/*
 * 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.analysis.miscellaneous;

import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.KeywordTokenizer;
import org.apache.lucene.analysis.synonym.SynonymGraphFilter;
import org.apache.lucene.analysis.synonym.SynonymMap;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.util.CharsRef;
import org.apache.lucene.util.TestUtil;

public class TestRemoveDuplicatesTokenFilter extends BaseTokenStreamTestCase {

  public static Token tok(int pos, String t, int start, int end) {
    Token tok = new Token(t, start, end);
    tok.setPositionIncrement(pos);
    return tok;
  }

  public static Token tok(int pos, String t) {
    return tok(pos, t, 0, 0);
  }

  public void testDups(final String expected, final Token... tokens) throws Exception {

    final Iterator<Token> toks = Arrays.asList(tokens).iterator();
    final TokenStream ts =
        new RemoveDuplicatesTokenFilter(
            (new TokenStream() {
              CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
              OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
              PositionIncrementAttribute posIncAtt = addAttribute(PositionIncrementAttribute.class);

              @Override
              public boolean incrementToken() {
                if (toks.hasNext()) {
                  clearAttributes();
                  Token tok = toks.next();
                  termAtt.setEmpty().append(tok);
                  offsetAtt.setOffset(tok.startOffset(), tok.endOffset());
                  posIncAtt.setPositionIncrement(tok.getPositionIncrement());
                  return true;
                } else {
                  return false;
                }
              }
            }));

    assertTokenStreamContents(ts, expected.split("\\s"));
  }

  public void testNoDups() throws Exception {

    testDups(
        "A B B C D E",
        tok(1, "A", 0, 4),
        tok(1, "B", 5, 10),
        tok(1, "B", 11, 15),
        tok(1, "C", 16, 20),
        tok(0, "D", 16, 20),
        tok(1, "E", 21, 25));
  }

  public void testSimpleDups() throws Exception {

    testDups(
        "A B C D E",
        tok(1, "A", 0, 4),
        tok(1, "B", 5, 10),
        tok(0, "B", 11, 15),
        tok(1, "C", 16, 20),
        tok(0, "D", 16, 20),
        tok(1, "E", 21, 25));
  }

  public void testComplexDups() throws Exception {

    testDups(
        "A B C D E F G H I J K",
        tok(1, "A"),
        tok(1, "B"),
        tok(0, "B"),
        tok(1, "C"),
        tok(1, "D"),
        tok(0, "D"),
        tok(0, "D"),
        tok(1, "E"),
        tok(1, "F"),
        tok(0, "F"),
        tok(1, "G"),
        tok(0, "H"),
        tok(0, "H"),
        tok(1, "I"),
        tok(1, "J"),
        tok(0, "K"),
        tok(0, "J"));
  }

  // some helper methods for the below test with synonyms
  private String randomNonEmptyString() {
    while (true) {
      final String s = TestUtil.randomUnicodeString(random()).trim();
      if (s.length() != 0 && s.indexOf('\u0000') == -1) {
        return s;
      }
    }
  }

  private void add(SynonymMap.Builder b, String input, String output, boolean keepOrig) {
    b.add(
        new CharsRef(input.replaceAll(" +", "\u0000")),
        new CharsRef(output.replaceAll(" +", "\u0000")),
        keepOrig);
  }

  /** blast some random strings through the analyzer */
  public void testRandomStrings() throws Exception {
    final int numIters = atLeast(3);
    for (int i = 0; i < numIters; i++) {
      SynonymMap.Builder b = new SynonymMap.Builder(random().nextBoolean());
      final int numEntries = atLeast(10);
      for (int j = 0; j < numEntries; j++) {
        add(b, randomNonEmptyString(), randomNonEmptyString(), random().nextBoolean());
      }
      final SynonymMap map = b.build();
      final boolean ignoreCase = random().nextBoolean();

      final Analyzer analyzer =
          new Analyzer() {
            @Override
            protected TokenStreamComponents createComponents(String fieldName) {
              Tokenizer tokenizer = new MockTokenizer(MockTokenizer.SIMPLE, true);
              TokenStream stream = new SynonymGraphFilter(tokenizer, map, ignoreCase);
              return new TokenStreamComponents(tokenizer, new RemoveDuplicatesTokenFilter(stream));
            }
          };

      checkRandomData(random(), analyzer, 200);
      analyzer.close();
    }
  }

  public void testEmptyTerm() throws IOException {
    Analyzer a =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Tokenizer tokenizer = new KeywordTokenizer();
            return new TokenStreamComponents(tokenizer, new RemoveDuplicatesTokenFilter(tokenizer));
          }
        };
    checkOneTerm(a, "", "");
    a.close();
  }
}