enum FoldType { FoldUp, FoldDown, TuckIn, BendUp, BendDown, Bend, Undecided };

class Fold{
public:
	// for pick
	class Vertex    *vertex;
	int              vertexID;
	class Face      *face;
	int              faceID;
	class FaceGroup *faceGroup;
	// for move
	Vector      destination;
	FoldType    type;
	Plane       boundary;
	Line        axis;
	double      angle;
	// for animation
	Vector      destination2;
	FoldType    type2;
	Plane       boundary2;
	Line        axis2;
	double      angle2;

	// pick
	bool setPick(Face &face); // face.h
	bool setPick( FaceGroup &faceGroup, Vector &viewDirection ); // facegroup.h
	Vector pickedVertexPosition(); // vertex.h
	// update
	bool update( double margin=0.1 );
	bool isBend(){ return type == BendUp || type == BendDown; }
	bool update( Vector &destination, Vector &eyePosition, bool inBending );
	bool update( Vector &destination ){ this->destination = destination; return this->update(); }

	// renew
	FaceGroup *pickedFaceGroup(){ return faceGroup; }
	Face *pickedFace(){ return face; }
	enum VertexLabel vertexLabel( Vector &position, double margin );  // vertex.h

	Vector newVertexPosition( Vector &v1, Vector &v2 ){
		Line edge( v1, v2 );
		Vector position;
		position.intersection( boundary, edge );
		return position;
	}

	Vector rotateVertexPosition( Vector &v ){ Vector position; position.rotate( v, axis, angle ); return position; }
	Vector rotateNormal( Vector &normal ){
		normal.print();
		axis.print();
		Vector v1, v2, vo(0,0,0);
		v2.rotate( normal, axis, angle );
		v1.rotate( vo, axis, angle );
		vo = v2 - v1;
		v2.print();
		v1.print();
		return vo;
	}

	// file io
	void save( FILE *fp );
	bool load( FILE *fp, FaceGroup ** &faceGroup );
	// animation
	void backup(){
		destination2 = destination;
		type2        = type;
		boundary2    = boundary;
		axis2        = axis;
		angle2       = angle;
	}
	void modify( double position ); // vertex.h

	void print();
};