// -*- C++ -*-
/**
 * \file Undo.h
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Asger Alstrup
 * \author Lars Gullik Bjønnes
 * \author John Levon
 * \author André Pönitz
 * \author Jürgen Vigna
 * \author Abdelrazak Younes
 *
 * Full author contact details are available in file CREDITS.
 */

#ifndef UNDO_H
#define UNDO_H

#include "support/types.h"

namespace lyx {

class Buffer;
class BufferParams;
class DocIterator;
class MathData;
class ParagraphList;

/// This is used to combine consecutive undo recordings of the same kind.
enum UndoKind {
	/**
	* Insert something - these will combine to one big chunk
	* when many inserts come after each other.
	*/
	INSERT_UNDO,
	/**
	* Delete something - these will combine to one big chunk
	* when many deletes come after each other.
	*/
	DELETE_UNDO,
	/// Atomic - each of these will have its own entry in the stack
	ATOMIC_UNDO
};


/**
 * Record undo information - call with the current cursor and the 'other
 * end' of the range of changed  paragraphs.  So we give an inclusive range.
 * This is called before you make the changes to the paragraph, and it
 * will record the original information of the paragraphs in the undo stack.
 *
 * FIXME: We need something to record undo in partial grids for mathed.
 * Right now we use recordUndoInset if more than one cell is changed,
 * but that puts the cursor in front of the inset after undo. We would need
 * something like
 * recordUndoGrid(DocIterator & cur, UndoKind kind, idx_type from, idx_type to);
 * and store the cell information in class Undo.
 */
class Undo
{
public:

	Undo(Buffer &);

	~Undo();

	/// this will undo the last action - returns false if no undo possible
	bool textUndo(DocIterator &);

	/// this will redo the last undo - returns false if no redo possible
	bool textRedo(DocIterator &);

	/// makes sure the next operation will be stored
	void finishUndo();

	///
	bool hasUndoStack() const;
	///
	bool hasRedoStack() const;

	/// open a new group of undo operations. Groups can be nested.
	void beginUndoGroup();

	/// end the current undo group
	void endUndoGroup();

	/// The general case: prepare undo for an arbitrary range.
	void recordUndo(DocIterator const & cur, UndoKind kind,
		pit_type from, pit_type to);

	/// Convenience: prepare undo for the range between 'from' and cursor.
	void recordUndo(DocIterator const & cur, UndoKind kind, pit_type from);

	/// Convenience: prepare undo for the single paragraph or cell
	/// containing the cursor
	void recordUndo(DocIterator const & cur, UndoKind kind = ATOMIC_UNDO);
	/// Convenience: prepare undo for the inset containing the cursor
	void recordUndoInset(DocIterator const & cur, UndoKind kind = ATOMIC_UNDO);

	/// Convenience: prepare undo for the whole buffer
	void recordUndoFullDocument(DocIterator const & cur);

private:
	struct Private;
	Private * const d;
};



} // namespace lyx

#endif // UNDO_H