////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code for adherence to a set of rules.
   // Copyright (C) 2001-2019 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 java.io.File;
  import java.io.IOException;
  import java.lang.reflect.Field;
  import java.text.MessageFormat;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Locale;
  import java.util.Properties;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  import com.google.common.reflect.ClassPath;
  import com.puppycrawl.tools.checkstyle.checks.regexp.RegexpMultilineCheck;
  import com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineCheck;
  import com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineJavaCheck;
  import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
  import com.puppycrawl.tools.checkstyle.utils.ModuleReflectionUtil;
  import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
  
  public final class CheckUtil {
  
      private CheckUtil() {
      }
  
      public static Set<String> getConfigCheckStyleModules() {
          return getCheckStyleModulesReferencedInConfig("config/checkstyle_checks.xml");
      }
  
      public static Set<String> getConfigSunStyleModules() {
          return getCheckStyleModulesReferencedInConfig("src/main/resources/sun_checks.xml");
      }
  
      public static Set<String> getConfigGoogleStyleModules() {
          return getCheckStyleModulesReferencedInConfig("src/main/resources/google_checks.xml");
      }
  
      /**
       * Retrieves a list of class names, removing 'Check' from the end if the class is
       * a checkstyle check.
       * @param checks class instances.
       * @return a set of simple names.
       */
      public static Set<String> getSimpleNames(Set<Class<?>> checks) {
          return checks.stream().map(check -> {
              String name = check.getSimpleName();
  
              if (name.endsWith("Check")) {
                  name = name.substring(0, name.length() - 5);
              }
  
              return name;
          }).collect(Collectors.toSet());
      }
  
      /**
       * Gets a set of names of checkstyle's checks which are referenced in checkstyle_checks.xml.
       *
       * @param configFilePath
       *            file path of checkstyle_checks.xml.
       * @return names of checkstyle's checks which are referenced in checkstyle_checks.xml.
       */
      private static Set<String> getCheckStyleModulesReferencedInConfig(String configFilePath) {
          try {
              final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  
              // Validations of XML file make parsing too slow, that is why we
              // disable all validations.
              factory.setNamespaceAware(false);
              factory.setValidating(false);
              factory.setFeature("http://xml.org/sax/features/namespaces", false);
             factory.setFeature("http://xml.org/sax/features/validation", false);
             factory.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar",
                     false);
             factory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd",
                     false);
 
             final DocumentBuilder builder = factory.newDocumentBuilder();
             final Document document = builder.parse(new File(configFilePath));
 
             // optional, but recommended
             // FYI:
             // http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-
             // how-does-it-work
             document.getDocumentElement().normalize();
 
             final NodeList nodeList = document.getElementsByTagName("module");
 
             final Set<String> checksReferencedInCheckstyleChecksXml = new HashSet<>();
             for (int i = 0; i < nodeList.getLength(); i++) {
                 final Node currentNode = nodeList.item(i);
                 if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
                     final Element module = (Element) currentNode;
                     final String checkName = module.getAttribute("name");
                     checksReferencedInCheckstyleChecksXml.add(checkName);
                 }
             }
             return checksReferencedInCheckstyleChecksXml;
         }
         catch (Exception exception) {
             throw new IllegalStateException(exception);
         }
     }
 
     /**
      * Gets all checkstyle's non-abstract checks.
      * @return the set of checkstyle's non-abstract check classes.
      * @throws IOException if the attempt to read class path resources failed.
      */
     public static Set<Class<?>> getCheckstyleChecks() throws IOException {
         final ClassLoader loader = Thread.currentThread()
                 .getContextClassLoader();
         final String packageName = "com.puppycrawl.tools.checkstyle";
         return getCheckstyleModulesRecursive(packageName, loader).stream()
                 .filter(ModuleReflectionUtil::isCheckstyleTreeWalkerCheck)
                 .collect(Collectors.toSet());
     }
 
     /**
      * Gets all checkstyle's modules.
      * @return the set of checkstyle's module classes.
      * @throws IOException if the attempt to read class path resources failed.
      */
     public static Set<Class<?>> getCheckstyleModules() throws IOException {
         final ClassLoader loader = Thread.currentThread()
                 .getContextClassLoader();
         final String packageName = "com.puppycrawl.tools.checkstyle";
         return getCheckstyleModulesRecursive(packageName, loader);
     }
 
     /**
      * Gets checkstyle's modules in the given package recursively.
      * @param packageName the package name to use
      * @param loader the class loader used to load Checkstyle package name
      * @return the set of checkstyle's module classes
      * @throws IOException if the attempt to read class path resources failed
      * @see ModuleReflectionUtil#isCheckstyleModule(Class)
      */
     private static Set<Class<?>> getCheckstyleModulesRecursive(
             String packageName, ClassLoader loader) throws IOException {
         final ClassPath classPath = ClassPath.from(loader);
         return classPath.getTopLevelClassesRecursive(packageName).stream()
                 .map(ClassPath.ClassInfo::load)
                 .filter(ModuleReflectionUtil::isCheckstyleModule)
                 .filter(cls -> !cls.getCanonicalName()
                         .startsWith("com.puppycrawl.tools.checkstyle.internal.testmodules"))
                 .filter(cls -> !cls.getCanonicalName()
                         .startsWith("com.puppycrawl.tools.checkstyle.packageobjectfactory"))
                 .collect(Collectors.toSet());
     }
 
     /**
      * Get's the check's messages.
      * @param module class to examine.
      * @return a set of checkstyle's module message fields.
      * @throws ClassNotFoundException if the attempt to read a protected class fails.
      */
     public static Set<Field> getCheckMessages(Class<?> module) throws ClassNotFoundException {
         final Set<Field> checkstyleMessages = new HashSet<>();
 
         // get all fields from current class
         final Field[] fields = module.getDeclaredFields();
 
         for (Field field : fields) {
             if (field.getName().startsWith("MSG_")) {
                 checkstyleMessages.add(field);
             }
         }
 
         // deep scan class through hierarchy
         final Class<?> superModule = module.getSuperclass();
 
         if (superModule != null) {
             checkstyleMessages.addAll(getCheckMessages(superModule));
         }
 
         // special cases that require additional classes
         if (module == RegexpMultilineCheck.class) {
             checkstyleMessages.addAll(getCheckMessages(Class
                     .forName("com.puppycrawl.tools.checkstyle.checks.regexp.MultilineDetector")));
         }
         else if (module == RegexpSinglelineCheck.class
                 || module == RegexpSinglelineJavaCheck.class) {
             checkstyleMessages.addAll(getCheckMessages(Class
                     .forName("com.puppycrawl.tools.checkstyle.checks.regexp.SinglelineDetector")));
         }
 
         return checkstyleMessages;
     }
 
     /**
      * Gets the check message 'as is' from appropriate 'messages.properties'
      * file.
      *
      * @param module The package the message is located in.
      * @param locale the locale to get the message for.
      * @param messageKey the key of message in 'messages*.properties' file.
      * @param arguments the arguments of message in 'messages*.properties' file.
      * @return the check's formatted message.
      */
     public static String getCheckMessage(Class<?> module, Locale locale, String messageKey,
             Object... arguments) {
         String checkMessage;
         try {
             final Properties pr = new Properties();
             if (locale == Locale.ENGLISH) {
                 pr.load(module.getResourceAsStream("messages.properties"));
             }
             else {
                 pr.load(module
                         .getResourceAsStream("messages_" + locale.getLanguage() + ".properties"));
             }
             final MessageFormat formatter = new MessageFormat(pr.getProperty(messageKey), locale);
             checkMessage = formatter.format(arguments);
         }
         catch (IOException ignored) {
             checkMessage = null;
         }
         return checkMessage;
     }
 
     public static String getTokenText(int[] tokens, int... subtractions) {
         final String tokenText;
         if (subtractions.length == 0 && Arrays.equals(tokens, TokenUtil.getAllTokenIds())) {
             tokenText = "TokenTypes.";
         }
         else {
             final StringBuilder result = new StringBuilder(50);
             boolean first = true;
 
             for (int token : tokens) {
                 boolean found = false;
 
                 for (int subtraction : subtractions) {
                     if (subtraction == token) {
                         found = true;
                         break;
                     }
                 }
 
                 if (found) {
                     continue;
                 }
 
                 if (first) {
                     first = false;
                 }
                 else {
                     result.append(", ");
                 }
 
                 result.append(TokenUtil.getTokenName(token));
             }
 
             if (result.length() == 0) {
                 result.append("empty");
             }
             else {
                 result.append('.');
             }
 
             tokenText = result.toString();
         }
         return tokenText;
     }
 
     public static Set<String> getTokenNameSet(int... tokens) {
         final Set<String> result = new HashSet<>();
 
         for (int token : tokens) {
             result.add(TokenUtil.getTokenName(token));
         }
 
         return result;
     }
 
     public static String getJavadocTokenText(int[] tokens, int... subtractions) {
         final StringBuilder result = new StringBuilder(50);
         boolean first = true;
 
         for (int token : tokens) {
             boolean found = false;
 
             for (int subtraction : subtractions) {
                 if (subtraction == token) {
                     found = true;
                     break;
                 }
             }
 
             if (found) {
                 continue;
             }
 
             if (first) {
                 first = false;
             }
             else {
                 result.append(", ");
             }
 
             result.append(JavadocUtil.getTokenName(token));
         }
 
         if (result.length() == 0) {
             result.append("empty");
         }
         else {
             result.append('.');
         }
 
         return result.toString();
     }
 
 }