/*
Copyright (c) by respective owners including Yahoo!, Microsoft, and
individual contributors. All rights reserved.  Released under a BSD (revised)
license as described in the file LICENSE.
*/

#pragma once

#include "vw_clr.h"
#include <stack>
#include "vw_interface.h"
#include "vw_arguments.h"

using namespace System::Collections::Generic;

namespace VW
{
ref class VowpalWabbitPrediction;
ref class VowpalWabbitModel;

/// <summary>
/// A base wrapper around vowpal wabbit machine learning instance.
/// </summary>
/// <remarks>
/// Since the model class must delay diposal of <see cref="m_vw"/> until all referencing
/// VowpalWabbit instances are disposed, the base class does not dispose <see cref="m_vw"/>.
/// </remarks>
public ref class VowpalWabbitBase abstract
{
private:
  /// <summary>
  /// The settings used for this instance.
  /// </summary>
  initonly VowpalWabbitSettings^ m_settings;

  /// <summary>
  /// Handle to trace listener delegate, required to keep safe from garbage collection.
  /// </summary>
  GCHandle m_traceListener;

  /// <summary>
  /// An optional shared model.
  /// </summary>
  VowpalWabbitModel^ m_model;

  /// <summary>
  /// Extracted command line arguments.
  /// </summary>
  VowpalWabbitArguments^ m_arguments;

  /// <summary>
  /// Reference count to native data structure.
  /// </summary>
  System::Int32 m_instanceCount;

internal:
  /// <summary>
  /// The native vowpal wabbit data structure.
  /// </summary>
  vw* m_vw;

  /// <summary>
  /// Thread-safe increment of reference count.
  /// </summary>
  void IncrementReference();

  /// <summary>
  /// Thread-safe decrement of reference count.
  /// </summary>
  void DecrementReference();

protected:
  /// <summary>
  /// True if all nativedata structures are disposed.
  /// </summary>
  bool m_isDisposed;

  /// <summary>
  /// Example pool. Kept in base to simplify deallocation.
  /// </summary>
  IBag<VowpalWabbitExample^>^ m_examples;

  /// <summary>
  /// Initializes a new <see cref="VowpalWabbitBase"/> instance.
  /// </summary>
  /// <param name="settings">Command line arguments.</param>
  VowpalWabbitBase(VowpalWabbitSettings^ settings);

  /// <summary>
  /// Cleanup.
  /// </summary>
  !VowpalWabbitBase();

  /// <summary>
  /// Internal dipose using reference counting to delay disposal of shared native data structures.
  /// </summary>
  void InternalDispose();

  void DisposeExample(VowpalWabbitExample^ ex);

public:
  /// <summary>
  /// Cleanup.
  /// </summary>
  virtual ~VowpalWabbitBase();

  /// <summary>
  /// The settings used for this instance.
  /// </summary>
  property VowpalWabbitSettings^ Settings
  { VowpalWabbitSettings^ get();
  }

  /// <summary>
  /// Extracted command line arguments.
  /// </summary>
  property VowpalWabbitArguments^ Arguments
  { VowpalWabbitArguments^ get();
  }

  /// <summary>
  /// The read/writable model id.
  /// </summary>
  property String^ ID
  { String^ get();
    void set(String^ id);
  }

  /// <summary>
  /// Performs the following steps to reset the learning state:
  ///
  /// - Save model to in-memory buffer
  /// - Dispose existing instance
  /// - Initialize new instance from in-memory buffer
  /// </summary>
  void Reload([System::Runtime::InteropServices::Optional] String^ args);

  /// <summary>
  /// Compares features created by current instance are compatible to features created by <paramref name="other"/>.
  /// </summary>
  /// <returns>
  /// Null if compatible, otherwise the difference
  /// </returns>
  String^ AreFeaturesCompatible(VowpalWabbitBase^ other);

  /// <summary>
  /// Persist model to file specified by -i.
  /// </summary>
  void SaveModel();

  /// <summary>
  /// Persist model to <paramref name="filename"/>.
  /// </summary>
  /// <param name="filename">The destination filename for the model.</param>
  void SaveModel(String^ filename);

  /// <summary>
  /// Persist model to <paramref name="stream"/>.
  /// </summary>
  /// <param name="stream">The destination stream for the model.</param>
  /// <remarks>The stream is not closed to support embedded schemes.</remarks>
  void SaveModel(Stream^ stream);
};
}