#ifndef SEEN_SNAPPER_H

#define SEEN_SNAPPER_H

#include <map>

#include <list>

#include <boost/optional.hpp>

#include <glib.h> // for g_assert

#include "snapped-point.h"

#include "snapped-line.h"

#include "snapped-curve.h"

#include "snap-preferences.h"

#include "snap-candidate.h"

struct IntermSnapResults {

std::list<Inkscape::SnappedPoint> points;

std::list<Inkscape::SnappedLine> grid_lines;

std::list<Inkscape::SnappedLine> guide_lines;

std::list<Inkscape::SnappedCurve> curves;

};

class SnapManager;

class SPItem;

namespace Inkscape

{

class Snapper

{

public:

//Snapper() {} //does not seem to be used somewhere

Snapper(SnapManager *sm, ::Geom::Coord const t);

virtual ~Snapper() {}

virtual Geom::Coord getSnapperTolerance() const = 0; //returns the tolerance of the snapper in screen pixels (i.e. independent of zoom)

virtual bool getSnapperAlwaysSnap() const = 0; //if true, then the snapper will always snap, regardless of its tolerance

/**

virtual bool ThisSnapperMightSnap() const {return _snap_enabled;} // will likely be overridden by derived classes

// These four methods are only used for grids, for which snapping can be enabled individually

void setEnabled(bool s);

void setSnapVisibleOnly(bool s);

bool getEnabled() const {return _snap_enabled;}

bool getSnapVisibleOnly() const {return _snap_visible_only;}

virtual void freeSnap(IntermSnapResults &/*isr*/,

Inkscape::SnapCandidatePoint const &/*p*/,

Geom::OptRect const &/*bbox_to_snap*/,

std::vector<SPItem const *> const */*it*/,

std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};

// Class for storing the constraint for constrained snapping; can be

// - a line (infinite line with origin, running through _point pointing in _direction)

// - a direction (infinite line without origin, i.e. only a direction vector, stored in _direction)

// - a circle (_point denotes the center, _radius doesn't need an explanation, _direction contains

// the vector from the origin to the original untransformed point);

class SnapConstraint

{

private:

enum SnapConstraintType {LINE, DIRECTION, CIRCLE, UNDEFINED};

public:

// Constructs a direction constraint, e.g. horizontal or vertical but without a specified point

SnapConstraint(Geom::Point const &d) : _direction(d), _type(DIRECTION) {}

// Constructs a linear constraint

SnapConstraint(Geom::Point const &p, Geom::Point const &d) : _point(p), _direction(d), _type(LINE) {}

SnapConstraint(Geom::Line const &l) : _point(l.origin()), _direction(l.versor()), _type(LINE) {}

// Constructs a circular constraint

SnapConstraint(Geom::Point const &p, Geom::Point const &d, Geom::Coord const &r) : _point(p), _direction(d), _radius(r), _type(CIRCLE) {}

// Undefined, or empty constraint

SnapConstraint() : _type(UNDEFINED) {}

bool hasPoint() const {return _type != DIRECTION && _type != UNDEFINED;}

Geom::Point getPoint() const {

g_assert(_type != DIRECTION && _type != UNDEFINED);

return _point;

}

Geom::Point getDirection() const {

return _direction;

}

Geom::Coord getRadius() const {

g_assert(_type == CIRCLE);

return _radius;

}

bool isCircular() const { return _type == CIRCLE; }

bool isLinear() const { return _type == LINE; }

bool isDirection() const { return _type == DIRECTION; }

bool isUndefined() const { return _type == UNDEFINED; }

Geom::Point projection(Geom::Point const &p) const { // returns the projection of p on this constraint

if (_type == CIRCLE) {

// project on to a circular constraint

Geom::Point v_orig = p - _point;

Geom::Coord l = Geom::L2(v_orig);

if (l > 0) {

return _point + _radius * v_orig/l; // Length of _direction is equal to the radius

} else {

// point to be projected is exactly at the center of the circle, so any point on the circle is a projection

return _point + Geom::Point(_radius, 0);

}

} else if (_type != UNDEFINED){

// project on to a linear constraint

Geom::Point const p1_on_cl = (_type == LINE) ? _point : p;

Geom::Point const p2_on_cl = p1_on_cl + _direction;

return Geom::projection(p, Geom::Line(p1_on_cl, p2_on_cl));

} else {

g_warning("Bug: trying to find the projection onto an undefined constraint");

return Geom::Point();

}

}

private:

Geom::Point _point;

Geom::Point _direction;

Geom::Coord _radius;

SnapConstraintType _type;

};

virtual void constrainedSnap(IntermSnapResults &/*isr*/,

Inkscape::SnapCandidatePoint const &/*p*/,

Geom::OptRect const &/*bbox_to_snap*/,

SnapConstraint const &/*c*/,

std::vector<SPItem const *> const */*it*/,

std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};

protected:

SnapManager *_snapmanager;

// This is only used for grids, for which snapping can be enabled individually

bool _snap_enabled; ///< true if this snapper is enabled, otherwise false

bool _snap_visible_only;

};

}

#endif /* !SEEN_SNAPPER_H */