/*
    * 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.io.FileUtils;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  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.xml.pom.PomUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.net.URL;
  import java.util.List;
  import org.owasp.dependencycheck.utils.DownloadFailedException;
  import org.owasp.dependencycheck.utils.Downloader;
  import org.owasp.dependencycheck.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.InvalidSettingException;
  import org.owasp.dependencycheck.utils.Settings;
  
  /**
   * Analyzer which will attempt to locate a dependency, and the GAV information, by querying Central for the dependency's SHA-1
   * digest.
   *
   * @author colezlaw
   */
  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 analyzer should be disabled if there are errors, so this is a flag to determine if such an error has occurred.
       */
      private boolean errorFlag = false;
  
      /**
       * The searcher itself.
       */
      private CentralSearch searcher;
      /**
       * Field indicating if the analyzer is enabled.
       */
      private final boolean enabled = checkEnabled();
  
      /**
       * Determine whether to enable this analyzer or not.
       *
       * @return whether the analyzer should be enabled
       */
      @Override
      public boolean isEnabled() {
          return enabled;
      }
  
      /**
       * Determines if this analyzer is enabled.
       *
       * @return <code>true</code> if the analyzer is enabled; otherwise <code>false</code>
      */
     private boolean checkEnabled() {
         boolean retval = false;
 
         try {
             if (Settings.getBoolean(Settings.KEYS.ANALYZER_CENTRAL_ENABLED)) {
                 if (!Settings.getBoolean(Settings.KEYS.ANALYZER_NEXUS_ENABLED)
                         || NexusAnalyzer.DEFAULT_URL.equals(Settings.getString(Settings.KEYS.ANALYZER_NEXUS_URL))) {
                     LOGGER.debug("Enabling the Central analyzer");
                     retval = true;
                 } else {
                     LOGGER.info("Nexus analyzer is enabled, disabling the Central Analyzer");
                 }
             } else {
                 LOGGER.info("Central analyzer disabled");
             }
         } catch (InvalidSettingException ise) {
             LOGGER.warn("Invalid setting. Disabling the Central analyzer");
         }
         return retval;
     }
 
     /**
      * Initializes the analyzer once before any analysis is performed.
      *
      * @throws Exception if there's an error during initialization
      */
     @Override
     public void initializeFileTypeAnalyzer() throws Exception {
         LOGGER.debug("Initializing Central analyzer");
         LOGGER.debug("Central analyzer enabled: {}", isEnabled());
         if (isEnabled()) {
             final String searchUrl = Settings.getString(Settings.KEYS.ANALYZER_CENTRAL_URL);
             LOGGER.debug("Central Analyzer URL: {}", searchUrl);
             searcher = new CentralSearch(new URL(searchUrl));
         }
     }
 
     /**
      * 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;
     }
 
     /**
      * The file filter used to determine which files this analyzer supports.
      */
     private static final FileFilter FILTER = FileFilterBuilder.newInstance().addExtensions(SUPPORTED_EXTENSIONS).build();
 
     @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 analyzeFileType(Dependency dependency, Engine engine) throws AnalysisException {
         if (errorFlag || !isEnabled()) {
             return;
         }
 
         try {
             final List<MavenArtifact> mas = searcher.searchSha1(dependency.getSha1sum());
             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);
                 boolean pomAnalyzed = false;
                 for (Evidence e : dependency.getVendorEvidence()) {
                     if ("pom".equals(e.getSource())) {
                         pomAnalyzed = true;
                         break;
                     }
                 }
                 if (!pomAnalyzed && ma.getPomUrl() != null) {
                     File pomFile = null;
                     try {
                         final File baseDir = Settings.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");
                         }
                         LOGGER.debug("Downloading {}", ma.getPomUrl());
                         Downloader.fetchFile(new URL(ma.getPomUrl()), pomFile);
                         PomUtils.analyzePOM(dependency, pomFile);
 
                     } catch (DownloadFailedException ex) {
                         LOGGER.warn("Unable to download pom.xml for {} from Central; "
                                 + "this could result in undetected CPE/CVEs.", dependency.getFileName());
                     } finally {
                         if (pomFile != null && !FileUtils.deleteQuietly(pomFile)) {
                             pomFile.deleteOnExit();
                         }
                     }
                 }
 
             }
         } 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) {
             LOGGER.debug("Could not connect to Central search", ioe);
             errorFlag = true;
         }
     }
 }