/*
    * 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) 2014 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import org.apache.commons.jcs3.access.exception.CacheException;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.analyzer.exception.UnexpectedAnalysisException;
  import org.owasp.dependencycheck.data.cache.DataCache;
  import org.owasp.dependencycheck.data.cache.DataCacheFactory;
  import org.owasp.dependencycheck.data.central.CentralSearch;
  import org.owasp.dependencycheck.data.nexus.MavenArtifact;
  import org.owasp.dependencycheck.dependency.Confidence;
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.dependency.Evidence;
  import org.owasp.dependencycheck.dependency.EvidenceType;
  import org.owasp.dependencycheck.exception.InitializationException;
  import org.owasp.dependencycheck.utils.DownloadFailedException;
  import org.owasp.dependencycheck.utils.Downloader;
  import org.owasp.dependencycheck.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.FileUtils;
  import org.owasp.dependencycheck.utils.InvalidSettingException;
  import org.owasp.dependencycheck.utils.ResourceNotFoundException;
  import org.owasp.dependencycheck.utils.Settings;
  import org.owasp.dependencycheck.utils.TooManyRequestsException;
  import org.owasp.dependencycheck.xml.pom.Model;
  import org.owasp.dependencycheck.xml.pom.PomUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.annotation.concurrent.ThreadSafe;
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.text.MessageFormat;
  import java.util.List;
  
  /**
   * Analyzer which will attempt to locate a dependency, and the GAV information,
   * by querying Central for the dependency's SHA-1 digest.
   *
   * @author colezlaw
   */
  @ThreadSafe
  public class CentralAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(CentralAnalyzer.class);
  
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "Central Analyzer";
  
      /**
       * The phase in which this analyzer runs.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.INFORMATION_COLLECTION;
  
      /**
       * The types of files on which this will work.
       */
      private static final String SUPPORTED_EXTENSIONS = "jar";
  
      /**
       * The file filter used to determine which files this analyzer supports.
       */
      private static final FileFilter FILTER = FileFilterBuilder.newInstance().addExtensions(SUPPORTED_EXTENSIONS).build();
  
      /**
       * The base wait time between retrying a failed connection to Central.
       */
      private static final int BASE_RETRY_WAIT = 1500;
      /**
       * There may be temporary issues when connecting to MavenCentral. In order
       * to compensate for 99% of the issues, we perform a retry before finally
       * failing the analysis.
       */
      private static int numberOfRetries = 7;
 
     /**
      * The searcher itself.
      */
     private CentralSearch searcher;
     /**
      * A reference to the cache for POM model data collected from Central.
      */
     private DataCache<Model> cache;
 
     /**
      * Initializes the analyzer with the configured settings.
      *
      * @param settings the configured settings to use
      */
     @Override
     public synchronized void initialize(Settings settings) {
         super.initialize(settings);
         setEnabled(checkEnabled());
         numberOfRetries = getSettings().getInt(Settings.KEYS.ANALYZER_CENTRAL_RETRY_COUNT, numberOfRetries);
         if (settings.getBoolean(Settings.KEYS.ANALYZER_CENTRAL_USE_CACHE, true)) {
             try {
                 final DataCacheFactory factory = new DataCacheFactory(settings);
                 cache = factory.getPomCache();
             } catch (CacheException ex) {
                 settings.setBoolean(Settings.KEYS.ANALYZER_CENTRAL_USE_CACHE, false);
                 LOGGER.debug("Error creating cache, disabling caching", ex);
             }
         }
     }
 
     /**
      * Whether the analyzer is configured to support parallel processing.
      *
      * @return true if configured to support parallel processing; otherwise
      * false
      */
     @Override
     public boolean supportsParallelProcessing() {
         return getSettings().getBoolean(Settings.KEYS.ANALYZER_CENTRAL_PARALLEL_ANALYSIS, true);
     }
 
     /**
      * Determines if this analyzer is enabled.
      *
      * @return <code>true</code> if the analyzer is enabled; otherwise
      * <code>false</code>
      */
     private boolean checkEnabled() {
         try {
             return getSettings().getBoolean(Settings.KEYS.ANALYZER_CENTRAL_ENABLED);
         } catch (InvalidSettingException ise) {
             LOGGER.warn("Invalid setting. Disabling the Central analyzer");
         }
         return false;
     }
 
     /**
      * Initializes the analyzer once before any analysis is performed.
      *
      * @param engine a reference to the dependency-check engine
      * @throws InitializationException if there's an error during initialization
      */
     @Override
     public void prepareFileTypeAnalyzer(Engine engine) throws InitializationException {
         LOGGER.debug("Initializing Central analyzer");
         LOGGER.debug("Central analyzer enabled: {}", isEnabled());
         if (isEnabled()) {
             try {
                 searcher = new CentralSearch(getSettings());
             } catch (MalformedURLException ex) {
                 setEnabled(false);
                 throw new InitializationException("The configured URL to Maven Central is malformed", ex);
             }
         }
     }
 
     /**
      * Returns the analyzer's name.
      *
      * @return the name of the analyzer
      */
     @Override
     public String getName() {
         return ANALYZER_NAME;
     }
 
     /**
      * Returns the key used in the properties file to to reference the
      * analyzer's enabled property.
      *
      * @return the analyzer's enabled property setting key.
      */
     @Override
     protected String getAnalyzerEnabledSettingKey() {
         return Settings.KEYS.ANALYZER_CENTRAL_ENABLED;
     }
 
     /**
      * Returns the analysis phase under which the analyzer runs.
      *
      * @return the phase under which the analyzer runs
      */
     @Override
     public AnalysisPhase getAnalysisPhase() {
         return ANALYSIS_PHASE;
     }
 
     @Override
     protected FileFilter getFileFilter() {
         return FILTER;
     }
 
     /**
      * Performs the analysis.
      *
      * @param dependency the dependency to analyze
      * @param engine the engine
      * @throws AnalysisException when there's an exception during analysis
      */
     @Override
     public void analyzeDependency(Dependency dependency, Engine engine) throws AnalysisException {
         for (Evidence e : dependency.getEvidence(EvidenceType.VENDOR)) {
             if ("pom".equals(e.getSource())) {
                 return;
             }
         }
         try {
             final List<MavenArtifact> mas = fetchMavenArtifacts(dependency);
             final Confidence confidence = mas.size() > 1 ? Confidence.HIGH : Confidence.HIGHEST;
             for (MavenArtifact ma : mas) {
                 LOGGER.debug("Central analyzer found artifact ({}) for dependency ({})", ma, dependency.getFileName());
                 dependency.addAsEvidence("central", ma, confidence);
 
                 if (ma.getPomUrl() != null) {
                     File pomFile = null;
                     try {
                         final File baseDir = getSettings().getTempDirectory();
                         pomFile = File.createTempFile("pom", ".xml", baseDir);
                         if (!pomFile.delete()) {
                             LOGGER.warn("Unable to fetch pom.xml for {} from Central; "
                                     + "this could result in undetected CPE/CVEs.", dependency.getFileName());
                             LOGGER.debug("Unable to delete temp file");
                         }
                         final Downloader downloader = new Downloader(getSettings());
                         final int maxAttempts = this.getSettings().getInt(Settings.KEYS.ANALYZER_CENTRAL_RETRY_COUNT, 3);
                         int retryCount = 0;
                         long sleepingTimeBetweenRetriesInMillis = BASE_RETRY_WAIT;
                         boolean success = false;
                         Model model = null;
                         if (cache != null) {
                             model = cache.get(ma.getPomUrl());
                         }
                         if (model != null) {
                             success = true;
                             LOGGER.debug("Cache hit for {}", ma.getPomUrl());
                         } else {
                             LOGGER.debug("Downloading {}", ma.getPomUrl());
                             do {
                                 //CSOFF: NestedTryDepth
                                 try {
                                     downloader.fetchFile(new URL(ma.getPomUrl()), pomFile);
                                     success = true;
                                 } catch (DownloadFailedException ex) {
                                     try {
                                         Thread.sleep(sleepingTimeBetweenRetriesInMillis);
                                     } catch (InterruptedException ex1) {
                                         Thread.currentThread().interrupt();
                                         throw new UnexpectedAnalysisException(ex1);
                                     }
                                     sleepingTimeBetweenRetriesInMillis *= 2;
                                 } catch (ResourceNotFoundException ex) {
                                     LOGGER.debug("pom.xml does not exist in Central for {}", dependency.getFileName());
                                     return;
                                 }
                                 //CSON: NestedTryDepth
                             } while (!success && retryCount++ < maxAttempts);
                         }
                         if (success) {
                             if (model == null) {
                                 model = PomUtils.readPom(pomFile);
                                 if (cache != null) {
                                     cache.put(ma.getPomUrl(), model);
                                 }
                             }
                             final boolean isMainPom = mas.size() == 1 || dependency.getActualFilePath().contains(ma.getVersion());
                             JarAnalyzer.setPomEvidence(dependency, model, null, isMainPom);
                         } else {
                             LOGGER.warn("Unable to download pom.xml for {} from Central; "
                                     + "this could result in undetected CPE/CVEs.", dependency.getFileName());
                         }
 
                     } catch (AnalysisException ex) {
                         LOGGER.warn(MessageFormat.format("Unable to analyze pom.xml for {0} from Central; "
                                 + "this could result in undetected CPE/CVEs.", dependency.getFileName()), ex);
 
                     } finally {
                         if (pomFile != null && pomFile.exists() && !FileUtils.delete(pomFile)) {
                             LOGGER.debug("Failed to delete temporary pom file {}", pomFile);
                             pomFile.deleteOnExit();
                         }
                     }
                 }
             }
         } catch (TooManyRequestsException tre) {
             this.setEnabled(false);
             final String message = "Connections to Central search refused. Analysis failed.";
             LOGGER.error(message, tre);
             throw new AnalysisException(message, tre);
         } catch (IllegalArgumentException iae) {
             LOGGER.info("invalid sha1-hash on {}", dependency.getFileName());
         } catch (FileNotFoundException fnfe) {
             LOGGER.debug("Artifact not found in repository: '{}", dependency.getFileName());
         } catch (IOException ioe) {
             final String message = "Could not connect to Central search. Analysis failed.";
             LOGGER.error(message, ioe);
             throw new AnalysisException(message, ioe);
         }
     }
 
     /**
      * Downloads the corresponding list of MavenArtifacts of the given
      * dependency from MavenCentral.
      * <p>
      * As the connection to MavenCentral is known to be unreliable, we implement
      * a simple retry logic in order to compensate for 99% of the issues.
      *
      * @param dependency the dependency to analyze
      * @return the downloaded list of MavenArtifacts
      * @throws FileNotFoundException if the specified artifact is not found
      * @throws IOException if connecting to MavenCentral finally failed
      * @throws TooManyRequestsException if Central has received too many
      * requests.
      */
     protected List<MavenArtifact> fetchMavenArtifacts(Dependency dependency) throws IOException, TooManyRequestsException {
         IOException lastException = null;
         long sleepingTimeBetweenRetriesInMillis = BASE_RETRY_WAIT;
         int triesLeft = numberOfRetries;
         while (triesLeft-- > 0) {
             try {
                 return searcher.searchSha1(dependency.getSha1sum());
             } catch (FileNotFoundException fnfe) {
                 // retry does not make sense, just throw the exception
                 throw fnfe;
             } catch (IOException ioe) {
                 LOGGER.debug("Could not connect to Central search (tries left: {}): {}",
                         triesLeft, ioe.getMessage());
                 lastException = ioe;
 
                 if (triesLeft > 0) {
                     try {
                         Thread.sleep(sleepingTimeBetweenRetriesInMillis);
                     } catch (InterruptedException e) {
                         Thread.currentThread().interrupt();
                         throw new UnexpectedAnalysisException(e);
                     }
                     sleepingTimeBetweenRetriesInMillis *= 2;
                 }
             }
         }
 
         final String message = "Finally failed connecting to Central search."
                 + " Giving up after " + numberOfRetries + " tries.";
         throw new IOException(message, lastException);
     }
 
     /**
      * Method used by unit tests to setup the analyzer.
      *
      * @param searcher the Central Search object to use.
      */
     protected void setCentralSearch(CentralSearch searcher) {
         this.searcher = searcher;
     }
 }