/*
 * 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.search;


import org.apache.lucene.index.Term;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.automaton.Automata;
import org.apache.lucene.util.automaton.Automaton;

A Query that matches documents within an range of terms.
This query matches the documents looking for terms that fall into the supplied range according to BytesRef.compareTo(BytesRef). 
NOTE: TermRangeQuery performs significantly slower than point-based ranges as it needs to visit all terms that match the range and merges their matches. 
This query uses the MultiTermQuery.CONSTANT_SCORE_REWRITE rewrite method. 
Since:
2.9/**
 * A Query that matches documents within an range of terms.
 *
 * <p>This query matches the documents looking for terms that fall into the
 * supplied range according to {@link BytesRef#compareTo(BytesRef)}.
 *
 * <p><b>NOTE</b>: {@link TermRangeQuery} performs significantly slower than
 * {@link PointRangeQuery point-based ranges} as it needs to visit all terms
 * that match the range and merges their matches. 
 *
 * <p>This query uses the {@link
 * MultiTermQuery#CONSTANT_SCORE_REWRITE}
 * rewrite method.
 * @since 2.9
 */

public class TermRangeQuery extends AutomatonQuery {
  private final BytesRef lowerTerm;
  private final BytesRef upperTerm;
  private final boolean includeLower;
  private final boolean includeUpper;

  
Constructs a query selecting all terms greater/equal than lowerTerm
but less/equal than upperTerm. 

If an endpoint is null, it is said 
to be "open". Either or both endpoints may be open.  Open endpoints may not 
be exclusive (you can't select all but the first or last term without 
explicitly specifying the term to exclude.)
Params:
field – The field that holds both lower and upper terms.
lowerTerm – 
         The term text at the lower end of the range
upperTerm – 
         The term text at the upper end of the range
includeLower – 
         If true, the lowerTerm is
         included in the range.
includeUpper – 
         If true, the upperTerm is
         included in the range./**
   * Constructs a query selecting all terms greater/equal than <code>lowerTerm</code>
   * but less/equal than <code>upperTerm</code>. 
   * 
   * <p>
   * If an endpoint is null, it is said 
   * to be "open". Either or both endpoints may be open.  Open endpoints may not 
   * be exclusive (you can't select all but the first or last term without 
   * explicitly specifying the term to exclude.)
   * 
   * @param field The field that holds both lower and upper terms.
   * @param lowerTerm
   *          The term text at the lower end of the range
   * @param upperTerm
   *          The term text at the upper end of the range
   * @param includeLower
   *          If true, the <code>lowerTerm</code> is
   *          included in the range.
   * @param includeUpper
   *          If true, the <code>upperTerm</code> is
   *          included in the range.
   */
  public TermRangeQuery(String field, BytesRef lowerTerm, BytesRef upperTerm, boolean includeLower, boolean includeUpper) {
    super(new Term(field, lowerTerm), toAutomaton(lowerTerm, upperTerm, includeLower, includeUpper), Integer.MAX_VALUE, true);
    this.lowerTerm = lowerTerm;
    this.upperTerm = upperTerm;
    this.includeLower = includeLower;
    this.includeUpper = includeUpper;
  }

  public static Automaton toAutomaton(BytesRef lowerTerm, BytesRef upperTerm, boolean includeLower, boolean includeUpper) {

    if (lowerTerm == null) {
      // makeBinaryInterval is more picky than we are:
      includeLower = true;
    }

    if (upperTerm == null) {
      // makeBinaryInterval is more picky than we are:
      includeUpper = true;
    }

    return Automata.makeBinaryInterval(lowerTerm, includeLower, upperTerm, includeUpper);
  }

  
Factory that creates a new TermRangeQuery using Strings for term text.
/**
   * Factory that creates a new TermRangeQuery using Strings for term text.
   */
  public static TermRangeQuery newStringRange(String field, String lowerTerm, String upperTerm, boolean includeLower, boolean includeUpper) {
    BytesRef lower = lowerTerm == null ? null : new BytesRef(lowerTerm);
    BytesRef upper = upperTerm == null ? null : new BytesRef(upperTerm);
    return new TermRangeQuery(field, lower, upper, includeLower, includeUpper);
  }

  
Returns the lower value of this range query /** Returns the lower value of this range query */
  public BytesRef getLowerTerm() { return lowerTerm; }

  
Returns the upper value of this range query /** Returns the upper value of this range query */
  public BytesRef getUpperTerm() { return upperTerm; }
  
  
Returns true if the lower endpoint is inclusive /** Returns <code>true</code> if the lower endpoint is inclusive */
  public boolean includesLower() { return includeLower; }
  
  
Returns true if the upper endpoint is inclusive /** Returns <code>true</code> if the upper endpoint is inclusive */
  public boolean includesUpper() { return includeUpper; }
  
  
Prints a user-readable version of this query. /** Prints a user-readable version of this query. */
  @Override
  public String toString(String field) {
    StringBuilder buffer = new StringBuilder();
    if (!getField().equals(field)) {
      buffer.append(getField());
      buffer.append(":");
    }
    buffer.append(includeLower ? '[' : '{');
    // TODO: all these toStrings for queries should just output the bytes, it might not be UTF-8!
    buffer.append(lowerTerm != null ? ("*".equals(Term.toString(lowerTerm)) ? "\\*" : Term.toString(lowerTerm))  : "*");
    buffer.append(" TO ");
    buffer.append(upperTerm != null ? ("*".equals(Term.toString(upperTerm)) ? "\\*" : Term.toString(upperTerm)) : "*");
    buffer.append(includeUpper ? ']' : '}');
    return buffer.toString();
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = super.hashCode();
    result = prime * result + (includeLower ? 1231 : 1237);
    result = prime * result + (includeUpper ? 1231 : 1237);
    result = prime * result + ((lowerTerm == null) ? 0 : lowerTerm.hashCode());
    result = prime * result + ((upperTerm == null) ? 0 : upperTerm.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (!super.equals(obj))
      return false;
    if (getClass() != obj.getClass())
      return false;
    TermRangeQuery other = (TermRangeQuery) obj;
    if (includeLower != other.includeLower)
      return false;
    if (includeUpper != other.includeUpper)
      return false;
    if (lowerTerm == null) {
      if (other.lowerTerm != null)
        return false;
    } else if (!lowerTerm.equals(other.lowerTerm))
      return false;
    if (upperTerm == null) {
      if (other.upperTerm != null)
        return false;
    } else if (!upperTerm.equals(other.upperTerm))
      return false;
    return true;
  }
}