/*
 * 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.lucene.legacy;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.MultiFields;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.legacy.LegacyDoubleField;
import org.apache.lucene.legacy.LegacyFloatField;
import org.apache.lucene.legacy.LegacyIntField;
import org.apache.lucene.legacy.LegacyLongField;
import org.apache.lucene.legacy.LegacyNumericUtils;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util.NumericUtils;

public class TestLegacyTerms extends LuceneTestCase {

  public void testEmptyIntFieldMinMax() throws Exception {
    assertNull(LegacyNumericUtils.getMinInt(EMPTY_TERMS));
    assertNull(LegacyNumericUtils.getMaxInt(EMPTY_TERMS));
  }
  
  public void testIntFieldMinMax() throws Exception {
    Directory dir = newDirectory();
    RandomIndexWriter w = new RandomIndexWriter(random(), dir);
    int numDocs = atLeast(100);
    int minValue = Integer.MAX_VALUE;
    int maxValue = Integer.MIN_VALUE;
    for(int i=0;i<numDocs;i++ ){
      Document doc = new Document();
      int num = random().nextInt();
      minValue = Math.min(num, minValue);
      maxValue = Math.max(num, maxValue);
      doc.add(new LegacyIntField("field", num, Field.Store.NO));
      w.addDocument(doc);
    }
    
    IndexReader r = w.getReader();
    Terms terms = MultiFields.getTerms(r, "field");
    assertEquals(new Integer(minValue), LegacyNumericUtils.getMinInt(terms));
    assertEquals(new Integer(maxValue), LegacyNumericUtils.getMaxInt(terms));

    r.close();
    w.close();
    dir.close();
  }

  public void testEmptyLongFieldMinMax() throws Exception {
    assertNull(LegacyNumericUtils.getMinLong(EMPTY_TERMS));
    assertNull(LegacyNumericUtils.getMaxLong(EMPTY_TERMS));
  }
  
  public void testLongFieldMinMax() throws Exception {
    Directory dir = newDirectory();
    RandomIndexWriter w = new RandomIndexWriter(random(), dir);
    int numDocs = atLeast(100);
    long minValue = Long.MAX_VALUE;
    long maxValue = Long.MIN_VALUE;
    for(int i=0;i<numDocs;i++ ){
      Document doc = new Document();
      long num = random().nextLong();
      minValue = Math.min(num, minValue);
      maxValue = Math.max(num, maxValue);
      doc.add(new LegacyLongField("field", num, Field.Store.NO));
      w.addDocument(doc);
    }
    
    IndexReader r = w.getReader();

    Terms terms = MultiFields.getTerms(r, "field");
    assertEquals(new Long(minValue), LegacyNumericUtils.getMinLong(terms));
    assertEquals(new Long(maxValue), LegacyNumericUtils.getMaxLong(terms));

    r.close();
    w.close();
    dir.close();
  }

  public void testFloatFieldMinMax() throws Exception {
    Directory dir = newDirectory();
    RandomIndexWriter w = new RandomIndexWriter(random(), dir);
    int numDocs = atLeast(100);
    float minValue = Float.POSITIVE_INFINITY;
    float maxValue = Float.NEGATIVE_INFINITY;
    for(int i=0;i<numDocs;i++ ){
      Document doc = new Document();
      float num = random().nextFloat();
      minValue = Math.min(num, minValue);
      maxValue = Math.max(num, maxValue);
      doc.add(new LegacyFloatField("field", num, Field.Store.NO));
      w.addDocument(doc);
    }
    
    IndexReader r = w.getReader();
    Terms terms = MultiFields.getTerms(r, "field");
    assertEquals(minValue, NumericUtils.sortableIntToFloat(LegacyNumericUtils.getMinInt(terms)), 0.0f);
    assertEquals(maxValue, NumericUtils.sortableIntToFloat(LegacyNumericUtils.getMaxInt(terms)), 0.0f);

    r.close();
    w.close();
    dir.close();
  }

  public void testDoubleFieldMinMax() throws Exception {
    Directory dir = newDirectory();
    RandomIndexWriter w = new RandomIndexWriter(random(), dir);
    int numDocs = atLeast(100);
    double minValue = Double.POSITIVE_INFINITY;
    double maxValue = Double.NEGATIVE_INFINITY;
    for(int i=0;i<numDocs;i++ ){
      Document doc = new Document();
      double num = random().nextDouble();
      minValue = Math.min(num, minValue);
      maxValue = Math.max(num, maxValue);
      doc.add(new LegacyDoubleField("field", num, Field.Store.NO));
      w.addDocument(doc);
    }
    
    IndexReader r = w.getReader();

    Terms terms = MultiFields.getTerms(r, "field");

    assertEquals(minValue, NumericUtils.sortableLongToDouble(LegacyNumericUtils.getMinLong(terms)), 0.0);
    assertEquals(maxValue, NumericUtils.sortableLongToDouble(LegacyNumericUtils.getMaxLong(terms)), 0.0);

    r.close();
    w.close();
    dir.close();
  }

  /**
   * A complete empty Terms instance that has no terms in it and supports no optional statistics
   */
  private static Terms EMPTY_TERMS = new Terms() {
    public TermsEnum iterator() { return TermsEnum.EMPTY; }
    public long size() { return -1; }
    public long getSumTotalTermFreq() { return -1; }
    public long getSumDocFreq() { return -1; }
    public int getDocCount() { return -1; }
    public boolean hasFreqs() { return false; }
    public boolean hasOffsets() { return false; }
    public boolean hasPositions() { return false; }
    public boolean hasPayloads() { return false; }
  };
}