/*******************************************************************************
 * Copyright (c) 2014, 2015 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:
 *     Semantum Oy - initial API and implementation
 *******************************************************************************/
package org.simantics.modeling;

import gnu.trove.set.hash.THashSet;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import org.simantics.databoard.Bindings;
import org.simantics.databoard.util.URIStringUtils;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.Statement;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.NamedResource;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.layer0.Layer0;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.structural2.modelingRules.AllowedConnectionTypes;
import org.simantics.utils.ObjectUtils;
import org.simantics.utils.datastructures.Triple;

/**
 * @author Antti Villberg
 */
public class MigrateModel {

	public static class MigrationOperation {
		
		public NamedResource instanceToMigrate;
		public NamedResource targetType;
		public NamedResource targetSymbol;
		
		public MigrationOperation(NamedResource nr, NamedResource targetType, NamedResource targetSymbol) {
			this.instanceToMigrate = nr;
			this.targetType = targetType;
			this.targetSymbol = targetSymbol;
		}
		
		@Override
		public String toString() {
			return instanceToMigrate.getName();
		}
		
		public String getDescription(ReadGraph graph) throws DatabaseException {
			String sourceURI = graph.getPossibleURI(instanceToMigrate.getResource());
			if(sourceURI == null) sourceURI = NameUtils.getSafeName(graph, instanceToMigrate.getResource());
			sourceURI = sourceURI.replace("http://Projects/Development%20Project/", "");
			if(targetSymbol != null) {
				String targetURI = graph.getURI(targetSymbol.getResource());
				return URIStringUtils.unescape(sourceURI) + " into " + URIStringUtils.unescape(targetURI);
			} else {
				String targetURI = graph.getURI(targetType.getResource());
				return URIStringUtils.unescape(sourceURI) + " into " + URIStringUtils.unescape(targetURI);
			}
		}
		
		private Resource getPossibleReplacement(ReadGraph graph, Resource type, Resource predicate) throws DatabaseException {
			Layer0 L0 = Layer0.getInstance(graph);
			String name = graph.getPossibleRelatedValue(predicate, L0.HasName, Bindings.STRING);
			if(name == null) return null;
			Resource child = Layer0Utils.getPossibleChild(graph, type, name);
			if(child != null) return child;
			for(Resource r : graph.getObjects(type, L0.DomainOf)) {
				String rName = graph.getPossibleRelatedValue(r, L0.HasName, Bindings.STRING);
				if(name.equals(rName)) return r;
			}
			return null; 
		}
		
		public String replace(WriteGraph graph, Resource instanceToMigrate, Resource type) throws DatabaseException {

			Layer0 L0 = Layer0.getInstance(graph);
			StructuralResource2 STR = StructuralResource2.getInstance(graph);

			Collection<Resource> currentTypes = graph.getPrincipalTypes(instanceToMigrate);
			if(currentTypes.size() == 1 && currentTypes.contains(type)) return null;
			
			StringBuilder problems = new StringBuilder();
			
			// Validate operation
			for(Statement stm : graph.getStatements(instanceToMigrate, L0.IsWeaklyRelatedTo)) {

				Resource predicate = stm.getPredicate();
				if(stm.isAsserted(instanceToMigrate)) continue;
				
				if(graph.isInstanceOf(predicate, STR.Property)) {
					Resource replacement = getPossibleReplacement(graph, type, predicate);
					// OK for a property to disappear
					if(replacement == null) continue;
					if(!graph.isInstanceOf(replacement, STR.Property)) {
						String name = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
						problems.append(" " + name + " was a property in the source type\n");
						continue;
					}
					String sourceValueType = graph.getPossibleRelatedValue(predicate, L0.RequiresValueType, Bindings.STRING);
					String replacementValueType = graph.getPossibleRelatedValue(replacement, L0.RequiresValueType, Bindings.STRING);
					if(!ObjectUtils.objectEquals(sourceValueType, replacementValueType)) {
						String name = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
						problems.append(" value types for property " + name + " differ (" + sourceValueType + " vs. " + replacementValueType + ")\n");
						continue;
					}
				}

				if(graph.isInstanceOf(predicate, STR.ConnectionRelation)) {
					Resource replacement = getPossibleReplacement(graph, type, predicate);
					if(replacement == null) {
						String name = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
						problems.append(" used connection point " + name + " has been removed from target type\n");
						continue;
					}
					if(!graph.isInstanceOf(replacement, STR.ConnectionRelation)) {
						String name = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
						problems.append(" " + name + " was a connection point in the source type\n");
						continue;
					}

					Collection<Resource> sourceConnetionTypes = graph.syncRequest(new AllowedConnectionTypes(predicate));
					Collection<Resource> replacementConnectionTypes = graph.syncRequest(new AllowedConnectionTypes(replacement));
					
					Set<Resource> sourceSet = new THashSet<>(sourceConnetionTypes);
					Set<Resource> replacementSet = new THashSet<>(replacementConnectionTypes);
					
					if(!sourceSet.equals(replacementSet)) {
						String name = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
						problems.append(" allowed connection types for connection point " + name + " differ (" + NameUtils.getSafeName(graph, sourceSet) + " vs. " + NameUtils.getSafeName(graph, replacementSet) + ")\n");
						continue;
					}

				}
				
			}
			
			if(problems.length() > 0) {
				return problems.toString();
			}

			// Perform operation
			for(Statement stm : graph.getStatements(instanceToMigrate, L0.IsWeaklyRelatedTo)) {

				Resource predicate = stm.getPredicate();
				if(stm.isAsserted(instanceToMigrate)) continue;
						
				if(L0.InstanceOf.equals(predicate)) {
					graph.deny(stm);
					graph.claim(instanceToMigrate, L0.InstanceOf, type);
				}
				
				if(graph.isInstanceOf(predicate, STR.Property) || graph.isInstanceOf(predicate, STR.ConnectionRelation)) {
					Resource replacement = getPossibleReplacement(graph, type, predicate);
					graph.deny(stm);
					if(replacement == null) continue;
					graph.claim(stm.getSubject(), replacement, stm.getObject());
				}
				
			}
			
			return null;

		}
		
		public String perform(WriteGraph graph) throws DatabaseException {
			
			Resource instance = instanceToMigrate.getResource();
			Resource type = targetType.getResource();
			Resource symbol = targetSymbol != null ? targetSymbol.getResource() : null;
			
			String result = replace(graph, instance, type);
			if(result != null) return result;
			
			ModelingResources MOD = ModelingResources.getInstance(graph);
			Resource element = graph.getPossibleObject(instance, MOD.ComponentToElement);
			if(element == null) return null;
			
			Resource targetSymbol = symbol;
			if(targetSymbol == null) {
				Layer0 L0 = Layer0.getInstance(graph);
				DiagramResource DIA = DiagramResource.getInstance(graph);
				Resource currentSymbol = graph.getPossibleType(element, DIA.Element);
				if(currentSymbol != null) {
					String currentSymbolName = graph.getRelatedValue(currentSymbol, L0.HasName, Bindings.STRING);
					targetSymbol = Layer0Utils.getPossibleChild(graph, type, DIA.ElementClass, currentSymbolName);
					if(targetSymbol == null)
						return "Did not find symbol '" + currentSymbolName + "' from target type.\n";
				} else {
					// No symbol - fine 
					return null;
				}

			}
			
			return replace(graph, element, targetSymbol);
			
		}
		
	}

	public int instanceCount = 0;
	public Set<Resource> activeModels = new THashSet<>();
	public List<Triple<String, NamedResource, Collection<MigrationOperation>>> instances = new ArrayList<>();
	public List<MigrationOperation> sortedShownInstances = Collections.emptyList();

}