/*
    This file is part of the Okteta Gui library, made within the KDE community.

    Copyright 2003,2009 Friedrich W. H. Kossebau <kossebau@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) version 3, or any
    later version accepted by the membership of KDE e.V. (or its
    successor approved by the membership of KDE e.V.), which shall
    act as a proxy defined in Section 6 of version 3 of the license.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef OKTETA_COORD_H
#define OKTETA_COORD_H

// lib
#include <okteta/lineposition.h>
#include <okteta/line.h>
// Okteta core
#include <okteta/address.h>
#include <okteta/size.h>


namespace Okteta
{

/**
  * a class which represents a coord in a 2-dim. system
  *
  * It consists of a line number and a position in the line.
  * The coord starts at (0,0). Line numbers increase downwards, positions to the right.
  * With any of both at a negative number the coord is invalid.
  * The index at coord(0,0) is 0.
  *
  * @author Friedrich W. H. Kossebau
  */
class Coord
{
  public:
    /** constructs a section by width
     * @param index starting index
     * @param lineWidth width of the section
     */
    static Coord fromIndex( Address index, LinePositionSize lineWidth );
  public:
    /** creates a coord with 0,0 */
    Coord();
    Coord( LinePosition pos, Line line );
    Coord( const Coord& other );
    Coord& operator=( const Coord& other );

    ~Coord();


  public: // logic
    bool operator==( const Coord& other ) const;
    bool operator!=( const Coord& other ) const;
    bool operator<( const Coord& other ) const;
    bool operator<=( const Coord& other ) const;
    bool operator>( const Coord& other ) const;
    bool operator>=( const Coord& other ) const;

    /** tests if the coord is prior in the same line than the given coord.
     * If at least one of both is invalid the result is undefined.
     * @return true if the pos is left to the pos of other and both are in the same line, otherwise false.
     */
    bool isPriorInLineThan( const Coord& other ) const;
    /** tests if the coord is later in the same line than the given coord.
     * If at least one of both is invalid the result is undefined.
     * @return true if the pos is right to the pos of other and both are in the same line, otherwise false 
     */
    bool isLaterInLineThan( const Coord& other ) const;
    /** @return true if the line is below lines, otherwise false */
    bool isBelow( Line line ) const;
    /** @return true if the line is above lines, otherwise false */
    bool isAbove( Line line ) const;
    /** @return true if the coord is at (0,0) */
    bool isAtStart() const;
    /** @return true if the pos is greater than 0, otherwise false */
    bool isBehindLineStart() const;
    /** @return true if the pos is smaller than maxPos, otherwise false */
    bool isBeforeLineEnd( LinePosition maxPos ) const;

    /** calculates the index the coord is at with a given line width
     * If the coord is invalid the result is undefined.
     * @param lineWidth given width of line
     * @return index the coord is at 
     */
    Address indexByLineWidth( LinePositionSize lineWidth ) const;

  public:
    /** set the coord by calculating it for an index with a given line width
     * @param index index in the buffer
     * @param lineWidth given line width
     */
    void setByIndexNWidth( Address index, LinePositionSize lineWidth );
    /** sets both position and line */
    void set( LinePosition pos, Line line );
    /** sets the position */
    void setPos( LinePosition pos );
    /** sets the line */
    void setLine( Line line );

    /** moves the coord one position to the left. If the coord is invalid the result is undefined. */
    void goLeft();
    /** moves the coord a given number of positions to the left. 
     * If the coord is invalid the result is undefined or the position smaller than the given number 
     * the behaviour is undefined.
     * @param positions number of positions
     */
    void goLeft( LinePositionSize positions );
    /** moves the coord one position to the left, or if the position is already at the line start
     * to the given position in the previous line. If the coord is invalid the result is undefined. 
     * @param maxPos maximal allowed position
     */
    void goCLeft( LinePosition maxPos );
    /** moves the coord one position to the right. If the coord is invalid the result is undefined. */
    void goRight();
    /** moves the coord a given number of positions to the right. If the coord is invalid the result is undefined.
     * @param positions number of positions
     */
    void goRight( LinePositionSize positions );
    /** moves the coord one position to the right, or if the position has already reached or passed maxPos 
     * to the first position in the next line. If the coord is invalid the result is undefined. 
     * @param maxPos maximal allowed position
     */
    void goCRight( LinePosition maxPos );
    /** sets coord to (0,0) */
    void gotoStart();
    void gotoEndOfPreviousLine( LinePosition lastPos );
    /** sets the coord to the start of the next line. 
      * If the coord is invalid the behaviour is undefined.
      */
    void gotoStartOfNextLine();
    /** sets the position to the start of the line or 
      * if the line is the same as that of the given coord to the position of it. 
      * If one or more of the coords is invalid the behaviour is undefined.
      * @param other a possible line start coord
      */
    void goLineStart( const Coord& other );
    /** sets the position to the given pos or 
      * if the line is the same as that of the given coord to the position of that. 
      * If one or more of the coords is invalid the behaviour is undefined.
      * @param lastPos last position in normal line
      * @param other a possible line end coord
      */
    void goLineEnd( LinePosition lastPos, const Coord& other );
    /** moves the coord 1 lines upwards. There is no check whether the first line is overstepped. */
    void goUp();
    /** moves the coord lines lines downwards. */
    void goDown();
    /** moves the coord lines lines upwards. There is no check whether the first line is overstepped.
     * @param lines number of lines
     */
    void goUp( LineSize lines );
    /** moves the coord lines lines downwards. 
     * @param lines number of lines
     */
    void goDown( LineSize lines );

  public: // state value access
    /** @return the pos in the line */
    LinePosition pos() const;
    /** @return the line number */
    Line line() const;
    /** @return true if the coord is valid */
    bool isValid() const;

  private: // member variables
    /** Position in mLine */
    LinePosition mPos;
    /** mLine */
    Line mLine;
};


inline Coord::Coord() : mPos( 0 ), mLine( 0 ) {}
inline Coord::Coord( LinePosition pos, Line line ) : mPos( pos ), mLine( line ) {}

inline Coord Coord::fromIndex( Address index, LinePositionSize lineWidth )
{
    const Line line = index / lineWidth;
    const LinePosition pos  = index - line*lineWidth;
    return Coord( pos, line );
}

inline Coord::Coord( const Coord& other ) : mPos( other.mPos ), mLine( other.mLine ) {}
inline Coord& Coord::operator=( const Coord& other ) { mPos = other.mPos; mLine = other.mLine; return *this; }
inline Coord::~Coord() {}

inline bool Coord::operator==( const Coord& other ) const { return mPos == other.mPos && mLine == other.mLine; }
inline bool Coord::operator!=( const Coord& other ) const { return !(*this == other); }

inline bool Coord::operator<( const Coord& other ) const
{ return mLine < other.mLine || (mLine == other.mLine && mPos<other.mPos); }
inline bool Coord::operator<=( const Coord& other ) const
{ return mLine < other.mLine || (mLine == other.mLine && mPos<=other.mPos); }
inline bool Coord::operator>( const Coord& other ) const
{ return mLine > other.mLine || (mLine == other.mLine && mPos>other.mPos); }
inline bool Coord::operator>=( const Coord& other ) const
{ return mLine > other.mLine || (mLine == other.mLine && mPos>=other.mPos); }

inline LinePosition  Coord::pos() const { return mPos; }
inline Line  Coord::line()        const { return mLine; }
inline bool Coord::isValid()      const { return mLine >= 0 && mPos >= 0; }

inline void Coord::setByIndexNWidth( Address index, LinePositionSize lineWidth )
{
    mLine = index / lineWidth;
    mPos  = index - mLine*lineWidth;
}

inline void Coord::set( LinePosition pos, Line line )
{
    mPos  = pos;
    mLine = line;
}
inline void Coord::setPos( LinePosition pos )  { mPos  = pos; }
inline void Coord::setLine( Line line ) { mLine = line; }

inline void Coord::goCRight( LinePosition maxPos )
{
    if( isBeforeLineEnd(maxPos) )
        goRight();
    else
        gotoStartOfNextLine();
}
inline void Coord::goCLeft( LinePosition maxPos )
{
    if( isBehindLineStart() )
        goLeft();
    else
        gotoEndOfPreviousLine( maxPos );
}

inline void Coord::goRight() { ++mPos; }
inline void Coord::goLeft()  { --mPos; }
inline void Coord::goRight( LinePositionSize positions ) { mPos += positions; }
inline void Coord::goLeft( LinePositionSize positions )  { mPos -= positions; }

inline void Coord::gotoStart() { mPos = mLine = 0; }

inline void Coord::gotoEndOfPreviousLine( LinePosition lastPos )
{
    --mLine;
    mPos = lastPos;
}

inline void Coord::gotoStartOfNextLine()
{
    ++mLine;
    mPos = 0;
}


inline void Coord::goLineStart( const Coord& other )
{
    mPos = ( mLine == other.mLine ) ? other.mPos : 0;
}

inline void Coord::goLineEnd( LinePosition lastPos, const Coord& other )
{
    mPos = ( mLine == other.mLine ) ? other.mPos : lastPos;
}

inline void Coord::goUp()           { --mLine; }
inline void Coord::goDown()         { ++mLine; }
inline void Coord::goUp( LineSize lines )    { mLine -= lines; }
inline void Coord::goDown( LineSize lines )  { mLine += lines; }


inline Address Coord::indexByLineWidth( LinePositionSize lineWidth ) const
{
    return mLine * lineWidth + mPos;
}


inline bool Coord::isPriorInLineThan( const Coord& other ) const
{
    return mLine == other.mLine && mPos < other.mPos;
}

inline bool Coord::isLaterInLineThan( const Coord& other ) const
{
    return mLine == other.mLine && mPos > other.mPos;
}

inline bool Coord::isBelow( Line line ) const { return mLine > line; }
inline bool Coord::isAbove( Line line ) const { return mLine < line; }

inline bool Coord::isBehindLineStart()           const { return mPos > 0; }
inline bool Coord::isBeforeLineEnd( LinePosition maxPos ) const { return mPos < maxPos; }

inline bool Coord::isAtStart()                   const { return mPos == 0 && mLine == 0; }

inline Coord operator+( const Coord& other, LinePosition pos )
{
    return Coord( other.pos()+pos, other.line() );
}

}

#endif
