/*******************************************************************************
 * Copyright (c) 2017 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
 *     Semantum Oy - #7313
 *******************************************************************************/
package org.simantics.charts.internal;

import java.util.Collections;
import java.util.List;
import java.util.Optional;

import org.simantics.databoard.type.Datatype;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.request.PossibleActiveVariableFromVariable;
import org.simantics.db.layer0.variable.RVI;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.db.layer0.variable.VariableReference;
import org.simantics.db.layer0.variable.Variables;
import org.simantics.modeling.utils.VariableReferences;

/**
 * @author Tuukka Lehtonen
 * @since 1.28.1, 1.29.0
 */
public class VariableUtils {

    public static Datatype getDatatype(ReadGraph graph, Resource resource, RVI rvi) throws DatabaseException {
        Variable configuration = Variables.getConfigurationContext(graph, resource);
        Variable active = graph.syncRequest(new PossibleActiveVariableFromVariable(configuration));
        Variable var = rvi.resolve(graph, active != null ? active : configuration);
        return var.getDatatype(graph);
    }

    /**
     * @param graph
     * @param targetModel
     * @param source
     * @return <code>null</code> if the value is valid JSON but does not contain
     *         a variable reference
     * @throws DatabaseException
     *             if the value fails to resolve as either JSON or an RVI string
     */
    public static List<VariableReference> getVariableReferencesFromString(ReadGraph graph, Resource targetModel, String source) throws DatabaseException {
        try {
            // JSON ?
            Optional<Variable> v = JsonUtils.tryParseJsonPropertyVariable(graph, source);
            if (v.isPresent())
                return graph.syncRequest(VariableReferences.variablesToReferences(targetModel, Collections.singletonList(v.get())));
            // JSON, but no variable info in it.
            return null;
        } catch (DatabaseException e) {
            // RVI as String?
            RVI rvi = RVI.fromResourceFormat(graph, source);
            return Collections.singletonList(new VariableReference(rvi, getDatatype(graph, targetModel, rvi), null));
        }
    }

}