/*
 * 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.core;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.net.URI;
import java.net.URL;
import java.nio.CharBuffer;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.regex.Pattern;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.CachingTokenFilter;
import org.apache.lucene.analysis.CharArrayMap;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.CharFilter;
import org.apache.lucene.analysis.CrankyTokenFilter;
import org.apache.lucene.analysis.MockTokenFilter;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.ValidatingTokenFilter;
import org.apache.lucene.analysis.boost.DelimitedBoostTokenFilter;
import org.apache.lucene.analysis.charfilter.NormalizeCharMap;
import org.apache.lucene.analysis.cjk.CJKBigramFilter;
import org.apache.lucene.analysis.commongrams.CommonGramsFilter;
import org.apache.lucene.analysis.commongrams.CommonGramsQueryFilter;
import org.apache.lucene.analysis.compound.HyphenationCompoundWordTokenFilter;
import org.apache.lucene.analysis.compound.TestCompoundWordTokenFilter;
import org.apache.lucene.analysis.compound.hyphenation.HyphenationTree;
import org.apache.lucene.analysis.hunspell.Dictionary;
import org.apache.lucene.analysis.hunspell.TestHunspellStemFilter;
import org.apache.lucene.analysis.minhash.MinHashFilter;
import org.apache.lucene.analysis.miscellaneous.ConcatenateGraphFilter;
import org.apache.lucene.analysis.miscellaneous.ConditionalTokenFilter;
import org.apache.lucene.analysis.miscellaneous.DelimitedTermFrequencyTokenFilter;
import org.apache.lucene.analysis.miscellaneous.FingerprintFilter;
import org.apache.lucene.analysis.miscellaneous.HyphenatedWordsFilter;
import org.apache.lucene.analysis.miscellaneous.LimitTokenCountFilter;
import org.apache.lucene.analysis.miscellaneous.LimitTokenOffsetFilter;
import org.apache.lucene.analysis.miscellaneous.LimitTokenPositionFilter;
import org.apache.lucene.analysis.miscellaneous.StemmerOverrideFilter;
import org.apache.lucene.analysis.miscellaneous.StemmerOverrideFilter.StemmerOverrideMap;
import org.apache.lucene.analysis.miscellaneous.WordDelimiterFilter;
import org.apache.lucene.analysis.miscellaneous.WordDelimiterGraphFilter;
import org.apache.lucene.analysis.path.PathHierarchyTokenizer;
import org.apache.lucene.analysis.path.ReversePathHierarchyTokenizer;
import org.apache.lucene.analysis.pattern.PatternTypingFilter;
import org.apache.lucene.analysis.payloads.IdentityEncoder;
import org.apache.lucene.analysis.payloads.PayloadEncoder;
import org.apache.lucene.analysis.shingle.FixedShingleFilter;
import org.apache.lucene.analysis.shingle.ShingleFilter;
import org.apache.lucene.analysis.snowball.TestSnowball;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.analysis.synonym.SynonymMap;
import org.apache.lucene.analysis.wikipedia.WikipediaTokenizer;
import org.apache.lucene.store.ByteBuffersDirectory;
import org.apache.lucene.util.AttributeFactory;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.CharsRef;
import org.apache.lucene.util.Rethrow;
import org.apache.lucene.util.TestUtil;
import org.apache.lucene.util.Version;
import org.apache.lucene.util.automaton.Automaton;
import org.apache.lucene.util.automaton.AutomatonTestUtil;
import org.apache.lucene.util.automaton.CharacterRunAutomaton;
import org.apache.lucene.util.automaton.Operations;
import org.apache.lucene.util.automaton.RegExp;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.tartarus.snowball.SnowballStemmer;
import org.xml.sax.InputSource;

/** tests random analysis chains */
public class TestRandomChains extends BaseTokenStreamTestCase {

  static List<Constructor<? extends Tokenizer>> tokenizers;
  static List<Constructor<? extends TokenFilter>> tokenfilters;
  static List<Constructor<? extends CharFilter>> charfilters;

  private static final Predicate<Object[]> ALWAYS = (objects -> true);

  private static final Set<Class<?>> avoidConditionals = new HashSet<>();

  static {
    // These filters needs to consume the whole tokenstream, so conditionals don't make sense here
    avoidConditionals.add(FingerprintFilter.class);
    avoidConditionals.add(MinHashFilter.class);
    avoidConditionals.add(ConcatenateGraphFilter.class);
    // ShingleFilter doesn't handle input graphs correctly, so wrapping it in a condition can
    // expose inconsistent offsets
    // https://issues.apache.org/jira/browse/LUCENE-4170
    avoidConditionals.add(ShingleFilter.class);
    avoidConditionals.add(FixedShingleFilter.class);
    // FlattenGraphFilter changes the output graph entirely, so wrapping it in a condition
    // can break position lengths
    avoidConditionals.add(FlattenGraphFilter.class);
    // LimitToken*Filters don't set end offsets correctly
    avoidConditionals.add(LimitTokenOffsetFilter.class);
    avoidConditionals.add(LimitTokenCountFilter.class);
    avoidConditionals.add(LimitTokenPositionFilter.class);
  }

  private static final Map<Constructor<?>, Predicate<Object[]>> brokenConstructors =
      new HashMap<>();

  static {
    initBrokenConstructors();
  }

  @SuppressWarnings("deprecation")
  private static void initBrokenConstructors() {
    try {
      brokenConstructors.put(
          LimitTokenCountFilter.class.getConstructor(TokenStream.class, int.class), ALWAYS);
      brokenConstructors.put(
          LimitTokenCountFilter.class.getConstructor(TokenStream.class, int.class, boolean.class),
          args -> {
            assert args.length == 3;
            return !((Boolean) args[2]); // args are broken if consumeAllTokens is false
          });
      brokenConstructors.put(
          LimitTokenOffsetFilter.class.getConstructor(TokenStream.class, int.class), ALWAYS);
      brokenConstructors.put(
          LimitTokenOffsetFilter.class.getConstructor(TokenStream.class, int.class, boolean.class),
          args -> {
            assert args.length == 3;
            return !((Boolean) args[2]); // args are broken if consumeAllTokens is false
          });
      brokenConstructors.put(
          LimitTokenPositionFilter.class.getConstructor(TokenStream.class, int.class), ALWAYS);
      brokenConstructors.put(
          LimitTokenPositionFilter.class.getConstructor(
              TokenStream.class, int.class, boolean.class),
          args -> {
            assert args.length == 3;
            return !((Boolean) args[2]); // args are broken if consumeAllTokens is false
          });
      for (Class<?> c :
          Arrays.<Class<?>>asList(
              // doesn't actual reset itself!  TODO this statement is probably obsolete as of
              // LUCENE-6121 ?
              CachingTokenFilter.class,
              // LUCENE-8092: doesn't handle graph inputs
              CJKBigramFilter.class,
              // TODO: LUCENE-4983
              CommonGramsFilter.class,
              // TODO: doesn't handle graph inputs
              CommonGramsQueryFilter.class,
              // Not broken, simulates brokenness:
              CrankyTokenFilter.class,
              // TODO: doesn't handle graph inputs (or even look at positionIncrement)
              HyphenatedWordsFilter.class,
              // broken offsets
              PathHierarchyTokenizer.class,
              // broken offsets
              ReversePathHierarchyTokenizer.class,
              // Not broken: we forcefully add this, so we shouldn't
              // also randomly pick it:
              ValidatingTokenFilter.class,
              // TODO: it seems to mess up offsets!?
              WikipediaTokenizer.class,
              // TODO: needs to be a tokenizer, doesnt handle graph inputs properly (a shingle or
              // similar following will then cause pain)
              WordDelimiterFilter.class,
              // Cannot correct offsets when a char filter had changed them:
              WordDelimiterGraphFilter.class,
              // requires a special encoded token value, so it may fail with random data:
              DelimitedTermFrequencyTokenFilter.class,
              // requires a special encoded token value, so it may fail with random data:
              DelimitedBoostTokenFilter.class,
              // clones of core's filters:
              org.apache.lucene.analysis.core.StopFilter.class,
              org.apache.lucene.analysis.core.LowerCaseFilter.class)) {
        for (Constructor<?> ctor : c.getConstructors()) {
          brokenConstructors.put(ctor, ALWAYS);
        }
      }
    } catch (Exception e) {
      throw new Error(e);
    }
  }

  @BeforeClass
  public static void beforeClass() throws Exception {
    List<Class<?>> analysisClasses = getClassesForPackage("org.apache.lucene.analysis");
    tokenizers = new ArrayList<>();
    tokenfilters = new ArrayList<>();
    charfilters = new ArrayList<>();
    for (final Class<?> c : analysisClasses) {
      final int modifiers = c.getModifiers();
      if (
      // don't waste time with abstract classes or deprecated known-buggy ones
      Modifier.isAbstract(modifiers)
          || !Modifier.isPublic(modifiers)
          || c.isSynthetic()
          || c.isAnonymousClass()
          || c.isMemberClass()
          || c.isInterface()
          || c.isAnnotationPresent(Deprecated.class)
          || !(Tokenizer.class.isAssignableFrom(c)
              || TokenFilter.class.isAssignableFrom(c)
              || CharFilter.class.isAssignableFrom(c))) {
        continue;
      }

      for (final Constructor<?> ctor : c.getConstructors()) {
        // don't test synthetic or deprecated ctors, they likely have known bugs:
        if (ctor.isSynthetic()
            || ctor.isAnnotationPresent(Deprecated.class)
            || brokenConstructors.get(ctor) == ALWAYS) {
          continue;
        }
        // conditional filters are tested elsewhere
        if (ConditionalTokenFilter.class.isAssignableFrom(c)) {
          continue;
        }
        if (Tokenizer.class.isAssignableFrom(c)) {
          assertTrue(
              ctor.toGenericString() + " has unsupported parameter types",
              allowedTokenizerArgs.containsAll(Arrays.asList(ctor.getParameterTypes())));
          tokenizers.add(castConstructor(Tokenizer.class, ctor));
        } else if (TokenFilter.class.isAssignableFrom(c)) {
          assertTrue(
              ctor.toGenericString() + " has unsupported parameter types",
              allowedTokenFilterArgs.containsAll(Arrays.asList(ctor.getParameterTypes())));
          tokenfilters.add(castConstructor(TokenFilter.class, ctor));
        } else if (CharFilter.class.isAssignableFrom(c)) {
          assertTrue(
              ctor.toGenericString() + " has unsupported parameter types",
              allowedCharFilterArgs.containsAll(Arrays.asList(ctor.getParameterTypes())));
          charfilters.add(castConstructor(CharFilter.class, ctor));
        } else {
          fail("Cannot get here");
        }
      }
    }

    final Comparator<Constructor<?>> ctorComp =
        (arg0, arg1) -> arg0.toGenericString().compareTo(arg1.toGenericString());
    Collections.sort(tokenizers, ctorComp);
    Collections.sort(tokenfilters, ctorComp);
    Collections.sort(charfilters, ctorComp);
    if (VERBOSE) {
      System.out.println("tokenizers = " + tokenizers);
      System.out.println("tokenfilters = " + tokenfilters);
      System.out.println("charfilters = " + charfilters);
    }
  }

  @AfterClass
  public static void afterClass() {
    tokenizers = null;
    tokenfilters = null;
    charfilters = null;
  }

  /**
   * Hack to work around the stupidness of Oracle's strict Java backwards compatibility. {@code
   * Class<T>#getConstructors()} should return unmodifiable {@code List<Constructor<T>>} not array!
   */
  @SuppressWarnings("unchecked")
  private static <T> Constructor<T> castConstructor(Class<T> instanceClazz, Constructor<?> ctor) {
    return (Constructor<T>) ctor;
  }

  public static List<Class<?>> getClassesForPackage(String pckgname) throws Exception {
    final List<Class<?>> classes = new ArrayList<>();
    collectClassesForPackage(pckgname, classes);
    assertFalse(
        "No classes found in package '"
            + pckgname
            + "'; maybe your test classes are packaged as JAR file?",
        classes.isEmpty());
    return classes;
  }

  private static void collectClassesForPackage(String pckgname, List<Class<?>> classes)
      throws Exception {
    final ClassLoader cld = TestRandomChains.class.getClassLoader();
    final String path = pckgname.replace('.', '/');
    final Enumeration<URL> resources = cld.getResources(path);
    while (resources.hasMoreElements()) {
      final URI uri = resources.nextElement().toURI();
      if (!"file".equalsIgnoreCase(uri.getScheme())) continue;
      final Path directory = Paths.get(uri);
      if (Files.exists(directory)) {
        try (DirectoryStream<Path> stream = Files.newDirectoryStream(directory)) {
          for (Path file : stream) {
            if (Files.isDirectory(file)) {
              // recurse
              String subPackage = pckgname + "." + file.getFileName().toString();
              collectClassesForPackage(subPackage, classes);
            }
            String fname = file.getFileName().toString();
            if (fname.endsWith(".class")) {
              String clazzName = fname.substring(0, fname.length() - 6);
              // exclude Test classes that happen to be in these packages.
              // class.ForName'ing some of them can cause trouble.
              if (!clazzName.endsWith("Test") && !clazzName.startsWith("Test")) {
                // Don't run static initializers, as we won't use most of them.
                // Java will do that automatically once accessed/instantiated.
                classes.add(Class.forName(pckgname + '.' + clazzName, false, cld));
              }
            }
          }
        }
      }
    }
  }

  private static final Map<Class<?>, Function<Random, Object>> argProducers =
      new IdentityHashMap<Class<?>, Function<Random, Object>>() {
        {
          put(
              int.class,
              random -> {
                // TODO: could cause huge ram usage to use full int range for some filters
                // (e.g. allocate enormous arrays)
                // return Integer.valueOf(random.nextInt());
                return Integer.valueOf(TestUtil.nextInt(random, -50, 50));
              });
          put(
              char.class,
              random -> {
                // TODO: fix any filters that care to throw IAE instead.
                // also add a unicode validating filter to validate termAtt?
                // return Character.valueOf((char)random.nextInt(65536));
                while (true) {
                  char c = (char) random.nextInt(65536);
                  if (c < '\uD800' || c > '\uDFFF') {
                    return Character.valueOf(c);
                  }
                }
              });
          put(float.class, Random::nextFloat);
          put(boolean.class, Random::nextBoolean);
          put(byte.class, random -> (byte) random.nextInt(256));
          put(
              byte[].class,
              random -> {
                byte bytes[] = new byte[random.nextInt(256)];
                random.nextBytes(bytes);
                return bytes;
              });
          put(Random.class, random -> new Random(random.nextLong()));
          put(Version.class, random -> Version.LATEST);
          put(AttributeFactory.class, BaseTokenStreamTestCase::newAttributeFactory);
          put(
              Set.class,
              random -> {
                // TypeTokenFilter
                Set<String> set = new HashSet<>();
                int num = random.nextInt(5);
                for (int i = 0; i < num; i++) {
                  set.add(
                      StandardTokenizer.TOKEN_TYPES[
                          random.nextInt(StandardTokenizer.TOKEN_TYPES.length)]);
                }
                return set;
              });
          put(
              Collection.class,
              random -> {
                // CapitalizationFilter
                Collection<char[]> col = new ArrayList<>();
                int num = random.nextInt(5);
                for (int i = 0; i < num; i++) {
                  col.add(TestUtil.randomSimpleString(random).toCharArray());
                }
                return col;
              });
          put(
              CharArraySet.class,
              random -> {
                int num = random.nextInt(10);
                CharArraySet set = new CharArraySet(num, random.nextBoolean());
                for (int i = 0; i < num; i++) {
                  // TODO: make nastier
                  set.add(TestUtil.randomSimpleString(random));
                }
                return set;
              });
          // TODO: don't want to make the exponentially slow ones Dawid documents
          // in TestPatternReplaceFilter, so dont use truly random patterns (for now)
          put(Pattern.class, random -> Pattern.compile("a"));
          put(
              Pattern[].class,
              random -> new Pattern[] {Pattern.compile("([a-z]+)"), Pattern.compile("([0-9]+)")});
          put(
              PayloadEncoder.class,
              random ->
                  new IdentityEncoder()); // the other encoders will throw exceptions if tokens
          // arent numbers?
          put(
              Dictionary.class,
              random -> {
                // TODO: make nastier
                InputStream affixStream =
                    TestHunspellStemFilter.class.getResourceAsStream("simple.aff");
                InputStream dictStream =
                    TestHunspellStemFilter.class.getResourceAsStream("simple.dic");
                try {
                  return new Dictionary(
                      new ByteBuffersDirectory(), "dictionary", affixStream, dictStream);
                } catch (Exception ex) {
                  Rethrow.rethrow(ex);
                  return null; // unreachable code
                }
              });
          put(
              HyphenationTree.class,
              random -> {
                // TODO: make nastier
                try {
                  InputSource is =
                      new InputSource(
                          TestCompoundWordTokenFilter.class
                              .getResource("da_UTF8.xml")
                              .toExternalForm());
                  HyphenationTree hyphenator =
                      HyphenationCompoundWordTokenFilter.getHyphenationTree(is);
                  return hyphenator;
                } catch (Exception ex) {
                  Rethrow.rethrow(ex);
                  return null; // unreachable code
                }
              });
          put(
              SnowballStemmer.class,
              random -> {
                try {
                  String lang =
                      TestSnowball.SNOWBALL_LANGS.get(
                          random.nextInt(TestSnowball.SNOWBALL_LANGS.size()));
                  Class<? extends SnowballStemmer> clazz =
                      Class.forName("org.tartarus.snowball.ext." + lang + "Stemmer")
                          .asSubclass(SnowballStemmer.class);
                  return clazz.getConstructor().newInstance();
                } catch (Exception ex) {
                  Rethrow.rethrow(ex);
                  return null; // unreachable code
                }
              });
          put(
              String.class,
              random -> {
                // TODO: make nastier
                if (random.nextBoolean()) {
                  // a token type
                  return StandardTokenizer.TOKEN_TYPES[
                      random.nextInt(StandardTokenizer.TOKEN_TYPES.length)];
                } else {
                  return TestUtil.randomSimpleString(random);
                }
              });
          put(
              NormalizeCharMap.class,
              random -> {
                NormalizeCharMap.Builder builder = new NormalizeCharMap.Builder();
                // we can't add duplicate keys, or NormalizeCharMap gets angry
                Set<String> keys = new HashSet<>();
                int num = random.nextInt(5);
                // System.out.println("NormalizeCharMap=");
                for (int i = 0; i < num; i++) {
                  String key = TestUtil.randomSimpleString(random);
                  if (!keys.contains(key) && key.length() > 0) {
                    String value = TestUtil.randomSimpleString(random);
                    builder.add(key, value);
                    keys.add(key);
                    // System.out.println("mapping: '" + key + "' => '" + value + "'");
                  }
                }
                return builder.build();
              });
          put(
              CharacterRunAutomaton.class,
              random -> {
                // TODO: could probably use a purely random automaton
                switch (random.nextInt(5)) {
                  case 0:
                    return MockTokenizer.KEYWORD;
                  case 1:
                    return MockTokenizer.SIMPLE;
                  case 2:
                    return MockTokenizer.WHITESPACE;
                  case 3:
                    return MockTokenFilter.EMPTY_STOPSET;
                  default:
                    return MockTokenFilter.ENGLISH_STOPSET;
                }
              });
          put(
              CharArrayMap.class,
              random -> {
                int num = random.nextInt(10);
                CharArrayMap<String> map = new CharArrayMap<>(num, random.nextBoolean());
                for (int i = 0; i < num; i++) {
                  // TODO: make nastier
                  map.put(TestUtil.randomSimpleString(random), TestUtil.randomSimpleString(random));
                }
                return map;
              });
          put(
              StemmerOverrideMap.class,
              random -> {
                int num = random.nextInt(10);
                StemmerOverrideFilter.Builder builder =
                    new StemmerOverrideFilter.Builder(random.nextBoolean());
                for (int i = 0; i < num; i++) {
                  String input = "";
                  do {
                    input = TestUtil.randomRealisticUnicodeString(random);
                  } while (input.isEmpty());
                  String out = "";
                  TestUtil.randomSimpleString(random);
                  do {
                    out = TestUtil.randomRealisticUnicodeString(random);
                  } while (out.isEmpty());
                  builder.add(input, out);
                }
                try {
                  return builder.build();
                } catch (Exception ex) {
                  Rethrow.rethrow(ex);
                  return null; // unreachable code
                }
              });
          put(
              SynonymMap.class,
              new Function<Random, Object>() {
                @Override
                public Object apply(Random random) {
                  SynonymMap.Builder b = new SynonymMap.Builder(random.nextBoolean());
                  final int numEntries = atLeast(10);
                  for (int j = 0; j < numEntries; j++) {
                    addSyn(
                        b,
                        randomNonEmptyString(random),
                        randomNonEmptyString(random),
                        random.nextBoolean());
                  }
                  try {
                    return b.build();
                  } catch (Exception ex) {
                    Rethrow.rethrow(ex);
                    return null; // unreachable code
                  }
                }

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

                private String randomNonEmptyString(Random random) {
                  while (true) {
                    final String s = TestUtil.randomUnicodeString(random).trim();
                    if (s.length() != 0 && s.indexOf('\u0000') == -1) {
                      return s;
                    }
                  }
                }
              });
          put(
              DateFormat.class,
              random -> {
                if (random.nextBoolean()) return null;
                return DateFormat.getDateInstance(DateFormat.DEFAULT, randomLocale(random));
              });
          put(
              Automaton.class,
              random -> {
                return Operations.determinize(
                    new RegExp(AutomatonTestUtil.randomRegexp(random), RegExp.NONE).toAutomaton(),
                    Operations.DEFAULT_MAX_DETERMINIZED_STATES);
              });
          put(
              PatternTypingFilter.PatternTypingRule[].class,
              random -> {
                int numRules = TestUtil.nextInt(random, 1, 3);
                PatternTypingFilter.PatternTypingRule[] patternTypingRules =
                    new PatternTypingFilter.PatternTypingRule[numRules];
                for (int i = 0; i < patternTypingRules.length; i++) {
                  String s = TestUtil.randomSimpleString(random, 1, 2);
                  // random regex with one group
                  String regex = s + "(.*)";
                  // pattern rule with a template that accepts one group.
                  patternTypingRules[i] =
                      new PatternTypingFilter.PatternTypingRule(
                          Pattern.compile(regex), TestUtil.nextInt(random, 1, 8), s + "_$1");
                }
                return patternTypingRules;
              });
        }
      };

  static final Set<Class<?>> allowedTokenizerArgs, allowedTokenFilterArgs, allowedCharFilterArgs;

  static {
    allowedTokenizerArgs = Collections.newSetFromMap(new IdentityHashMap<Class<?>, Boolean>());
    allowedTokenizerArgs.addAll(argProducers.keySet());
    allowedTokenizerArgs.add(Reader.class);
    allowedTokenizerArgs.add(AttributeFactory.class);
    allowedTokenizerArgs.add(AttributeSource.class);
    allowedTokenizerArgs.add(Automaton.class);

    allowedTokenFilterArgs = Collections.newSetFromMap(new IdentityHashMap<Class<?>, Boolean>());
    allowedTokenFilterArgs.addAll(argProducers.keySet());
    allowedTokenFilterArgs.add(TokenStream.class);
    // TODO: fix this one, thats broken:
    allowedTokenFilterArgs.add(CommonGramsFilter.class);

    allowedCharFilterArgs = Collections.newSetFromMap(new IdentityHashMap<Class<?>, Boolean>());
    allowedCharFilterArgs.addAll(argProducers.keySet());
    allowedCharFilterArgs.add(Reader.class);
  }

  @SuppressWarnings("unchecked")
  static <T> T newRandomArg(Random random, Class<T> paramType) {
    final Function<Random, Object> producer = argProducers.get(paramType);
    assertNotNull("No producer for arguments of type " + paramType.getName() + " found", producer);
    return (T) producer.apply(random);
  }

  static Object[] newTokenizerArgs(Random random, Class<?>[] paramTypes) {
    Object[] args = new Object[paramTypes.length];
    for (int i = 0; i < args.length; i++) {
      Class<?> paramType = paramTypes[i];
      if (paramType == AttributeSource.class) {
        // TODO: args[i] = new AttributeSource();
        // this is currently too scary to deal with!
        args[i] = null; // force IAE
      } else {
        args[i] = newRandomArg(random, paramType);
      }
    }
    return args;
  }

  static Object[] newCharFilterArgs(Random random, Reader reader, Class<?>[] paramTypes) {
    Object[] args = new Object[paramTypes.length];
    for (int i = 0; i < args.length; i++) {
      Class<?> paramType = paramTypes[i];
      if (paramType == Reader.class) {
        args[i] = reader;
      } else {
        args[i] = newRandomArg(random, paramType);
      }
    }
    return args;
  }

  static Object[] newFilterArgs(Random random, TokenStream stream, Class<?>[] paramTypes) {
    Object[] args = new Object[paramTypes.length];
    for (int i = 0; i < args.length; i++) {
      Class<?> paramType = paramTypes[i];
      if (paramType == TokenStream.class) {
        args[i] = stream;
      } else if (paramType == CommonGramsFilter.class) {
        // TODO: fix this one, thats broken: CommonGramsQueryFilter takes this one explicitly
        args[i] = new CommonGramsFilter(stream, newRandomArg(random, CharArraySet.class));
      } else {
        args[i] = newRandomArg(random, paramType);
      }
    }
    return args;
  }

  static class MockRandomAnalyzer extends Analyzer {
    final long seed;

    MockRandomAnalyzer(long seed) {
      this.seed = seed;
    }

    @Override
    protected TokenStreamComponents createComponents(String fieldName) {
      Random random = new Random(seed);
      TokenizerSpec tokenizerSpec = newTokenizer(random);
      // System.out.println("seed=" + seed + ",create tokenizer=" + tokenizerSpec.toString);
      TokenFilterSpec filterSpec = newFilterChain(random, tokenizerSpec.tokenizer);
      // System.out.println("seed=" + seed + ",create filter=" + filterSpec.toString);
      return new TokenStreamComponents(tokenizerSpec.tokenizer, filterSpec.stream);
    }

    @Override
    protected Reader initReader(String fieldName, Reader reader) {
      Random random = new Random(seed);
      CharFilterSpec charfilterspec = newCharFilterChain(random, reader);
      return charfilterspec.reader;
    }

    @Override
    public String toString() {
      Random random = new Random(seed);
      StringBuilder sb = new StringBuilder();
      CharFilterSpec charFilterSpec = newCharFilterChain(random, new StringReader(""));
      sb.append("\ncharfilters=");
      sb.append(charFilterSpec.toString);
      // intentional: initReader gets its own separate random
      random = new Random(seed);
      TokenizerSpec tokenizerSpec = newTokenizer(random);
      sb.append("\n");
      sb.append("tokenizer=");
      sb.append(tokenizerSpec.toString);
      TokenFilterSpec tokenFilterSpec = newFilterChain(random, tokenizerSpec.tokenizer);
      sb.append("\n");
      sb.append("filters=");
      sb.append(tokenFilterSpec.toString);
      return sb.toString();
    }

    private <T> T createComponent(
        Constructor<T> ctor, Object[] args, StringBuilder descr, boolean isConditional) {
      try {
        final T instance = ctor.newInstance(args);
        /*
        if (descr.length() > 0) {
          descr.append(",");
        }
        */
        descr.append("\n  ");
        if (isConditional) {
          descr.append("Conditional:");
        }
        descr.append(ctor.getDeclaringClass().getName());
        String params = Arrays.deepToString(args);
        params = params.substring(1, params.length() - 1);
        descr.append("(").append(params).append(")");
        return instance;
      } catch (InvocationTargetException ite) {
        final Throwable cause = ite.getCause();
        if (cause instanceof IllegalArgumentException
            || cause instanceof UnsupportedOperationException) {
          // thats ok, ignore
          if (VERBOSE) {
            System.err.println("Ignoring IAE/UOE from ctor:");
            cause.printStackTrace(System.err);
          }
        } else {
          Rethrow.rethrow(cause);
        }
      } catch (IllegalAccessException | InstantiationException iae) {
        Rethrow.rethrow(iae);
      }
      return null; // no success
    }

    private boolean broken(Constructor<?> ctor, Object[] args) {
      final Predicate<Object[]> pred = brokenConstructors.get(ctor);
      return pred != null && pred.test(args);
    }

    // create a new random tokenizer from classpath
    private TokenizerSpec newTokenizer(Random random) {
      TokenizerSpec spec = new TokenizerSpec();
      while (spec.tokenizer == null) {
        final Constructor<? extends Tokenizer> ctor =
            tokenizers.get(random.nextInt(tokenizers.size()));
        final StringBuilder descr = new StringBuilder();
        final Object args[] = newTokenizerArgs(random, ctor.getParameterTypes());
        if (broken(ctor, args)) {
          continue;
        }
        spec.tokenizer = createComponent(ctor, args, descr, false);
        if (spec.tokenizer != null) {
          spec.toString = descr.toString();
        }
      }
      return spec;
    }

    private CharFilterSpec newCharFilterChain(Random random, Reader reader) {
      CharFilterSpec spec = new CharFilterSpec();
      spec.reader = reader;
      StringBuilder descr = new StringBuilder();
      int numFilters = random.nextInt(3);
      for (int i = 0; i < numFilters; i++) {
        while (true) {
          final Constructor<? extends CharFilter> ctor =
              charfilters.get(random.nextInt(charfilters.size()));
          final Object args[] = newCharFilterArgs(random, spec.reader, ctor.getParameterTypes());
          if (broken(ctor, args)) {
            continue;
          }
          reader = createComponent(ctor, args, descr, false);
          if (reader != null) {
            spec.reader = reader;
            break;
          }
        }
      }
      spec.toString = descr.toString();
      return spec;
    }

    private TokenFilterSpec newFilterChain(Random random, Tokenizer tokenizer) {
      TokenFilterSpec spec = new TokenFilterSpec();
      spec.stream = tokenizer;
      StringBuilder descr = new StringBuilder();
      int numFilters = random.nextInt(5);
      for (int i = 0; i < numFilters; i++) {

        // Insert ValidatingTF after each stage so we can
        // catch problems right after the TF that "caused"
        // them:
        spec.stream = new ValidatingTokenFilter(spec.stream, "stage " + i);

        while (true) {
          final Constructor<? extends TokenFilter> ctor =
              tokenfilters.get(random.nextInt(tokenfilters.size()));
          if (random.nextBoolean()
              && avoidConditionals.contains(ctor.getDeclaringClass()) == false) {
            long seed = random.nextLong();
            spec.stream =
                new ConditionalTokenFilter(
                    spec.stream,
                    in -> {
                      final Object args[] = newFilterArgs(random, in, ctor.getParameterTypes());
                      if (broken(ctor, args)) {
                        return in;
                      }
                      TokenStream ts = createComponent(ctor, args, descr, true);
                      if (ts == null) {
                        return in;
                      }
                      return ts;
                    }) {
                  Random random = new Random(seed);

                  @Override
                  public void reset() throws IOException {
                    super.reset();
                    random = new Random(seed);
                  }

                  @Override
                  protected boolean shouldFilter() throws IOException {
                    return random.nextBoolean();
                  }
                };
            break;
          } else {
            final Object args[] = newFilterArgs(random, spec.stream, ctor.getParameterTypes());
            if (broken(ctor, args)) {
              continue;
            }
            final TokenFilter flt = createComponent(ctor, args, descr, false);
            if (flt != null) {
              spec.stream = flt;
              break;
            }
          }
        }
      }

      // Insert ValidatingTF after each stage so we can
      // catch problems right after the TF that "caused"
      // them:
      spec.stream = new ValidatingTokenFilter(spec.stream, "last stage");

      spec.toString = descr.toString();
      return spec;
    }
  }

  static class CheckThatYouDidntReadAnythingReaderWrapper extends CharFilter {
    boolean readSomething;

    CheckThatYouDidntReadAnythingReaderWrapper(Reader in) {
      super(in);
    }

    @Override
    public int correct(int currentOff) {
      return currentOff; // we don't change any offsets
    }

    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
      readSomething = true;
      return input.read(cbuf, off, len);
    }

    @Override
    public int read() throws IOException {
      readSomething = true;
      return input.read();
    }

    @Override
    public int read(CharBuffer target) throws IOException {
      readSomething = true;
      return input.read(target);
    }

    @Override
    public int read(char[] cbuf) throws IOException {
      readSomething = true;
      return input.read(cbuf);
    }

    @Override
    public long skip(long n) throws IOException {
      readSomething = true;
      return input.skip(n);
    }

    @Override
    public void mark(int readAheadLimit) throws IOException {
      input.mark(readAheadLimit);
    }

    @Override
    public boolean markSupported() {
      return input.markSupported();
    }

    @Override
    public boolean ready() throws IOException {
      return input.ready();
    }

    @Override
    public void reset() throws IOException {
      input.reset();
    }
  }

  static class TokenizerSpec {
    Tokenizer tokenizer;
    String toString;
  }

  static class TokenFilterSpec {
    TokenStream stream;
    String toString;
  }

  static class CharFilterSpec {
    Reader reader;
    String toString;
  }

  public void testRandomChains() throws Throwable {
    int numIterations = TEST_NIGHTLY ? atLeast(20) : 3;
    Random random = random();
    for (int i = 0; i < numIterations; i++) {
      try (MockRandomAnalyzer a = new MockRandomAnalyzer(random.nextLong())) {
        if (VERBOSE) {
          System.out.println("Creating random analyzer:" + a);
        }
        try {
          checkNormalize(a);
          checkRandomData(
              random,
              a,
              500 * RANDOM_MULTIPLIER,
              20,
              false,
              false /* We already validate our own offsets... */);
        } catch (Throwable e) {
          System.err.println("Exception from random analyzer: " + a);
          throw e;
        }
      }
    }
  }

  public void checkNormalize(Analyzer a) {
    // normalization should not modify characters that may be used for wildcards
    // or regular expressions
    String s = "([0-9]+)?*";
    assertEquals(s, a.normalize("dummy", s).utf8ToString());
  }

  // we might regret this decision...
  public void testRandomChainsWithLargeStrings() throws Throwable {
    int numIterations = TEST_NIGHTLY ? atLeast(20) : 3;
    Random random = random();
    for (int i = 0; i < numIterations; i++) {
      try (MockRandomAnalyzer a = new MockRandomAnalyzer(random.nextLong())) {
        if (VERBOSE) {
          System.out.println("Creating random analyzer:" + a);
        }
        try {
          checkRandomData(
              random,
              a,
              50 * RANDOM_MULTIPLIER,
              80,
              false,
              false /* We already validate our own offsets... */);
        } catch (Throwable e) {
          System.err.println("Exception from random analyzer: " + a);
          throw e;
        }
      }
    }
  }
}