///////////////////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
   // Copyright (C) 2001-2025 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;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.io.StringWriter;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.regex.Pattern;
  
  import com.puppycrawl.tools.checkstyle.api.AuditEvent;
  import com.puppycrawl.tools.checkstyle.api.AuditListener;
  import com.puppycrawl.tools.checkstyle.api.AutomaticBean;
  import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
  
  /**
   * Simple SARIF logger.
   * SARIF stands for the static analysis results interchange format.
   * See <a href="https://sarifweb.azurewebsites.net/">reference</a>
   */
  public class SarifLogger extends AbstractAutomaticBean implements AuditListener {
  
      /** The length of unicode placeholder. */
      private static final int UNICODE_LENGTH = 4;
  
      /** Unicode escaping upper limit. */
      private static final int UNICODE_ESCAPE_UPPER_LIMIT = 0x1F;
  
      /** Input stream buffer size. */
      private static final int BUFFER_SIZE = 1024;
  
      /** The placeholder for message. */
      private static final String MESSAGE_PLACEHOLDER = "${message}";
  
      /** The placeholder for severity level. */
      private static final String SEVERITY_LEVEL_PLACEHOLDER = "${severityLevel}";
  
      /** The placeholder for uri. */
      private static final String URI_PLACEHOLDER = "${uri}";
  
      /** The placeholder for line. */
      private static final String LINE_PLACEHOLDER = "${line}";
  
      /** The placeholder for column. */
      private static final String COLUMN_PLACEHOLDER = "${column}";
  
      /** The placeholder for rule id. */
      private static final String RULE_ID_PLACEHOLDER = "${ruleId}";
  
      /** The placeholder for version. */
      private static final String VERSION_PLACEHOLDER = "${version}";
  
      /** The placeholder for results. */
      private static final String RESULTS_PLACEHOLDER = "${results}";
  
      /** Two backslashes to not duplicate strings. */
      private static final String TWO_BACKSLASHES = "\\\\";
  
      /** A pattern for two backslashes. */
      private static final Pattern A_SPACE_PATTERN = Pattern.compile(" ");
  
      /** A pattern for two backslashes. */
      private static final Pattern TWO_BACKSLASHES_PATTERN = Pattern.compile(TWO_BACKSLASHES);
  
      /** A pattern to match a file with a Windows drive letter. */
      private static final Pattern WINDOWS_DRIVE_LETTER_PATTERN =
              Pattern.compile("\\A[A-Z]:", Pattern.CASE_INSENSITIVE);
  
      /** Helper writer that allows easy encoding and printing. */
      private final PrintWriter writer;
  
      /** Close output stream in auditFinished. */
      private final boolean closeStream;
  
      /** The results. */
     private final List<String> results = new ArrayList<>();
 
     /** Content for the entire report. */
     private final String report;
 
     /** Content for result representing an error with source line and column. */
     private final String resultLineColumn;
 
     /** Content for result representing an error with source line only. */
     private final String resultLineOnly;
 
     /** Content for result representing an error with filename only and without source location. */
     private final String resultFileOnly;
 
     /** Content for result representing an error without filename or location. */
     private final String resultErrorOnly;
 
     /**
      * Creates a new {@code SarifLogger} instance.
      *
      * @param outputStream where to log audit events
      * @param outputStreamOptions if {@code CLOSE} that should be closed in auditFinished()
      * @throws IllegalArgumentException if outputStreamOptions is null
      * @throws IOException if there is reading errors.
      * @noinspection deprecation
      * @noinspectionreason We are forced to keep AutomaticBean compatability
      *     because of maven-checkstyle-plugin. Until #12873.
      */
     public SarifLogger(
         OutputStream outputStream,
         AutomaticBean.OutputStreamOptions outputStreamOptions) throws IOException {
         this(outputStream, OutputStreamOptions.valueOf(outputStreamOptions.name()));
     }
 
     /**
      * Creates a new {@code SarifLogger} instance.
      *
      * @param outputStream where to log audit events
      * @param outputStreamOptions if {@code CLOSE} that should be closed in auditFinished()
      * @throws IllegalArgumentException if outputStreamOptions is null
      * @throws IOException if there is reading errors.
      */
     public SarifLogger(
         OutputStream outputStream,
         OutputStreamOptions outputStreamOptions) throws IOException {
         if (outputStreamOptions == null) {
             throw new IllegalArgumentException("Parameter outputStreamOptions can not be null");
         }
         writer = new PrintWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
         closeStream = outputStreamOptions == OutputStreamOptions.CLOSE;
         report = readResource("/com/puppycrawl/tools/checkstyle/sarif/SarifReport.template");
         resultLineColumn =
             readResource("/com/puppycrawl/tools/checkstyle/sarif/ResultLineColumn.template");
         resultLineOnly =
             readResource("/com/puppycrawl/tools/checkstyle/sarif/ResultLineOnly.template");
         resultFileOnly =
             readResource("/com/puppycrawl/tools/checkstyle/sarif/ResultFileOnly.template");
         resultErrorOnly =
             readResource("/com/puppycrawl/tools/checkstyle/sarif/ResultErrorOnly.template");
     }
 
     @Override
     protected void finishLocalSetup() {
         // No code by default
     }
 
     @Override
     public void auditStarted(AuditEvent event) {
         // No code by default
     }
 
     @Override
     public void auditFinished(AuditEvent event) {
         String rendered = replaceVersionString(report);
         rendered = rendered.replace(RESULTS_PLACEHOLDER, String.join(",\n", results));
         writer.print(rendered);
         if (closeStream) {
             writer.close();
         }
         else {
             writer.flush();
         }
     }
 
     /**
      * Returns the version string.
      *
      * @param report report content where replace should happen
      * @return a version string based on the package implementation version
      */
     private static String replaceVersionString(String report) {
         final String version = SarifLogger.class.getPackage().getImplementationVersion();
         return report.replace(VERSION_PLACEHOLDER, String.valueOf(version));
     }
 
     @Override
     public void addError(AuditEvent event) {
         if (event.getColumn() > 0) {
             results.add(resultLineColumn
                 .replace(SEVERITY_LEVEL_PLACEHOLDER, renderSeverityLevel(event.getSeverityLevel()))
                 .replace(URI_PLACEHOLDER, renderFileNameUri(event.getFileName()))
                 .replace(COLUMN_PLACEHOLDER, Integer.toString(event.getColumn()))
                 .replace(LINE_PLACEHOLDER, Integer.toString(event.getLine()))
                 .replace(MESSAGE_PLACEHOLDER, escape(event.getMessage()))
                 .replace(RULE_ID_PLACEHOLDER, event.getViolation().getKey())
             );
         }
         else {
             results.add(resultLineOnly
                 .replace(SEVERITY_LEVEL_PLACEHOLDER, renderSeverityLevel(event.getSeverityLevel()))
                 .replace(URI_PLACEHOLDER, renderFileNameUri(event.getFileName()))
                 .replace(LINE_PLACEHOLDER, Integer.toString(event.getLine()))
                 .replace(MESSAGE_PLACEHOLDER, escape(event.getMessage()))
                 .replace(RULE_ID_PLACEHOLDER, event.getViolation().getKey())
             );
         }
     }
 
     @Override
     public void addException(AuditEvent event, Throwable throwable) {
         final StringWriter stringWriter = new StringWriter();
         final PrintWriter printer = new PrintWriter(stringWriter);
         throwable.printStackTrace(printer);
         if (event.getFileName() == null) {
             results.add(resultErrorOnly
                 .replace(SEVERITY_LEVEL_PLACEHOLDER, renderSeverityLevel(event.getSeverityLevel()))
                 .replace(MESSAGE_PLACEHOLDER, escape(stringWriter.toString()))
             );
         }
         else {
             results.add(resultFileOnly
                 .replace(SEVERITY_LEVEL_PLACEHOLDER, renderSeverityLevel(event.getSeverityLevel()))
                 .replace(URI_PLACEHOLDER, renderFileNameUri(event.getFileName()))
                 .replace(MESSAGE_PLACEHOLDER, escape(stringWriter.toString()))
             );
         }
     }
 
     @Override
     public void fileStarted(AuditEvent event) {
         // No need to implement this method in this class
     }
 
     @Override
     public void fileFinished(AuditEvent event) {
         // No need to implement this method in this class
     }
 
     /**
      * Render the file name URI for the given file name.
      *
      * @param fileName the file name to render the URI for
      * @return the rendered URI for the given file name
      */
     private static String renderFileNameUri(final String fileName) {
         String normalized =
                 A_SPACE_PATTERN
                         .matcher(TWO_BACKSLASHES_PATTERN.matcher(fileName).replaceAll("/"))
                         .replaceAll("%20");
         if (WINDOWS_DRIVE_LETTER_PATTERN.matcher(normalized).find()) {
             normalized = '/' + normalized;
         }
         return "file:" + normalized;
     }
 
     /**
      * Render the severity level into SARIF severity level.
      *
      * @param severityLevel the Severity level.
      * @return the rendered severity level in string.
      */
     private static String renderSeverityLevel(SeverityLevel severityLevel) {
         final String renderedSeverityLevel;
         switch (severityLevel) {
             case IGNORE:
                 renderedSeverityLevel = "none";
                 break;
             case INFO:
                 renderedSeverityLevel = "note";
                 break;
             case WARNING:
                 renderedSeverityLevel = "warning";
                 break;
             case ERROR:
             default:
                 renderedSeverityLevel = "error";
                 break;
         }
         return renderedSeverityLevel;
     }
 
     /**
      * Escape \b, \f, \n, \r, \t, \", \\ and U+0000 through U+001F.
      * See <a href="https://www.ietf.org/rfc/rfc4627.txt">reference</a> - 2.5. Strings
      *
      * @param value the value to escape.
      * @return the escaped value if necessary.
      */
     public static String escape(String value) {
         final int length = value.length();
         final StringBuilder sb = new StringBuilder(length);
         for (int i = 0; i < length; i++) {
             final char chr = value.charAt(i);
             switch (chr) {
                 case '"':
                     sb.append("\\\"");
                     break;
                 case '\\':
                     sb.append(TWO_BACKSLASHES);
                     break;
                 case '\b':
                     sb.append("\\b");
                     break;
                 case '\f':
                     sb.append("\\f");
                     break;
                 case '\n':
                     sb.append("\\n");
                     break;
                 case '\r':
                     sb.append("\\r");
                     break;
                 case '\t':
                     sb.append("\\t");
                     break;
                 case '/':
                     sb.append("\\/");
                     break;
                 default:
                     if (chr <= UNICODE_ESCAPE_UPPER_LIMIT) {
                         sb.append(escapeUnicode1F(chr));
                     }
                     else {
                         sb.append(chr);
                     }
                     break;
             }
         }
         return sb.toString();
     }
 
     /**
      * Escape the character between 0x00 to 0x1F in JSON.
      *
      * @param chr the character to be escaped.
      * @return the escaped string.
      */
     private static String escapeUnicode1F(char chr) {
         final String hexString = Integer.toHexString(chr);
         return "\\u"
                 + "0".repeat(UNICODE_LENGTH - hexString.length())
                 + hexString.toUpperCase(Locale.US);
     }
 
     /**
      * Read string from given resource.
      *
      * @param name name of the desired resource
      * @return the string content from the give resource
      * @throws IOException if there is reading errors
      */
     public static String readResource(String name) throws IOException {
         try (InputStream inputStream = SarifLogger.class.getResourceAsStream(name);
              ByteArrayOutputStream result = new ByteArrayOutputStream()) {
             if (inputStream == null) {
                 throw new IOException("Cannot find the resource " + name);
             }
             final byte[] buffer = new byte[BUFFER_SIZE];
             int length = 0;
             while (length != -1) {
                 result.write(buffer, 0, length);
                 length = inputStream.read(buffer);
             }
             return result.toString(StandardCharsets.UTF_8);
         }
     }
 }