/*
 * RiskScape™ Copyright New Zealand Institute for Earth Science Limited
 * (Earth Sciences New Zealand) is distributed for research purposes only
 * under the terms of AGPLv3.
 *
 * RiskScape™ Copyright 2026 New Zealand Institute for Earth Science
 * Limited (Earth Sciences New Zealand). All rights reserved. Source code
 * available under the AGPLv3.
 * 
 * This program is free software: you can redistribute it and/or modify it under
 *  the terms of the GNU Affero General Public License as published by the Free
 *  Software Foundation, either version 3 of the License, or (at your option) any
 *  later version.
 * 
 * This program is distributed for RESEARCH PURPOSES ONLY, in the hope that it will
 * be useful for research and education initiatives.
 * 
 * If you are not a researcher, or you are a researcher who wishes to use this
 * program on terms other than AGPLv3 (including those who wish to restrict the
 * distribution of any source code created using this program), please contact:
 * https://riskscape.org.nz
 * 
 * This program is distributed WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Affero General Public License for more details.  You should have received a copy
 * of the GNU Affero General Public License along with this program.  If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * By way of summary only, under the AGPLv3:
 *     • Permissions of this strongest copyleft license are conditioned
 *       on making available complete source code of licensed works and
 *       modifications, which include larger works using a licensed work,
 *       under the same license.
 *     • Copyright and license notices must be preserved.
 *     • Contributors provide an express grant of patent rights.
 *     • When a modified version is used to provide a service over a
 *       network, the complete source code of the modified version must be made
 *       available.
 */
package nz.org.riskscape.engine.join;

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

import lombok.RequiredArgsConstructor;
import nz.org.riskscape.engine.Tuple;
import nz.org.riskscape.engine.join.JoinIndexer.Constructor;
import nz.org.riskscape.engine.relation.TupleIterator;
import nz.org.riskscape.engine.rl.ExpressionRealizer;
import nz.org.riskscape.engine.types.Struct;

import lombok.extern.slf4j.Slf4j;

@RequiredArgsConstructor
@Slf4j
public class DefaultJoiner implements LopsidedJoiner<JoinIndexer> {

  private final Join join;
  private final List<Constructor> indexConstructors;
  private final ExpressionRealizer expressionRealizer;
  private final Optional<Integer> initalIndexSize;

  @Override
  public Struct getLhs() {
    return join.getLhs();
  }

  @Override
  public Struct getRhs() {
    return join.getRhs();
  }

  @Override
  public Struct getProducedType() {
    return join.getJoinedType();
  }

  @Override
  public JoinIndexer createRhsIndex() {
    JoinIndexer indexer = NoIndexIndexer.CONSTRUCTOR.construct(join, expressionRealizer, initalIndexSize);
    for (Constructor indexConstructor : indexConstructors) {
      JoinIndexer possible = indexConstructor.construct(join, expressionRealizer, initalIndexSize);
      if (possible.isUsable()) {
        indexer = possible;
        break;
      }
    }
    return indexer;
  }

  @Override
  public void addToRhsIndex(Tuple rhs, JoinIndexer index) {
    index.addToIndex(rhs);
  }

  @Override
  public TupleIterator join(JoinIndexer index, Tuple lhs) {
    return new LopsidedJoinIterator(join, lhs, index.createRhsIterator(lhs));
  }

}
