///////////////////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
   // Copyright (C) 2001-2026 the original author or authors.
   //
   // This library is free software; you can redistribute it and/or
   // modify it under the terms of the GNU Lesser General Public
   // License as published by the Free Software Foundation; either
   // version 2.1 of the License, or (at your option) any later version.
   //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.internal.utils;
  
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import java.io.File;
  import java.io.OutputStream;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Field;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.FutureTask;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Predicate;
  import java.util.function.Supplier;
  import java.util.regex.Pattern;
  import java.util.stream.Stream;
  
  import org.junit.jupiter.api.function.Executable;
  import org.mockito.internal.util.Checks;
  
  import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean;
  import com.puppycrawl.tools.checkstyle.PackageNamesLoader;
  import com.puppycrawl.tools.checkstyle.PackageObjectFactory;
  import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
  import com.puppycrawl.tools.checkstyle.TreeWalkerFilter;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.AuditListener;
  import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TextBlock;
  
  public final class TestUtil {
  
      /**
       * The stack size used in {@link TestUtil#getResultWithLimitedResources}.
       * This value should be as small as possible. Some JVM requires this value to be
       * at least 144k.
       *
       * @see <a href="https://www.baeldung.com/jvm-configure-stack-sizes">
       *      Configuring Stack Sizes in the JVM</a>
       */
      private static final int MINIMAL_STACK_SIZE = 147456;
  
      private TestUtil() {
      }
  
      /**
       * Verifies that utils class has private constructor and invokes it to satisfy code coverage.
       *
       * @param utilClass class to test for c-tor
       * @return true if constructor is expected.
       */
      public static boolean isUtilsClassHasPrivateConstructor(final Class<?> utilClass)
              throws ReflectiveOperationException {
          final Constructor<?> constructor = utilClass.getDeclaredConstructor();
          final boolean result = Modifier.isPrivate(constructor.getModifiers());
          constructor.setAccessible(true);
          constructor.newInstance();
          return result;
      }
  
      /**
       * Retrieves the specified field by its name in the class or its direct super.
       *
       * @param targetClass the class to retrieve the field for
       * @param fieldName the name of the field to retrieve
       * @return the class' field if found
       */
      private static Field getClassDeclaredField(Class<?> targetClass, String fieldName) {
          return Stream.<Class<?>>iterate(targetClass, Objects::nonNull, Class::getSuperclass)
              .flatMap(cls -> Arrays.stream(cls.getDeclaredFields()))
             .filter(field -> fieldName.equals(field.getName()))
             .findFirst()
             .map(field -> {
                 field.setAccessible(true);
                 return field;
             })
             .orElseThrow(() -> {
                 return new IllegalStateException(String.format(Locale.ROOT,
                         "Field '%s' not found in '%s'", fieldName, targetClass.getCanonicalName()));
             });
     }
 
     /**
      * Retrieves the specified method by its name in the class or its direct super.
      *
      * @param targetClass the class to retrieve the method for
      * @param methodName the name of the method to retrieve
      * @param parameters the expected number of parameters
      * @return the class' method
      */
     private static Method getClassDeclaredMethod(Class<?> targetClass,
                                                  String methodName,
                                                  int parameters) {
         final Stream<Method> methods = Stream.<Class<?>>iterate(targetClass, Class::getSuperclass)
                 .flatMap(cls -> Arrays.stream(cls.getDeclaredMethods()))
                 .filter(method -> {
                     return methodName.equals(method.getName());
                 });
 
         final Supplier<String> exceptionMessage = () -> {
             return String.format(Locale.ROOT, "Method '%s' with %d parameters not found in '%s'",
                     methodName, parameters, targetClass.getCanonicalName());
         };
 
         return getMatchingExecutable(methods, parameters, exceptionMessage);
     }
 
     /**
      * Retrieves the specified executable from a class.
      *
      * @param <T> the type of executable to search
      * @param execs The stream of executables to search
      * @param parameters the expected number of parameters
      * @param exceptionMessage the exception message to use if executable is not found
      * @return the matching executable
      */
     private static <T extends java.lang.reflect.Executable> T getMatchingExecutable(
             Stream<T> execs, int parameters, Supplier<String> exceptionMessage) {
         return execs.filter(method -> {
             return parameters == method.getParameterCount();
         })
         .findFirst()
         .map(method -> {
             method.setAccessible(true);
             return method;
         })
         .orElseThrow(() -> {
             return new IllegalStateException(exceptionMessage.get());
         });
     }
 
     /**
      * Checks if stateful field is cleared during {@link AbstractCheck#beginTree} in check.
      *
      * @param check      check object which field is to be verified
      * @param astToVisit ast to pass into check methods
      * @param fieldName  name of the field to be checked
      * @param isClear    function for checking field state
      * @return {@code true} if state of the field is cleared
      */
     public static boolean isStatefulFieldClearedDuringBeginTree(AbstractCheck check,
                                                                 DetailAST astToVisit,
                                                                 String fieldName,
                                                                 Predicate<Object> isClear) {
         check.beginTree(astToVisit);
         check.visitToken(astToVisit);
         check.beginTree(null);
         return isClear.test(getInternalState(check, fieldName, Object.class));
     }
 
     /**
      * Checks if stateful field is cleared during {@link AbstractAutomaticBean}'s finishLocalSetup.
      *
      * @param filter filter object which field is to be verified
      * @param event event to pass into filter methods
      * @param fieldName name of the field to be checked
      * @param isClear function for checking field state
      * @return {@code true} if state of the field is cleared
      * @throws Exception if there was an error.
      */
     public static boolean isStatefulFieldClearedDuringLocalSetup(
             TreeWalkerFilter filter, TreeWalkerAuditEvent event,
             String fieldName, Predicate<Object> isClear) throws Exception {
         filter.accept(event);
         invokeVoidMethod(filter, "finishLocalSetup");
         final Field resultField = getClassDeclaredField(filter.getClass(), fieldName);
         return isClear.test(resultField.get(filter));
     }
 
     /**
      * Returns the default PackageObjectFactory with the default package names.
      *
      * @return the default PackageObjectFactory.
      */
     public static PackageObjectFactory getPackageObjectFactory() throws CheckstyleException {
         final ClassLoader cl = TestUtil.class.getClassLoader();
         final Set<String> packageNames = PackageNamesLoader.getPackageNames(cl);
         return new PackageObjectFactory(packageNames, cl);
     }
 
     /**
      * Finds node of specified type among root children, siblings, siblings children
      * on any deep level.
      *
      * @param root      DetailAST
      * @param predicate predicate
      * @return {@link Optional} of {@link DetailAST} node which matches the predicate.
      */
     public static Optional<DetailAST> findTokenInAstByPredicate(DetailAST root,
                                                                 Predicate<DetailAST> predicate) {
         DetailAST curNode = root;
         while (!predicate.test(curNode)) {
             DetailAST toVisit = curNode.getFirstChild();
             while (curNode != null && toVisit == null) {
                 toVisit = curNode.getNextSibling();
                 if (toVisit == null) {
                     curNode = curNode.getParent();
                 }
             }
 
             if (curNode == toVisit || curNode == root.getParent()) {
                 curNode = null;
                 break;
             }
 
             curNode = toVisit;
         }
         return Optional.ofNullable(curNode);
     }
 
     /**
      * Returns the JDK version as a number that is easy to compare.
      *
      * <p>
      * For JDK "1.8" it will be 8; for JDK "11" it will be 11.
      * </p>
      *
      * @return JDK version as integer
      */
     public static int getJdkVersion() {
         String version = System.getProperty("java.specification.version");
         if (version.startsWith("1.")) {
             version = version.substring(2);
         }
         return Integer.parseInt(version);
     }
 
     /**
      * Adjusts the expected number of flushes for tests that call {@link OutputStream#close} method.
      *
      * <p>
      * After <a href="https://bugs.openjdk.java.net/browse/JDK-8220477">JDK-8220477</a>
      * there is one additional flush from {@code sun.nio.cs.StreamEncoder#implClose}.
      * </p>
      *
      * @param flushCount flush count to adjust
      * @return adjusted flush count
      */
     public static int adjustFlushCountForOutputStreamClose(int flushCount) {
         int result = flushCount;
         if (getJdkVersion() >= 13) {
             ++result;
         }
         return result;
     }
 
     /**
      * Runs a given task with limited stack size and time duration, then
      * returns the result. See AbstractModuleTestSupport#verifyWithLimitedResources
      * for an example of how to use this method when task does not return a result, i.e.
      * the given method's return type is {@code void}.
      *
      * @param callable the task to execute
      * @param <V> return type of task - {@code Void} if task does not return result
      * @return result
      * @throws Exception if getting result fails
      */
     public static <V> V getResultWithLimitedResources(Callable<V> callable) throws Exception {
         final FutureTask<V> futureTask = new FutureTask<>(callable);
         final Thread thread = new Thread(null, futureTask,
                 "LimitedStackSizeThread", MINIMAL_STACK_SIZE);
         thread.start();
         return futureTask.get(10, TimeUnit.SECONDS);
     }
 
     /**
      * Reads the value of a field using reflection. This method will traverse the
      * super class hierarchy until a field with name {@code fieldName} is found.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      */
     public static <T> T getInternalState(Object instance, String fieldName, Class<T> clazz) {
         try {
             final Field field = getClassDeclaredField(instance.getClass(), fieldName);
             return clazz.cast(field.get(instance));
         }
         catch (ReflectiveOperationException exc) {
             final String message = String.format(Locale.ROOT,
                     "Failed to get field '%s' for instance of class '%s'",
                     fieldName, instance.getClass().getSimpleName());
             throw new IllegalStateException(message, exc);
         }
     }
 
     /**
      * Helper method for casting collection type Map.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Map<String, String> getInternalStateMap(Object instance, String fieldName) {
         return getInternalState(instance, fieldName, Map.class);
     }
 
     /**
      * Helper method for casting collection type Map.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Map<Integer, List<TextBlock>> getInternalStateMapIntegerList(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, Map.class);
     }
 
     /**
      * Helper method for casting collection type List.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static List<AuditListener> getInternalStateListAuditListener(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, List.class);
     }
 
     /**
      * Helper method for casting collection type List.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static List<Pattern> getInternalStateListPattern(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, List.class);
     }
 
     /**
      * Helper method for casting collection type List.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static List<Comparable<Object>> getInternalStateListComparable(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, List.class);
     }
 
     /**
      * Helper method for casting to Collection.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Collection<Checks> getInternalStateCollectionChecks(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, Collection.class);
     }
 
     /**
      * Helper method for casting to collection type Set.
      *
      * @param instance the instance to read
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Set<TreeWalkerFilter> getInternalStateSetTreeWalkerFilter(
             Object instance, String fieldName) {
         return getInternalState(instance, fieldName, Set.class);
     }
 
     /**
      * Reads the value of a static field using reflection. This method will traverse the
      * super class hierarchy until a field with name {@code fieldName} is found.
      *
      * @param targetClass the class of the field
      * @param fieldName the name of the field
      * @param clazz the expected type of the field value, used for type-safe casting
      * @throws RuntimeException if the field  can't be read
      */
     public static <T> T getInternalStaticState(Class<?> targetClass, String fieldName,
             Class<T> clazz) {
         try {
             final Field field = getClassDeclaredField(targetClass, fieldName);
             return clazz.cast(field.get(null));
         }
         catch (ReflectiveOperationException exc) {
             final String message = String.format(Locale.ROOT,
                     "Failed to get static field '%s' for class '%s'",
                     fieldName, targetClass);
             throw new IllegalStateException(message, exc);
         }
     }
 
     /**
      * Helper method for casting to collection type Map.
      *
      * @param targetClass the class of the field
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Map<String, String> getInternalStaticStateMap(Class<?> targetClass,
             String fieldName) {
         return getInternalStaticState(targetClass, fieldName, Map.class);
     }
 
     /**
      * Helper method for casting to collection type Map.
      *
      * @param targetClass the class of the field
      * @param fieldName the name of the field
      * @throws RuntimeException if the field  can't be read
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static ThreadLocal<List<Object>> getInternalStaticStateThreadLocal(
             Class<?> targetClass, String fieldName) {
         return getInternalStaticState(targetClass, fieldName, ThreadLocal.class);
     }
 
     /**
      * Writes the value of a field using reflection. This method will traverse the
      * super class hierarchy until a field with name {@code fieldName} is found.
      *
      * @param instance the instance whose field to modify
      * @param fieldName the name of the field
      * @param value the new value of the field
      * @throws RuntimeException if the field  can't be changed
      */
     public static void setInternalState(Object instance, String fieldName, Object value) {
         try {
             final Field field = getClassDeclaredField(instance.getClass(), fieldName);
             field.set(instance, value);
         }
         catch (ReflectiveOperationException exc) {
             final String message = String.format(Locale.ROOT,
                     "Failed to set field '%s' for instance of class '%s'",
                     fieldName, instance.getClass().getSimpleName());
             throw new IllegalStateException(message, exc);
         }
     }
 
     /**
      * Invokes a private method for an instance.
      *
      * @param instance the instance whose method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param resultClazz used for cast of result
      * @param arguments the optional arguments
      * @param <T> the type of the result
      * @return the method's result
      * @throws ReflectiveOperationException if the method invocation failed
      */
     public static <T> T invokeMethod(Object instance, String methodToExecute,
                                      Class<T> resultClazz, Object... arguments)
             throws ReflectiveOperationException {
         final Class<?> ownerClass = instance.getClass();
         final Method method = getClassDeclaredMethod(ownerClass, methodToExecute, arguments.length);
         return resultClazz.cast(method.invoke(instance, arguments));
     }
 
     /**
      * Helper method to invoke private method for an instance with cast to Object.
      *
      * @param instance the instance whose method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param arguments the optional arguments
      * @throws ReflectiveOperationException if the method invocation failed
      */
     public static void invokeVoidMethod(Object instance,
                                         String methodToExecute, Object... arguments)
             throws ReflectiveOperationException {
         invokeMethod(instance, methodToExecute, Object.class, arguments);
     }
 
     /**
      * Helper method to invoke private method for an instance with cast to Set.
      *
      * @param instance the instance whose method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param arguments the optional arguments
      * @return the method's result
      * @throws ReflectiveOperationException if the method invocation failed
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static Set<String> invokeMethodSet(Object instance, String methodToExecute,
                                        Object... arguments) throws ReflectiveOperationException {
         return (Set<String>) invokeMethod(instance, methodToExecute, Set.class, arguments);
     }
 
     /**
      * Invokes a static private method for a class.
      *
      * @param ownerClass the class whose static method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param resultClass used for cast of result
      * @param arguments the optional arguments
      * @param <T> the type of the result
      * @return the method's result
      * @throws ReflectiveOperationException if the method invocation failed
      */
     public static <T> T invokeStaticMethod(Class<?> ownerClass,
             String methodToExecute, Class<T> resultClass, Object... arguments)
             throws ReflectiveOperationException {
         final Method method = getClassDeclaredMethod(ownerClass, methodToExecute, arguments.length);
         return resultClass.cast(method.invoke(null, arguments));
     }
 
     /**
      * Helper method to invoke static private method for an instance with cast to Object.
      *
      * @param ownerClass the class whose static method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param arguments the optional arguments
      * @throws ReflectiveOperationException if the method invocation failed
      */
     public static void invokeVoidStaticMethod(Class<?> ownerClass,
                                               String methodToExecute, Object... arguments)
             throws ReflectiveOperationException {
         invokeStaticMethod(ownerClass, methodToExecute, Object.class, arguments);
     }
 
     /**
      * Helper method to invoke static private method for an instance with cast to List.
      *
      * @param ownerClass the class whose static method to invoke
      * @param methodToExecute the name of the method to invoke
      * @param arguments the optional arguments
      * @return the method's result
      * @throws ReflectiveOperationException if the method invocation failed
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static List<File> invokeStaticMethodList(Class<?> ownerClass,
                                                     String methodToExecute, Object... arguments)
             throws ReflectiveOperationException {
         return (List<File>) invokeStaticMethod(ownerClass, methodToExecute, List.class, arguments);
     }
 
     /**
      * Instantiates an object of the given class with the given arguments,
      * even if the constructor is private.
      *
      * @param targetClass The class to instantiate
      * @param arguments The arguments to pass to the constructor
      * @param <T> the type of the object to instantiate
      * @return  The instantiated object
      * @throws ReflectiveOperationException if the constructor invocation failed
      */
     @SuppressWarnings("unchecked")
     public static <T> T instantiate(Class<T> targetClass, Object... arguments)
             throws ReflectiveOperationException {
 
         final Stream<Constructor<T>> ctors =
                 Arrays.stream(targetClass.getDeclaredConstructors()).map(Constructor.class::cast);
 
         final Supplier<String> exceptionMessage = () -> {
             return String.format(Locale.ROOT, "Constructor with %d parameters not found in '%s'",
                     arguments.length, targetClass.getCanonicalName());
         };
 
         final Constructor<T> constructor =
                 getMatchingExecutable(ctors, arguments.length, exceptionMessage);
         constructor.setAccessible(true);
 
         return constructor.newInstance(arguments);
     }
 
     /**
      * Returns the inner class type by its name.
      *
      * @param declaringClass the class in which the inner class is declared
      * @param name the unqualified name (simple name) of the inner class
      * @return the inner class type
      * @throws ClassNotFoundException if the class not found
      * @noinspection unchecked
      * @noinspectionreason unchecked - unchecked cast is ok on test code
      */
     public static <T> Class<T> getInnerClassType(Class<?> declaringClass, String name)
             throws ClassNotFoundException {
         return (Class<T>) Class.forName(declaringClass.getName() + "$" + name);
     }
 
     /**
      * Executes the provided executable and expects it to throw an exception of the specified type.
      *
      * @param expectedType the class of the expected exception type.
      * @param executable the executable to be executed
      * @param message the message to be used in case of assertion failure.
      * @return the expected exception thrown by the executable.
      */
     public static <T extends Throwable> T getExpectedThrowable(Class<T> expectedType,
                                                                Executable executable,
                                                                String message) {
         return assertThrows(expectedType, executable, message);
     }
 
     /**
      *  Executes the provided executable and expects it to throw an exception of the specified type.
      *
      * @param expectedType the class of the expected exception type.
      * @param executable the executable to be executed
      * @return the expected exception thrown by the executable.
      */
     public static <T extends Throwable> T getExpectedThrowable(Class<T> expectedType,
                                                                Executable executable) {
         return assertThrows(expectedType, executable);
     }
 
 }