/*******************************************************************************
 * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
 * Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.g3d.vtk.common;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;

import org.simantics.db.ReadGraph;
import org.simantics.db.Session;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.db.service.UndoRedoSupport;
import org.simantics.g3d.ontology.G3D;
import org.simantics.g3d.scenegraph.RenderListener;
import org.simantics.g3d.scenegraph.base.INode;
import org.simantics.g3d.scenegraph.base.NodeListener;
import org.simantics.g3d.scenegraph.base.ParentNode;
import org.simantics.objmap.exceptions.MappingException;
import org.simantics.objmap.graph.IMapping;
import org.simantics.objmap.graph.IMappingListener;
import org.simantics.utils.datastructures.Callback;
import org.simantics.utils.datastructures.MapList;
import org.simantics.utils.datastructures.MapSet;
import org.simantics.utils.datastructures.Pair;
import org.simantics.utils.ui.ExceptionUtils;

import vtk.vtkProp;

public abstract class AbstractVTKNodeMap<E extends INode> implements VTKNodeMap<E>, IMappingListener, RenderListener, NodeListener, UndoRedoSupport.ChangeListener{

	private static final boolean DEBUG = false;
	
	protected Session session;
	protected IMapping<Object,E> mapping;
	protected VtkView view;
	
	protected MapList<E, vtkProp> nodeToActor = new MapList<E, vtkProp>();
	protected Map<vtkProp,E> actorToNode = new HashMap<vtkProp, E>();

	protected ParentNode<E> rootNode;
	
	protected UndoRedoSupport undoRedoSupport;
	protected int undoOpCount = 0;
	protected boolean runUndo = false;
	public AbstractVTKNodeMap(Session session, IMapping<Object,E> mapping, VtkView view, ParentNode<E> rootNode) {
		this.session = session;
		this.mapping = mapping;
		this.view = view;
		this.rootNode = rootNode;
		view.addListener(this);
		mapping.addMappingListener(this);
		rootNode.addListener(this);
		
		undoRedoSupport = session.getService(UndoRedoSupport.class);
		undoRedoSupport.subscribe(this);
		try {
		    undoOpCount = undoRedoSupport.getUndoContext(session).getAll().size();
		} catch(DatabaseException e) {
		    e.printStackTrace();
		}
	}
	
	
	
	protected abstract void addActor(E node);
	protected abstract void removeActor(E node);
	protected abstract void updateActor(E node,Set<String> ids);
	
	public void repaint() {
		view.refresh();
	}
	
	public void populate() {
		for (E node : rootNode.getNodes()) {
			receiveAdd(node, node.getParentRel(),true);
		}
		repaint();
	}
	
	@Override
	public E getNode(vtkProp prop) {
		return actorToNode.get(prop);
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public Collection<vtkProp> getRenderObjects(INode node) {
		return nodeToActor.getValues((E)node);
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public ParentNode<E> getRootNode() {
		return (ParentNode<E>)rootNode;
	}
	
	
	
	@Override
	public boolean isChangeTracking() {
		return changeTracking;
	}
	
	@Override
	public void setChangeTracking(boolean enabled) {
		changeTracking = enabled;
	}
	
	private boolean changeTracking = true;
	
	protected Object syncMutex = new Object(); 
	

	private List<Pair<E,String>> added = new ArrayList<Pair<E,String>>();
	private List<Pair<E,String>> removed = new ArrayList<Pair<E,String>>();
	//private List<Pair<E,String>> updated = new ArrayList<Pair<E,String>>();
	private MapSet<E, String> updated = new MapSet.Hash<E, String>();

	private boolean rangeModified = false;
	
	@Override
	public void onChanged() {
	    try {
	        int count = undoRedoSupport.getUndoContext(session).getAll().size();
            if (count < undoOpCount) {
                runUndo = true;
            } else {
                runUndo = false;
            }
            undoOpCount = count;
            if (DEBUG) System.out.println("Undo " + runUndo);
        } catch (DatabaseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
	    
	    
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public void updateRenderObjectsFor(INode node) {
		List<vtkProp> toDelete = new ArrayList<vtkProp>();
		view.lock();
		for (vtkProp prop : nodeToActor.getValues((E)node)) {
			if (prop.GetVTKId() != 0) {
				view.getRenderer().RemoveActor(prop);
				//prop.Delete();
				toDelete.add(prop);
			}
			actorToNode.remove(prop);
		}
		view.unlock();
		nodeToActor.remove((E)node);
		Collection<vtkProp> coll = getActors((E)node);
		if (coll == null)
			return;
		for (vtkProp prop : coll) {
			nodeToActor.add((E)node,prop);
			actorToNode.put(prop, (E)node);
			toDelete.remove(prop);
		}
		for (vtkProp p : toDelete)
			p.Delete();
	}
	
	protected abstract  Collection<vtkProp> getActors(E node);
	
	@SuppressWarnings("unchecked")
	private void receiveAdd(E node, String id, boolean db) {
		if (DEBUG) System.out.println("receiveAdd " + debugString(node)  + " " + id + " " + db);
		synchronized (syncMutex) {
			for (Pair<E, String> n : added) {
				if (n.first.equals(node))
					return;
			}
			if (changeTracking) {
				mapping.rangeModified((E)node.getParent());
			}
			added.add(new Pair<E, String>(node, id));
			rangeModified = true;
		}
		view.refresh();
	}
	
	@SuppressWarnings("unchecked")
	private void receiveRemove(E node, String id, boolean db) {
		if (DEBUG) System.out.println("receiveRemove " + debugString(node)  + " " + id + " " + db);
		synchronized (syncMutex) {
			for (Pair<E, String> n : removed) {
				if (n.first.equals(node))
					return;
			}
			if (changeTracking && !db)
				mapping.rangeModified((E)node.getParent());
			removed.add(new Pair<E, String>(node, id));
			rangeModified = true;
		}
		view.refresh();
	}
	
	@SuppressWarnings("unchecked")
	private void receiveUpdate(E node, String id, boolean db) {
		if (DEBUG) System.out.println("receiveUpdate " + debugString(node)  + " " + id + " " + db);
		synchronized (syncMutex) {
//			for (Pair<E, String> n : updated) {
//				if (n.first.equals(node))
//					return;
//			}
			if (changeTracking && !db)
				mapping.rangeModified(node);
			//updated.add(new Pair<E, String>(node, id));
			updated.add(node, id);
			rangeModified = true;
		}
		view.refresh();
	}
	
	private boolean graphUpdates = false;
	private Set<E> graphModified = new HashSet<E>();
	
	private boolean requestCommit = false;
	private String commitMessage = null;
	
	@Override
	public void commit(String message) {
		requestCommit = true;
		commitMessage = message;
	}
	
	protected void doCommit() {
		session.asyncRequest(new WriteRequest() {
			
			@Override
			public void perform(WriteGraph graph) throws DatabaseException {
			    if (DEBUG) System.out.println("Commit " + commitMessage);
				if (commitMessage != null) {
				    Layer0Utils.addCommentMetadata(graph, commitMessage);
				    graph.markUndoPoint();
				    commitMessage = null;
				}
		        commit(graph);
			}
			
		}, new Callback<DatabaseException>() {
			
			@Override
			public void run(DatabaseException parameter) {
				if (parameter != null)
					ExceptionUtils.logAndShowError("Cannot commit editor changes", parameter);
			}
		});
	}
	
	protected void commit(WriteGraph graph) throws DatabaseException {
		synchronized(syncMutex) {
			if (DEBUG) System.out.println("Commit");
			graphUpdates = true;
			mapping.updateDomain(graph);
			graphUpdates = false;
			clearDeletes();
	        if (DEBUG) System.out.println("Commit done");
		}
	}
	
	
	
	@Override
	public void domainModified() {
		if (graphUpdates)
			return;
		if (DEBUG)System.out.println("domainModified");
		session.asyncRequest(new ReadRequest() {
			
			@SuppressWarnings("unchecked")
			@Override
			public void run(ReadGraph graph) throws DatabaseException {
				update(graph);
			}
		});
		
	}
	
	protected void reset(ReadGraph graph) throws MappingException {
	    if (DEBUG) System.out.println("Reset");
        synchronized (syncMutex) {
            graphUpdates = true;
            mapping.getRangeModified().clear();
            for (Object o : mapping.getDomain())
                mapping.domainModified(o);
            mapping.updateRange(graph);
            graphModified.clear();
            graphUpdates = false;
        }
	}
	
	private boolean useFullSyncWithUndo = false;
	
	protected void update(ReadGraph graph) throws DatabaseException {
	    if (DEBUG) System.out.println("Graph update start");
	    if (runUndo && useFullSyncWithUndo) {
	        reset(graph);
	    } else {
    		synchronized (syncMutex) {
    			graphUpdates = true;
    			for (Object domainObject : mapping.getDomainModified()) {
    				E rangeObject = mapping.get(domainObject);
    				if (rangeObject != null)
    					graphModified.add(rangeObject);
    			}
    			mapping.updateRange(graph);
    			graphModified.clear();
    			syncDeletes();
    			clearDeletes();
    			graphUpdates = false;
    		}
	    }
		
		//if (mapping.isRangeModified() && !runUndo) // FIXME : redo?
	    if (mapping.isRangeModified())
			commit((String)null);
		if (DEBUG) System.out.println("Graph update done");
	}
	
	@Override
	public void rangeModified() {
		//System.out.println("rangeModified");

	}
	
	@Override
	public void postRender() {
		// Commit changes if
		// 1. Commit has been requested
		// 2. There are no pending changes that should be processed in preRender() 
		if (requestCommit && !rangeModified) { // FIXME : not thread safe.
			requestCommit = false;
			doCommit();
		}
	}
	
	// Reusable containers for data synchronisation
	List<Pair<E, String>> rem = new ArrayList<Pair<E,String>>();  // Removed objects
	List<Pair<E, String>> add = new ArrayList<Pair<E,String>>();  // Added objects
	MapSet<E, String> mod = new MapSet.Hash<E, String>();         // Modified objects
	Set<E> propagation = new HashSet<E>();                        // Objects with propagated changes 
	Stack<E> stack = new Stack<E>();                              // Stack for handling propagation
	Set<E> delete = Collections.synchronizedSet(new HashSet<E>()); // Objects to be completely deleted
	Set<E> deleteUC = new HashSet<E>();
	
	@Override
	public synchronized void preRender() {
		updateCycle();
	}
	
	
	/**
	 * When objects are removed (either from Java or Graph), after remove processing the Java objects remain in mapping cache.
	 * This causes problems with Undo and Redo, whcih the end up re-using the removed objects from mapping cache.
	 * 
	 * This code here synchronizes removed and added objects to collect deletable objects. (a deletable object is one which is removed but not added).  
	 * 
	 */
	protected void syncDeletes() {
	    deleteUC.clear();
	    for (Pair<E, String> n : removed) {
            deleteUC.add(n.first);   
         }
         for (Pair<E, String> n : added) {
             deleteUC.remove(n.first);   
         } 
         if (DEBUG && deleteUC.size() > 0) {
             System.out.println("Delete sync");
             for (E n : delete) {
                 System.out.println(debugString(n));
             }
         }
         delete.addAll(deleteUC);
         deleteUC.clear();
	}
	
	/**
	 * Clears deletable objects from mapping cache.
	 */
	protected void clearDeletes() {
        if (DEBUG && delete.size() > 0) System.out.println("Delete");
        for (E n : delete) {
            if (DEBUG) System.out.println(debugString(n));
            mapping.getRange().remove(n);
        }
        delete.clear();
    }
	
	protected String debugString(E n) {
	    return n + "@" + Integer.toHexString(n.hashCode());
	}
	
	@SuppressWarnings("unchecked")
	protected void updateCycle() {
		rem.clear();
		add.clear();
		mod.clear();
		propagation.clear();
		
		
		synchronized (syncMutex) {
			rem.addAll(removed);
			add.addAll(added);
			for (E e : updated.getKeys()) {
				for (String s : updated.getValues(e)) {
					mod.add(e, s);
				}
			}
			syncDeletes();
			removed.clear();
			added.clear();
			updated.clear();
		}
		
		for (Pair<E, String> n : rem) {
			stopListening(n.first);
			removeActor(n.first);
		}
		
		for (Pair<E, String> n : add) {
			addActor(n.first);
			listen(n.first);
		}
		
		for (E e : mod.getKeys()) {
			Set<String> ids = mod.getValues(e);
			if (ids.contains(G3D.URIs.hasPosition) || ids.contains(G3D.URIs.hasOrientation)) {
				if (!propagation.contains(e))
					propagation.add(e);
			}
		}

		if (propagation.size() > 0) {
			stack.clear();
			stack.addAll(propagation);
			propagation.clear();
			while (!stack.isEmpty()) {
				E node = stack.pop();
				if (propagation.contains(node))
					continue;
				propagation.add(node);
				for (NodeListener l : node.getListeners()) {
					if (l == this) {
						//changeTracking = false;
						//l.propertyChanged(node, G3D.URIs.hasPosition);
						//changeTracking = true;
					} else {
						l.propertyChanged(node, G3D.URIs.hasWorldPosition);
					}
				}
				if (node instanceof ParentNode) {
					stack.addAll(((ParentNode<E>)node).getNodes());
				}
			}
		}
		
//		synchronized (syncMutex) {
//			rem.addAll(removed);
//			add.addAll(added);
//			//mod.addAll(updated);
//			for (E e : updated.getKeys()) {
//				for (String s : updated.getValues(e))
//					mod.add(e, s);
//			}
//			
//			removed.clear();
//			added.clear();
//			updated.clear();
//		}
		
		for (E e : mod.getKeys()) {
			Set<String> ids = mod.getValues(e);
			updateActor(e,ids);
		}
		
		
		for (Pair<E, String> n : rem) {
			for (NodeListener l : nodeListeners)
				l.nodeRemoved(null, n.first, n.second);
		}
		for (Pair<E, String> n : add) {
			for (NodeListener l : nodeListeners)
				l.nodeAdded(n.first.getParent(), n.first, n.second);
		}
//		for (Pair<E, String> n : mod) {
//			for (NodeListener l : nodeListeners)
//				l.propertyChanged(n.first, n.second);
//		}
		for (E e : mod.getKeys()) {
			for (NodeListener l : nodeListeners)
				for (String s : mod.getValues(e))
					l.propertyChanged(e, s);
		}
		
		synchronized (syncMutex) {
		    if (added.isEmpty() && removed.isEmpty() && updated.getKeys().size() == 0)
				rangeModified = false;
		}
	}
	
	@SuppressWarnings("unchecked")
	private void listen(INode node) {
		node.addListener(this);
		if (node instanceof ParentNode<?>) {
			ParentNode<INode> parentNode = (ParentNode<INode>)node;
			for (INode n : parentNode.getNodes())
				listen(n);
		}
	}
	
	private void stopListening(INode node) {
		node.removeListener(this);
		if (node instanceof ParentNode<?>) {
			@SuppressWarnings("unchecked")
			ParentNode<INode> parentNode = (ParentNode<INode>)node;
			for (INode n : parentNode.getNodes())
				stopListening(n);
		}
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public void propertyChanged(INode node, String id) {
		//receiveUpdate((E)node, id, graphUpdates);
		receiveUpdate((E)node, id, graphModified.contains(node));
		
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public <T extends INode> void nodeAdded(ParentNode<T> node, INode child,
			String rel) {
		if (DEBUG) System.out.println("Node added " + child + " parent " + node);
		//receiveAdd((E)child, rel ,graphUpdates);
		receiveAdd((E)child, rel ,graphModified.contains(node));
		
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public <T extends INode> void nodeRemoved(ParentNode<T> node, INode child,
			String rel) {
		if (DEBUG) System.out.println("Node removed " + child + " parent " + node);
		//receiveRemove((E)child, rel, graphUpdates);
		receiveRemove((E)child, rel, graphModified.contains(node));
		
		//FIXME : sometimes removed structural models cause ObjMap to add their children again.
		//        removing the listener here prevents corruption of visual model, but better fix is needed.
		stopListening(child);
	}
	
	@Override
	public void delete() {
	    if (undoRedoSupport != null)
	        undoRedoSupport.cancel(this);
        
		changeTracking = false;
		view.removeListener(this);
		mapping.removeMappingListener(this);

		List<E> nodes = new ArrayList<E>(nodeToActor.getKeySize());
		nodes.addAll(nodeToActor.getKeys());
		for (E node : nodes) {
			node.removeListener(this);
			removeActor(node);
			node.cleanup();
		}
		for (vtkProp prop : actorToNode.keySet()) {
			if (prop.GetVTKId() != 0) 
				prop.Delete();
		}
		actorToNode.clear();
		nodeToActor.clear();
		
	}
	
	
	private List<NodeListener> nodeListeners = new ArrayList<NodeListener>();
	@Override
	public void addListener(NodeListener listener) {
		nodeListeners.add(listener);
		
	}
	
	@Override
	public void removeListener(NodeListener listener) {
		nodeListeners.remove(listener);
		
	}
	
	public IMapping<Object,E> getMapping() {
		return mapping;
	}
	
	
}