sclass BaseBase {
  S text;
  S textForRender() { ret text; }
}

sclass Base extends BaseBase {
}

sclass CirclesAndLines {
  new L<Circle> circles;
  new L<Line> lines;
  Class<? extends Arrow> arrowClass = Arrow;
  Class<? extends Circle> circleClass = Circle;
  transient Lock lock = fairLock();
  transient S defaultImageID = #1007372;
  double imgZoom = 1;
  Pt translate;
  Circle hoverCircle; // which one we are hovering over
  O onUserMadeArrow, onUserMadeCircle, onLayoutChange;
  O onFullLayoutChange, onDeleteCircle, onDeleteLine;
  BufferedImage imageForUserMadeNodes;
  static int maxDistanceToLine = 20; // for clicking

  // auto-visualize
  Circle circle_autoVis(S text, S visualizationText, double x, double y) {
    ret addAndReturn(circles, nu(circleClass, +x, +y, +text, img := processImage(quickVisualizeOr(visualizationText, defaultImageID))));
  }
  
  S makeVisualizationText(S text) {
    ret possibleGlobalID(text) ? "" : text;
  }

  Circle circle_autoVis(S text, double x, double y) {
    ret circle_autoVis(text, makeVisualizationText(text), x, y);
  }
  
  Circle circle(BufferedImage img, double x, double y, S text) {
    ret addAndReturn(circles, nu(circleClass, +x, +y, +text, img := processImage(img));
  }
  
  Circle circle(S text, BufferedImage img, double x, double y) {
    ret circle(img, x, y, text);
  }
  
  Circle circle(S text, double x, double y) {
    ret addAndReturn(circles, nu(circleClass, +x, +y, +text, img := processImage(loadImage2(#1007452))); // white
  }
  
  Circle addCircle(S imageID, double x, double y) {
    ret addCircle(imageID, x, y, "");
  }
  
  Circle addCircle(S imageID, double x, double y, S text) {
    ret addAndReturn(circles, nu(circleClass, +x, +y, +text, img := processImage(loadImage2(imageID))));
  }
  
  Arrow findArrow(Circle a, Circle b) {
    for (Line l : getWhere(lines, +a, +b))
      if (l instanceof Arrow)
        ret (Arrow) l;
    null;
  }
  
  Line addLine(Circle a, Circle b) {
    Line line = findWhere(lines, +a, +b);
    if (line == null)
      lines.add(line = nu(Line, +a, +b));
    ret line;
  }
  
  Arrow arrow(Circle a, S text, Circle b) {
    ret addArrow(a, b, text);
  }
  
  Arrow addArrow(Circle a, Circle b) {
    ret addArrow(a, b, "");
  }
  
  Arrow addArrow(Circle a, Circle b, S text) {
    ret addAndReturn(lines, nu(arrowClass, +a, +b, +text));
  }
  
  BufferedImage makeImage(int w, int h) {
    BufferedImage bg = renderTiledBackground(#1007195, w, h, ptX(translate), ptY(translate));
    if (!lock.tryLock()) null;
    try {
      // Lines
      
      for (Line l : lines) {
        Pt a = translatePt(translate, l.a.pt(w, h));
        Pt b = translatePt(translate, l.b.pt(w, h));
        if (l << Arrow)
          drawThoughtArrow(bg, l.a.img(), a.x, a.y, l.b.img(), b.x, b.y, l.color);
        else
          drawThoughtLine(bg, l.a.img(), a.x, a.y, l.b.img(), b.x, b.y, l.color);
        S text = l.textForRender();
        if (nempty(text))
          drawThoughtLineText(bg, l.a.img(), a.x, a.y, l.b.img(), b.x, b.y, text, l.color);
      }
      
      // Circles
      
      for (Circle c : circles) {
        Pt p = translatePt(translate, c.pt(w, h));
        drawThoughtCircle(bg, c.img(), p.x, p.y);
        S text = c.textForRender();
        if (nempty(text))
          drawThoughtCircleText(bg, c.img(), p, text);
          
        if (c == hoverCircle)
          drawThoughtCirclePlus(bg, c.img(), p.x, p.y);
      }
    } finally {
      lock.unlock();
    }
    ret bg;
  }
  
  Canvas showAsFrame(int w, int h) {
    Canvas canvas = showAsFrame();
    frameInnerSize(canvas, w, h);
    centerFrame(getFrame(canvas));
    ret canvas;
  }
  
  Canvas showAsFrame() {
    ret (Canvas) swing(func {
      Canvas canvas = makeCanvas();
      showCenterFrame(canvas);
      ret canvas;
    });
  }
  
  Canvas makeCanvas() {
    fO makeImg = func(int w, int h) { makeImage(w, h) };
    final Canvas canvas = jcanvas(makeImg);
    disableImageSurfaceSelector(canvas);
    new CircleDragger(this, canvas, r { updateCanvas(canvas, makeImg) });
    
    componentPopupMenu(canvas, voidfunc(JPopupMenu menu) {
      Pt p = canvas.pointFromEvent(componentPopupMenu_mouseEvent.get());
      final Line l = findLine(canvas, p);
      if (l != null)
        addMenuItem(menu, "Delete Relation", r {
          deleteLine(l);
          canvas.update();
        });
      
      final Circle c = findCircle(canvas, p);
      if (c != null)
        addMenuItem(menu, "Delete Circle", r {
          deleteCircle(c);
          canvas.update();
        });
    });
    
    ret canvas;
  }
  
  Canvas show() { ret showAsFrame(); }
  Canvas show(int w, int h) { ret showAsFrame(w, h); }
  
  Circle findCircle(S text) {
    for (Circle c : circles)
      if (eqic(c.text, text))
        ret c;
    null;
  }
  
  void clear {
    clearAll(circles, lines);
  }
  
  // only finds actually containing circles
  Circle findCircle(ImageSurface canvas, Pt p) {
    p = untranslatePt(translate, p);
    new Lowest<Circle> best;
    for (Circle c : circles)
      if (c.contains(canvas, p))
        best.put(c, pointDistance(p, c.pt(canvas)));
    ret best!;
  }
  
  Circle findNearestCircle(ImageSurface canvas, Pt p) {
    new Lowest<Circle> best;
    for (Circle c : circles)
      if (c.contains(canvas, p))
        best.put(c, pointDistance(p, c.pt(canvas)));
    ret best.get();
  }
  
  BufferedImage processImage(BufferedImage img) {
    ret scaleImage(img, imgZoom);
  }
  
  void deleteCircle(Circle c) {
    for (Line l : cloneList(lines))
      if (l.a == c || l.b == c) deleteLine(l);
    circles.remove(c);
    pcallF(onDeleteCircle, c);
  }
  
  void deleteLine(Line l) {
    lines.remove(l);
    pcallF(onDeleteLine, l);
  }
  
  void openPlusDialog(Circle c) {
    if (c == null) ret;
    
    final JTextField tfFrom = jtextfield(c.text);
    final JTextField tfRel = jtextfield(web_defaultRelationName());
    final JTextField tfTo = jtextfield();
    
    showFormTitled("Add connection",
      "From node", tfFrom,
      "Conection name", tfRel,
      "To node", tfTo,
      func {
        Circle a = findOrMakeCircle(getTextTrim(tfFrom));
        if (a == null) { messageBox("Not found: " + getTextTrim(tfFrom)); false; }
        Circle b = findOrMakeCircle(getTextTrim(tfTo));
        if (b == null) { messageBox("Not found: " + getTextTrim(tfTo)); false; }
        pcallF(onUserMadeArrow, arrow(a, getTextTrim(tfRel), b));
        null;
      });
    awtLater(tfRel, 100, r { requestFocus(tfRel) });
  }
  
  Circle findOrMakeCircle(S text) {
    Circle c = findCircle(text);
    if (c == null) {
      if (imageForUserMadeNodes == null)
        imageForUserMadeNodes = whiteImage(20, 20);
      c = circle(imageForUserMadeNodes, random(), random(), text);
      pcallF(onUserMadeCircle, c);
    }
    ret c;
  }
  
  Line findLine(Canvas is, Pt p) {
    p = untranslatePt(translate, p);
    new Lowest<Line> best;
    for (Line line : lines) {
      double d = distancePointToLineSegment(line.a.pt(is), line.b.pt(is), p);
      if (d <= maxDistanceToLine)
        best.put(line, d);
    }
    ret best!;
  }
} // end of class CirclesAndLines

sclass Circle extends Base {
  transient BufferedImage img;
  double x, y;
  static BufferedImage defaultImage;
  
  BufferedImage img() {
    if (img != null) ret img;
    if (defaultImage == null) defaultImage = loadImage2(#1007372);
    ret defaultImage;
  }
  
  Pt pt(ImageSurface is) {
    ret pt(is.getWidth(), is.getHeight());
  }
  
  Pt pt(int w, int h) {
    ret new Pt(iround(x*w), iround(y*h));
  }
  
  bool contains(ImageSurface is, Pt p) {
    ret pointDistance(p, pt(is)) <= thoughtCircleSize(img())/2+1;
  }
}

sclass Line extends Base {
  Circle a, b;
  Color color = Color.white;
  
  Line setColor(Color color) {
    this.color = color;
    this;
  }
}

Line > Arrow {}

sclass CircleDragger extends MouseAdapter {
  CirclesAndLines cal;
  ImageSurface is;
  O update;
  int dx, dy;
  Circle circle;
  Pt startPoint;
  
  *(CirclesAndLines *cal, ImageSurface *is, O *update) {
    if (containsInstance(is.tools, CircleDragger)) ret;
    is.tools.add(this);
    is.addMouseListener(this);
    is.addMouseMotionListener(this);
  }

  public void mouseMoved(MouseEvent e) {
    Pt p = is.pointFromEvent(e);
    Circle c = cal.findCircle(is, p);
    if (c != cal.hoverCircle) {
      cal.hoverCircle = c;
      callF(update);
    }
  }
  
  public void mousePressed(MouseEvent e) {
    if (e.getButton() == MouseEvent.BUTTON1) {
      Pt p = is.pointFromEvent(e);
      startPoint = p;
      circle = cal.findCircle(is, p);
      if (circle != null) {
        dx = p.x-iround(circle.x*is.getWidth());
        dy = p.y-iround(circle.y*is.getHeight());
      } else { 
        Pt t = unnull(cal.translate);
        dx = p.x-t.x;
        dy = p.y-t.y;
      }
    }
  }

  public void mouseDragged(MouseEvent e) {
    if (startPoint == null) ret;
    Pt p = is.pointFromEvent(e);
    if (circle != null) {
      circle.x = (p.x-dx)/(double) is.getWidth();
      circle.y = (p.y-dy)/(double) is.getHeight();
      pcallF(cal.onLayoutChange, circle);
      callF(update);
    } else {
      cal.translate = new Pt(p.x-dx, p.y-dy);
      print("drag translate");
      callF(update);
    }
  }

  public void mouseReleased(MouseEvent e) {
    mouseDragged(e);
    if (eq(is.pointFromEvent(e), startPoint))
      cal.openPlusDialog(circle);
    circle = null;
    startPoint = null;
  }
}