#ifndef T_UNDO_INCLUDED

#define T_UNDO_INCLUDED

#include <memory></memory>

// TnzCore includes

#include "tsmartpointer.h"

// Qt includes

#include <qobject></qobject>

#include <qstring></qstring>

#undef DVAPI

#undef DVVAR

#ifdef TNZCORE_EXPORTS

#define DVAPI DV_EXPORT_API

#define DVVAR DV_EXPORT_VAR

#else

#define DVAPI DV_IMPORT_API

#define DVVAR DV_IMPORT_VAR

#endif

//************************************************************************

//    TUndo  class

//************************************************************************

class DVAPI TUndo

{

public:

	bool m_isLastInBlock;

public:

	TUndo() {}

	virtual ~TUndo() {}

	virtual int getSize() const = 0;

	virtual void undo() const = 0;

	virtual void redo() const = 0;

	virtual void onAdd() {}

	// for history viewer panel

	virtual QString getHistoryString() { return QObject::tr("Unidentified Action"); }

	virtual int getHistoryType() { return 0; } //HistoryType::Unidentified

private:

	// Noncopyable

	TUndo(const TUndo &undo);

	TUndo &operator=(const TUndo &undo);

};

//************************************************************************

//    TUndoManager  class

//************************************************************************

class DVAPI TUndoManager : public QObject

{

	Q_OBJECT

public:

	TUndoManager();

	~TUndoManager();

	static TUndoManager *manager();

	void beginBlock();

	void endBlock();

	void add(TUndo *undo);

	bool undo();

	bool redo();

	void reset();

	/*!If forward = false remove n elements in the stack before m_imp->m_current;

    else if forward = true remove n elements in the stack after m_imp->m_current.

    If n = -1 remove all elements before or after m_imp->m_current.*/

	void popUndo(int n = -1, bool forward = false);

	//! undo() and redo() methods call TUndoManager::manager()->skip() if

	//! they want another undo/redo performed

	void skip();

	//! Set the size of memory used for undo redo.

	//! \b memorySyze is expressed in MB

	void setUndoMemorySize(int memorySyze);

	// for history viewer pane

	int getHistoryCount();

	int getCurrentHistoryIndex();

	TUndo *getUndoItem(int index);

	Q_SIGNALS :

		void

		historyChanged();

	void somethingChanged();

private:

	struct TUndoManagerImp;

	std::unique_ptr<tundomanagerimp> m_imp;</tundomanagerimp>

private:

	// Noncopyable

	TUndoManager(const TUndoManager &);

	TUndoManager &operator=(const TUndoManager &);

};

//************************************************************************

//    TUndoScopedBlock  class

//************************************************************************

struct TUndoScopedBlock {

	TUndoScopedBlock() { TUndoManager::manager()->beginBlock(); }

	~TUndoScopedBlock() { TUndoManager::manager()->endBlock(); }

private:

	// Noncopyable

	TUndoScopedBlock(const TUndoScopedBlock &);

	TUndoScopedBlock &operator=(const TUndoScopedBlock &);

};

#endif // T_UNDO_INCLUDED