosed,

        /// <summary>
        /// Query execution has ended.
        /// </summary>
        QueryClosed,

        /// <summary>
        /// The statement to be executed has been created.
        /// </summary>
        StatementPrepared,

        /// <summary>
        /// The statement has been executed.
        /// </summary>
        StatementExecuted,

        /// <summary>
        /// The statement is no longer required.
        /// </summary>
        StatementClosed,

        /// <summary>
        /// The query provided is of a nonquery type.
        /// </summary>
        NonQuery,

        /// <summary>
        /// Usage advisor warnings have been requested.
        /// </summary>
        UsageAdvisorWarning,

        /// <summary>
        /// Noncritical problem.
        /// </summary>
        Warning,

        /// <summary>
        /// An error has been raised during data retrieval.
        /// </summary>
        Error,

        /// <summary>
        /// The query has been normalized.
        /// </summary>
        QueryNormalized
    }
}