package org.simantics.g3d.scl;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
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.g3d.ontology.G3D;
import org.simantics.g3d.scenegraph.NodeMap;
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.MapSet;
import org.simantics.utils.datastructures.Pair;

/**
 * NodeMap implementation used with SCL scripts.
 * 
 * In practice, there are no visible objects to synchronize.
 * 
 * TODO:
 * This implementation is Copy-paste of AbstractVTKNodeMap with VTK references removed.
 * There may be more sensible way to do this.
 * 
 * 
 * @author luukkainen
 *
 * @param <E>
 */
public abstract class ScriptNodeMap<E extends INode> implements NodeMap<Object,E>, IMappingListener, NodeListener {

	private static final boolean DEBUG = false;
	
	protected Session session;
	protected IMapping<Object,E> mapping;
	
	protected ParentNode<E> rootNode;
	
	protected Set<E> nodes = new HashSet<E>();
	
	private boolean dirty = false;
	
	public ScriptNodeMap(Session session, IMapping<Object,E> mapping, ParentNode<E> rootNode) {
		this.session = session;
		this.mapping = mapping;
		this.rootNode = rootNode;
		mapping.addMappingListener(this);
		rootNode.addListener(this); 
	}
	
	
	
	protected abstract void addActor(E node);
	protected abstract void removeActor(E node);
	protected abstract void updateActor(E node,Set<String> ids);
	
	public void repaint() {
		dirty = true;
	}
	
	public void populate() {
		for (E node : rootNode.getNodes()) {
			receiveAdd(node, node.getParentRel(),true);
		}
		repaint();
	}
	
	@Override
	public E getNode(Object o) {
		return null;
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public Collection<Object> getRenderObjects(INode node) {
		return Collections.EMPTY_LIST;
	}
	
	@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 MapSet<E, String> updated = new MapSet.Hash<E, String>();

	private boolean rangeModified = false;
	
	@SuppressWarnings("unchecked")
	@Override
	public void updateRenderObjectsFor(E node) {
		nodes.add((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;
		}
		repaint();
	}
	
	@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;
		}
		repaint();
	}
	
	@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;
		}
		repaint();
	}
	
	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() throws DatabaseException {
		session.syncRequest(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);
			}
			
		});
	}
	
	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");
		// FIXME : this is called by IMapping id DB thread
		dirty = true;
//        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;
		}
	}
	
	protected void update(ReadGraph graph) throws DatabaseException {
		if (DEBUG) System.out.println("Graph update start");
		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");

	}
	
	public void update() throws DatabaseException{
		while (dirty) {
			dirty = false;
			// preRender
			updateCycle();
			// postRender
			if (requestCommit && !rangeModified) { // FIXME : not thread safe.
				requestCommit = false;
				doCommit();
			}
			session.syncRequest(new ReadRequest() { 
				@SuppressWarnings("unchecked")
				@Override
				public void run(ReadGraph graph) throws DatabaseException {
					update(graph);
				}
			});
		}
	}
	

	
	// 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>();
	
	
	
	/**
	 * 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() {
		
		changeTracking = false;
		mapping.removeMappingListener(this);

		for (E node : nodes) {
			node.removeListener(this);
			removeActor(node);
			node.cleanup();
		}
		nodes.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;
	}
	
	
}