/*
    * 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;
  
  /**
   * Checks that every {@code @checkstyle} suppression names an enabled check.
   *
   * <p>A comment like {@code @checkstyle LineLength (N lines)} tells the
   * suppression filters to ignore violations of {@code LineLength} nearby.
   * When the name belongs to no enabled check, because it is misspelled or
   * because the check has left {@code checks.xml} since, the comment
   * suppresses nothing and stays in the source as a lie about the code.
   * PMD reports the same mistake in {@code @SuppressWarnings} annotations.
   * The other half, a suppression that names an enabled check but covers no
   * violation of it, is reported by {@link UnusedSuppressions}.</p>
   *
   * @since 1.0
   */
  public final class UnknownSuppressionCheck extends AbstractCheck {
  
      /**
       * The forms of suppression that the filters of {@code checks.xml} honor.
       */
      private static final Pattern TAG = Pattern.compile(
          "@checkstyle (\\w+) (?:\\(\\d+ lines?\\)|disable|enable)"
      );
  
      /**
       * Checks that {@code checks.xml} enables.
       */
      private final ConfiguredChecks checks;
  
      /**
       * Default constructor.
       */
      public UnknownSuppressionCheck() {
          this.checks = new ConfiguredChecks();
      }
  
      @Override
      public boolean isCommentNodesRequired() {
          return true;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return new int[]{TokenTypes.COMMENT_CONTENT};
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return this.getDefaultTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return this.getDefaultTokens();
      }
  
      @Override
      public void visitToken(final DetailAST ast) {
          final String text = ast.getText();
          final Matcher matcher = UnknownSuppressionCheck.TAG.matcher(text);
          while (matcher.find()) {
              final String name = matcher.group(1);
              if (!this.checks.covers(name)) {
                  this.log(
                      ast.getLineNo()
                          + UnknownSuppressionCheck.breaks(text, matcher.start()),
                      String.format(
                          "Check \"%s\" is not enabled, this suppression has no effect",
                          name
                      )
                  );
              }
          }
      }
  
      private static int breaks(final String text, final int position) {
          int count = 0;
          for (int idx = 0; idx < position; ++idx) {
              if (text.charAt(idx) == '\n') {
                  ++count;
              }
          }
          return count;
      }
  }