class Stage{
public:
	int         ID;
	FaceGroup **faceGroup;
	int	        faceGroupSize;
	Fold        fold;

	Stage( FILE *fp ){ ID = 0; faceGroup = new FaceGroup *[faceGroupSize = 1]; faceGroup[0] = new FaceGroup( fp ); }

	// pick
	Vector closestVertexPosition( Line &line ){
		Vertex *closest=NULL;
		double distance = DBL_MAX;
		for( int i=0; i<faceGroupSize; i++ ){
			double d;
			Vertex *v;
			faceGroup[i]->closestVertex( line, v, d );
			if( d < distance ){
				closest  = v;
				distance = d;
			}
		}
		return closest->position;
	}

	void labelPickedCandidate( Vector &position ){ for( int i=0; i<faceGroupSize; i++ ) faceGroup[i]->labelPickedCandidate( position ); }

	Vector pick( Line &cursorLine ){
		this->labelPickedCandidate( this->closestVertexPosition(cursorLine) );
		for( int i=0; faceGroupSize; i++ ){ if( fold.setPick( *faceGroup[i], cursorLine.direction ) ) return fold.pickedVertexPosition(); }
		Vector v(0,0,0); return v;
	}
	//renew
	bool renew(){
		if( fold.pickedFaceGroup()->renew( ID+1, fold )==RenewFailure ) return true;
		else return false;
	}
	bool renew( Vector &destination, Vector &eyePosition, bool inBending ){
		if( fold.update( destination, eyePosition, inBending ) ) return true; // error
		return this->renew();
	}

	int childFaceGroupSize(){ return fold.isBend() ? faceGroupSize + 1 : faceGroupSize; };
	bool isPickedFaceGroup( int n ){ return faceGroup[n] == fold.pickedFaceGroup(); }

	Stage( Stage &parentStage ){
		ID = parentStage.ID + 1;
		faceGroupSize = parentStage.childFaceGroupSize();
		faceGroup = new FaceGroup *[faceGroupSize];
		for( int i=0; i<parentStage.faceGroupSize; i++ ){
			if( parentStage.isPickedFaceGroup(i) ){
				faceGroup[i] = new FaceGroup( ID, *parentStage.faceGroup[i], parentStage.fold );
			}else{
				faceGroup[i] = parentStage.faceGroup[i];
			}
		}
		if( parentStage.fold.isBend() ){
			faceGroup[faceGroupSize-1] = new FaceGroup( ID, *parentStage.fold.pickedFaceGroup(), parentStage.fold, faceGroupSize-1 );
			faceGroup[faceGroupSize-1]->normal = parentStage.fold.rotateNormal( parentStage.fold.pickedFaceGroup()->normal );
		}
	}

	//reset
	~Stage(){ if( faceGroup == NULL ) return; if( faceGroup[faceGroupSize-1]->birthStage == ID ) delete faceGroup[faceGroupSize-1]; delete faceGroup; }
	void reset(){ fold.pickedFaceGroup()->reset( ID+1 ); }

	//draw
	void draw( Vector &eyePosition, FaceProperty &faceProperty ){
		FaceGroup **renderGroup = new FaceGroup *[faceGroupSize];
		renderGroup[0] = faceGroup[0];
		int i;
		for( i=1; i<faceGroupSize; i++ ){
			renderGroup[i] = faceGroup[i];
			int j = i - 1;
			while( j>=0 && renderGroup[j]->sort( *renderGroup[j+1], eyePosition ) == 1 ){
				FaceGroup *tmp = renderGroup[j];
				renderGroup[j] = renderGroup[j+1];
				renderGroup[j+1] = tmp;
				j--;
			}
		}
		for( i=faceGroupSize-1; i>=0; i-- ) renderGroup[i]->draw( eyePosition, faceProperty );//render from far to near
		delete renderGroup;
	}
	// file io
	void saveFold( FILE *fp ){ fold.save( fp ); }
	bool loadFold( FILE *fp ){ return fold.load( fp, faceGroup ); }
};