/*
    * 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) 2016 IBM Corporation. All Rights Reserved.
   */
  package org.owasp.dependencycheck.analyzer;
  
  import java.io.File;
  import java.io.FileFilter;
  import java.io.IOException;
  import java.nio.charset.Charset;
  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.utils.FileFilterBuilder;
  import org.owasp.dependencycheck.utils.Settings;
  
  /**
   * This analyzer is used to analyze the SWIFT Package Manager
   * (https://swift.org/package-manager/). It collects information about a package
   * from Package.swift files.
   *
   * @author Bianca Jiang (https://twitter.com/biancajiang)
   */
  @Experimental
  public class SwiftPackageManagerAnalyzer extends AbstractFileTypeAnalyzer {
  
      /**
       * The name of the analyzer.
       */
      private static final String ANALYZER_NAME = "SWIFT Package Manager Analyzer";
  
      /**
       * The phase that this analyzer is intended to run in.
       */
      private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.INFORMATION_COLLECTION;
  
      /**
       * The file name to scan.
       */
      public static final String SPM_FILE_NAME = "Package.swift";
  
      /**
       * Filter that detects files named "package.json".
       */
      private static final FileFilter SPM_FILE_FILTER = FileFilterBuilder.newInstance().addFilenames(SPM_FILE_NAME).build();
  
      /**
       * The capture group #1 is the block variable. e.g. "import
       * PackageDescription let package = Package( name: "Gloss" )"
       */
      private static final Pattern SPM_BLOCK_PATTERN = Pattern.compile("let[^=]+=\\s*Package\\s*\\(\\s*([^)]*)\\s*\\)", Pattern.DOTALL);
  
      /**
       * Returns the FileFilter
       *
       * @return the FileFilter
       */
      @Override
      protected FileFilter getFileFilter() {
          return SPM_FILE_FILTER;
      }
  
      @Override
      protected void initializeFileTypeAnalyzer() {
          // 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_SWIFT_PACKAGE_MANAGER_ENABLED;
     }
 
     @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 = SPM_BLOCK_PATTERN.matcher(contents);
         if (matcher.find()) {
             final String packageDescription = matcher.group(1);
             if (packageDescription.isEmpty()) {
                 return;
             }
 
             final EvidenceCollection product = dependency.getProductEvidence();
             final EvidenceCollection vendor = dependency.getVendorEvidence();
 
             //SPM is currently under development for SWIFT 3. Its current metadata includes package name and dependencies.
             //Future interesting metadata: version, license, homepage, author, summary, etc.
             final String name = addStringEvidence(product, packageDescription, "name", "name", Confidence.HIGHEST);
             if (name != null && !name.isEmpty()) {
                 vendor.addEvidence(SPM_FILE_NAME, "name_project", name, Confidence.HIGHEST);
             }
         }
         setPackagePath(dependency);
     }
 
     /**
      * Extracts evidence from the package description and adds it to the given
      * evidence collection.
      *
      * @param evidences the evidence collection to update
      * @param packageDescription the text to extract evidence from
      * @param field the name of the field being searched for
      * @param fieldPattern the field pattern within the contents to search for
      * @param confidence the confidence level of the evidence if found
      * @return the string that was added as evidence
      */
     private String addStringEvidence(EvidenceCollection evidences,
             String packageDescription, String field, String fieldPattern, Confidence confidence) {
         String value = "";
 
         final Matcher matcher = Pattern.compile(
                 String.format("%s *:\\s*\"([^\"]*)", fieldPattern), Pattern.DOTALL).matcher(packageDescription);
         if (matcher.find()) {
             value = matcher.group(1);
         }
 
         if (value != null) {
             value = value.trim();
             if (value.length() > 0) {
                 evidences.addEvidence(SPM_FILE_NAME, field, value, confidence);
             }
         }
 
         return value;
     }
 
     /**
      * Sets the package path on the given dependency.
      *
      * @param dep the dependency to update
      */
     private void setPackagePath(Dependency dep) {
         final File file = new File(dep.getFilePath());
         final String parent = file.getParent();
         if (parent != null) {
             dep.setPackagePath(parent);
         }
     }
 }