/*
    * This file is part of dependency-check-core.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * Copyright (c) 2013 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.StandardCopyOption;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  import java.util.regex.Pattern;
  import javax.annotation.concurrent.ThreadSafe;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.data.update.HostedSuppressionsDataSource;
  import org.owasp.dependencycheck.data.update.exception.UpdateException;
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.exception.InitializationException;
  import org.owasp.dependencycheck.exception.WriteLockException;
  import org.owasp.dependencycheck.utils.WriteLock;
  import org.owasp.dependencycheck.xml.suppression.SuppressionParseException;
  import org.owasp.dependencycheck.xml.suppression.SuppressionParser;
  import org.owasp.dependencycheck.xml.suppression.SuppressionRule;
  import org.owasp.dependencycheck.utils.DownloadFailedException;
  import org.owasp.dependencycheck.utils.Downloader;
  import org.owasp.dependencycheck.utils.FileUtils;
  import org.owasp.dependencycheck.utils.ResourceNotFoundException;
  import org.owasp.dependencycheck.utils.Settings;
  import org.owasp.dependencycheck.utils.TooManyRequestsException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.SAXException;
  
  /**
   * Abstract base suppression analyzer that contains methods for parsing the
   * suppression XML file.
   *
   * @author Jeremy Long
   */
  @ThreadSafe
  public abstract class AbstractSuppressionAnalyzer extends AbstractAnalyzer {
  
      /**
       * The Logger for use throughout the class.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(AbstractSuppressionAnalyzer.class);
      /**
       * The file name of the base suppression XML file.
       */
      private static final String BASE_SUPPRESSION_FILE = "dependencycheck-base-suppression.xml";
      /**
       * The key used to store and retrieve the suppression files.
       */
      public static final String SUPPRESSION_OBJECT_KEY = "suppression.rules";
  
      /**
       * Returns a list of file EXTENSIONS supported by this analyzer.
       *
       * @return a list of file EXTENSIONS supported by this analyzer.
       */
      @SuppressWarnings("SameReturnValue")
      public Set<String> getSupportedExtensions() {
          return null;
      }
  
      /**
       * The prepare method loads the suppression XML file.
       *
       * @param engine a reference the dependency-check engine
       * @throws InitializationException thrown if there is an exception
       */
      @Override
      public synchronized void prepareAnalyzer(Engine engine) throws InitializationException {
          if (engine.hasObject(SUPPRESSION_OBJECT_KEY)) {
              return;
          }
          try {
              loadSuppressionBaseData(engine);
          } catch (SuppressionParseException ex) {
             throw new InitializationException("Error initializing the suppression analyzer: " + ex.getLocalizedMessage(), ex, true);
         }
 
         try {
             loadSuppressionData(engine);
         } catch (SuppressionParseException ex) {
             throw new InitializationException("Warn initializing the suppression analyzer: " + ex.getLocalizedMessage(), ex, false);
         }
     }
 
     @Override
     protected void analyzeDependency(Dependency dependency, Engine engine) throws AnalysisException {
         if (engine == null) {
             return;
         }
         @SuppressWarnings("unchecked")
         final List<SuppressionRule> rules = (List<SuppressionRule>) engine.getObject(SUPPRESSION_OBJECT_KEY);
         if (rules.isEmpty()) {
             return;
         }
         for (SuppressionRule rule : rules) {
             if (filter(rule)) {
                 rule.process(dependency);
             }
         }
     }
 
     /**
      * Determines whether a suppression rule should be retained when filtering a
      * set of suppression rules for a concrete suppression analyzer.
      *
      * @param rule the suppression rule to evaluate
      * @return <code>true</code> if the rule should be retained; otherwise
      * <code>false</code>
      */
     abstract boolean filter(SuppressionRule rule);
 
     /**
      * Loads all the suppression rules files configured in the {@link Settings}.
      *
      * @param engine a reference to the ODC engine.
      * @throws SuppressionParseException thrown if the XML cannot be parsed.
      */
     private void loadSuppressionData(Engine engine) throws SuppressionParseException {
         final List<SuppressionRule> ruleList = new ArrayList<>();
         final SuppressionParser parser = new SuppressionParser();
         final String[] suppressionFilePaths = getSettings().getArray(Settings.KEYS.SUPPRESSION_FILE);
         final List<String> failedLoadingFiles = new ArrayList<>();
         if (suppressionFilePaths != null && suppressionFilePaths.length > 0) {
             // Load all the suppression file paths
             for (final String suppressionFilePath : suppressionFilePaths) {
                 try {
                     ruleList.addAll(loadSuppressionFile(parser, suppressionFilePath));
                 } catch (SuppressionParseException ex) {
                     final String msg = String.format("Failed to load %s, caused by %s. ", suppressionFilePath, ex.getMessage());
                     failedLoadingFiles.add(msg);
                 }
             }
         }
 
         LOGGER.debug("{} suppression rules were loaded.", ruleList.size());
         if (!ruleList.isEmpty()) {
             if (engine.hasObject(SUPPRESSION_OBJECT_KEY)) {
                 @SuppressWarnings("unchecked")
                 final List<SuppressionRule> rules = (List<SuppressionRule>) engine.getObject(SUPPRESSION_OBJECT_KEY);
                 rules.addAll(ruleList);
             } else {
                 engine.putObject(SUPPRESSION_OBJECT_KEY, ruleList);
             }
         }
         if (!failedLoadingFiles.isEmpty()) {
             LOGGER.debug("{} suppression files failed to load.", failedLoadingFiles.size());
             final StringBuilder sb = new StringBuilder();
             failedLoadingFiles.forEach(sb::append);
             throw new SuppressionParseException(sb.toString());
         }
     }
 
     /**
      * Loads all the base suppression rules files.
      *
      * @param engine a reference the dependency-check engine
      * @throws SuppressionParseException thrown if the XML cannot be parsed.
      */
     private void loadSuppressionBaseData(final Engine engine) throws SuppressionParseException {
         final SuppressionParser parser = new SuppressionParser();
         loadPackagedSuppressionBaseData(parser, engine);
         loadHostedSuppressionBaseData(parser, engine);
     }
 
     /**
      * Loads all the base suppression rules packaged with the application.
      *
      * @param parser The suppression parser to use
      * @param engine a reference the dependency-check engine
      * @throws SuppressionParseException thrown if the XML cannot be parsed.
      */
     private void loadPackagedSuppressionBaseData(final SuppressionParser parser, final Engine engine) throws SuppressionParseException {
         final List<SuppressionRule> ruleList;
         try (InputStream in = FileUtils.getResourceAsStream(BASE_SUPPRESSION_FILE)) {
             if (in == null) {
                 throw new SuppressionParseException("Suppression rules `" + BASE_SUPPRESSION_FILE + "` could not be found");
             }
             ruleList = parser.parseSuppressionRules(in);
         } catch (SAXException | IOException ex) {
             throw new SuppressionParseException("Unable to parse the base suppression data file", ex);
         }
         if (!ruleList.isEmpty()) {
             if (engine.hasObject(SUPPRESSION_OBJECT_KEY)) {
                 @SuppressWarnings("unchecked")
                 final List<SuppressionRule> rules = (List<SuppressionRule>) engine.getObject(SUPPRESSION_OBJECT_KEY);
                 rules.addAll(ruleList);
             } else {
                 engine.putObject(SUPPRESSION_OBJECT_KEY, ruleList);
             }
         }
     }
 
     /**
      * Loads all the base suppression rules from the hosted suppression file
      * generated/updated automatically by the FP Suppression GitHub Action for
      * approved FP suppression.<br>
      * Uses local caching as a fall-back in case the hosted location cannot be
      * accessed, ignore any errors in the loading of the hosted suppression file
      * emitting only a warning that some False Positives may emerge that have
      * already been resolved by the dependency-check project.
      *
      * @param engine a reference the dependency-check engine
      * @param parser The suppression parser to use
      */
     private void loadHostedSuppressionBaseData(final SuppressionParser parser, final Engine engine) {
         final File repoFile;
         boolean repoEmpty = false;
         final boolean enabled = getSettings().getBoolean(Settings.KEYS.HOSTED_SUPPRESSIONS_ENABLED, true);
         if (!enabled) {
             return;
         }
         final boolean autoupdate = getSettings().getBoolean(Settings.KEYS.AUTO_UPDATE, true);
         final boolean forceupdate = getSettings().getBoolean(Settings.KEYS.HOSTED_SUPPRESSIONS_FORCEUPDATE, false);
 
         try {
             final String configuredUrl = getSettings().getString(Settings.KEYS.HOSTED_SUPPRESSIONS_URL,
                     HostedSuppressionsDataSource.DEFAULT_SUPPRESSIONS_URL);
             final URL url = new URL(configuredUrl);
             final String fileName = new File(url.getPath()).getName();
             repoFile = new File(getSettings().getDataDirectory(), fileName);
             if (!repoFile.isFile() || repoFile.length() <= 1L) {
                 repoEmpty = true;
                 LOGGER.warn("Hosted Suppressions file is empty or missing - attempting to force the update");
                 getSettings().setBoolean(Settings.KEYS.HOSTED_SUPPRESSIONS_FORCEUPDATE, true);
             }
             if ((!autoupdate && forceupdate) || (autoupdate && repoEmpty)) {
                 if (engine == null) {
                     LOGGER.warn("Engine was null, this should only happen in tests - skipping forced update");
                 } else {
                     repoEmpty = forceUpdateHostedSuppressions(engine, repoFile);
                 }
             }
             if (!repoEmpty) {
                 loadCachedHostedSuppressionsRules(parser, repoFile, engine);
             } else {
                 LOGGER.warn("Empty Hosted Suppression file after update, results may contain false positives "
                         + "already resolved by the DependencyCheck project due to failed download of the hosted suppression file");
             }
         } catch (IOException | InitializationException ex) {
             LOGGER.warn("Unable to load hosted suppressions", ex);
         }
     }
 
     /**
      * Load the hosted suppression file from the web resource
      *
      * @param parser The suppressionParser to use for loading
      * @param repoFile The cached web resource
      * @param engine a reference the dependency-check engine
      *
      * @throws InitializationException When errors occur trying to create a
      * defensive copy of the web resource before loading
      */
     private void loadCachedHostedSuppressionsRules(final SuppressionParser parser, final File repoFile, final Engine engine)
             throws InitializationException {
         // take a defensive copy to avoid a risk of corrupted file by a competing parallel new download.
         final Path defensiveCopy;
         try (WriteLock lock = new WriteLock(getSettings(), true, repoFile.getName() + ".lock")) {
             defensiveCopy = Files.createTempFile("dc-basesuppressions", ".xml");
             LOGGER.debug("copying hosted suppressions file {} to {}", repoFile.toPath(), defensiveCopy);
             Files.copy(repoFile.toPath(), defensiveCopy, StandardCopyOption.REPLACE_EXISTING);
         } catch (WriteLockException | IOException ex) {
             throw new InitializationException("Failed to copy the hosted suppressions file", ex);
         }
 
         try (InputStream in = Files.newInputStream(defensiveCopy)) {
             final List<SuppressionRule> ruleList;
             ruleList = parser.parseSuppressionRules(in);
             if (!ruleList.isEmpty()) {
                 if (engine.hasObject(SUPPRESSION_OBJECT_KEY)) {
                     @SuppressWarnings("unchecked")
                     final List<SuppressionRule> rules = (List<SuppressionRule>) engine.getObject(SUPPRESSION_OBJECT_KEY);
                     rules.addAll(ruleList);
                 } else {
                     engine.putObject(SUPPRESSION_OBJECT_KEY, ruleList);
                 }
             }
         } catch (SAXException | IOException ex) {
             LOGGER.warn("Unable to parse the hosted suppressions data file, results may contain false positives already resolved "
                     + "by the DependencyCheck project", ex);
         }
         try {
             Files.delete(defensiveCopy);
         } catch (IOException ex) {
             LOGGER.warn("Could not delete defensive copy of hosted suppressions file {}", defensiveCopy, ex);
         }
     }
 
     private static boolean forceUpdateHostedSuppressions(final Engine engine, final File repoFile) {
         final HostedSuppressionsDataSource ds = new HostedSuppressionsDataSource();
         boolean repoEmpty = true;
         try {
             ds.update(engine);
             repoEmpty = !repoFile.isFile() || repoFile.length() <= 1L;
         } catch (UpdateException ex) {
             LOGGER.warn("Failed to update the Hosted Suppression file", ex);
         }
         return repoEmpty;
     }
 
     /**
      * Load a single suppression rules file from the path provided using the
      * parser provided.
      *
      * @param parser the parser to use for loading the file
      * @param suppressionFilePath the path to load
      * @return the list of loaded suppression rules
      * @throws SuppressionParseException thrown if the suppression file cannot
      * be loaded and parsed.
      */
     private List<SuppressionRule> loadSuppressionFile(final SuppressionParser parser,
             final String suppressionFilePath) throws SuppressionParseException {
         LOGGER.debug("Loading suppression rules from '{}'", suppressionFilePath);
         final List<SuppressionRule> list = new ArrayList<>();
         File file = null;
         boolean deleteTempFile = false;
         try {
             final Pattern uriRx = Pattern.compile("^(https?|file):.*", Pattern.CASE_INSENSITIVE);
             if (uriRx.matcher(suppressionFilePath).matches()) {
                 deleteTempFile = true;
                 file = getSettings().getTempFile("suppression", "xml");
                 final URL url = new URL(suppressionFilePath);
                 try {
                     Downloader.getInstance().fetchFile(url, file, false, Settings.KEYS.SUPPRESSION_FILE_USER,
                             Settings.KEYS.SUPPRESSION_FILE_PASSWORD);
                 } catch (DownloadFailedException ex) {
                     LOGGER.trace("Failed download suppression file - first attempt", ex);
                     try {
                         Thread.sleep(500);
                         Downloader.getInstance().fetchFile(url, file, true, Settings.KEYS.SUPPRESSION_FILE_USER,
                                 Settings.KEYS.SUPPRESSION_FILE_PASSWORD);
                     } catch (TooManyRequestsException ex1) {
                         throw new SuppressionParseException("Unable to download supression file `" + file
                                 + "`; received 429 - too many requests", ex1);
                     } catch (ResourceNotFoundException ex1) {
                         throw new SuppressionParseException("Unable to download supression file `" + file
                                 + "`; received 404 - resource not found", ex1);
                     } catch (InterruptedException ex1) {
                         Thread.currentThread().interrupt();
                         throw new SuppressionParseException("Unable to download supression file `" + file + "`", ex1);
                     }
                 } catch (TooManyRequestsException ex) {
                     throw new SuppressionParseException("Unable to download supression file `" + file
                             + "`; received 429 - too many requests", ex);
                 } catch (ResourceNotFoundException ex) {
                     throw new SuppressionParseException("Unable to download supression file `" + file + "`; received 404 - resource not found", ex);
                 }
             } else {
                 file = new File(suppressionFilePath);
 
                 if (!file.exists()) {
                     try (InputStream suppressionFromClasspath = FileUtils.getResourceAsStream(suppressionFilePath)) {
                         deleteTempFile = true;
                         file = getSettings().getTempFile("suppression", "xml");
                         try {
                             Files.copy(suppressionFromClasspath, file.toPath());
                         } catch (IOException ex) {
                             throwSuppressionParseException("Unable to locate suppression file in classpath", ex, suppressionFilePath);
                         }
                     }
                 }
             }
             if (file != null) {
                 if (!file.exists()) {
                     final String msg = String.format("Suppression file '%s' does not exist", file.getPath());
                     LOGGER.warn(msg);
                     throw new SuppressionParseException(msg);
                 }
                 try {
                     list.addAll(parser.parseSuppressionRules(file));
                 } catch (SuppressionParseException ex) {
                     LOGGER.warn("Unable to parse suppression xml file '{}'", file.getPath());
                     LOGGER.warn(ex.getMessage());
                     throw ex;
                 }
             }
         } catch (DownloadFailedException ex) {
             throwSuppressionParseException("Unable to fetch the configured suppression file", ex, suppressionFilePath);
         } catch (MalformedURLException ex) {
             throwSuppressionParseException("Configured suppression file has an invalid URL", ex, suppressionFilePath);
         } catch (SuppressionParseException ex) {
             throw ex;
         } catch (IOException ex) {
             throwSuppressionParseException("Unable to read suppression file", ex, suppressionFilePath);
         } finally {
             if (deleteTempFile && file != null) {
                 FileUtils.delete(file);
             }
         }
         return list;
     }
 
     /**
      * Utility method to throw parse exceptions.
      *
      * @param message the exception message
      * @param exception the cause of the exception
      * @param suppressionFilePath the path file
      * @throws SuppressionParseException throws the generated
      * SuppressionParseException
      */
     private void throwSuppressionParseException(String message, Exception exception, String suppressionFilePath) throws SuppressionParseException {
         LOGGER.warn(String.format(message + " '%s'", suppressionFilePath));
         LOGGER.debug("", exception);
         throw new SuppressionParseException(message, exception);
     }
 
     /**
      * Returns the number of suppression rules currently loaded in the engine.
      *
      * @param engine a reference to the ODC engine
      * @return the count of rules loaded
      */
     public static int getRuleCount(Engine engine) {
         if (engine.hasObject(SUPPRESSION_OBJECT_KEY)) {
             @SuppressWarnings("unchecked")
             final List<SuppressionRule> rules = (List<SuppressionRule>) engine.getObject(SUPPRESSION_OBJECT_KEY);
             return rules.size();
         }
         return 0;
     }
 }