/*
    * SPDX-FileCopyrightText: Copyright (c) 2011-2026 Yegor Bugayenko
    * SPDX-License-Identifier: MIT
    */
   package com.qulice.checkstyle;
   
   import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
   import com.puppycrawl.tools.checkstyle.api.DetailAST;
   import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * C++ style inline comment is not allowed.
   * Use //-style comment instead.
   * @since 0.18
   */
  public final class SingleLineCommentCheck extends AbstractCheck {
  
      /**
       * Pattern that matches an empty string only.
       */
      private static final Pattern EMPTY = Pattern.compile("^$");
  
      /**
       * Pattern for check.
       * It is not final as it is initialized from the configuration.
       */
      private Pattern format;
  
      /**
       * The message to report for a match.
       * It is not final as it is initialized from the configuration.
       */
      private String message;
  
      /**
       * Comment line.
       * It is not final because the visitToken method is called many times
       * during the class under test and the field is reinitialized with a new object.
       */
      @SuppressWarnings("PMD.AvoidStringBufferField")
      private final StringBuilder line;
  
      /**
       * When inside a block comment, holds begin line number.
       */
      private int begin;
  
      /**
       * Default constructor.
       */
      public SingleLineCommentCheck() {
          this.format = SingleLineCommentCheck.EMPTY;
          this.message = "";
          this.line = new StringBuilder();
      }
  
      @Override
      public boolean isCommentNodesRequired() {
          return true;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return new int[]{
              TokenTypes.BLOCK_COMMENT_BEGIN,
              TokenTypes.COMMENT_CONTENT,
              TokenTypes.BLOCK_COMMENT_END,
          };
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return this.getDefaultTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return this.getDefaultTokens();
      }
  
      @Override
      public void visitToken(final DetailAST ast) {
          if (ast.getType() == TokenTypes.BLOCK_COMMENT_BEGIN) {
              this.line.setLength(0);
              this.line.append(ast.getText());
              this.begin = ast.getLineNo();
          } else if (ast.getType() == TokenTypes.COMMENT_CONTENT) {
              this.line.append(ast.getText());
          } else {
              this.line.append(ast.getText());
              final Matcher matcher = this.format.matcher(this.line.toString());
              if (matcher.matches() && this.singleLineCStyleComment(ast)) {
                  this.log(ast, this.message);
              }
          }
      }
  
     /**
      * The method is called from checkstyle to configure this class.
      * The parameter is set from the checks.xml file
      * {@code <module name="com.qulice.checkstyle.SingleLineCommentCheck"/>} and
      * {@code <property name="format" value=" this regexp "/>} property
      * @param fmt Validatig regexp
      */
     public void setFormat(final String fmt) {
         this.format = Pattern.compile(fmt);
     }
 
     /**
      * The method is called from checkstyle to configure this class.
      * The parameter is set from the checks.xml file
      * {@code <module name="com.qulice.checkstyle.SingleLineCommentCheck"/>} and
      * {@code <property name="message" value="This comment is not allowed."/>}
      * property
      * @param msg Error message
      */
     public void setMessage(final String msg) {
         this.message = msg;
     }
 
     /**
      * Checks for the end of a comment line.
      * @param ast Checkstyle's AST nodes
      * @return True if this is the end of the comment
      *  and the starting line number is equal to the ending line number
      */
     private boolean singleLineCStyleComment(final DetailAST ast) {
         return ast.getType() == TokenTypes.BLOCK_COMMENT_END && this.begin == ast.getLineNo();
     }
 }