/*
    * 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) 2012 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import com.google.common.annotations.VisibleForTesting;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  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.FileUtils;
  import org.owasp.dependencycheck.utils.ResourceNotFoundException;
  import org.owasp.dependencycheck.utils.Settings;
  import org.owasp.dependencycheck.utils.TooManyRequestsException;
  import org.owasp.dependencycheck.xml.hints.EvidenceMatcher;
  import org.owasp.dependencycheck.xml.hints.HintParseException;
  import org.owasp.dependencycheck.xml.hints.HintParser;
  import org.owasp.dependencycheck.xml.hints.HintRule;
  import org.owasp.dependencycheck.xml.hints.VendorDuplicatingHintRule;
  import org.owasp.dependencycheck.xml.suppression.PropertyType;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.SAXException;
  
  import javax.annotation.concurrent.ThreadSafe;
  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.util.List;
  import java.util.Set;
  import java.util.regex.Pattern;
  
  /**
   * This analyzer adds evidence to dependencies to enhance the accuracy of
   * library identification.
   *
   * @author Jeremy Long
   */
  @ThreadSafe
  public class HintAnalyzer extends AbstractAnalyzer {
  
      /**
       * The Logger for use throughout the class
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(HintAnalyzer.class);
      /**
       * The name of the hint rule file
       */
      private static final String HINT_RULE_FILE_NAME = "dependencycheck-base-hint.xml";
      /**
       * The array of hint rules.
       */
      private HintRule[] hints = null;
      /**
       * The array of vendor duplicating hint rules.
       */
      private VendorDuplicatingHintRule[] vendorHints;
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "Hint Analyzer";
      /**
       * The phase that this analyzer is intended to run in.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.POST_INFORMATION_COLLECTION2;
  
      /**
       * Returns the name of the analyzer.
       *
       * @return the name of the analyzer.
       */
      @Override
      public String getName() {
          return ANALYZER_NAME;
      }
  
      /**
       * Returns the phase that the analyzer is intended to run in.
      *
      * @return the phase that the analyzer is intended to run in.
      */
     @Override
     public AnalysisPhase getAnalysisPhase() {
         return ANALYSIS_PHASE;
     }
 
     /**
      * <p>
      * Returns the setting key to determine if the analyzer is enabled.</p>
      *
      * @return the key for the analyzer's enabled property
      */
     @Override
     protected String getAnalyzerEnabledSettingKey() {
         return Settings.KEYS.ANALYZER_HINT_ENABLED;
     }
 
     /**
      * The prepare method does nothing for this Analyzer.
      *
      * @param engine a reference the dependency-check engine
      * @throws InitializationException thrown if there is an exception
      */
     @Override
     public void prepareAnalyzer(Engine engine) throws InitializationException {
         try {
             loadHintRules();
         } catch (HintParseException ex) {
             LOGGER.debug("Unable to parse hint file", ex);
             throw new InitializationException("Unable to parse the hint file", ex);
         }
     }
 
     /**
      * The HintAnalyzer uses knowledge about a dependency to add additional
      * information to help in identification of identifiers or vulnerabilities.
      *
      * @param dependency The dependency being analyzed
      * @param engine The scanning engine
      * @throws AnalysisException is thrown if there is an exception analyzing
      * the dependency.
      */
     @Override
     @SuppressWarnings("StringSplitter")
     protected void analyzeDependency(Dependency dependency, Engine engine) throws AnalysisException {
         for (HintRule hint : hints) {
             boolean matchFound = false;
             for (EvidenceMatcher given : hint.getGivenVendor()) {
                 if (hasMatchingEvidence(dependency.getEvidence(EvidenceType.VENDOR), given)) {
                     matchFound = true;
                     break;
                 }
             }
             if (!matchFound) {
                 for (EvidenceMatcher given : hint.getGivenProduct()) {
                     if (hasMatchingEvidence(dependency.getEvidence(EvidenceType.PRODUCT), given)) {
                         matchFound = true;
                         break;
                     }
                 }
             }
             if (!matchFound) {
                 for (EvidenceMatcher given : hint.getGivenVersion()) {
                     if (hasMatchingEvidence(dependency.getEvidence(EvidenceType.VERSION), given)) {
                         matchFound = true;
                         break;
                     }
                 }
             }
             if (!matchFound) {
                 for (PropertyType pt : hint.getFileNames()) {
                     if (pt.matches(dependency.getFileName())) {
                         matchFound = true;
                         break;
                     }
                 }
             }
             if (matchFound) {
                 hint.getAddVendor().forEach((e) -> {
                     dependency.addEvidence(EvidenceType.VENDOR, e);
                     for (String weighting : e.getValue().split(" ")) {
                         dependency.addVendorWeighting(weighting);
                     }
                 });
                 hint.getAddProduct().forEach((e) -> {
                     dependency.addEvidence(EvidenceType.PRODUCT, e);
                     for (String weighting : e.getValue().split(" ")) {
                         dependency.addProductWeighting(weighting);
                     }
                 });
                 hint.getAddVersion().forEach((e) -> dependency.addEvidence(EvidenceType.VERSION, e));
 
                 hint.getRemoveVendor().forEach((e) -> removeMatchingEvidences(dependency, EvidenceType.VENDOR, e));
                 hint.getRemoveProduct().forEach((e) -> removeMatchingEvidences(dependency, EvidenceType.PRODUCT, e));
                 hint.getRemoveVersion().forEach((e) -> removeMatchingEvidences(dependency, EvidenceType.VERSION, e));
             }
         }
 
         for (Evidence e : dependency.getEvidence(EvidenceType.VENDOR)) {
             for (VendorDuplicatingHintRule dhr : vendorHints) {
                 if (dhr.getValue().equalsIgnoreCase(e.getValue())) {
                     dependency.addEvidence(EvidenceType.VENDOR, new Evidence(e.getSource() + " (hint)",
                             e.getName(), dhr.getDuplicate(), e.getConfidence(), true));
                 }
             }
         }
     }
 
     /**
      * Determine if there is matching evidence.
      *
      * @param evidences the evidence to test
      * @param criterion the criteria for a match
      * @return true if the evidence matches, otherwise false
      */
     private boolean hasMatchingEvidence(Set<Evidence> evidences, EvidenceMatcher criterion) {
         for (Evidence evidence : evidences) {
             if (criterion.matches(evidence)) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Removes any matching evidence from the dependency.
      *
      * @param dependency the dependency to update
      * @param type the type of evidence to inspect and possibly remove
      * @param e the evidence matcher
      */
     private void removeMatchingEvidences(Dependency dependency, EvidenceType type, EvidenceMatcher e) {
         for (Evidence evidence : dependency.getEvidence(type)) {
             if (e.matches(evidence)) {
                 dependency.removeEvidence(type, evidence);
             }
         }
     }
 
     /**
      * Loads the hint rules file.
      *
      * @throws HintParseException thrown if the XML cannot be parsed.
      */
     private void loadHintRules() throws HintParseException {
         final List<HintRule> localHints;
         final List<VendorDuplicatingHintRule> localVendorHints;
         final HintParser parser = new HintParser();
         File file = null;
         try (InputStream in = FileUtils.getResourceAsStream(HINT_RULE_FILE_NAME)) {
             parser.parseHints(in);
         } catch (SAXException | IOException ex) {
             throw new HintParseException("Error parsing hints: " + ex.getMessage(), ex);
         }
         localHints = parser.getHintRules();
         localVendorHints = parser.getVendorDuplicatingHintRules();
 
         final String filePath = getSettings().getString(Settings.KEYS.HINTS_FILE);
         if (filePath != null) {
             boolean deleteTempFile = false;
             try {
                 final Pattern uriRx = Pattern.compile("^(https?|file):.*", Pattern.CASE_INSENSITIVE);
                 if (uriRx.matcher(filePath).matches()) {
                     deleteTempFile = true;
                     file = getSettings().getTempFile("hint", "xml");
                     final URL url = new URL(filePath);
                     try {
                         Downloader.getInstance().fetchFile(url, file, false);
                     } catch (DownloadFailedException ex) {
                         try {
                             Thread.sleep(500);
                             Downloader.getInstance().fetchFile(url, file, true);
                         } catch (TooManyRequestsException ex1) {
                             throw new HintParseException("Unable to download hint file `" + file + "`; received 429 - too many requests", ex1);
                         } catch (ResourceNotFoundException ex1) {
                             throw new HintParseException("Unable to download hint file `" + file + "`; received 404 - resource not found", ex1);
                         } catch (InterruptedException ex1) {
                             Thread.currentThread().interrupt();
                             throw new HintParseException("Unable to download hint file `" + file + "`", ex1);
                         }
                     } catch (TooManyRequestsException ex) {
                         throw new HintParseException("Unable to download hint file `" + file + "`; received 429 - too many requests", ex);
                     } catch (ResourceNotFoundException ex) {
                         throw new HintParseException("Unable to download hint file `" + file + "`; received 404 - resource not found", ex);
                     }
                 } else {
                     file = new File(filePath);
                     if (!file.exists()) {
                         try (InputStream fromClasspath = FileUtils.getResourceAsStream(filePath)) {
                             deleteTempFile = true;
                             file = getSettings().getTempFile("hint", "xml");
                             Files.copy(fromClasspath, file.toPath());
                         } catch (IOException ex) {
                             throw new HintParseException("Unable to locate hints file in classpath", ex);
                         }
                     }
                 }
 
                 try {
                     parser.parseHints(file);
                     if (parser.getHintRules() != null && !parser.getHintRules().isEmpty()) {
                         localHints.addAll(parser.getHintRules());
                     }
                     if (parser.getVendorDuplicatingHintRules() != null && !parser.getVendorDuplicatingHintRules().isEmpty()) {
                         localVendorHints.addAll(parser.getVendorDuplicatingHintRules());
                     }
                 } catch (HintParseException ex) {
                     LOGGER.warn("Unable to parse hint rule xml file '{}'", file.getPath());
                     LOGGER.warn(ex.getMessage());
                     LOGGER.debug("", ex);
                     throw ex;
                 }
             } catch (DownloadFailedException ex) {
                 throw new HintParseException("Unable to fetch the configured hint file", ex);
             } catch (MalformedURLException ex) {
                 throw new HintParseException("Configured hint file has an invalid URL", ex);
             } catch (IOException ex) {
                 throw new HintParseException("Unable to create temp file for hints", ex);
             } finally {
                 if (deleteTempFile && file != null) {
                     FileUtils.delete(file);
                 }
             }
         }
         hints = localHints.toArray(new HintRule[0]);
         vendorHints = localVendorHints.toArray(new VendorDuplicatingHintRule[0]);
         LOGGER.debug("{} hint rules were loaded.", hints.length);
         LOGGER.debug("{} duplicating hint rules were loaded.", vendorHints.length);
     }
 
     @VisibleForTesting
     HintRule[] getHintRules() {
         return hints;
     }
 
     @VisibleForTesting
     VendorDuplicatingHintRule[] getVendorDuplicatingHintRules() {
         return vendorHints;
     }
 }