/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.core.assembler;

import static org.apache.jena.assembler.JA.data;
import static org.apache.jena.query.DatasetFactory.createTxnMem;
import static org.apache.jena.riot.RDFDataMgr.read;
import static org.apache.jena.sparql.core.assembler.AssemblerUtils.mergeContext;
import static org.apache.jena.sparql.core.assembler.DatasetAssemblerVocab.pGraphName;
import static org.apache.jena.sparql.core.assembler.DatasetAssemblerVocab.pNamedGraph;
import static org.apache.jena.sparql.util.graph.GraphUtils.getAsStringValue;
import static org.apache.jena.sparql.util.graph.GraphUtils.multiValueAsString;
import static org.apache.jena.sparql.util.graph.GraphUtils.multiValueResource;

import org.apache.jena.assembler.Assembler;
import org.apache.jena.assembler.Mode;
import org.apache.jena.assembler.assemblers.AssemblerBase;
import org.apache.jena.query.Dataset;
import org.apache.jena.rdf.model.Resource;
import org.apache.jena.system.Txn;
import org.apache.jena.vocabulary.RDF;

/**
 * An {@link Assembler} that creates in-memory {@link Dataset}s.
 */
public class InMemDatasetAssembler extends AssemblerBase implements Assembler {

    public static Resource getType() {
        return DatasetAssemblerVocab.tMemoryDataset ;
    }

    @Override
    public Dataset open(final Assembler assembler, final Resource root, final Mode mode) {
        // Old name : bypass.
        if ( ! root.hasProperty( RDF.type, DatasetAssemblerVocab.tDatasetTxnMem ) )
            checkType(root, DatasetAssemblerVocab.tMemoryDataset);
        final Dataset dataset = createTxnMem();
        mergeContext(root, dataset.getContext());

        Txn.executeWrite(dataset, ()->{ 
            // Load data into the default graph
            // This also loads quads into the dataset.
            multiValueAsString(root, data)
                .forEach(dataURI -> read(dataset, dataURI));

            // load data into named graphs
            multiValueResource(root, pNamedGraph).forEach(namedGraphResource -> {
                final String graphName = getAsStringValue(namedGraphResource, pGraphName);
                if (namedGraphResource.hasProperty(data)) {
                    multiValueAsString(namedGraphResource, data)
                        .forEach(namedGraphData -> read(dataset.getNamedModel(graphName), namedGraphData));
                }
            });
        });
        return dataset;
    }
}
