package bluej.editor.stride;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.IdentityHashMap;
import javafx.collections.ListChangeListener;

import bluej.stride.framedjava.frames.GreenfootFrameUtil;
import bluej.stride.generic.Frame;
import bluej.utility.Debug;
import bluej.utility.Utility;
import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.ParsingException;
import threadchecker.OnThread;
import threadchecker.Tag;




| The central storage (one per project) for frame shelf contents.  Each GUI FXTabbedWindow
| has its own instance of FrameShelf.  This class is the authoritative storage for the GUI
| shelves, and copies any changes in one shelf across to the other editor windows.
|
public class FrameShelfStorage
{       
private final IdentityHashMap<FrameShelf, ListChangeListener<Frame>> shelves = new IdentityHashMap<>();
   
   


| A <frames>...</frames> XML element with the content of the shelf.
|
private Element contentXML;
   
   private final File shelfFilename;
   
   private boolean updatingShelves = false;

   @OnThread(Tag.Any)
   
   public FrameShelfStorage(File projectDir)
   {        
      shelfFilename = new File(projectDir, "shelf.xml");
       
      try
       {            
         Document xml = new Builder().build(shelfFilename);
         contentXML = xml.getRootElement();
         if (!contentXML.getLocalName().equals("frames"))
           {                
            throw new IOException("XML top-level element not \"frames\" as expected");             
            }         
         }
       
      catch (ParsingException | IOException e)
       {
         
         
         contentXML = new Element("frames");         
         }     
      }

   
   public void registerShelf(FrameShelf shelfInterface)
   {
      ListChangeListener<Frame> listener = c -> pullFrom(shelfInterface);
      shelves.put(shelfInterface, listener);
      shelfInterface.setContent(contentXML);
      shelfInterface.getContent().addListener(listener);     
      }

   
   public void deregisterShelf(FrameShelf shelfInterface)
   {
      if (shelves.get(shelfInterface) != null)
       {
         shelfInterface.getContent().removeListener(shelves.remove(shelfInterface));         
         }     
      }

   
   private void pullFrom(FrameShelf changed)
   {
      if (updatingShelves)
       {            
         
         
         return;         
         }

       
      
      contentXML = GreenfootFrameUtil.getXmlElementForMultipleFrames(changed.getContent());
       
      updatingShelves = true;
       
      
      shelves.forEach((shelf, listener) -> {
      if (shelf != changed)
      shelf.setContent(contentXML);         
      });
   save();
       
   updatingShelves = false;     
   }

   
private void save()
   {        
   try (FileOutputStream os = new FileOutputStream(shelfFilename)) {
      Utility.serialiseCodeTo(contentXML, os);         
      }
       
   catch (IOException e)
       {
      Debug.reportError("Cannot save shelf contents", e);         
      }     
   } 
}