/*
    * 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.File;
  import java.io.FileFilter;
  import java.io.FilenameFilter;
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.commons.io.FileUtils;
  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.owasp.dependencycheck.exception.InitializationException;
  import org.owasp.dependencycheck.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.Settings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Used to analyze Ruby Gem specifications and collect information that can be
   * used to determine the associated CPE. Regular expressions are used to parse
   * the well-defined Ruby syntax that forms the specification.
   *
   * @author Dale Visser
   */
  @Experimental
  public class RubyGemspecAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * The logger.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(RubyGemspecAnalyzer.class);
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "Ruby Gemspec Analyzer";
  
      /**
       * The phase that this analyzer is intended to run in.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.INFORMATION_COLLECTION;
  
      /**
       * The gemspec file extension.
       */
      private static final String GEMSPEC = "gemspec";
  
      /**
       * The file filter containing the list of file extensions that can be
       * analyzed.
       */
      private static final FileFilter FILTER = FileFilterBuilder.newInstance().addExtensions(GEMSPEC).build();
      //TODO: support Rakefile
      //= FileFilterBuilder.newInstance().addExtensions(GEMSPEC).addFilenames("Rakefile").build();
  
      /**
       * The name of the version file.
       */
      private static final String VERSION_FILE_NAME = "VERSION";
  
      /**
       * @return a filter that accepts files matching the glob pattern, *.gemspec
       */
      @Override
      protected FileFilter getFileFilter() {
          return FILTER;
      }
  
      @Override
      protected void initializeFileTypeAnalyzer() throws InitializationException {
          // NO-OP
      }
  
      /**
       * 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_RUBY_GEMSPEC_ENABLED;
     }
 
     /**
      * The capture group #1 is the block variable.
      */
     private static final Pattern GEMSPEC_BLOCK_INIT = Pattern.compile("Gem::Specification\\.new\\s+?do\\s+?\\|(.+?)\\|");
 
     @Override
     protected void analyzeDependency(Dependency dependency, Engine engine)
             throws AnalysisException {
         String contents;
         try {
             contents = FileUtils.readFileToString(dependency.getActualFile(), Charset.defaultCharset());
         } catch (IOException e) {
             throw new AnalysisException(
                     "Problem occurred while reading dependency file.", e);
         }
         final Matcher matcher = GEMSPEC_BLOCK_INIT.matcher(contents);
         if (matcher.find()) {
             contents = contents.substring(matcher.end());
             final String blockVariable = matcher.group(1);
 
             final EvidenceCollection vendor = dependency.getVendorEvidence();
             final EvidenceCollection product = dependency.getProductEvidence();
             final String name = addStringEvidence(product, contents, blockVariable, "name", "name", Confidence.HIGHEST);
             if (!name.isEmpty()) {
                 vendor.addEvidence(GEMSPEC, "name_project", name + "_project", Confidence.LOW);
             }
             addStringEvidence(product, contents, blockVariable, "summary", "summary", Confidence.LOW);
 
             addStringEvidence(vendor, contents, blockVariable, "author", "authors?", Confidence.HIGHEST);
             addStringEvidence(vendor, contents, blockVariable, "email", "emails?", Confidence.MEDIUM);
             addStringEvidence(vendor, contents, blockVariable, "homepage", "homepage", Confidence.HIGHEST);
             addStringEvidence(vendor, contents, blockVariable, "license", "licen[cs]es?", Confidence.HIGHEST);
 
             final String value = addStringEvidence(dependency.getVersionEvidence(), contents,
                     blockVariable, "version", "version", Confidence.HIGHEST);
             if (value.length() < 1) {
                 addEvidenceFromVersionFile(dependency.getActualFile(), dependency.getVersionEvidence());
             }
         }
 
         setPackagePath(dependency);
     }
 
     /**
      * Adds the specified evidence to the given evidence collection.
      *
      * @param evidences the collection to add the evidence to
      * @param contents the evidence contents
      * @param blockVariable the variable
      * @param field the field
      * @param fieldPattern the field pattern
      * @param confidence the confidence of the evidence
      * @return the evidence string value added
      */
     private String addStringEvidence(EvidenceCollection evidences, String contents,
             String blockVariable, String field, String fieldPattern, Confidence confidence) {
         String value = "";
 
         //capture array value between [ ]
         final Matcher arrayMatcher = Pattern.compile(
                 String.format("\\s*?%s\\.%s\\s*?=\\s*?\\[(.*?)\\]", blockVariable, fieldPattern), Pattern.CASE_INSENSITIVE).matcher(contents);
         if (arrayMatcher.find()) {
             final String arrayValue = arrayMatcher.group(1);
             value = arrayValue.replaceAll("['\"]", "").trim(); //strip quotes
         } else { //capture single value between quotes
             final Matcher matcher = Pattern.compile(
                     String.format("\\s*?%s\\.%s\\s*?=\\s*?(['\"])(.*?)\\1", blockVariable, fieldPattern), Pattern.CASE_INSENSITIVE).matcher(contents);
             if (matcher.find()) {
                 value = matcher.group(2);
             }
         }
         if (value.length() > 0) {
             evidences.addEvidence(GEMSPEC, field, value, confidence);
         }
 
         return value;
     }
 
     /**
      * Adds evidence from the version file.
      *
      * @param dependencyFile the dependency being analyzed
      * @param versionEvidences the version evidence
      */
     private void addEvidenceFromVersionFile(File dependencyFile, EvidenceCollection versionEvidences) {
         final File parentDir = dependencyFile.getParentFile();
         if (parentDir != null) {
             final File[] matchingFiles = parentDir.listFiles(new FilenameFilter() {
                 @Override
                 public boolean accept(File dir, String name) {
                     return name.contains(VERSION_FILE_NAME);
                 }
             });
             if (matchingFiles == null) {
                 return;
             }
             for (File f : matchingFiles) {
                 try {
                     final List<String> lines = FileUtils.readLines(f, Charset.defaultCharset());
                     if (lines.size() == 1) { //TODO other checking?
                         final String value = lines.get(0).trim();
                         versionEvidences.addEvidence(GEMSPEC, "version", value, Confidence.HIGH);
                     }
                 } catch (IOException e) {
                     LOGGER.debug("Error reading gemspec", e);
                 }
             }
         }
     }
 
     /**
      * Sets the package path on the dependency.
      *
      * @param dep the dependency to alter
      */
     private void setPackagePath(Dependency dep) {
         final File file = new File(dep.getFilePath());
         final String parent = file.getParent();
         if (parent != null) {
             dep.setPackagePath(parent);
         }
     }
 }