/*******************************************************************************
 * Copyright (c) 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:
 *     Semantum Oy - initial API and implementation
 *******************************************************************************/
package org.simantics.db.layer0.adapter.impl;

import gnu.trove.map.hash.THashMap;

import java.util.Collections;
import java.util.Map;

import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.uri.UnescapedChildMapOfResource;
import org.simantics.db.common.utils.Versions;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.adapter.StringModifier;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.layer0.Layer0;

/**
 * Makes sure that two things apply for L0.HasName of any entity:
 * <ol>
 * <li>An entity must not have the same name as any of its
 * L0.PartOf/L0.ConsistsOf related siblings</li>
 * <li>An entity's name must not begin with one or more dots ('.'). Due to
 * limitations imposed by the Variable specification no resources in the
 * simantics database should be named beginning with one or more dots. '.' is
 * variable browsing syntax for "parent" (see
 * {@link Variable#browse(ReadGraph, String)}). This is comparable to file
 * systems and the use of '.' and '..' therein.</li>
 * </ol>
 * 
 * @author Tuukka Lehtonen
 */
public final class EntityNameModifier implements StringModifier {

    private Resource              entity;
    private Resource              property;

    private boolean               hasUri;
    private Map<String, Resource> namesInUse = Collections.emptyMap();

    private Layer0                L0;
    
    final private String                initial;
    final private String                version;

    public EntityNameModifier(ReadGraph graph, Resource entity, Resource property) throws DatabaseException {
        this.entity = entity;
        this.property = property;
        initialize(graph);
        this.initial = Versions.getBaseName(graph, entity);
    	this.version = Versions.getVersion(graph, entity);
    }

    @Override
    public String getValue() {
    	return initial;
    }
    
    private void initialize(ReadGraph graph) throws DatabaseException {
        this.L0 = Layer0.getInstance(graph);
        refreshUsedSiblingNames(graph);
        if(Layer0Utils.isPublished(graph, entity)) throw new DatabaseException("Published resources cannot be renamed.");
        if(Layer0Utils.isContainerPublished(graph, entity)) throw new DatabaseException("Cannot rename in a published shared library.");
    }

    private void refreshUsedSiblingNames(ReadGraph graph) throws DatabaseException {
        String uri = graph.getPossibleURI(entity);
        this.hasUri = uri != null;

        Map<String, Resource> used = new THashMap<String, Resource>();
        for (Resource partOf : graph.getObjects(entity, L0.PartOf)) {
            Map<String, Resource> childMap = graph.syncRequest(new UnescapedChildMapOfResource(partOf));
            used.putAll(childMap);
        }
        String originalName = graph.getPossibleValue(property, Bindings.STRING);
//        System.out.println("used names:" + used);
//        System.out.println("original name:" + originalName);
        used.remove(originalName);

        this.namesInUse = used;
//        System.out.println("final used names:" + used);
    }

    public String finalValue(String value) {
    	return version != null ? value + "@" + version : value;
    }
    
    @Override
    public String isValid(String value_) {
    	String value = finalValue(value_); 
        if (value.isEmpty())
            return "Name is empty.";
        if (namesInUse.containsKey(value))
            return "Name is already used by a sibling.";
        if (hasUri && value.startsWith("."))
            return "Name of an entity with URI must not begin with a dot ('.')";
        return null;
    }

    @Override
    final public void modify(WriteGraph graph, String value_) throws DatabaseException {
    	String value = finalValue(value_); 
        graph.claimLiteral(entity, L0.HasName, L0.NameOf, value, Bindings.STRING);
    }

}