////////////////////////////////////////////////////////////////////////////////
   // 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.checks;
  
  import java.io.File;
  import java.util.regex.Pattern;
  
  import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  
  /**
   * Checks that the outer type name and the file name match.
   */
  @FileStatefulCheck
  public class OuterTypeFilenameCheck extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "type.file.mismatch";
  
      /** Pattern matching any file extension with dot included. */
      private static final Pattern FILE_EXTENSION_PATTERN = Pattern.compile("\\.[^.]*$");
  
      /** Indicates whether the first token has been seen in the file. */
      private boolean seenFirstToken;
  
      /** Current file name. */
      private String fileName;
  
      /** If file has public type. */
      private boolean hasPublic;
  
      /** Outer type with mismatched file name. */
      private DetailAST wrongType;
  
      @Override
      public int[] getDefaultTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return new int[] {
              TokenTypes.CLASS_DEF,
              TokenTypes.INTERFACE_DEF,
              TokenTypes.ENUM_DEF,
              TokenTypes.ANNOTATION_DEF,
          };
      }
  
      @Override
      public void beginTree(DetailAST rootAST) {
          fileName = getFileName();
          seenFirstToken = false;
          hasPublic = false;
          wrongType = null;
      }
  
      @Override
      public void visitToken(DetailAST ast) {
          if (seenFirstToken) {
              final DetailAST modifiers = ast.findFirstToken(TokenTypes.MODIFIERS);
              if (modifiers.findFirstToken(TokenTypes.LITERAL_PUBLIC) != null
                      && ast.getParent() == null) {
                  hasPublic = true;
              }
          }
          else {
              final String outerTypeName = ast.findFirstToken(TokenTypes.IDENT).getText();
  
              if (!fileName.equals(outerTypeName)) {
                  wrongType = ast;
              }
         }
         seenFirstToken = true;
     }
 
     @Override
     public void finishTree(DetailAST rootAST) {
         if (!hasPublic && wrongType != null) {
             log(wrongType.getLineNo(), MSG_KEY);
         }
     }
 
     /**
      * Get source file name.
      * @return source file name.
      */
     private String getFileName() {
         String name = getFileContents().getFileName();
         name = name.substring(name.lastIndexOf(File.separatorChar) + 1);
         name = FILE_EXTENSION_PATTERN.matcher(name).replaceAll("");
         return name;
     }
 
 }