package bluej.editor.stride;

import bluej.utility.javafx.JavaFXUtil;
import threadchecker.OnThread;
import threadchecker.Tag;

import javafx.beans.binding.DoubleBinding;
import javafx.beans.binding.DoubleExpression;
import javafx.scene.Node;
import javafx.scene.canvas.Canvas;
import javafx.scene.effect.DropShadow;
import javafx.scene.layout.Pane;
import javafx.scene.layout.Region;
import javafx.scene.paint.Color;




| A CodeOverlayPane is an overlay that sits on top of the entire code.  The
| CodeOverlayPane is inside the ScrollPane, and moves up and down as you scroll.
|
| It is useful for when you want an overlay that is fixed with respect to a particular
| item in the code, for example you might want an autocomplete beneath a slot or a tooltip
| above a slot.  If you want something that is fixed with respect to the window, see
| WindowOverlayPane instead.
|
public class CodeOverlayPane
{       



| The actual Pane
|
private final Pane pane = new Pane();
    
   
   public CodeOverlayPane()
   {
      JavaFXUtil.addStyleClass(pane, "code-overlay-pane");
       
      
      pane.pickOnBoundsProperty().set(false);
      pane.setMouseTransparent(false);     
      }

   
   public static enum WidthLimit
   {        
      NO_WIDTH_LIMIT,
       
      
/***
| Limits the width of the given graphical element
| so that it doesn't extend beyond the right-hand side edge of the pane
|
LIMIT_WIDTH,
       
      

| As above, but also move it left to make sure its minimum width can show
|
LIMIT_WIDTH_AND_SLIDE_LEFT     
      }

   @OnThread(Tag.FXPlatform)
   
   public void addOverlay(final Node overlay, final Node relativeTo, final DoubleExpression xOffset, final DoubleExpression yOffset)
   {
      addOverlay(overlay, relativeTo, xOffset, yOffset, WidthLimit.NO_WIDTH_LIMIT);     
      }

    
   
   


| Adds the given overlay (first parameter) to the overlay pane so that its position always
| remains at the top left of relativeTo (second parameter), plus xOffset (or 0 if null) and
| yOffset (or 0 if null)
|
@OnThread(Tag.FXPlatform)
   
   public void addOverlay(final Node overlay, final Node relativeTo, final DoubleExpression xOffset, final DoubleExpression yOffset, WidthLimit widthLimit)
   {               
      final DoubleBinding xPosition = new DoubleBinding() {{ super.bind(relativeTo.layoutBoundsProperty());
            super.bind(relativeTo.localToSceneTransformProperty()); 
            super.bind(pane.layoutBoundsProperty());
            super.bind(pane.localToSceneTransformProperty());
             
            if (xOffset != null) super.bind(xOffset);
            }
            
           
         @Override
           
         protected double computeValue()
           {
            double usualX = relativeTo.localToScene(relativeTo.getBoundsInLocal()).getMinX() + (xOffset == null ? 0 : xOffset.get());
            if (widthLimit == WidthLimit.LIMIT_WIDTH_AND_SLIDE_LEFT)
               {
               return Math.max(0, Math.min(usualX, pane.widthProperty().subtract(((Region) overlay).minWidthProperty()).get()));                 
               }
               

            else
               {                    
               return usualX;                 
               }             
            }         
         };
      final DoubleBinding yPosition = new DoubleBinding() {{ super.bind(relativeTo.layoutBoundsProperty());
            super.bind(relativeTo.localToSceneTransformProperty());
            super.bind(pane.layoutBoundsProperty());
            super.bind(pane.localToSceneTransformProperty());
             
            if (yOffset != null) super.bind(yOffset);
            }
            
            
           
         @Override
           
         protected double computeValue()
           {
            double endRef = relativeTo.localToScene(relativeTo.getBoundsInLocal()).getMinY();
            return sceneYToCodeOverlayY(endRef + (yOffset == null ? 0 : yOffset.get()));             
            }         
         };
      overlay.layoutXProperty().bind(xPosition);
      overlay.layoutYProperty().bind(yPosition);

      if (widthLimit != WidthLimit.NO_WIDTH_LIMIT)
      ((Region)overlay).maxWidthProperty().bind(pane.widthProperty().subtract(overlay.layoutXProperty()));

      pane.getChildren().add(overlay);     
      }

   
   


| Converts a scene Y coordinate into a Y coordinate in this pane
|
public double sceneYToCodeOverlayY(double sceneY)
   {
      return pane.sceneToLocal(0, sceneY).getY();     
      }

   @OnThread(Tag.FXPlatform)
   
   public void removeOverlay(Node node)
   {
      pane.getChildren().remove(node);             
      }
    
   
   public Node getNode()
   {        
      return pane;     
      }

   
   


| Adds a drop shadow to the given node
|
public static void setDropShadow(Node n)
   {        
      DropShadow dropShadow = new DropShadow();
      dropShadow.setRadius(8.0);
      dropShadow.setOffsetX(4.0);
      dropShadow.setOffsetY(4.0);
      dropShadow.setColor(Color.color(0.6, 0.6, 0.6));
      n.setEffect(dropShadow);              
      }

   
   


| Adds a canvas to the pane, which is the same size as the pane, and returns it.
|
public Canvas addFullSizeCanvas()
   {        
      Canvas c = new Canvas(pane.getWidth(), pane.getHeight());
      c.setLayoutX(0.0);
      c.setLayoutY(0.0);
      c.setMouseTransparent(true);
      pane.getChildren().add(c);
       
      return c;     
      } 
   }