/*
    * 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) 2015 Institute for Defense Analyses. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileFilter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.UnsupportedEncodingException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.nio.charset.Charset;
  import org.apache.commons.io.FileUtils;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.data.nvdcve.CveDB;
  import org.owasp.dependencycheck.dependency.Confidence;
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.dependency.Reference;
  import org.owasp.dependencycheck.dependency.Vulnerability;
  import org.owasp.dependencycheck.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.Settings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.owasp.dependencycheck.data.nvdcve.DatabaseException;
  import org.owasp.dependencycheck.exception.InitializationException;
  
  /**
   * Used to analyze Ruby Bundler Gemspec.lock files utilizing the 3rd party
   * bundle-audit tool.
   *
   * @author Dale Visser
   */
  @Experimental
  public class RubyBundleAuditAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(RubyBundleAuditAnalyzer.class);
  
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "Ruby Bundle Audit Analyzer";
  
      /**
       * The phase that this analyzer is intended to run in.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.PRE_INFORMATION_COLLECTION;
      /**
       * The filter defining which files will be analyzed.
       */
      private static final FileFilter FILTER = FileFilterBuilder.newInstance().addFilenames("Gemfile.lock").build();
      /**
       * Name.
       */
      public static final String NAME = "Name: ";
      /**
       * Version.
       */
      public static final String VERSION = "Version: ";
      /**
       * Advisory.
       */
      public static final String ADVISORY = "Advisory: ";
      /**
       * Criticality.
       */
      public static final String CRITICALITY = "Criticality: ";
  
      /**
       * The DAL.
       */
      private CveDB cvedb;
  
      /**
       * @return a filter that accepts files named Gemfile.lock
       */
      @Override
      protected FileFilter getFileFilter() {
         return FILTER;
     }
 
     /**
      * Launch bundle-audit.
      *
      * @param folder directory that contains bundle audit
      * @return a handle to the process
      * @throws AnalysisException thrown when there is an issue launching bundle
      * audit
      */
     private Process launchBundleAudit(File folder) throws AnalysisException {
         if (!folder.isDirectory()) {
             throw new AnalysisException(String.format("%s should have been a directory.", folder.getAbsolutePath()));
         }
         final List<String> args = new ArrayList<String>();
         final String bundleAuditPath = Settings.getString(Settings.KEYS.ANALYZER_BUNDLE_AUDIT_PATH);
         args.add(null == bundleAuditPath ? "bundle-audit" : bundleAuditPath);
         args.add("check");
         args.add("--verbose");
         final ProcessBuilder builder = new ProcessBuilder(args);
         builder.directory(folder);
         try {
             LOGGER.info("Launching: " + args + " from " + folder);
             return builder.start();
         } catch (IOException ioe) {
             throw new AnalysisException("bundle-audit failure", ioe);
         }
     }
 
     /**
      * Initialize the analyzer. In this case, extract GrokAssembly.exe to a
      * temporary location.
      *
      * @throws InitializationException if anything goes wrong
      */
     @Override
     public void initializeFileTypeAnalyzer() throws InitializationException {
         try {
             cvedb = new CveDB();
             cvedb.open();
         } catch (DatabaseException ex) {
             LOGGER.warn("Exception opening the database");
             LOGGER.debug("error", ex);
             setEnabled(false);
             throw new InitializationException("Error connecting to the database", ex);
         }
         // Now, need to see if bundle-audit actually runs from this location.
         Process process = null;
         try {
             process = launchBundleAudit(Settings.getTempDirectory());
         } catch (AnalysisException ae) {
 
             setEnabled(false);
             cvedb.close();
             cvedb = null;
             final String msg = String.format("Exception from bundle-audit process: %s. Disabling %s", ae.getCause(), ANALYZER_NAME);
             throw new InitializationException(msg, ae);
         } catch (IOException ex) {
             setEnabled(false);
             throw new InitializationException("Unable to create temporary file, the Ruby Bundle Audit Analyzer will be disabled", ex);
         }
 
         final int exitValue;
         try {
             exitValue = process.waitFor();
         } catch (InterruptedException ex) {
             setEnabled(false);
             final String msg = String.format("Bundle-audit process was interupted. Disabling %s", ANALYZER_NAME);
             throw new InitializationException(msg);
         }
         if (0 == exitValue) {
             setEnabled(false);
             final String msg = String.format("Unexpected exit code from bundle-audit process. Disabling %s: %s", ANALYZER_NAME, exitValue);
             throw new InitializationException(msg);
         } else {
             BufferedReader reader = null;
             try {
                 reader = new BufferedReader(new InputStreamReader(process.getErrorStream(), "UTF-8"));
                 if (!reader.ready()) {
                     LOGGER.warn("Bundle-audit error stream unexpectedly not ready. Disabling " + ANALYZER_NAME);
                     setEnabled(false);
                     throw new InitializationException("Bundle-audit error stream unexpectedly not ready.");
                 } else {
                     final String line = reader.readLine();
                     if (line == null || !line.contains("Errno::ENOENT")) {
                         LOGGER.warn("Unexpected bundle-audit output. Disabling {}: {}", ANALYZER_NAME, line);
                         setEnabled(false);
                         throw new InitializationException("Unexpected bundle-audit output.");
                     }
                 }
             } catch (UnsupportedEncodingException ex) {
                 setEnabled(false);
                 throw new InitializationException("Unexpected bundle-audit encoding.", ex);
             } catch (IOException ex) {
                 setEnabled(false);
                 throw new InitializationException("Unable to read bundle-audit output.", ex);
             } finally {
                 if (null != reader) {
                     try {
                         reader.close();
                     } catch (IOException ex) {
                         LOGGER.debug("Error closing reader", ex);
                     }
                 }
             }
         }
 
         if (isEnabled()) {
             LOGGER.info(ANALYZER_NAME + " is enabled. It is necessary to manually run \"bundle-audit update\" "
                     + "occasionally to keep its database up to date.");
         }
     }
 
     /**
      * 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;
     }
 
     /**
      * Returns the key used in the properties file to reference the analyzer's
      * enabled property.
      *
      * @return the analyzer's enabled property setting key
      */
     @Override
     protected String getAnalyzerEnabledSettingKey() {
         return Settings.KEYS.ANALYZER_BUNDLE_AUDIT_ENABLED;
     }
 
     /**
      * If {@link #analyzeFileType(Dependency, Engine)} is called, then we have
      * successfully initialized, and it will be necessary to disable
      * {@link RubyGemspecAnalyzer}.
      */
     private boolean needToDisableGemspecAnalyzer = true;
 
     /**
      * Determines if the analyzer can analyze the given file type.
      *
      * @param dependency the dependency to determine if it can analyze
      * @param engine the dependency-check engine
      * @throws AnalysisException thrown if there is an analysis exception.
      */
     @Override
     protected void analyzeFileType(Dependency dependency, Engine engine)
             throws AnalysisException {
         if (needToDisableGemspecAnalyzer) {
             boolean failed = true;
             final String className = RubyGemspecAnalyzer.class.getName();
             for (FileTypeAnalyzer analyzer : engine.getFileTypeAnalyzers()) {
                 if (analyzer instanceof RubyBundlerAnalyzer) {
                     ((RubyBundlerAnalyzer) analyzer).setEnabled(false);
                     LOGGER.info("Disabled " + RubyBundlerAnalyzer.class.getName() + " to avoid noisy duplicate results.");
                 } else if (analyzer instanceof RubyGemspecAnalyzer) {
                     ((RubyGemspecAnalyzer) analyzer).setEnabled(false);
                     LOGGER.info("Disabled " + className + " to avoid noisy duplicate results.");
                     failed = false;
                 }
             }
             if (failed) {
                 LOGGER.warn("Did not find " + className + '.');
             }
             needToDisableGemspecAnalyzer = false;
         }
         final File parentFile = dependency.getActualFile().getParentFile();
         final Process process = launchBundleAudit(parentFile);
         try {
             process.waitFor();
         } catch (InterruptedException ie) {
             throw new AnalysisException("bundle-audit process interrupted", ie);
         }
         BufferedReader rdr = null;
         BufferedReader errReader = null;
         try {
             errReader = new BufferedReader(new InputStreamReader(process.getErrorStream(), "UTF-8"));
             while (errReader.ready()) {
                 final String error = errReader.readLine();
                 LOGGER.warn(error);
             }
             rdr = new BufferedReader(new InputStreamReader(process.getInputStream(), "UTF-8"));
             processBundlerAuditOutput(dependency, engine, rdr);
         } catch (IOException ioe) {
             LOGGER.warn("bundle-audit failure", ioe);
         } finally {
             if (errReader != null) {
                 try {
                     errReader.close();
                 } catch (IOException ioe) {
                     LOGGER.warn("bundle-audit close failure", ioe);
                 }
             }
             if (null != rdr) {
                 try {
                     rdr.close();
                 } catch (IOException ioe) {
                     LOGGER.warn("bundle-audit close failure", ioe);
                 }
             }
         }
 
     }
 
     /**
      * Processes the bundler audit output.
      *
      * @param original the dependency
      * @param engine the dependency-check engine
      * @param rdr the reader of the report
      * @throws IOException thrown if the report cannot be read.
      */
     private void processBundlerAuditOutput(Dependency original, Engine engine, BufferedReader rdr) throws IOException {
         final String parentName = original.getActualFile().getParentFile().getName();
         final String fileName = original.getFileName();
         final String filePath = original.getFilePath();
         Dependency dependency = null;
         Vulnerability vulnerability = null;
         String gem = null;
         final Map<String, Dependency> map = new HashMap<String, Dependency>();
         boolean appendToDescription = false;
         while (rdr.ready()) {
             final String nextLine = rdr.readLine();
             if (null == nextLine) {
                 break;
             } else if (nextLine.startsWith(NAME)) {
                 appendToDescription = false;
                 gem = nextLine.substring(NAME.length());
                 if (!map.containsKey(gem)) {
                     map.put(gem, createDependencyForGem(engine, parentName, fileName, filePath, gem));
                 }
                 dependency = map.get(gem);
                 LOGGER.debug(String.format("bundle-audit (%s): %s", parentName, nextLine));
             } else if (nextLine.startsWith(VERSION)) {
                 vulnerability = createVulnerability(parentName, dependency, gem, nextLine);
             } else if (nextLine.startsWith(ADVISORY)) {
                 setVulnerabilityName(parentName, dependency, vulnerability, nextLine);
             } else if (nextLine.startsWith(CRITICALITY)) {
                 addCriticalityToVulnerability(parentName, vulnerability, nextLine);
             } else if (nextLine.startsWith("URL: ")) {
                 addReferenceToVulnerability(parentName, vulnerability, nextLine);
             } else if (nextLine.startsWith("Description:")) {
                 appendToDescription = true;
                 if (null != vulnerability) {
                     vulnerability.setDescription("*** Vulnerability obtained from bundle-audit verbose report. "
                             + "Title link may not work. CPE below is guessed. CVSS score is estimated (-1.0 "
                             + " indicates unknown). See link below for full details. *** ");
                 }
             } else if (appendToDescription) {
                 if (null != vulnerability) {
                     vulnerability.setDescription(vulnerability.getDescription() + nextLine + "\n");
                 }
             }
         }
     }
 
     /**
      * Sets the vulnerability name.
      *
      * @param parentName the parent name
      * @param dependency the dependency
      * @param vulnerability the vulnerability
      * @param nextLine the line to parse
      */
     private void setVulnerabilityName(String parentName, Dependency dependency, Vulnerability vulnerability, String nextLine) {
         final String advisory = nextLine.substring((ADVISORY.length()));
         if (null != vulnerability) {
             vulnerability.setName(advisory);
         }
         if (null != dependency) {
             dependency.getVulnerabilities().add(vulnerability); // needed to wait for vulnerability name to avoid NPE
         }
         LOGGER.debug(String.format("bundle-audit (%s): %s", parentName, nextLine));
     }
 
     /**
      * Adds a reference to the vulnerability.
      *
      * @param parentName the parent name
      * @param vulnerability the vulnerability
      * @param nextLine the line to parse
      */
     private void addReferenceToVulnerability(String parentName, Vulnerability vulnerability, String nextLine) {
         final String url = nextLine.substring(("URL: ").length());
         if (null != vulnerability) {
             final Reference ref = new Reference();
             ref.setName(vulnerability.getName());
             ref.setSource("bundle-audit");
             ref.setUrl(url);
             vulnerability.getReferences().add(ref);
         }
         LOGGER.debug(String.format("bundle-audit (%s): %s", parentName, nextLine));
     }
 
     /**
      * Adds the criticality to the vulnerability
      *
      * @param parentName the parent name
      * @param vulnerability the vulnerability
      * @param nextLine the line to parse
      */
     private void addCriticalityToVulnerability(String parentName, Vulnerability vulnerability, String nextLine) {
         if (null != vulnerability) {
             final String criticality = nextLine.substring(CRITICALITY.length()).trim();
             float score = -1.0f;
             Vulnerability v = null;
             try {
                 v = cvedb.getVulnerability(vulnerability.getName());
             } catch (DatabaseException ex) {
                 LOGGER.debug("Unable to look up vulnerability {}", vulnerability.getName());
             }
             if (v != null) {
                 score = v.getCvssScore();
             } else if ("High".equalsIgnoreCase(criticality)) {
                 score = 8.5f;
             } else if ("Medium".equalsIgnoreCase(criticality)) {
                 score = 5.5f;
             } else if ("Low".equalsIgnoreCase(criticality)) {
                 score = 2.0f;
             }
             vulnerability.setCvssScore(score);
         }
         LOGGER.debug(String.format("bundle-audit (%s): %s", parentName, nextLine));
     }
 
     /**
      * Creates a vulnerability.
      *
      * @param parentName the parent name
      * @param dependency the dependency
      * @param gem the gem name
      * @param nextLine the line to parse
      * @return the vulnerability
      */
     private Vulnerability createVulnerability(String parentName, Dependency dependency, String gem, String nextLine) {
         Vulnerability vulnerability = null;
         if (null != dependency) {
             final String version = nextLine.substring(VERSION.length());
             dependency.getVersionEvidence().addEvidence(
                     "bundler-audit",
                     "Version",
                     version,
                     Confidence.HIGHEST);
             vulnerability = new Vulnerability(); // don't add to dependency until we have name set later
             vulnerability.setMatchedCPE(
                     String.format("cpe:/a:%1$s_project:%1$s:%2$s::~~~ruby~~", gem, version),
                     null);
             vulnerability.setCvssAccessVector("-");
             vulnerability.setCvssAccessComplexity("-");
             vulnerability.setCvssAuthentication("-");
             vulnerability.setCvssAvailabilityImpact("-");
             vulnerability.setCvssConfidentialityImpact("-");
             vulnerability.setCvssIntegrityImpact("-");
         }
         LOGGER.debug(String.format("bundle-audit (%s): %s", parentName, nextLine));
         return vulnerability;
     }
 
     /**
      * Creates the dependency based off of the gem.
      *
      * @param engine the engine used for scanning
      * @param parentName the gem parent
      * @param fileName the file name
      * @param filePath the file path
      * @param gem the gem name
      * @return the dependency to add
      * @throws IOException thrown if a temporary gem file could not be written
      */
     private Dependency createDependencyForGem(Engine engine, String parentName, String fileName, String filePath, String gem) throws IOException {
         final File gemFile = new File(Settings.getTempDirectory(), gem + "_Gemfile.lock");
         gemFile.createNewFile();
         final String displayFileName = String.format("%s%c%s:%s", parentName, File.separatorChar, fileName, gem);
 
         FileUtils.write(gemFile, displayFileName, Charset.defaultCharset()); // unique contents to avoid dependency bundling
         final Dependency dependency = new Dependency(gemFile);
         dependency.getProductEvidence().addEvidence("bundler-audit", "Name", gem, Confidence.HIGHEST);
         dependency.setDisplayFileName(displayFileName);
         dependency.setFileName(fileName);
         dependency.setFilePath(filePath);
         engine.getDependencies().add(dependency);
         return dependency;
     }
 }