/*
 * 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.tests.analysis;

import java.io.IOException;
import java.util.Random;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.index.IndexWriter;

public class TestLookaheadTokenFilter extends BaseTokenStreamTestCase {

  public void testRandomStrings() throws Exception {
    Analyzer a =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Random random = random();
            Tokenizer tokenizer =
                new MockTokenizer(
                    MockTokenizer.WHITESPACE,
                    random.nextBoolean(),
                    IndexWriter.MAX_TERM_LENGTH / 2);
            TokenStream output = new MockRandomLookaheadTokenFilter(random, tokenizer);
            return new TokenStreamComponents(tokenizer, output);
          }
        };
    int maxLength = TEST_NIGHTLY ? 8192 : 1024;
    checkRandomData(random(), a, 50 * RANDOM_MULTIPLIER, maxLength);
  }

  private static class NeverPeeksLookaheadTokenFilter
      extends LookaheadTokenFilter<LookaheadTokenFilter.Position> {
    public NeverPeeksLookaheadTokenFilter(TokenStream input) {
      super(input);
    }

    @Override
    public Position newPosition() {
      return new Position();
    }

    @Override
    public boolean incrementToken() throws IOException {
      return nextToken();
    }
  }

  public void testNeverCallingPeek() throws Exception {
    Analyzer a =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Tokenizer tokenizer =
                new MockTokenizer(
                    MockTokenizer.WHITESPACE,
                    random().nextBoolean(),
                    IndexWriter.MAX_TERM_LENGTH / 2);
            TokenStream output = new NeverPeeksLookaheadTokenFilter(tokenizer);
            return new TokenStreamComponents(tokenizer, output);
          }
        };
    int maxLength = TEST_NIGHTLY ? 8192 : 1024;
    checkRandomData(random(), a, 50 * RANDOM_MULTIPLIER, maxLength);
  }

  public void testMissedFirstToken() throws Exception {
    Analyzer analyzer =
        new Analyzer() {
          @Override
          protected TokenStreamComponents createComponents(String fieldName) {
            Tokenizer source = new MockTokenizer(MockTokenizer.WHITESPACE, false);
            TrivialLookaheadFilter filter = new TrivialLookaheadFilter(source);
            return new TokenStreamComponents(source, filter);
          }
        };

    assertAnalyzesTo(
        analyzer,
        "Only he who is running knows .",
        new String[] {
          "Only",
          "Only-huh?",
          "he",
          "he-huh?",
          "who",
          "who-huh?",
          "is",
          "is-huh?",
          "running",
          "running-huh?",
          "knows",
          "knows-huh?",
          ".",
          ".-huh?"
        });
  }
}
