/*
    * 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) 2017 Steve Springett. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import com.github.packageurl.MalformedPackageURLException;
  import com.github.packageurl.PackageURL;
  import com.github.packageurl.PackageURL.StandardTypes;
  import com.github.packageurl.PackageURLBuilder;
  import org.semver4j.Semver;
  import org.semver4j.SemverException;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.data.nodeaudit.Advisory;
  import org.owasp.dependencycheck.data.nodeaudit.NodeAuditSearch;
  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.dependency.VulnerableSoftware;
  import org.owasp.dependencycheck.dependency.VulnerableSoftwareBuilder;
  import org.owasp.dependencycheck.exception.InitializationException;
  import org.owasp.dependencycheck.utils.InvalidSettingException;
  import org.owasp.dependencycheck.utils.Settings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import java.io.File;
  import java.io.IOException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.Collection;
  import java.util.List;
  import java.util.Map;
  import javax.annotation.concurrent.ThreadSafe;
  import javax.json.Json;
  import javax.json.JsonArray;
  import javax.json.JsonObject;
  import javax.json.JsonObjectBuilder;
  import javax.json.JsonString;
  import javax.json.JsonValue;
  import javax.json.JsonValue.ValueType;
  import org.apache.commons.collections4.MultiValuedMap;
  import org.apache.commons.lang3.StringUtils;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.analyzer.exception.UnexpectedAnalysisException;
  import org.owasp.dependencycheck.data.nvd.ecosystem.Ecosystem;
  import org.owasp.dependencycheck.dependency.EvidenceType;
  import org.owasp.dependencycheck.dependency.naming.GenericIdentifier;
  import org.owasp.dependencycheck.dependency.naming.Identifier;
  import org.owasp.dependencycheck.dependency.naming.PurlIdentifier;
  import org.owasp.dependencycheck.utils.Checksum;
  import us.springett.parsers.cpe.exceptions.CpeValidationException;
  import us.springett.parsers.cpe.values.Part;
  
  /**
   * An abstract NPM analyzer that contains common methods for concrete
   * implementations.
   *
   * @author Steve Springett
   */
  @ThreadSafe
  public abstract class AbstractNpmAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(AbstractNpmAnalyzer.class);
  
      /**
       * A descriptor for the type of dependencies processed or added by this
       * analyzer.
       */
      public static final String NPM_DEPENDENCY_ECOSYSTEM = Ecosystem.NODEJS;
      /**
       * The file name to scan.
       */
      private static final String PACKAGE_JSON = "package.json";
  
      /**
       * The Node Audit Searcher.
       */
      private NodeAuditSearch searcher;
  
      /**
       * Determines if the file can be analyzed by the analyzer.
       *
      * @param pathname the path to the file
      * @return true if the file can be analyzed by the given analyzer; otherwise
      * false
      */
     @Override
     public boolean accept(File pathname) {
         boolean accept = super.accept(pathname);
         if (accept) {
             try {
                 accept = shouldProcess(pathname);
             } catch (AnalysisException ex) {
                 throw new UnexpectedAnalysisException(ex.getMessage(), ex.getCause());
             }
         }
         return accept;
     }
 
     /**
      * Determines if the path contains "/node_modules/" or "/bower_components/"
      * (i.e. it is a child module). This analyzer does not scan child modules.
      *
      * @param pathname the path to test
      * @return <code>true</code> if the path does not contain "/node_modules/"
      * or "/bower_components/"
      * @throws AnalysisException thrown if the canonical path cannot be obtained
      * from the given file
      */
     public static boolean shouldProcess(File pathname) throws AnalysisException {
         try {
             // Do not scan the node_modules (or bower_components) directory
             final String canonicalPath = pathname.getCanonicalPath();
             if (canonicalPath.contains(File.separator + "node_modules" + File.separator)
                     || canonicalPath.contains(File.separator + "bower_components" + File.separator)) {
                 LOGGER.debug("Skipping analysis of node/bower module: {}", canonicalPath);
                 return false;
             }
         } catch (IOException ex) {
             throw new AnalysisException("Unable to process dependency", ex);
         }
         return true;
     }
 
     /**
      * Construct a dependency object.
      *
      * @param dependency the parent dependency
      * @param name the name of the dependency to create
      * @param version the version of the dependency to create
      * @param scope the scope of the dependency being created
      * @return the generated dependency
      */
     protected Dependency createDependency(Dependency dependency, String name, String version, String scope) {
         final Dependency nodeModule = new Dependency(new File(dependency.getActualFile() + "?" + name), true);
         nodeModule.setEcosystem(NPM_DEPENDENCY_ECOSYSTEM);
         //this is virtual - the sha1 is purely for the hyperlink in the final html report
         nodeModule.setSha1sum(Checksum.getSHA1Checksum(String.format("%s:%s", name, version)));
         nodeModule.setSha256sum(Checksum.getSHA256Checksum(String.format("%s:%s", name, version)));
         nodeModule.setMd5sum(Checksum.getMD5Checksum(String.format("%s:%s", name, version)));
         nodeModule.addEvidence(EvidenceType.PRODUCT, "package.json", "name", name, Confidence.HIGHEST);
         nodeModule.addEvidence(EvidenceType.VENDOR, "package.json", "name", name, Confidence.HIGH);
         if (!StringUtils.isBlank(version)) {
             nodeModule.addEvidence(EvidenceType.VERSION, "package.json", "version", version, Confidence.HIGHEST);
             nodeModule.setVersion(version);
         }
         if (dependency.getName() != null) {
             nodeModule.addProjectReference(dependency.getName() + ": " + scope);
         } else {
             nodeModule.addProjectReference(dependency.getDisplayFileName() + ": " + scope);
         }
         nodeModule.setName(name);
 
         //TODO  - we can likely create a valid CPE as a low confidence guess using cpe:2.3:a:[name]_project:[name]:[version]
         //(and add a targetSw of npm/node)
         Identifier id;
         try {
             final PackageURL purl = PackageURLBuilder.aPackageURL().withType(StandardTypes.NPM)
                     .withName(name).withVersion(version).build();
             id = new PurlIdentifier(purl, Confidence.HIGHEST);
         } catch (MalformedPackageURLException ex) {
             LOGGER.debug("Unable to generate Purl - using a generic identifier instead " + ex.getMessage());
             id = new GenericIdentifier(String.format("npm:%s@%s", dependency.getName(), version), Confidence.HIGHEST);
         }
         nodeModule.addSoftwareIdentifier(id);
         return nodeModule;
     }
 
     /**
      * Processes a part of package.json (as defined by JsonArray) and update the
      * specified dependency with relevant info.
      *
      * @param engine the dependency-check engine
      * @param dependency the Dependency to update
      * @param jsonArray the jsonArray to parse
      * @param depType the dependency type
      */
     protected void processPackage(Engine engine, Dependency dependency, JsonArray jsonArray, String depType) {
         final JsonObjectBuilder builder = Json.createObjectBuilder();
         jsonArray.getValuesAs(JsonString.class).forEach((str) -> builder.add(str.toString(), ""));
         final JsonObject jsonObject = builder.build();
         processPackage(engine, dependency, jsonObject, depType);
     }
 
     /**
      * Processes a part of package.json (as defined by JsonObject) and update
      * the specified dependency with relevant info.
      *
      * @param engine the dependency-check engine
      * @param dependency the Dependency to update
      * @param jsonObject the jsonObject to parse
      * @param depType the dependency type
      */
     protected void processPackage(Engine engine, Dependency dependency, JsonObject jsonObject, String depType) {
         for (int i = 0; i < jsonObject.size(); i++) {
             jsonObject.forEach((name, value) -> {
                 String version = "";
                 if (value != null && value.getValueType() == ValueType.STRING) {
                     version = ((JsonString) value).getString();
                 }
                 final Dependency existing = findDependency(engine, name, version);
                 if (existing == null) {
                     final Dependency nodeModule = createDependency(dependency, name, version, depType);
                     engine.addDependency(nodeModule);
                 } else {
                     existing.addProjectReference(dependency.getName() + ": " + depType);
                 }
             });
         }
     }
 
     /**
      * Adds information to an evidence collection from the node json
      * configuration.
      *
      * @param dep the dependency to add the evidence
      * @param t the type of evidence to add
      * @param json information from node.js
      * @return the actual string set into evidence
      * @param key the key to obtain the data from the json information
      */
     private static String addToEvidence(Dependency dep, EvidenceType t, JsonObject json, String key) {
         String evidenceStr = null;
         if (json.containsKey(key)) {
             final JsonValue value = json.get(key);
             if (value instanceof JsonString) {
                 evidenceStr = ((JsonString) value).getString();
                 dep.addEvidence(t, PACKAGE_JSON, key, evidenceStr, Confidence.HIGHEST);
             } else if (value instanceof JsonObject) {
                 final JsonObject jsonObject = (JsonObject) value;
                 for (final Map.Entry<String, JsonValue> entry : jsonObject.entrySet()) {
                     final String property = entry.getKey();
                     final JsonValue subValue = entry.getValue();
                     if (subValue instanceof JsonString) {
                         evidenceStr = ((JsonString) subValue).getString();
                         dep.addEvidence(t, PACKAGE_JSON,
                                 String.format("%s.%s", key, property),
                                 evidenceStr,
                                 Confidence.HIGHEST);
                     } else {
                         LOGGER.warn("JSON sub-value not string as expected: {}", subValue);
                     }
                 }
             } else if (value instanceof JsonArray) {
                 final JsonArray jsonArray = (JsonArray) value;
                 jsonArray.forEach(entry -> {
                     if (entry instanceof JsonObject) {
                         ((JsonObject) entry).keySet().forEach(item -> {
                             final JsonValue v = ((JsonObject) entry).get(item);
                             if (v instanceof JsonString) {
                                 final String eStr = ((JsonString) v).getString();
                                 dep.addEvidence(t, PACKAGE_JSON,
                                         String.format("%s.%s", key, item),
                                         eStr,
                                         Confidence.HIGHEST);
                             }
                         });
                     }
                 });
             } else {
                 LOGGER.warn("JSON value not string or JSON object as expected: {}", value);
             }
         }
         return evidenceStr;
     }
 
     /**
      * Locates the dependency from the list of dependencies that have been
      * scanned by the engine.
      *
      * @param engine the dependency-check engine
      * @param name the name of the dependency to find
      * @param version the version of the dependency to find
      * @return the identified dependency; otherwise null
      */
     protected Dependency findDependency(Engine engine, String name, String version) {
         for (Dependency d : engine.getDependencies()) {
             if (NPM_DEPENDENCY_ECOSYSTEM.equals(d.getEcosystem()) && name.equals(d.getName()) && version != null && d.getVersion() != null) {
                 final String dependencyVersion = d.getVersion();
                 if (DependencyBundlingAnalyzer.npmVersionsMatch(version, dependencyVersion)) {
                     return d;
                 }
             }
         }
         return null;
     }
 
     /**
      * Collects evidence from the given JSON for the associated dependency.
      *
      * @param json the JSON that contains the evidence to collect
      * @param dependency the dependency to add the evidence too
      */
     public void gatherEvidence(final JsonObject json, Dependency dependency) {
         String displayName = null;
         if (json.containsKey("name")) {
             final Object value = json.get("name");
             if (value instanceof JsonString) {
                 final String valueString = ((JsonString) value).getString();
                 displayName = valueString;
                 dependency.setName(valueString);
                 dependency.setPackagePath(valueString);
                 dependency.addEvidence(EvidenceType.PRODUCT, PACKAGE_JSON, "name", valueString, Confidence.HIGHEST);
                 dependency.addEvidence(EvidenceType.VENDOR, PACKAGE_JSON, "name", valueString, Confidence.HIGHEST);
                 dependency.addEvidence(EvidenceType.VENDOR, PACKAGE_JSON, "name", valueString + "_project", Confidence.HIGHEST);
             } else {
                 LOGGER.warn("JSON value not string as expected: {}", value);
             }
         }
         //TODO - if we start doing CPE analysis on node - we need to exclude description as it creates too many FP
         final String desc = addToEvidence(dependency, EvidenceType.VENDOR, json, "description");
         dependency.setDescription(desc);
         String vendor = addToEvidence(dependency, EvidenceType.VENDOR, json, "author");
         if (vendor == null) {
             vendor = addToEvidence(dependency, EvidenceType.VENDOR, json, "maintainers");
         } else {
             addToEvidence(dependency, EvidenceType.VENDOR, json, "maintainers");
         }
         addToEvidence(dependency, EvidenceType.VENDOR, json, "homepage");
         addToEvidence(dependency, EvidenceType.VENDOR, json, "bugs");
 
         final String version = addToEvidence(dependency, EvidenceType.VERSION, json, "version");
         if (version != null) {
             displayName = String.format("%s:%s", displayName, version);
             dependency.setVersion(version);
             dependency.setPackagePath(displayName);
             Identifier id;
             try {
                 final PackageURL purl = PackageURLBuilder.aPackageURL()
                         .withType(StandardTypes.NPM).withName(dependency.getName()).withVersion(version).build();
                 id = new PurlIdentifier(purl, Confidence.HIGHEST);
             } catch (MalformedPackageURLException ex) {
                 LOGGER.debug("Unable to generate Purl - using a generic identifier instead " + ex.getMessage());
                 id = new GenericIdentifier(String.format("npm:%s:%s", dependency.getName(), version), Confidence.HIGHEST);
             }
             dependency.addSoftwareIdentifier(id);
         }
         if (displayName != null) {
             dependency.setDisplayFileName(displayName);
             dependency.setPackagePath(displayName);
         } else {
             LOGGER.warn("Unable to determine package name or version for {}", dependency.getActualFilePath());
             if (vendor != null && !vendor.isEmpty()) {
                 dependency.setDisplayFileName(String.format("%s package.json", vendor));
             }
         }
         // Adds the license if defined in package.json
         if (json.containsKey("license")) {
             final Object value = json.get("license");
             if (value instanceof JsonString) {
                 dependency.setLicense(json.getString("license"));
             } else if (value instanceof JsonArray) {
                 final JsonArray array = (JsonArray) value;
                 final StringBuilder sb = new StringBuilder();
                 boolean addComma = false;
                 for (int x = 0; x < array.size(); x++) {
                     if (!array.isNull(x)) {
                         if (addComma) {
                             sb.append(", ");
                         } else {
                             addComma = true;
                         }
                         if (ValueType.STRING == array.get(x).getValueType()) {
                             sb.append(array.getString(x));
                         } else {
                             final JsonObject lo = array.getJsonObject(x);
                             if (lo.containsKey("type") && !lo.isNull("type")
                                     && lo.containsKey("url") && !lo.isNull("url")) {
                                 final String license = String.format("%s (%s)", lo.getString("type"), lo.getString("url"));
                                 sb.append(license);
                             } else if (lo.containsKey("type") && !lo.isNull("type")) {
                                 sb.append(lo.getString("type"));
                             } else if (lo.containsKey("url") && !lo.isNull("url")) {
                                 sb.append(lo.getString("url"));
                             }
                         }
                     }
                 }
                 dependency.setLicense(sb.toString());
             } else {
                 dependency.setLicense(json.getJsonObject("license").getString("type"));
             }
         }
     }
 
     /**
      * 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
     protected void prepareFileTypeAnalyzer(Engine engine) throws InitializationException {
         if (!isEnabled() || !getFilesMatched()) {
             this.setEnabled(false);
             return;
         }
         if (searcher == null) {
             LOGGER.debug("Initializing {}", getName());
             try {
                 searcher = new NodeAuditSearch(getSettings());
             } catch (MalformedURLException ex) {
                 setEnabled(false);
                 throw new InitializationException("The configured URL to NPM Audit API is malformed", ex);
             }
             try {
                 final Settings settings = engine.getSettings();
                 final boolean nodeEnabled = settings.getBoolean(Settings.KEYS.ANALYZER_NODE_PACKAGE_ENABLED);
                 if (!nodeEnabled) {
                     LOGGER.warn("The Node Package Analyzer has been disabled; the resulting report will only "
                             + "contain the known vulnerable dependency - not a bill of materials for the node project.");
                 }
             } catch (InvalidSettingException ex) {
                 throw new InitializationException("Unable to read configuration settings", ex);
             }
         }
     }
 
     /**
      * Processes the advisories creating the appropriate dependency objects and
      * adding the resulting vulnerabilities.
      *
      * @param advisories a collection of advisories from npm
      * @param engine a reference to the analysis engine
      * @param dependency a reference to the package-lock.json dependency
      * @param dependencyMap a collection of module/version pairs obtained from
      * the package-lock file - used in case the advisories do not include a
      * version number
      * @throws CpeValidationException thrown when a CPE cannot be created
      */
     protected void processResults(final List<Advisory> advisories, Engine engine,
             Dependency dependency, MultiValuedMap<String, String> dependencyMap)
             throws CpeValidationException {
         for (Advisory advisory : advisories) {
             //Create a new vulnerability out of the advisory returned by nsp.
             final Vulnerability vuln = new Vulnerability();
             vuln.setDescription(advisory.getOverview());
             vuln.setName(String.valueOf(advisory.getGhsaId()));
             vuln.setUnscoredSeverity(advisory.getSeverity());
             vuln.setCvssV3(advisory.getCvssV3());
             vuln.setSource(Vulnerability.Source.NPM);
             for (String cwe : advisory.getCwes()) {
                 vuln.addCwe(cwe);
             }
             if (advisory.getReferences() != null) {
                 final String[] references = advisory.getReferences().split("\\n");
                 for (String reference : references) {
                     if (reference.length() > 3) {
                         String url = reference.substring(2);
                         try {
                             new URL(url);
                         } catch (MalformedURLException ignored) {
                             // reference is not a format-valid URL, so null it to make the reference be used as plaintext
                             url = null;
                         }
                         vuln.addReference("NPM Advisory reference: ", url == null ? reference : url, url);
                     }
                 }
             }
 
             //Create a single vulnerable software object - these do not use CPEs unlike the NVD.
             final VulnerableSoftwareBuilder builder = new VulnerableSoftwareBuilder();
             builder.part(Part.APPLICATION).product(advisory.getModuleName().replace(" ", "_"))
                     .version(advisory.getVulnerableVersions().replace(" ", ""));
             final VulnerableSoftware vs = builder.build();
             vuln.addVulnerableSoftware(vs);
 
             String version = advisory.getVersion();
             if (version == null && dependencyMap.containsKey(advisory.getModuleName())) {
                 version = determineVersionFromMap(advisory.getVulnerableVersions(), dependencyMap.get(advisory.getModuleName()));
             }
             final Dependency existing = findDependency(engine, advisory.getModuleName(), version);
             if (existing == null) {
                 final Dependency nodeModule = createDependency(dependency, advisory.getModuleName(), version, "transitive");
                 nodeModule.addVulnerability(vuln);
                 engine.addDependency(nodeModule);
             } else {
                 replaceOrAddVulnerability(existing, vuln);
             }
         }
     }
 
     /**
      * Evaluates if the vulnerability is already present; if it is the
      * vulnerability is not added.
      *
      * @param dependency a reference to the dependency being analyzed
      * @param vuln the vulnerability to add
      */
     protected void replaceOrAddVulnerability(Dependency dependency, Vulnerability vuln) {
         boolean found = vuln.getSource() == Vulnerability.Source.NPM && 
                 dependency.getVulnerabilities().stream().anyMatch(existing -> {
             return existing.getReferences().stream().anyMatch(ref ->{
                     return ref.getName() != null
                             && ref.getName().equals("https://nodesecurity.io/advisories/" + vuln.getName());
             });
         });
         if (!found) {
             dependency.addVulnerability(vuln);
         }
     }
 
     /**
      * Returns the node audit search utility.
      *
      * @return the node audit search utility
      */
     protected NodeAuditSearch getSearcher() {
         return searcher;
     }
 
     /**
      * Give an NPM version range and a collection of versions, this method
      * attempts to select a specific version from the collection that is in the
      * range.
      *
      * @param versionRange the version range to evaluate
      * @param availableVersions the collection of possible versions to select
      * @return the selected range from the versionRange
      */
     public static String determineVersionFromMap(String versionRange, Collection<String> availableVersions) {
         if (availableVersions.size() == 1) {
             return availableVersions.iterator().next();
         }
         for (String v : availableVersions) {
             try {
                 final Semver version = new Semver(v);
                 if (version.satisfies(versionRange)) {
                     return v;
                 }
             } catch (SemverException ex) {
                 LOGGER.debug("invalid semver: " + v);
             }
         }
         return availableVersions.iterator().next();
     }
 }