/*
    * 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.BufferedInputStream;
  import java.io.File;
  import java.io.FileFilter;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FilenameFilter;
  import org.apache.commons.io.filefilter.NameFileFilter;
  import org.apache.commons.io.filefilter.SuffixFileFilter;
  import org.apache.commons.io.input.AutoCloseInputStream;
  import org.apache.commons.lang3.StringUtils;
  import org.owasp.dependencycheck.Engine;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.dependency.Confidence;
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.dependency.EvidenceCollection;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.mail.MessagingException;
  import javax.mail.internet.InternetHeaders;
  import org.owasp.dependencycheck.utils.ExtractionException;
  import org.owasp.dependencycheck.utils.ExtractionUtil;
  import org.owasp.dependencycheck.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.FileUtils;
  import org.owasp.dependencycheck.utils.Settings;
  import org.owasp.dependencycheck.utils.UrlStringUtils;
  
  /**
   * Used to analyze a Wheel or egg distribution files, or their contents in unzipped form, and collect information that can be used
   * to determine the associated CPE.
   *
   * @author Dale Visser <dvisser@ida.org>
   */
  public class PythonDistributionAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * Name of egg metadata files to analyze.
       */
      private static final String PKG_INFO = "PKG-INFO";
  
      /**
       * Name of wheel metadata files to analyze.
       */
      private static final String METADATA = "METADATA";
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory
              .getLogger(PythonDistributionAnalyzer.class);
  
      /**
       * The count of directories created during analysis. This is used for creating temporary directories.
       */
      private static int dirCount = 0;
  
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "Python Distribution Analyzer";
      /**
       * The phase that this analyzer is intended to run in.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.INFORMATION_COLLECTION;
  
      /**
       * The set of file extensions supported by this analyzer.
       */
      private static final String[] EXTENSIONS = {"whl", "egg", "zip"};
  
      /**
       * Used to match on egg archive candidate extensions.
       */
      private static final FileFilter EGG_OR_ZIP = FileFilterBuilder.newInstance().addExtensions("egg", "zip").build();
  
      /**
       * Used to detect files with a .whl extension.
       */
      private static final FileFilter WHL_FILTER = FileFilterBuilder.newInstance().addExtensions("whl").build();
  
     /**
      * The parent directory for the individual directories per archive.
      */
     private File tempFileLocation;
 
     /**
      * Filter that detects *.dist-info files (but doesn't verify they are directories.
      */
     private static final FilenameFilter DIST_INFO_FILTER = new SuffixFileFilter(
             ".dist-info");
 
     /**
      * Filter that detects files named "METADATA".
      */
     private static final FilenameFilter EGG_INFO_FILTER = new NameFileFilter(
             "EGG-INFO");
 
     /**
      * Filter that detects files named "METADATA".
      */
     private static final NameFileFilter METADATA_FILTER = new NameFileFilter(
             METADATA);
 
     /**
      * Filter that detects files named "PKG-INFO".
      */
     private static final NameFileFilter PKG_INFO_FILTER = new NameFileFilter(
             PKG_INFO);
 
     /**
      * The file filter used to determine which files this analyzer supports.
      */
     private static final FileFilter FILTER = FileFilterBuilder.newInstance().addFileFilters(
             METADATA_FILTER, PKG_INFO_FILTER).addExtensions(EXTENSIONS).build();
 
     /**
      * Returns the FileFilter
      *
      * @return the FileFilter
      */
     @Override
     protected FileFilter getFileFilter() {
         return FILTER;
     }
 
     /**
      * 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_PYTHON_DISTRIBUTION_ENABLED;
     }
 
     @Override
     protected void analyzeFileType(Dependency dependency, Engine engine)
             throws AnalysisException {
         final File actualFile = dependency.getActualFile();
         if (WHL_FILTER.accept(actualFile)) {
             collectMetadataFromArchiveFormat(dependency, DIST_INFO_FILTER,
                     METADATA_FILTER);
         } else if (EGG_OR_ZIP.accept(actualFile)) {
             collectMetadataFromArchiveFormat(dependency, EGG_INFO_FILTER,
                     PKG_INFO_FILTER);
         } else {
             final String name = actualFile.getName();
             final boolean metadata = METADATA.equals(name);
             if (metadata || PKG_INFO.equals(name)) {
                 final File parent = actualFile.getParentFile();
                 final String parentName = parent.getName();
                 dependency.setDisplayFileName(parentName + "/" + name);
                 if (parent.isDirectory()
                         && (metadata && parentName.endsWith(".dist-info")
                         || parentName.endsWith(".egg-info") || "EGG-INFO"
                         .equals(parentName))) {
                     collectWheelMetadata(dependency, actualFile);
                 }
             }
         }
     }
 
     /**
      * Collects the meta data from an archive.
      *
      * @param dependency the archive being scanned
      * @param folderFilter the filter to apply to the folder
      * @param metadataFilter the filter to apply to the meta data
      * @throws AnalysisException thrown when there is a problem analyzing the dependency
      */
     private void collectMetadataFromArchiveFormat(Dependency dependency,
             FilenameFilter folderFilter, FilenameFilter metadataFilter)
             throws AnalysisException {
         final File temp = getNextTempDirectory();
         LOGGER.debug("{} exists? {}", temp, temp.exists());
         try {
             ExtractionUtil.extractFilesUsingFilter(
                     new File(dependency.getActualFilePath()), temp,
                     metadataFilter);
         } catch (ExtractionException ex) {
             throw new AnalysisException(ex);
         }
 
         collectWheelMetadata(
                 dependency,
                 getMatchingFile(getMatchingFile(temp, folderFilter),
                         metadataFilter));
     }
 
     /**
      * Makes sure a usable temporary directory is available.
      *
      * @throws Exception an AnalyzeException is thrown when the temp directory cannot be created
      */
     @Override
     protected void initializeFileTypeAnalyzer() throws Exception {
         final File baseDir = Settings.getTempDirectory();
         tempFileLocation = File.createTempFile("check", "tmp", baseDir);
         if (!tempFileLocation.delete()) {
             final String msg = String.format(
                     "Unable to delete temporary file '%s'.",
                     tempFileLocation.getAbsolutePath());
             throw new AnalysisException(msg);
         }
         if (!tempFileLocation.mkdirs()) {
             final String msg = String.format(
                     "Unable to create directory '%s'.",
                     tempFileLocation.getAbsolutePath());
             throw new AnalysisException(msg);
         }
     }
 
     /**
      * Deletes any files extracted from the Wheel during analysis.
      */
     @Override
     public void close() {
         if (tempFileLocation != null && tempFileLocation.exists()) {
             LOGGER.debug("Attempting to delete temporary files");
             final boolean success = FileUtils.delete(tempFileLocation);
             if (!success) {
                 LOGGER.warn(
                         "Failed to delete some temporary files, see the log for more details");
             }
         }
     }
 
     /**
      * Gathers evidence from the METADATA file.
      *
      * @param dependency the dependency being analyzed
      * @param file a reference to the manifest/properties file
      */
     private static void collectWheelMetadata(Dependency dependency, File file) {
         final InternetHeaders headers = getManifestProperties(file);
         addPropertyToEvidence(headers, dependency.getVersionEvidence(),
                 "Version", Confidence.HIGHEST);
         addPropertyToEvidence(headers, dependency.getProductEvidence(), "Name",
                 Confidence.HIGHEST);
         final String url = headers.getHeader("Home-page", null);
         final EvidenceCollection vendorEvidence = dependency
                 .getVendorEvidence();
         if (StringUtils.isNotBlank(url)) {
             if (UrlStringUtils.isUrl(url)) {
                 vendorEvidence.addEvidence(METADATA, "vendor", url,
                         Confidence.MEDIUM);
             }
         }
         addPropertyToEvidence(headers, vendorEvidence, "Author", Confidence.LOW);
         final String summary = headers.getHeader("Summary", null);
         if (StringUtils.isNotBlank(summary)) {
             JarAnalyzer
                     .addDescription(dependency, summary, METADATA, "summary");
         }
     }
 
     /**
      * Adds a value to the evidence collection.
      *
      * @param headers the properties collection
      * @param evidence the evidence collection to add the value
      * @param property the property name
      * @param confidence the confidence of the evidence
      */
     private static void addPropertyToEvidence(InternetHeaders headers,
             EvidenceCollection evidence, String property, Confidence confidence) {
         final String value = headers.getHeader(property, null);
         LOGGER.debug("Property: {}, Value: {}", property, value);
         if (StringUtils.isNotBlank(value)) {
             evidence.addEvidence(METADATA, property, value, confidence);
         }
     }
 
     /**
      * Returns a list of files that match the given filter, this does not recursively scan the directory.
      *
      * @param folder the folder to filter
      * @param filter the filter to apply to the files in the directory
      * @return the list of Files in the directory that match the provided filter
      */
     private static File getMatchingFile(File folder, FilenameFilter filter) {
         File result = null;
         final File[] matches = folder.listFiles(filter);
         if (null != matches && 1 == matches.length) {
             result = matches[0];
         }
         return result;
     }
 
     /**
      * Reads the manifest entries from the provided file.
      *
      * @param manifest the manifest
      * @return the manifest entries
      */
     private static InternetHeaders getManifestProperties(File manifest) {
         final InternetHeaders result = new InternetHeaders();
         if (null == manifest) {
             LOGGER.debug("Manifest file not found.");
         } else {
             try {
                 result.load(new AutoCloseInputStream(new BufferedInputStream(
                         new FileInputStream(manifest))));
             } catch (MessagingException e) {
                 LOGGER.warn(e.getMessage(), e);
             } catch (FileNotFoundException e) {
                 LOGGER.warn(e.getMessage(), e);
             }
         }
         return result;
     }
 
     /**
      * Retrieves the next temporary destination directory for extracting an archive.
      *
      * @return a directory
      * @throws AnalysisException thrown if unable to create temporary directory
      */
     private File getNextTempDirectory() throws AnalysisException {
         File directory;
 
         // getting an exception for some directories not being able to be
         // created; might be because the directory already exists?
         do {
             dirCount += 1;
             directory = new File(tempFileLocation, String.valueOf(dirCount));
         } while (directory.exists());
         if (!directory.mkdirs()) {
             throw new AnalysisException(String.format(
                     "Unable to create temp directory '%s'.",
                     directory.getAbsolutePath()));
         }
         return directory;
     }
 }