/****************************************************************************
**
** This file is part of the LibreCAD project, a 2D CAD program
**
** Copyright (C) 2010 R. van Twisk (librecad@rvt.dds.nl)
** Copyright (C) 2001-2003 RibbonSoft. All rights reserved.
**
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file gpl-2.0.txt included in the
** packaging of this file.
**
** This program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
**
** This copyright notice MUST APPEAR in all copies of the script!
**
**********************************************************************/


#include <QFileInfo>
#include "rs_creation.h"

#include "rs_information.h"
#include "rs_graphic.h"
#include "rs_constructionline.h"
#include "rs_graphicview.h"
#include "rs_modification.h"
#include "lc_hyperbola.h"

/**
 * Default constructor.
 *
 * @param container The container to which we will add
 *        entities. Usually that's an RS_Graphic entity but
 *        it can also be a polyline, text, ...
 */
RS_Creation::RS_Creation(RS_EntityContainer* container,
                         RS_GraphicView* graphicView,
                         bool handleUndo) {
    this->container = container;
    this->graphicView = graphicView;
    this->handleUndo = handleUndo;
    if (container!=NULL) {
        graphic = container->getGraphic();
        document = container->getDocument();
    } else {
        graphic = NULL;
        document = NULL;
    }
}


/**
 * Creates a point entity.
 *
 * E.g.:<br>
 * <code>
 * creation.createPoint(RS_Vector(10.0, 15.0));
 * </code>
 *
 * @param p position
 */
/*void RS_Creation::createPoint(const RS_Vector& p) {
    entityContainer->addEntity(new RS_Point(entityContainer, p));
}*/


/**
 * Creates a line with two points given.
 *
 * E.g.:<br>
 * <code>
 * creation.createLine2P(RS_Vector(10.0, 10.0), RS_Vector(100.0, 200.0));
 * </code>
 *
 * @param p1 start point
 * @param p2 end point
 */
/*void RS_Creation::createLine2P(const RS_Vector& p1, const RS_Vector& p2) {
    entityContainer->addEntity(new RS_Line(entityContainer,
                                           RS_LineData(p1, p2)));
}*/

/**
 * Creates a rectangle with two edge points given.
 *
 * E.g.:<br>
 * <code>
 * creation.createRectangle(RS_Vector(5.0, 2.0), RS_Vector(7.5, 3.0));
 * </code>
 *
 * @param p1 edge one
 * @param p2 edge two
 */
/*void RS_Creation::createRectangle(const RS_Vector& e1, const RS_Vector& e2) {
    RS_Vector e21(e2.x, e1.y);
    RS_Vector e12(e1.x, e2.y);
    entityContainer->addEntity(new RS_Line(entityContainer,
                                           RS_LineData(e1, e12)));
    entityContainer->addEntity(new RS_Line(entityContainer,
                                           RS_LineData(e12, e2)));
    entityContainer->addEntity(new RS_Line(entityContainer,
                                           RS_LineData(e2, e21)));
    entityContainer->addEntity(new RS_Line(entityContainer,
                                           RS_LineData(e21, e1)));
}*/


/**
 * Creates a polyline from the given array of entities.
 * No checking if the entities actually fit together.
 * Currently this is like a group.
 *
 * E.g.:<br>
 * <code>
 * RS_Polyline *pl = creation.createPolyline(RS_Vector(25.0, 55.0));<br>
 * pl->addVertex(RS_Vector(50.0, 75.0));<br>
 * </code>
 *
 * @param entities array of entities
 * @param startPoint Start point of the polyline
 */
/*RS_Polyline* RS_Creation::createPolyline(const RS_Vector& startPoint) {
    RS_Polyline* pl = new RS_Polyline(entityContainer,
                RS_PolylineData(startPoint, RS_Vector(0.0,0.0), 0));
    entityContainer->addEntity(pl);
    return pl;
}*/



/**
 * Creates an entity parallel to the given entity e through the given
 * 'coord'.
 *
 * @param coord Coordinate to define the distance / side (typically a
 *              mouse coordinate).
 * @param number Number of parallels.
 * @param e Original entity.
 *
 * @return Pointer to the first created parallel or NULL if no
 *    parallel has been created.
 */
RS_Entity* RS_Creation::createParallelThrough(const RS_Vector& coord,
                                              int number,
                                              RS_Entity* e) {
    if (e==NULL) {
        return NULL;
    }

    double dist;

    if (e->rtti()==RS2::EntityLine) {
        RS_Line* l = (RS_Line*)e;
        RS_ConstructionLine cl(NULL,
                               RS_ConstructionLineData(l->getStartpoint(),
                                                       l->getEndpoint()));
        dist = cl.getDistanceToPoint(coord);
    } else {
        dist = e->getDistanceToPoint(coord);
    }

    if (dist<RS_MAXDOUBLE) {
        return createParallel(coord, dist, number, e);
    } else {
        return NULL;
    }
}



/**
 * Creates an entity parallel to the given entity e.
 * Out of the 2 possible parallels, the one closest to
 * the given coordinate is returned.
 * Lines, Arcs and Circles can have parallels.
 *
 * @param coord Coordinate to define which parallel we want (typically a
 *              mouse coordinate).
 * @param distance Distance of the parallel.
 * @param number Number of parallels.
 * @param e Original entity.
 *
 * @return Pointer to the first created parallel or NULL if no
 *    parallel has been created.
 */
RS_Entity* RS_Creation::createParallel(const RS_Vector& coord,
                                       double distance, int number,
                                       RS_Entity* e) {
    if (e==NULL) {
        return NULL;
    }

    switch (e->rtti()) {
    case RS2::EntityLine:
        return createParallelLine(coord, distance, number, (RS_Line*)e);
        break;

    case RS2::EntityArc:
        return createParallelArc(coord, distance, number, (RS_Arc*)e);
        break;

    case RS2::EntityCircle:
        return createParallelCircle(coord, distance, number, (RS_Circle*)e);
        break;

    default:
        break;
    }

    return NULL;
}



/**
 * Creates a line parallel to the given line e.
 * Out of the 2 possible parallels, the one closest to
 * the given coordinate is returned.
 *
 * @param coord Coordinate to define which parallel we want (typically a
 *              mouse coordinate).
 * @param distance Distance of the parallel.
 * @param number Number of parallels.
 * @param e Original entity.
 *
 * @return Pointer to the first created parallel or NULL if no
 *    parallel has been created.
 */
RS_Line* RS_Creation::createParallelLine(const RS_Vector& coord,
                                         double distance, int number,
                                         RS_Line* e) {

    if (e==NULL) {
        return NULL;
    }

    double ang = e->getAngle1() + M_PI/2.0;
    RS_Vector p1, p2;
    RS_LineData parallelData;
    RS_Line* ret = NULL;

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    for (int num=1; num<=number; ++num) {

        // calculate 1st parallel:
        p1.setPolar(distance*num, ang);
        p1 += e->getStartpoint();
        p2.setPolar(distance*num, ang);
        p2 += e->getEndpoint();
        RS_Line parallel1(NULL, RS_LineData(p1, p2));

        // calculate 2nd parallel:
        p1.setPolar(distance*num, ang+M_PI);
        p1 += e->getStartpoint();
        p2.setPolar(distance*num, ang+M_PI);
        p2 += e->getEndpoint();
        RS_Line parallel2(NULL, RS_LineData(p1, p2));

        double dist1 = parallel1.getDistanceToPoint(coord);
        double dist2 = parallel2.getDistanceToPoint(coord);
        double minDist = std::min(dist1, dist2);

        if (minDist<RS_MAXDOUBLE) {
            if (dist1<dist2) {
                parallelData = parallel1.getData();
            } else {
                parallelData = parallel2.getData();
            }


            RS_Line* newLine = new RS_Line(container, parallelData);
            newLine->setLayerToActive();
            newLine->setPenToActive();
            if (ret==NULL) {
                ret = newLine;
            }
            if (container!=NULL) {
                container->addEntity(newLine);
            }
            if (document!=NULL && handleUndo) {
                document->addUndoable(newLine);
                //document->endUndoCycle();
            }
            if (graphicView!=NULL) {
                graphicView->drawEntity(newLine);
            }
        }
    }

    if (document!=NULL && handleUndo) {
        document->endUndoCycle();
    }

    return ret;
}



/**
 * Creates a arc parallel to the given arc e.
 * Out of the 2 possible parallels, the one closest to
 * the given coordinate is returned.
 *
 * @param coord Coordinate to define which parallel we want (typically a
 *              mouse coordinate).
 * @param distance Distance of the parallel.
 * @param number Number of parallels.
 * @param e Original entity.
 *
 * @return Pointer to the first created parallel or NULL if no
 *    parallel has been created.
 */
RS_Arc* RS_Creation::createParallelArc(const RS_Vector& coord,
                                       double distance, int number,
                                       RS_Arc* e) {

    if (e==NULL) {
        return NULL;
    }

    RS_ArcData parallelData;
    RS_Arc* ret = NULL;

    bool inside = (e->getCenter().distanceTo(coord) < e->getRadius());

    if (inside) {
        distance *= -1;
    }

    for (int num=1; num<=number; ++num) {

        // calculate parallel:
        bool ok = true;
        RS_Arc parallel1(NULL, e->getData());
        parallel1.setRadius(e->getRadius() + distance*num);
        if (parallel1.getRadius()<0.0) {
            parallel1.setRadius(RS_MAXDOUBLE);
            ok = false;
        }

        // calculate 2nd parallel:
        //RS_Arc parallel2(NULL, e->getData());
        //parallel2.setRadius(e->getRadius()+distance*num);

        //double dist1 = parallel1.getDistanceToPoint(coord);
        //double dist2 = parallel2.getDistanceToPoint(coord);
        //double minDist = min(dist1, dist2);

        //if (minDist<RS_MAXDOUBLE) {
        if (ok==true) {
            //if (dist1<dist2) {
            parallelData = parallel1.getData();
            //} else {
            //    parallelData = parallel2.getData();
            //}

            if (document!=NULL && handleUndo) {
                document->startUndoCycle();
            }

            RS_Arc* newArc = new RS_Arc(container, parallelData);
            newArc->setLayerToActive();
            newArc->setPenToActive();
            if (ret==NULL) {
                ret = newArc;
            }
            if (container!=NULL) {
                container->addEntity(newArc);
            }
            if (document!=NULL && handleUndo) {
                document->addUndoable(newArc);
                document->endUndoCycle();
            }
            if (graphicView!=NULL) {
                graphicView->drawEntity(newArc);
            }
        }
    }

    return ret;
}



/**
 * Creates a circle parallel to the given circle e.
 * Out of the 2 possible parallels, the one closest to
 * the given coordinate is returned.
 *
 * @param coord Coordinate to define which parallel we want (typically a
 *              mouse coordinate).
 * @param distance Distance of the parallel.
 * @param number Number of parallels.
 * @param e Original entity.
 *
 * @return Pointer to the first created parallel or NULL if no
 *    parallel has been created.
 */
RS_Circle* RS_Creation::createParallelCircle(const RS_Vector& coord,
                                             double distance, int number,
                                             RS_Circle* e) {

    if (e==NULL) {
        return NULL;
    }

    RS_CircleData parallelData;
    RS_Circle* ret = NULL;

    bool inside = (e->getCenter().distanceTo(coord) < e->getRadius());

    if (inside) {
        distance *= -1;
    }

    for (int num=1; num<=number; ++num) {

        // calculate parallel:
        bool ok = true;
        RS_Circle parallel1(NULL, e->getData());
        parallel1.setRadius(e->getRadius() + distance*num);
        if (parallel1.getRadius()<0.0) {
            parallel1.setRadius(RS_MAXDOUBLE);
            ok = false;
        }

        // calculate 2nd parallel:
        //RS_Circle parallel2(NULL, e->getData());
        //parallel2.setRadius(e->getRadius()+distance*num);

        //double dist1 = parallel1.getDistanceToPoint(coord);
        //double dist2 = parallel2.getDistanceToPoint(coord);
        //double minDist = min(dist1, dist2);

        //if (minDist<RS_MAXDOUBLE) {
        if (ok==true) {
            //if (dist1<dist2) {
            parallelData = parallel1.getData();
            //} else {
            //    parallelData = parallel2.getData();
            //}

            if (document!=NULL && handleUndo) {
                document->startUndoCycle();
            }

            RS_Circle* newCircle = new RS_Circle(container, parallelData);
            newCircle->setLayerToActive();
            newCircle->setPenToActive();
            if (ret==NULL) {
                ret = newCircle;
            }
            if (container!=NULL) {
                container->addEntity(newCircle);
            }
            if (document!=NULL && handleUndo) {
                document->addUndoable(newCircle);
                document->endUndoCycle();
            }
            if (graphicView!=NULL) {
                graphicView->drawEntity(newCircle);
            }
        }
    }
    return ret;
}



/**
 * Creates a bisecting line of the angle between the entities
 * e1 and e2. Out of the 4 possible bisectors, the one closest to
 * the given coordinate is returned.
 *
 * @param coord Coordinate to define which bisector we want (typically a
 *              mouse coordinate).
 * @param length Length of the bisecting line.
 * @param num Number of bisectors
 * @param l1 First line.
 * @param l2 Second line.
 *
 * @return Pointer to the first bisector created or NULL if no bisectors
 *   were created.
 */
RS_Line* RS_Creation::createBisector(const RS_Vector& coord1,
                                     const RS_Vector& coord2,
                                     double length,
                                     int num,
                                     RS_Line* l1,
                                     RS_Line* l2) {

    RS_VectorSolutions sol;

    // check given entities:
    if (l1==NULL || l2==NULL ||
            l1->rtti()!=RS2::EntityLine || l2->rtti()!=RS2::EntityLine) {
        return NULL;
    }

    // intersection between entities:
    sol = RS_Information::getIntersection(l1, l2, false);
    RS_Vector inters = sol.get(0);
    if (inters.valid==false) {
        return NULL;
    }

    double angle1 = inters.angleTo(l1->getNearestPointOnEntity(coord1));
    double angle2 = inters.angleTo(l2->getNearestPointOnEntity(coord2));
    double angleDiff = RS_Math::getAngleDifference(angle1, angle2);
    if (angleDiff>M_PI) {
        angleDiff = angleDiff - 2*M_PI;
    }
    RS_Line* ret = NULL;

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    for (int n=1; n<=num; ++n) {

        double angle = angle1 +
                (angleDiff / (num+1) * n);

        RS_LineData d;
        RS_Vector v;

        RS_Vector c;
        v.setPolar(length, angle);
        d = RS_LineData(inters, inters + v);

        RS_Line* newLine = new RS_Line(container, d);
        if (container!=NULL) {
            newLine->setLayerToActive();
            newLine->setPenToActive();
            container->addEntity(newLine);
        }
        if (document!=NULL && handleUndo) {
            document->addUndoable(newLine);
        }
        if (graphicView!=NULL) {
            graphicView->drawEntity(newLine);
        }
        if (ret==NULL) {
            ret = newLine;
        }
    }
    if (document!=NULL && handleUndo) {
        document->endUndoCycle();
    }

    return ret;
}

/**
 * create a tangent line which is orthogonal to the given RS_Line(normal)
 * @coord, the tangent line closest to this point
 * @normal, the line orthogonal to the tangent line
 * @circle, arc/circle/ellipse for tangent line
 *
 * Author: Dongxu Li
 */
RS_Line* RS_Creation::createLineOrthTan(const RS_Vector& coord,
                                        RS_Line* normal,
                                        RS_Entity* circle) {
    RS_Line* ret = NULL;

    // check given entities:
    if (circle==NULL||normal==NULL
            ||!coord.valid ||
            (   circle->rtti()!=RS2::EntityArc
                && circle->rtti()!=RS2::EntityCircle
                && circle->rtti()!=RS2::EntityEllipse)) {

        return ret;
    }
    //if( normal->getLength()<RS_TOLERANCE) return ret;//line too short
    RS_Vector t0;

    // calculate tangent points for arcs / circles:
    t0= circle->getNearestOrthTan(coord,*normal,false);
    if(!t0.valid) return ret;
    RS_Vector vp(normal->getStartpoint());
    RS_Vector direction(normal->getEndpoint() - vp);
    RS_Vector vpt(t0 - vp);
    double a=direction.squared();
    if( a <RS_TOLERANCE2) {
        return NULL;//undefined direction
    } else {
        //find projection on the normal line
        vp += direction*( RS_Vector::dotP(direction,vpt)/a);
        if( fabs(vp.x - t0.x) <=RS_TOLERANCE || fabs(vp.y-t0.y)<=RS_TOLERANCE) {
            //t0 already on the given line, need to extend in the normal direction
            vp += RS_Vector(-direction.y,direction.x);
        }
    }
    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }
    ret = new RS_Line(container, RS_LineData(vp,t0));
    ret->setLayerToActive();
    ret->setPenToActive();
    return ret;
}

/**
* Creates a tangent between a given point and a circle or arc.
* Out of the 2 possible tangents, the one closest to
* the given coordinate is returned.
*
* @param coord Coordinate to define which tangent we want (typically a
*              mouse coordinate).
* @param point Point.
* @param circle Circle, arc or ellipse entity.
*/
RS_Line* RS_Creation::createTangent1(const RS_Vector& coord,
                                     const RS_Vector& point,
                                     RS_Entity* circle) {
    RS_Line* ret = NULL;
    //RS_Vector circleCenter;

    // check given entities:
    if (circle==NULL || !point.valid ||
            (circle->rtti()!=RS2::EntityArc && circle->rtti()!=RS2::EntityCircle
             && circle->rtti()!=RS2::EntityEllipse)) {

        return NULL;
    }

    // the two tangent points:
    RS_VectorSolutions sol=circle->getTangentPoint(point);

    if(sol.getNumber()==0) return NULL;
    RS_Vector vp2(sol.getClosest(coord));
    RS_LineData d;
    if( (vp2-point).squared() > RS_TOLERANCE2 ) {
        d=RS_LineData(vp2,point);
    }else{//the given point is a tangential point
        d=RS_LineData(point+circle->getTangentDirection(point),point);
    }


    // create the closest tangent:

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    ret = new RS_Line(container, d);
    ret->setLayerToActive();
    ret->setPenToActive();
    if (container!=NULL) {
        container->addEntity(ret);
    }
    if (document!=NULL && handleUndo) {
        document->addUndoable(ret);
        document->endUndoCycle();
    }
    if (graphicView!=NULL) {
        graphicView->drawEntity(ret);
    }

    return ret;
}

/**
* Creates a tangent between two circles or arcs.
* Out of the 4 possible tangents, the one closest to
* the given coordinate is returned.
*
* @param coord Coordinate to define which tangent we want (typically a
*              mouse coordinate).
* @param circle1 1st circle or arc entity.
* @param circle2 2nd circle or arc entity.
*/
RS_Line* RS_Creation::createTangent2(const RS_Vector& coord,
                                     RS_Entity* circle1,
                                     RS_Entity* circle2) {
    RS_Line* ret = NULL;
    RS_Vector circleCenter1;
    RS_Vector circleCenter2;
    double circleRadius1 = 0.0;
    double circleRadius2 = 0.0;

    // check given entities:
    if (circle1==NULL || circle2==NULL ||
            ((circle1->rtti()!=RS2::EntityArc &&
              circle1->rtti()!=RS2::EntityEllipse &&
              circle1->rtti()!=RS2::EntityCircle) ||
             (circle2->rtti()!=RS2::EntityArc &&
              circle2->rtti()!=RS2::EntityEllipse &&
              circle2->rtti()!=RS2::EntityCircle) )) {

        return NULL;
    }

    QVector<RS_Line*> poss;
    //        for (int i=0; i<4; ++i) {
    //            poss[i] = NULL;
    //        }
    RS_LineData d;
    if( circle1->rtti() == RS2::EntityEllipse) {
        std::swap(circle1,circle2);//move Ellipse to the second place
    }
    circleCenter1=circle1->getCenter();
    circleRadius1=circle1->getRadius();
    circleCenter2=circle2->getCenter();
    circleRadius2=circle2->getRadius();
    if(circle2->rtti() != RS2::EntityEllipse) {
        //no ellipse

        // create all possible tangents:

        double angle1 = circleCenter1.angleTo(circleCenter2);
        double dist1 = circleCenter1.distanceTo(circleCenter2);

        if (dist1>1.0e-6) {
            // outer tangents:
            double dist2 = circleRadius2 - circleRadius1;
            if (dist1>dist2) {
                double angle2 = asin(dist2/dist1);
                double angt1 = angle1 + angle2 + M_PI/2.0;
                double angt2 = angle1 - angle2 - M_PI/2.0;
                RS_Vector offs1;
                RS_Vector offs2;

                offs1.setPolar(circleRadius1, angt1);
                offs2.setPolar(circleRadius2, angt1);

                d = RS_LineData(circleCenter1 + offs1,
                                circleCenter2 + offs2);
                poss.push_back( new RS_Line(NULL, d));


                offs1.setPolar(circleRadius1, angt2);
                offs2.setPolar(circleRadius2, angt2);

                d = RS_LineData(circleCenter1 + offs1,
                                circleCenter2 + offs2);
                poss.push_back( new RS_Line(NULL, d));
            }

            // inner tangents:
            double dist3 = circleRadius2 + circleRadius1;
            if (dist1>dist3) {
                double angle3 = asin(dist3/dist1);
                double angt3 = angle1 + angle3 + M_PI/2.0;
                double angt4 = angle1 - angle3 - M_PI/2.0;
                RS_Vector offs1;
                RS_Vector offs2;

                offs1.setPolar(circleRadius1, angt3);
                offs2.setPolar(circleRadius2, angt3);

                d = RS_LineData(circleCenter1 - offs1,
                                circleCenter2 + offs2);
                poss.push_back( new RS_Line(NULL, d));


                offs1.setPolar(circleRadius1, angt4);
                offs2.setPolar(circleRadius2, angt4);

                d = RS_LineData(circleCenter1 - offs1,
                                circleCenter2 + offs2);
                poss.push_back( new RS_Line(NULL, d));
            }

        }
    }else{
        //circle2 is Ellipse
        RS_Ellipse* e2=(RS_Ellipse*)circle2->clone();
//        RS_Ellipse* e2=new RS_Ellipse(NULL,RS_EllipseData(RS_Vector(4.,1.),RS_Vector(2.,0.),0.5,0.,0.,false));
//        RS_Ellipse  e3(NULL,RS_EllipseData(RS_Vector(4.,1.),RS_Vector(2.,0.),0.5,0.,0.,false));
//        RS_Ellipse* circle1=new RS_Ellipse(NULL,RS_EllipseData(RS_Vector(0.,0.),RS_Vector(1.,0.),1.,0.,0.,false));
        RS_Vector m0(circle1->getCenter());
//        std::cout<<"translation: "<<-m0<<std::endl;
        e2->move(-m0); //circle1 centered at origin

        double a,b;
        double a0(0.);
        if(circle1->rtti() != RS2::EntityEllipse){//circle1 is either arc or circle
            a=fabs(circle1->getRadius());
            b=a;
            if(fabs(a)<RS_TOLERANCE) return NULL;
        }else{//circle1 is ellipse
            RS_Ellipse* e1=static_cast<RS_Ellipse*>(circle1);
            a0=e1->getAngle();
//            std::cout<<"rotation: "<<-a0<<std::endl;
            e2->rotate(-a0);//e1 major axis along x-axis
            a=e1->getMajorRadius();
            b=e1->getRatio()*a;
            if(fabs(a)<RS_TOLERANCE || fabs(b)<RS_TOLERANCE) return NULL;
        }
        RS_Vector factor1(1./a,1./b);
//        std::cout<<"scaling: factor1="<<factor1<<std::endl;
        e2->scale(RS_Vector(0.,0.),factor1);//circle1 is a unit circle
        factor1.set(a,b);
        double a2(e2->getAngle());
//        std::cout<<"rotation: a2="<<-a2<<std::endl;
        e2->rotate(-a2); //ellipse2 with major axis in x-axis direction
        a=e2->getMajorP().x;
        b=a*e2->getRatio();
        RS_Vector v(e2->getCenter());
//        std::cout<<"Center: (x,y)="<<v<<std::endl;


        std::vector<double> m(0,0.);
        m.push_back(1./(a*a)); //ma000
        m.push_back(1./(b*b)); //ma000
        m.push_back(v.y*v.y-1.); //ma100
        m.push_back(v.x*v.y); //ma101
        m.push_back(v.x*v.x-1.); //ma111
        m.push_back(2.*a*b*v.y); //mb10
        m.push_back(2.*a*b*v.x); //mb11
        m.push_back(a*a*b*b); //mc1

        auto&& vs0=RS_Math::simultaneousQuadraticSolver(m); //to hold solutions
        if (vs0.getNumber()<1) return NULL;
        for(int i=0;i<vs0.getNumber();i++){
//            std::cout<<"i="<<i<<"\n";
            RS_Vector vpec=vs0.get(i); //this holds ( a*sin(t), b*cos(t))
//            std::cout<<"solution "<<i<<" ="<<vpec<<std::endl;
            RS_Vector vpe2(e2->getCenter()+ RS_Vector(vpec.y/e2->getRatio(),vpec.x*e2->getRatio()));
            vpec.x *= -1.;//direction vector of tangent
            RS_Vector vpe1(vpe2 - vpec*(RS_Vector::dotP(vpec,vpe2)/vpec.squared()));
//            std::cout<<"vpe1.squared()="<<vpe1.squared()<<std::endl;
            RS_Line *l=new RS_Line(NULL,RS_LineData(vpe1,vpe2));
            l->rotate(a2);
            l->scale(factor1);
            l->rotate(a0);
            l->move(m0);
            poss.push_back(l);

        }
        delete e2;
        //debugging

    }
    // find closest tangent:
    if(poss.size()<1) return NULL;
    double minDist = RS_MAXDOUBLE;
    double dist;
    int idx = -1;
    for (int i=0; i<poss.size(); ++i) {
        if (poss[i]!=NULL) {
            poss[i]->getNearestPointOnEntity(coord,false,&dist);
//        std::cout<<poss.size()<<": i="<<i<<" dist="<<dist<<"\n";
            if (dist<minDist) {
                minDist = dist;
                idx = i;
            }
        }
    }
//idx=static_cast<int>(poss.size()*(random()/(double(1.0)+RAND_MAX)));
    if (idx!=-1) {
        RS_LineData d = poss[idx]->getData();
        for (int i=0; i<poss.size(); ++i) {
            if (poss[i]!=NULL) {
                delete poss[i];
            }
        }

        if (document!=NULL && handleUndo) {
            document->startUndoCycle();
        }

        ret = new RS_Line(container, d);
        ret->setLayerToActive();
        ret->setPenToActive();
        if (container!=NULL) {
            container->addEntity(ret);
        }
        if (document!=NULL && handleUndo) {
            document->addUndoable(ret);
            document->endUndoCycle();
        }
        if (graphicView!=NULL) {
            graphicView->drawEntity(ret);
        }
    } else {
        ret = NULL;
    }

    return ret;
}

/**
  * create the path of centers of common tangent circles of the two given circles
  *@ return NULL, if failed
  *@ at success return either an ellipse or hyperbola
  */
 std::vector<RS_Entity*> RS_Creation::createCircleTangent2( RS_Entity* circle1,RS_Entity* circle2)
{
      std::vector<RS_Entity*> ret(0, (RS_Entity*)NULL);
    if(circle1==NULL||circle2==NULL) return ret;
    RS_Entity* e1=circle1;
    RS_Entity* e2=circle2;

    if(e1->getRadius() < e2->getRadius()) std::swap(e1,e2);

    RS_Vector&& center1=e1->getCenter();
    RS_Vector&& center2=e2->getCenter();
    RS_Vector&& cp=(center1+center2)*0.5;
    double dist=center1.distanceTo(center2);
    if(dist<RS_TOLERANCE) return ret;
    RS_Vector&& vp= center1 - cp;
     double c=dist/(e1->getRadius()+e2->getRadius());
     if( c < 1. - RS_TOLERANCE) {
        //two circles intersection or one circle in the other, there's an ellipse path
         ret.push_back(new RS_Ellipse(NULL, RS_EllipseData(cp,vp,sqrt(1. - c*c),0.,0.,false)));
     }
    if( dist + e2 ->getRadius() < e1->getRadius() +RS_TOLERANCE ) {
        //one circle inside of another, the path is an ellipse
        return ret;
    }
    if(c > 1. + RS_TOLERANCE) {
        //not circle in circle, there's a hyperbola path
    c= (e1->getRadius()  - e2->getRadius())/dist;
    ret.push_back(new LC_Hyperbola(NULL, LC_HyperbolaData(cp,vp*c,sqrt(1. - c*c),0.,0.,false)));
    return ret;
}
    ret.push_back( new RS_Line(NULL, RS_LineData(cp, RS_Vector(cp.x - vp.y, cp.y+vp.x))));
    return ret;
}

/**
     * Creates a line with a relative angle to the given entity.
     *
     * @param coord Coordinate to define the point where the line should end.
     *              (typically a mouse coordinate).
     * @param entity Pointer to basis entity. The angle is relative to the
     *               angle of this entity.
     * @param angle Angle of the line relative to the angle of the basis entity.
     * @param length Length of the line we're creating.
     */
RS_Line* RS_Creation::createLineRelAngle(const RS_Vector& coord,
                                         RS_Entity* entity,
                                         double angle,
                                         double length) {

    // check given entity / coord:
    if (entity==NULL || !coord.valid ||
            (entity->rtti()!=RS2::EntityArc && entity->rtti()!=RS2::EntityCircle
             && entity->rtti()!=RS2::EntityLine)) {

        return NULL;
    }

    double a1=0.0;

    switch (entity->rtti()) {
    case RS2::EntityLine:
        a1 = ((RS_Line*)entity)->getAngle1();
        break;
    case RS2::EntityArc:
        a1 = ((RS_Arc*)entity)->getCenter().angleTo(coord) + M_PI/2.0;
        break;
    case RS2::EntityCircle:
        a1 = ((RS_Circle*)entity)->getCenter().angleTo(coord);
        break;
    default:
        // never reached
        break;
    }

    a1 += angle;

    RS_Vector v1;
    v1.setPolar(length, a1);
    //RS_ConstructionLineData(coord-v1, coord+v1);
    RS_LineData d(coord-v1, coord+v1);
    RS_Line* ret;

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    ret = new RS_Line(container, d);
    ret->setLayerToActive();
    ret->setPenToActive();
    if (container!=NULL) {
        container->addEntity(ret);
    }
    if (document!=NULL && handleUndo) {
        document->addUndoable(ret);
        document->endUndoCycle();
    }
    if (graphicView!=NULL) {
        graphicView->drawEntity(ret);
    }

    return ret;
}


/**
     * Creates a polygon with 'number' edges.
     *
     * @param center Center of the polygon.
     * @param corner The first corner of the polygon
     * @param number Number of edges / corners.
     */
RS_Line* RS_Creation::createPolygon(const RS_Vector& center,
                                    const RS_Vector& corner,
                                    int number) {

    // check given coords / number:
    if (!center.valid || !corner.valid || number<3) {
        return NULL;
    }

    RS_Line* ret = NULL;

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    RS_Vector c1(false);
    RS_Vector c2 = corner;
    RS_Line* line;

    for (int n=1; n<=number; ++n) {
        c1 = c2;
        c2 = c2.rotate(center, (M_PI*2)/number);

        line = new RS_Line(container, RS_LineData(c1, c2));
        line->setLayerToActive();
        line->setPenToActive();

        if (ret==NULL) {
            ret = line;
        }

        if (container!=NULL) {
            container->addEntity(line);
        }
        if (document!=NULL && handleUndo) {
            document->addUndoable(line);
        }
        if (graphicView!=NULL) {
            graphicView->drawEntity(line);
        }
    }

    if (document!=NULL && handleUndo) {
        document->endUndoCycle();
    }

    return ret;
}



/**
     * Creates a polygon with 'number' edges.
     *
     * @param corner1 The first corner of the polygon.
     * @param corner2 The second corner of the polygon.
     * @param number Number of edges / corners.
     */
RS_Line* RS_Creation::createPolygon2(const RS_Vector& corner1,
                                     const RS_Vector& corner2,
                                     int number) {

    // check given coords / number:
    if (!corner1.valid || !corner2.valid || number<3) {
        return NULL;
    }

    RS_Line* ret = NULL;

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    double len = corner1.distanceTo(corner2);
    double ang1 = corner1.angleTo(corner2);
    double ang = ang1;

    RS_Vector c1(false);
    RS_Vector c2 = corner1;
    RS_Vector edge;
    RS_Line* line;

    for (int n=1; n<=number; ++n) {
        c1 = c2;
        edge.setPolar(len, ang);
        c2 = c1 + edge;

        line = new RS_Line(container, RS_LineData(c1, c2));
        line->setLayerToActive();
        line->setPenToActive();

        if (ret==NULL) {
            ret = line;
        }

        if (container!=NULL) {
            container->addEntity(line);
        }
        if (document!=NULL && handleUndo) {
            document->addUndoable(line);
        }
        if (graphicView!=NULL) {
            graphicView->drawEntity(line);
        }

        // more accurate than incrementing the angle:
        ang = ang1 + (2*M_PI)/number*n;
    }

    if (document!=NULL && handleUndo) {
        document->endUndoCycle();
    }

    return ret;
}



/**
     * Creates an insert with the given data.
     *
     * @param data Insert data (position, block name, ..)
     */
RS_Insert* RS_Creation::createInsert(RS_InsertData& data) {

    RS_DEBUG->print("RS_Creation::createInsert");

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    RS_Insert* ins = new RS_Insert(container, data);
    // inserts are also on layers
    ins->setLayerToActive();
    ins->setPenToActive();

    if (container!=NULL) {
        container->addEntity(ins);
    }
    if (document!=NULL && handleUndo) {
        document->addUndoable(ins);
        document->endUndoCycle();
    }
    if (graphicView!=NULL) {
        graphicView->drawEntity(ins);
    }

    RS_DEBUG->print("RS_Creation::createInsert: OK");

    return ins;
}



/**
     * Creates an image with the given data.
     */
RS_Image* RS_Creation::createImage(RS_ImageData& data) {

    if (document!=NULL && handleUndo) {
        document->startUndoCycle();
    }

    RS_Image* img = new RS_Image(container, data);
    img->setLayerToActive();
    img->setPenToActive();
    img->update();

    if (container!=NULL) {
        container->addEntity(img);
    }
    if (document!=NULL && handleUndo) {
        document->addUndoable(img);
        document->endUndoCycle();
    }
    if (graphicView!=NULL) {
        graphicView->drawEntity(img);
    }

    return img;
}


/**
     * Creates a new block from the currently selected entitiies.
     *
     * @param referencePoint Reference point for the block.
     * @param name Block name
     * @param remove true: remove existing entities, false: don't touch entities
     */
RS_Block* RS_Creation::createBlock(const RS_BlockData& data,
                                   const RS_Vector& referencePoint,
                                   const bool remove) {

    // start undo cycle for the container if we're deleting the existing entities
    if (remove && document!=NULL) {
        document->startUndoCycle();
    }

    RS_Block* block =
            new RS_Block(container,
                         RS_BlockData(data.name, data.basePoint, data.frozen));

    // copy entities into a block
    for (RS_Entity* e=container->firstEntity();
         e!=NULL;
         e=container->nextEntity()) {
        //for (unsigned i=0; i<container->count(); ++i) {
        //RS_Entity* e = container->entityAt(i);

        if (e!=NULL && e->isSelected()) {

            // delete / redraw entity in graphic view:
            if (remove) {
                if (graphicView!=NULL) {
                    graphicView->deleteEntity(e);
                }
                e->setSelected(false);
            } else {
                if (graphicView!=NULL) {
                    graphicView->deleteEntity(e);
                }
                e->setSelected(false);
                if (graphicView!=NULL) {
                    graphicView->drawEntity(e);
                }
            }

            // add entity to block:
            RS_Entity* c = e->clone();
            c->move(-referencePoint);
            block->addEntity(c);

            if (remove) {
                //container->removeEntity(e);
                //i=0;
                e->changeUndoState();
                if (document!=NULL) {
                    document->addUndoable(e);
                }
            }
        }
    }

    if (remove && document!=NULL) {
        document->endUndoCycle();
    }

    if (graphic!=NULL) {
        graphic->addBlock(block);
    }

    return block;
}



/**
     * Inserts a library item from the given path into the drawing.
     */
RS_Insert* RS_Creation::createLibraryInsert(RS_LibraryInsertData& data) {

    RS_DEBUG->print("RS_Creation::createLibraryInsert");

    RS_Graphic g;
    if (!g.open(data.file, RS2::FormatUnknown)) {
        RS_DEBUG->print(RS_Debug::D_WARNING,
                        "RS_Creation::createLibraryInsert: Cannot open file: %s");
        return NULL;
    }

    // unit conversion:
    if (graphic!=NULL) {
        double uf = RS_Units::convert(1.0, g.getUnit(),
                                      graphic->getUnit());
        g.scale(RS_Vector(0.0, 0.0), RS_Vector(uf, uf));
    }

    //g.scale(RS_Vector(data.factor, data.factor));
    //g.rotate(data.angle);

    QString s;
    s = QFileInfo(data.file).completeBaseName();

    RS_Modification m(*container, graphicView);
    m.paste(
                RS_PasteData(
                    data.insertionPoint,
                    data.factor, data.angle, true,
                    s),
                &g);

    RS_DEBUG->print("RS_Creation::createLibraryInsert: OK");

    return NULL;
}

// EOF
