#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion
#if !NETCF && (NET_2_0 || NETSTANDARD2_0)
using System;
using System.IO;

using log4net.Util;
using log4net.Core;

namespace log4net.Layout.Pattern
{
  /// <summary>
  /// Write the caller stack frames to the output
  /// </summary>
  /// <remarks>
  /// <para>
  /// Writes the <see cref="LocationInfo.StackFrames"/> to the output writer, using format:
  /// type3.MethodCall3 > type2.MethodCall2 > type1.MethodCall1
  /// </para>
  /// </remarks>
  /// <author>Michael Cromwell</author>
  internal class StackTracePatternConverter : PatternLayoutConverter, IOptionHandler
  {
    private int m_stackFrameLevel = 1;
    
    /// <summary>
    /// Initialize the converter
    /// </summary>
    /// <remarks>
    /// <para>
    /// This is part of the <see cref="IOptionHandler"/> delayed object
    /// activation scheme. The <see cref="ActivateOptions"/> method must 
    /// be called on this object after the configuration properties have
    /// been set. Until <see cref="ActivateOptions"/> is called this
    /// object is in an undefined state and must not be used. 
    /// </para>
    /// <para>
    /// If any of the configuration properties are modified then 
    /// <see cref="ActivateOptions"/> must be called again.
    /// </para>
    /// </remarks>
    public void ActivateOptions()
    {
      if (Option == null)
        return;
      
      string optStr = Option.Trim();
      if (optStr.Length != 0)
      {
        int stackLevelVal;
        if (SystemInfo.TryParse(optStr, out stackLevelVal))
        {
          if (stackLevelVal <= 0) 
          {
            LogLog.Error(declaringType, "StackTracePatternConverter: StackeFrameLevel option (" + optStr + ") isn't a positive integer.");
          }
          else
          {
            m_stackFrameLevel = stackLevelVal;
          }
        } 
        else
        {
          LogLog.Error(declaringType, "StackTracePatternConverter: StackFrameLevel option \"" + optStr + "\" not a decimal integer.");
        }
      }
    }
    
    /// <summary>
    /// Write the strack frames to the output
    /// </summary>
    /// <param name="writer"><see cref="TextWriter" /> that will receive the formatted result.</param>
    /// <param name="loggingEvent">the event being logged</param>
    /// <remarks>
    /// <para>
    /// Writes the <see cref="LocationInfo.StackFrames"/> to the output writer.
    /// </para>
    /// </remarks>
    protected override void Convert(TextWriter writer, LoggingEvent loggingEvent)
    {
      StackFrameItem[] stackframes = loggingEvent.LocationInformation.StackFrames;
      if ((stackframes == null) || (stackframes.Length <= 0))
      {
        LogLog.Error(declaringType, "loggingEvent.LocationInformation.StackFrames was null or empty.");
        return;
      }
      
      int stackFrameIndex = m_stackFrameLevel - 1;
      while (stackFrameIndex >= 0)
      {
        if (stackFrameIndex >= stackframes.Length)
        {
          stackFrameIndex--;
          continue;
        }
        
        StackFrameItem stackFrame = stackframes[stackFrameIndex];
                writer.Write("{0}.{1}", stackFrame.ClassName, GetMethodInformation(stackFrame.Method));
        if (stackFrameIndex > 0)
        {
                    // TODO: make this user settable?
          writer.Write(" > ");
        }
        stackFrameIndex--;
      }
    }

                /// <summary>
        /// Returns the Name of the method
        /// </summary>
        /// <param name="method"></param>
        /// <remarks>This method was created, so this class could be used as a base class for StackTraceDetailPatternConverter</remarks>
        /// <returns>string</returns>
        internal virtual string GetMethodInformation(MethodItem method)
        {
            return method.Name;
        }
    
    #region Private Static Fields

      /// <summary>
      /// The fully qualified type of the StackTracePatternConverter class.
      /// </summary>
      /// <remarks>
      /// Used by the internal logger to record the Type of the
      /// log message.
      /// </remarks>
      private static readonly Type declaringType = typeof(StackTracePatternConverter);

      #endregion Private Static Fields
  }
}
#endif // !NETCF && NET_2_0