/*******************************************************************************
 * Copyright (c) 2007, 2010 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.db.layer0.adapter.impl;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.adapter.PasteHandlerAdapter;
import org.simantics.db.layer0.internal.SimanticsInternal;
import org.simantics.db.layer0.util.ClipboardUtils;
import org.simantics.db.layer0.util.ModelTransferableGraphSource;
import org.simantics.db.layer0.util.PasteEventHandler;
import org.simantics.db.layer0.util.RemoverUtil;
import org.simantics.db.layer0.util.SimanticsClipboard;
import org.simantics.db.layer0.util.SimanticsClipboard.Representation;
import org.simantics.db.layer0.util.SimanticsKeys;
import org.simantics.db.layer0.util.TransferableGraphConfiguration2.SeedSpec;
import org.simantics.db.layer0.util.TransferableGraphConfiguration2.SeedSpec.SeedSpecType;
import org.simantics.graph.db.IImportAdvisor;
import org.simantics.graph.db.IImportAdvisor2;
import org.simantics.graph.db.IImportAdvisor2.RootInfo;
import org.simantics.graph.db.TransferableGraphException;
import org.simantics.graph.db.TransferableGraphSource;
import org.simantics.graph.db.TransferableGraphs;
import org.simantics.graph.representation.Identity;
import org.simantics.graph.representation.Root;
import org.simantics.graph.representation.TransferableGraph1;
import org.simantics.graph.representation.TransferableGraphUtils;
import org.simantics.layer0.Layer0;

public class DefaultPasteHandler extends PasteHandlerAdapter {

    protected Resource resource;

    public DefaultPasteHandler(Resource resource) {
        this.resource = resource;
    }

    public static void defaultExecute(TransferableGraph1 tg, Resource resource, IImportAdvisor advisor) throws DatabaseException, TransferableGraphException {
        TransferableGraphs.importGraph1(SimanticsInternal.getSession(), tg, advisor);
    }

    public static void defaultExecute(WriteGraph graph, TransferableGraph1 tg, Resource resource, IImportAdvisor advisor) throws DatabaseException {
        TransferableGraphs.importGraph1(graph, tg, advisor);
    }

    public void execute(WriteGraph graph, TransferableGraph1 tg, Resource resource, IImportAdvisor advisor) throws DatabaseException {
    	defaultExecute(graph, tg, resource, advisor);
    }

    /**
     * Override this in your inherited class if post processing is done.
     */
    public void onPasteBegin(WriteGraph graph) throws DatabaseException {
    }

    /**
     * Override this in your inherited class if post processing is done
     * advisor.getTarget() returns an object under which data is copied
     * advisor.getRoot() returns the object which have been pasted.
     * @param representations TODO
     */
    public void onPaste(WriteGraph graph, IImportAdvisor2 advisor, Set<Representation> representations) throws DatabaseException {
    }

    /**
     * Override this in your inherited class if post processing is done.
     */
    public void onPasteEnd(WriteGraph graph) throws DatabaseException {
    }
    
    public IImportAdvisor2 getAdvisor(ReadGraph graph, TransferableGraph1 tg, Resource target, PasteEventHandler handler) throws DatabaseException {
    	
    	Collection<Identity> roots = TransferableGraphUtils.getRoots(tg);
    	if(roots.size() == 1) {
    		Root root = (Root)roots.iterator().next().definition;
    		Resource type = graph.getPossibleResource(root.type);
    		ImportAdvisorFactory factory = graph.getPossibleAdapter(type, ImportAdvisorFactory.class);
    		if(factory != null) {
    			if(handler != null)
    				return handler.createAdvisor(graph, factory, target);
    			else
    				return factory.create(graph, target, Collections.<String,Object>emptyMap());
    		}
    	}

    	return new DefaultPasteImportAdvisor(target);
    }

    public Collection<Resource> pasteObject(WriteGraph graph, Set<Representation> object, PasteEventHandler handler) throws DatabaseException {
    	Collection<Resource> result = new ArrayList<>();
        TransferableGraphSource tgs = ClipboardUtils.accept(graph, object, SimanticsKeys.KEY_TRANSFERABLE_GRAPH_SOURCE);
        if (tgs != null) {
        	TransferableGraph1 tg = TransferableGraphs.create(graph, tgs);
            IImportAdvisor2 advisor = getAdvisor(graph, tg, resource, handler); 
            execute(graph, tg, resource, advisor);
            Collection<RootInfo> roots = advisor.getRootInfo();
            if(handler != null) {
            	for(RootInfo r : roots) handler.postProcess(graph, r.resource);
            }
            onPaste(graph, advisor, object);
            if(tgs instanceof ModelTransferableGraphSource) {
            	
            	ModelTransferableGraphSource mtgs = (ModelTransferableGraphSource)tgs;
            	
            	loop: for(SeedSpec spec : mtgs.getConfiguration().seeds) {
            		if(SeedSpecType.SPECIAL_ROOT.equals(spec.specType)) continue;
            		for(RootInfo info : roots) {
            			if(spec.name.equals(info.root.name)) {
            				result.add(info.resource);
            				continue loop;
            			}
            		}
        			// Fallback
        			result.clear();
        			result.addAll(advisor.getRoots());
        			break;
            	}
            	
            } else {
            	result.addAll(advisor.getRoots());
            }
        }
        return result;
    }

    @Override
    public Collection<Resource> pasteFromClipboard(WriteGraph graph, SimanticsClipboard clipboard, PasteEventHandler handler) throws DatabaseException {
        
    	Collection<Resource> result = new ArrayList<>();
    	
    	
    	// Check if root resource is allowed for pasting
    	checkIfRootAllowsPaste(graph);
    	
    	Map<String,Object> hints = Collections.singletonMap(ClipboardUtils.HINT_TARGET_RESOURCE, resource);
    	
        onPasteBegin(graph);

        final Set<Resource> cuts = new HashSet<>();
        for(Set<Representation> object : clipboard.getContents()) {
            Collection<Resource> cut = ClipboardUtils.accept(object, SimanticsKeys.KEY_CUT_RESOURCES);
            TransferableGraphSource tg = ClipboardUtils.accept(graph, object, SimanticsKeys.KEY_TRANSFERABLE_GRAPH_SOURCE, hints);
            if(tg != null) {
            	result.addAll(pasteObject(graph, object, handler));
            	if (cut != null)
                    cuts.addAll(cut);
            } else {
            	Layer0 L0 = Layer0.getInstance(graph);
            	for(Resource r : cut) {
            		graph.deny(r, L0.PartOf);
            		graph.claim(resource, L0.ConsistsOf, L0.PartOf, r);
            		result.add(r);
            	}
            }
        }

        onPasteEnd(graph);

        if(!cuts.isEmpty()) {
        	for (Resource cut : cuts)
        		RemoverUtil.remove(graph, cut);
        }
        
        return result;
        
    }

    protected void checkIfRootAllowsPaste(ReadGraph graph) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        // check if root is published
        Boolean published = graph.getPossibleRelatedValue(resource, L0.Entity_published);
        if (published != null && published) {
            throw new DatabaseException("Target resource " + NameUtils.getSafeName(graph, resource) + " is published and does not allow paste.");
        }
    }

    @SuppressWarnings("rawtypes")
    @Override
    public Object getAdapter(Class adapter) {
        if(Resource.class == adapter) return resource;
        return null;
    }

}