package org.apache.lucene.spatial.prefix;

/*
 * 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.
 */

import com.spatial4j.core.shape.Shape;
import org.apache.lucene.queries.TermsFilter;
import org.apache.lucene.search.Filter;
import org.apache.lucene.spatial.prefix.tree.Cell;
import org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree;
import org.apache.lucene.spatial.query.SpatialArgs;
import org.apache.lucene.spatial.query.SpatialOperation;
import org.apache.lucene.spatial.query.UnsupportedSpatialOperation;
import org.apache.lucene.util.BytesRef;

import java.util.List;

/**
 * A basic implementation of {@link PrefixTreeStrategy} using a large {@link
 * TermsFilter} of all the cells from {@link SpatialPrefixTree#getCells(com.spatial4j.core.shape.Shape,
 * int, boolean, boolean)}. It only supports the search of indexed Point shapes.
 * <p/>
 * The precision of query shapes (distErrPct) is an important factor in using
 * this Strategy. If the precision is too precise then it will result in many
 * terms which will amount to a slower query.
 *
 * @lucene.experimental
 */
public class TermQueryPrefixTreeStrategy extends PrefixTreeStrategy {

  public TermQueryPrefixTreeStrategy(SpatialPrefixTree grid, String fieldName) {
    super(grid, fieldName,
        false);//do not simplify indexed cells
  }

  @Override
  public Filter makeFilter(SpatialArgs args) {
    final SpatialOperation op = args.getOperation();
    if (op != SpatialOperation.Intersects)
      throw new UnsupportedSpatialOperation(op);

    Shape shape = args.getShape();
    int detailLevel = grid.getLevelForDistance(args.resolveDistErr(ctx, distErrPct));
    List<Cell> cells = grid.getCells(shape, detailLevel,
        false,//no parents
        true);//simplify
    BytesRef[] terms = new BytesRef[cells.size()];
    int i = 0;
    for (Cell cell : cells) {
      terms[i++] = new BytesRef(cell.getTokenString());//TODO use cell.getTokenBytes()
    }
    return new TermsFilter(getFieldName(), terms);
  }

}
