/*
 * 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.tdb2.solver;

import java.util.function.Predicate;

import org.apache.jena.atlas.lib.tuple.Tuple;
import org.apache.jena.graph.Graph;
import org.apache.jena.sparql.core.BasicPattern;
import org.apache.jena.sparql.engine.ExecutionContext;
import org.apache.jena.sparql.engine.QueryIterator;
import org.apache.jena.sparql.engine.main.StageGenerator;
import org.apache.jena.tdb2.store.GraphTDB;
import org.apache.jena.tdb2.store.GraphViewSwitchable;
import org.apache.jena.tdb2.store.NodeId;

/**
 * Execute TDB requests directly -- no reordering Using OpExecutor is preferred.
 */
public class StageGeneratorDirectTDB implements StageGenerator {
    // Using OpExecutor is preferred.
    StageGenerator above = null;

    public StageGeneratorDirectTDB(StageGenerator original) {
        above = original;
    }

    @Override
    public QueryIterator execute(BasicPattern pattern, QueryIterator input, ExecutionContext execCxt) {
        // --- In case this isn't for TDB2
        Graph g = execCxt.getActiveGraph();

        if ( g instanceof GraphViewSwitchable ) {
            GraphViewSwitchable gvs = (GraphViewSwitchable)g;
            g = gvs.getBaseGraph();
        }

        if ( !(g instanceof GraphTDB) )
            // Not us - bounce up the StageGenerator chain
            return above.execute(pattern, input, execCxt);
        GraphTDB graph = (GraphTDB)g;
        Predicate<Tuple<NodeId>> filter = QC2.getFilter(execCxt.getContext());
        return PatternMatchTDB2.execute(graph, pattern, input, filter, execCxt);
    }
}
