/*
    * 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) 2019 Jason Dillon. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import io.github.jeremylong.openvulnerability.client.nvd.CvssV2;
  import io.github.jeremylong.openvulnerability.client.nvd.CvssV2Data;
  import org.sonatype.ossindex.service.api.componentreport.ComponentReport;
  import org.sonatype.ossindex.service.api.componentreport.ComponentReportVulnerability;
  import org.sonatype.ossindex.service.api.cvss.Cvss2Severity;
  import org.sonatype.ossindex.service.api.cvss.Cvss2Vector;
  import org.sonatype.ossindex.service.api.cvss.CvssVector;
  import org.sonatype.ossindex.service.api.cvss.CvssVectorFactory;
  import org.sonatype.ossindex.service.client.OssindexClient;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.data.ossindex.OssindexClientFactory;
  
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.dependency.Vulnerability;
  import org.owasp.dependencycheck.dependency.VulnerableSoftware;
  import org.owasp.dependencycheck.dependency.VulnerableSoftwareBuilder;
  import org.owasp.dependencycheck.dependency.naming.Identifier;
  import org.owasp.dependencycheck.dependency.naming.PurlIdentifier;
  import org.owasp.dependencycheck.utils.Settings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import us.springett.parsers.cpe.exceptions.CpeValidationException;
  import us.springett.parsers.cpe.values.Part;
  
  import org.sonatype.goodies.packageurl.PackageUrl;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import java.net.SocketTimeoutException;
  
  import javax.annotation.Nullable;
  import org.apache.commons.lang3.StringUtils;
  import org.owasp.dependencycheck.utils.CvssUtil;
  import org.sonatype.goodies.packageurl.InvalidException;
  import org.sonatype.ossindex.service.client.transport.Transport.TransportException;
  
  /**
   * Enrich dependency information from Sonatype OSS index.
   *
   * @author Jason Dillon
   * @since 5.0.0
   */
  public class OssIndexAnalyzer extends AbstractAnalyzer {
  
      /**
       * A reference to the logger.
       */
      private static final Logger LOG = LoggerFactory.getLogger(OssIndexAnalyzer.class);
  
      /**
       * A pattern to match CVE identifiers.
       */
      private static final Pattern CVE_PATTERN = Pattern.compile("\\bCVE-\\d{4}-\\d{4,10}\\b");
  
      /**
       * The reference type.
       */
      public static final String REFERENCE_TYPE = "OSSINDEX";
  
      /**
       * Fetched reports.
       */
      private static Map<PackageUrl, ComponentReport> reports;
  
      /**
       * Lock to protect fetching state.
       */
      private static final Object FETCH_MUTIX = new Object();
  
      @Override
      public String getName() {
          return "Sonatype OSS Index Analyzer";
     }
 
     @Override
     public AnalysisPhase getAnalysisPhase() {
         return AnalysisPhase.FINDING_ANALYSIS_PHASE2;
     }
 
     @Override
     protected String getAnalyzerEnabledSettingKey() {
         return Settings.KEYS.ANALYZER_OSSINDEX_ENABLED;
     }
 
     /**
      * Run without parallel support.
      *
      * @return false
      */
     @Override
     public boolean supportsParallelProcessing() {
         return true;
     }
 
     @Override
     protected void closeAnalyzer() throws Exception {
         synchronized (FETCH_MUTIX) {
             reports = null;
         }
     }
 
     @Override
     protected void analyzeDependency(final Dependency dependency, final Engine engine) throws AnalysisException {
         // batch request component-reports for all dependencies
         synchronized (FETCH_MUTIX) {
             if (reports == null) {
                 try {
                     requestDelay();
                     reports = requestReports(engine.getDependencies());
                 } catch (TransportException ex) {
                     final String message = ex.getMessage();
                     final boolean warnOnly = getSettings().getBoolean(Settings.KEYS.ANALYZER_OSSINDEX_WARN_ONLY_ON_REMOTE_ERRORS, false);
                     this.setEnabled(false);
                     if (StringUtils.endsWith(message, "401")) {
                         LOG.error("Invalid credentials for the OSS Index, disabling the analyzer");
                         throw new AnalysisException("Invalid credentials provided for OSS Index", ex);
                     } else if (StringUtils.endsWith(message, "403")) {
                         LOG.error("OSS Index access forbidden, disabling the analyzer");
                         throw new AnalysisException("OSS Index access forbidden", ex);
                     } else if (StringUtils.endsWith(message, "429")) {
                         if (warnOnly) {
                             LOG.warn("OSS Index rate limit exceeded, disabling the analyzer", ex);
                         } else {
                             throw new AnalysisException("OSS Index rate limit exceeded, disabling the analyzer", ex);
                         }
                     } else if (warnOnly) {
                         LOG.warn("Error requesting component reports, disabling the analyzer", ex);
                     } else {
                         LOG.debug("Error requesting component reports, disabling the analyzer", ex);
                         throw new AnalysisException("Failed to request component-reports", ex);
                     }
                 } catch (SocketTimeoutException e) {
                     final boolean warnOnly = getSettings().getBoolean(Settings.KEYS.ANALYZER_OSSINDEX_WARN_ONLY_ON_REMOTE_ERRORS, false);
                     this.setEnabled(false);
                     if (warnOnly) {
                         LOG.warn("OSS Index socket timeout, disabling the analyzer", e);
                     } else {
                         LOG.debug("OSS Index socket timeout", e);
                         throw new AnalysisException("Failed to establish socket to OSS Index", e);
                     }
                 } catch (Exception e) {
                     LOG.debug("Error requesting component reports", e);
                     throw new AnalysisException("Failed to request component-reports", e);
                 }
             }
 
             // skip enrichment if we failed to fetch reports
             if (reports != null) {
                 enrich(dependency);
             }
         }
 
     }
 
     /**
      * Delays each request (thread) by the configured amount of seconds, if the
      * configuration is present.
      */
     private void requestDelay() throws InterruptedException {
         final int delay = getSettings().getInt(Settings.KEYS.ANALYZER_OSSINDEX_REQUEST_DELAY, 0);
         if (delay > 0) {
             LOG.debug("Request delay: " + delay);
             TimeUnit.SECONDS.sleep(delay);
         }
     }
 
     /**
      * Helper to complain if unable to parse Package-URL.
      *
      * @param value the url to parse
      * @return the package url
      */
     @Nullable
     private PackageUrl parsePackageUrl(final String value) {
         try {
             return PackageUrl.parse(value);
         } catch (InvalidException e) {
             LOG.debug("Invalid Package-URL: {}", value, e);
             return null;
         }
     }
 
     /**
      * Batch request component-reports for all dependencies.
      *
      * @param dependencies the collection of dependencies
      * @return the map of dependency to OSS Index's component-report
      * @throws Exception thrown if there is an exception requesting the report
      */
     private Map<PackageUrl, ComponentReport> requestReports(final Dependency[] dependencies) throws Exception {
         LOG.debug("Requesting component-reports for {} dependencies", dependencies.length);
         // create requests for each dependency which has a PURL identifier
         final List<PackageUrl> packages = new ArrayList<>();
         Arrays.stream(dependencies).forEach(dependency -> dependency.getSoftwareIdentifiers().stream()
                 .filter(id -> id instanceof PurlIdentifier)
                 .map(id -> parsePackageUrl(id.getValue()))
                 .filter(id -> id != null && StringUtils.isNotBlank(id.getVersion()))
                 .forEach(packages::add));
         // only attempt if we have been able to collect some packages
         if (!packages.isEmpty()) {
             try (OssindexClient client = newOssIndexClient()) {
                 LOG.debug("OSS Index Analyzer submitting: " + packages);
                 return client.requestComponentReports(packages);
             }
         }
         LOG.warn("Unable to determine Package-URL identifiers for {} dependencies", dependencies.length);
         return Collections.emptyMap();
     }
 
     OssindexClient newOssIndexClient() {
         return OssindexClientFactory.create(getSettings());
     }
 
     /**
      * Attempt to enrich given dependency with vulnerability details from OSS
      * Index component-report.
      *
      * @param dependency the dependency to enrich
      */
     void enrich(final Dependency dependency) {
         LOG.debug("Enrich dependency: {}", dependency);
 
         for (Identifier id : dependency.getSoftwareIdentifiers()) {
             if (id instanceof PurlIdentifier) {
                 LOG.debug("  Package: {} -> {}", id, id.getConfidence());
 
                 final PackageUrl purl = parsePackageUrl(id.getValue());
                 if (purl != null && StringUtils.isNotBlank(purl.getVersion())) {
                     try {
                         final ComponentReport report = reports.get(purl);
                         if (report == null) {
                             LOG.debug("Missing component-report for: " + purl);
                             continue;
                         }
 
                         // expose the URL to the package details for report generation
                         id.setUrl(report.getReference().toString());
 
                         report.getVulnerabilities().stream()
                                 .map((vuln) -> transform(report, vuln))
                                 .forEachOrdered((v) -> {
                                     final Vulnerability existing = dependency.getVulnerabilities().stream()
                                             .filter(e -> e.getName().equals(v.getName())).findFirst()
                                             .orElse(null);
                                     if (existing != null) {
                                         //TODO - can we enhance anything other than the references?
                                         existing.getReferences().addAll(v.getReferences());
                                     } else {
                                         dependency.addVulnerability(v);
                                     }
                                 });
                     } catch (Exception e) {
                         LOG.warn("Failed to fetch component-report for: {}", purl, e);
                     }
                 }
             }
         }
     }
 
     /**
      * Transform OSS Index component-report to ODC vulnerability.
      *
      * @param report the component report
      * @param source the vulnerability from the report to transform
      * @return the transformed vulnerability
      */
     private Vulnerability transform(final ComponentReport report, final ComponentReportVulnerability source) {
         final Vulnerability result = new Vulnerability();
         result.setSource(Vulnerability.Source.OSSINDEX);
 
         if (source.getCve() != null) {
             result.setName(source.getCve());
         } else {
             String cve = null;
             if (source.getTitle() != null) {
                 final Matcher matcher = CVE_PATTERN.matcher(source.getTitle());
                 if (matcher.find()) {
                     cve = matcher.group();
                 } else {
                     cve = source.getTitle();
                 }
             }
             if (cve == null && source.getReference() != null) {
                 final Matcher matcher = CVE_PATTERN.matcher(source.getReference().toString());
                 if (matcher.find()) {
                     cve = matcher.group();
                 }
             }
             result.setName(cve != null ? cve : source.getId());
         }
         result.setDescription(source.getDescription());
         result.addCwe(source.getCwe());
 
         final double cvssScore = source.getCvssScore() != null ? source.getCvssScore().doubleValue() : -1;
 
         if (source.getCvssVector() != null) {
             if (source.getCvssVector().startsWith("CVSS:3")) {
                 result.setCvssV3(CvssUtil.vectorToCvssV3(source.getCvssVector(), cvssScore));
             } else {
                 // convert cvss details
                 final CvssVector cvssVector = CvssVectorFactory.create(source.getCvssVector());
                 final Map<String, String> metrics = cvssVector.getMetrics();
                 if (cvssVector instanceof Cvss2Vector) {
                     String tmp = metrics.get(Cvss2Vector.ACCESS_VECTOR);
                     CvssV2Data.AccessVectorType accessVector = null;
                     if (tmp != null) {
                         accessVector = CvssV2Data.AccessVectorType.fromValue(tmp);
                     }
                     tmp = metrics.get(Cvss2Vector.ACCESS_COMPLEXITY);
                     CvssV2Data.AccessComplexityType accessComplexity = null;
                     if (tmp != null) {
                         accessComplexity = CvssV2Data.AccessComplexityType.fromValue(tmp);
                     }
                     tmp = metrics.get(Cvss2Vector.AUTHENTICATION);
                     CvssV2Data.AuthenticationType authentication = null;
                     if (tmp != null) {
                         authentication = CvssV2Data.AuthenticationType.fromValue(tmp);
                     }
                     tmp = metrics.get(Cvss2Vector.CONFIDENTIALITY_IMPACT);
                     CvssV2Data.CiaType confidentialityImpact = null;
                     if (tmp != null) {
                         confidentialityImpact = CvssV2Data.CiaType.fromValue(tmp);
                     }
                     tmp = metrics.get(Cvss2Vector.INTEGRITY_IMPACT);
                     CvssV2Data.CiaType integrityImpact = null;
                     if (tmp != null) {
                         integrityImpact = CvssV2Data.CiaType.fromValue(tmp);
                     }
                     tmp = metrics.get(Cvss2Vector.AVAILABILITY_IMPACT);
                     CvssV2Data.CiaType availabilityImpact = null;
                     if (tmp != null) {
                         availabilityImpact = CvssV2Data.CiaType.fromValue(tmp);
                     }
                     final String severity = Cvss2Severity.of((float) cvssScore).name().toUpperCase();
                     final CvssV2Data cvssData = new CvssV2Data("2.0", source.getCvssVector(), accessVector,
                             accessComplexity, authentication, confidentialityImpact,
                             integrityImpact, availabilityImpact, cvssScore,
                             severity, null, null, null, null, null, null, null, null, null, null);
                     final CvssV2 cvssV2 = new CvssV2(null, null, cvssData, severity, null, null, null, null, null, null, null);
                     result.setCvssV2(cvssV2);
                 } else {
                     LOG.warn("Unsupported CVSS vector: {}", cvssVector);
                     result.setUnscoredSeverity(Double.toString(cvssScore));
                 }
             }
         } else {
             LOG.debug("OSS has no vector for {}", result.getName());
             result.setUnscoredSeverity(Double.toString(cvssScore));
         }
         // generate a reference to the vulnerability details on OSS Index
         result.addReference(REFERENCE_TYPE, source.getTitle(), source.getReference().toString());
 
         // generate references to other references reported by OSS Index
         source.getExternalReferences().forEach(externalReference
                 -> result.addReference("OSSIndex", externalReference.toString(), externalReference.toString()));
 
         // attach vulnerable software details as best we can
         final PackageUrl purl = report.getCoordinates();
         try {
             final VulnerableSoftwareBuilder builder = new VulnerableSoftwareBuilder()
                     .part(Part.APPLICATION)
                     .vendor(purl.getNamespaceAsString())
                     .product(purl.getName())
                     .version(purl.getVersion());
 
             // TODO: consider if we want/need to extract version-ranges to apply to vulnerable-software?
             final VulnerableSoftware software = builder.build();
             result.addVulnerableSoftware(software);
             result.setMatchedVulnerableSoftware(software);
         } catch (CpeValidationException e) {
             LOG.warn("Unable to construct vulnerable-software for: {}", purl, e);
         }
 
         return result;
     }
 }