/*=========================================================================

  Program:   ParaView
  Module:    $RCSfile: vtkSMUndoStackBuilder.h,v $

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkSMUndoStackBuilder - builds server manager undo sets and 
// pushes them on the undo stack.
// .SECTION Description
// vtkSMUndoStackBuilder records Server Manager changes that are undo/redo 
// able and collects them. To begin recording such changes one must call 
// Begin(). To end recording use End(). One can have multiple blocks
// of Begin-End before pushing the changes on the Undo Stack. To push all 
// collected changes onto the Undo Stack as a single undoable step,
// use PushToStack(). 
// Applications can subclass vtkSMUndoStackBuilder to record GUI related
// changes and add them to the undo stack.
// .SECTION TODO
// \li Mutiple clients are not supported. For now, the server can connect to only
// one client.

#ifndef __vtkSMUndoStackBuilder_h
#define __vtkSMUndoStackBuilder_h

#include "vtkSMObject.h"

class vtkSMGlobalPropertiesManager;
class vtkSMProxy;
class vtkSMUndoStack;
class vtkSMUndoStackBuilderObserver;
class vtkUndoElement;
class vtkUndoSet;

class VTK_EXPORT vtkSMUndoStackBuilder : public vtkSMObject
{
public:
  static vtkSMUndoStackBuilder* New();
  vtkTypeRevisionMacro(vtkSMUndoStackBuilder, vtkSMObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Get/Set the connection ID. Currently this class records
  // changes of proxies only on 1 connection at a time. 
  vtkGetMacro(ConnectionID, vtkIdType);
  vtkSetMacro(ConnectionID, vtkIdType);

  // Description:
  // Begins monitoring of the vtkSMProxyManager for undoable operations.
  // All noted actions are converted to UndoElements and collected.
  // One vtkUndoElement is created per action. All undo elements
  // become a part of a vtkUndoSet which is pushed on to
  // the Undo Stack on PushToStack().
  // \c label is a suggestion for the UndoSet that will be built. If the 
  // UndoSet already has elements implying it hasn't been pushed to the stack
  // then the label is ignored.
  virtual void Begin(const char* label);

  // Description:
  // Stops monitoring of the vtkSMProxyManager for undoable operations.
  // Any changes made to the proxy manager will not be converted
  // to UndoElements. This method does not push the vtkUndoSet of 
  // undo elements built. One must call PushToStack() to push
  // the UndoSet to the Undo stack. Alternatively, one can use the
  // EndAndPushToStack() method which combines End() and PushToStack().
  virtual void End();

  // Description:
  // Convenience method call End(); PushToStack(); in that order.
  void EndAndPushToStack()
    { 
    this->End();
    this->PushToStack();
    }

  // Description:
  // If any undoable changes were recorded by the builder, this will push
  // the vtkUndoSet formed on to the UndoStack. The UndoStack which the builder
  // is building must be set by using SetUndoStack(). If the UndoSet 
  // is empty, it is not pushed on the stack. After pushing, the UndoSet is cleared
  // so the builder is ready to collect new modifications.
  virtual void PushToStack();

  // Description:
  // Discard all recorded changes that haven't been pushed on the UndoStack.
  virtual void Clear();

  // Description
  // One can add arbritary elements to the active undo set.
  // It is essential that the StateLoader on the UndoStack can handle the 
  // arbritary undo elements.
  virtual void Add(vtkUndoElement* element);

  // Description:
  // Get/Set the undo stack that this builder will build.
  vtkGetObjectMacro(UndoStack, vtkSMUndoStack);
  virtual void SetUndoStack(vtkSMUndoStack*);

  // Description:
  // If IgnoreAllChanges is true, any server manager changes will be
  // ignored even if the changes happened within a Begin()-End() call.
  // This provides a mechanism for the application to perform non-undoable
  // operations irrespective of whether a undo set if being built.
  // By default, it is set to false.
  vtkSetMacro(IgnoreAllChanges, bool);
  vtkGetMacro(IgnoreAllChanges, bool);

//BTX
protected:
  vtkSMUndoStackBuilder();
  ~vtkSMUndoStackBuilder();

  friend class vtkSMUndoStackBuilderObserver;

  // Description:
  // Event handler.
  virtual void ExecuteEvent(vtkObject* called, unsigned long eventid, void* data);

  // Description:
  // Handler for specific vtkSMProxyManager events.
  virtual void OnRegisterProxy(const char* group, const char* name,
    vtkSMProxy*);
  virtual void OnUnRegisterProxy(const char* group, const char* name,
    vtkSMProxy*);
  virtual void OnPropertyModified(vtkSMProxy* proxy, const char* propname);
  virtual void OnUpdateInformation(vtkSMProxy* proxy);
  virtual void OnRegisterLink(const char* name);
  virtual void OnUnRegisterLink(const char* name);
  virtual void OnRegisterGlobalPropertiesManager(vtkSMGlobalPropertiesManager*);
  virtual void OnUnRegisterGlobalPropertiesManager(vtkSMGlobalPropertiesManager*);
  virtual void GlobalPropertiesLinkAdded( const char* mgrname,
    const char* globalname, vtkSMProxy* proxy, const char* propname);
  virtual void GlobalPropertiesLinkRemoved( const char* mgrname,
    const char* globalname, vtkSMProxy* proxy, const char* propname);

  vtkSMUndoStack* UndoStack;
  vtkIdType ConnectionID;
  vtkUndoSet* UndoSet;
  char* Label;
  vtkSetStringMacro(Label);

  // Description
  // Returns if the Builder is currently monitoring the ProxyManager
  // changes.
  vtkGetMacro(EnableMonitoring, int);

  // Description
  // Returns if the event raised by the proxy manager should be
  // converted to undo eleements.
  virtual bool HandleChangeEvents()
    {
    return (this->GetEnableMonitoring() > 0);
    }

  void InitializeUndoSet();

private:
  vtkSMUndoStackBuilderObserver* Observer;

private:
  vtkSMUndoStackBuilder(const vtkSMUndoStackBuilder&); // Not implemented.
  void operator=(const vtkSMUndoStackBuilder&); // Not implemented.

  int EnableMonitoring;
  bool IgnoreAllChanges;
//ETX
};

#endif

