/*
    * 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) 2012 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck;
  
  import org.owasp.dependencycheck.analyzer.AnalysisPhase;
  import org.owasp.dependencycheck.analyzer.Analyzer;
  import org.owasp.dependencycheck.analyzer.AnalyzerService;
  import org.owasp.dependencycheck.analyzer.FileTypeAnalyzer;
  import org.owasp.dependencycheck.analyzer.exception.AnalysisException;
  import org.owasp.dependencycheck.data.nvdcve.ConnectionFactory;
  import org.owasp.dependencycheck.data.nvdcve.CveDB;
  import org.owasp.dependencycheck.data.nvdcve.DatabaseException;
  import org.owasp.dependencycheck.data.update.CachedWebDataSource;
  import org.owasp.dependencycheck.data.update.UpdateService;
  import org.owasp.dependencycheck.data.update.exception.UpdateException;
  import org.owasp.dependencycheck.dependency.Dependency;
  import org.owasp.dependencycheck.exception.NoDataException;
  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.FileFilter;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.EnumMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * Scans files, directories, etc. for Dependencies. Analyzers are loaded and used to process the files found by the scan, if a
   * file is encountered and an Analyzer is associated with the file type then the file is turned into a dependency.
   *
   * @author Jeremy Long
   */
  public class Engine implements FileFilter {
  
      /**
       * The list of dependencies.
       */
      private List<Dependency> dependencies = new ArrayList<Dependency>();
      /**
       * A Map of analyzers grouped by Analysis phase.
       */
      private Map<AnalysisPhase, List<Analyzer>> analyzers = new EnumMap<AnalysisPhase, List<Analyzer>>(AnalysisPhase.class);
  
      /**
       * A Map of analyzers grouped by Analysis phase.
       */
      private Set<FileTypeAnalyzer> fileTypeAnalyzers = new HashSet<FileTypeAnalyzer>();
  
      /**
       * The ClassLoader to use when dynamically loading Analyzer and Update services.
       */
      private ClassLoader serviceClassLoader = Thread.currentThread().getContextClassLoader();
      /**
       * The Logger for use throughout the class.
       */
      private static final Logger LOGGER = LoggerFactory.getLogger(Engine.class);
  
      /**
       * Creates a new Engine.
       *
       * @throws DatabaseException thrown if there is an error connecting to the database
       */
      public Engine() throws DatabaseException {
          initializeEngine();
      }
  
      /**
       * Creates a new Engine.
       *
       * @param serviceClassLoader a reference the class loader being used
       * @throws DatabaseException thrown if there is an error connecting to the database
       */
      public Engine(ClassLoader serviceClassLoader) throws DatabaseException {
          this.serviceClassLoader = serviceClassLoader;
          initializeEngine();
      }
  
     /**
      * Creates a new Engine using the specified classloader to dynamically load Analyzer and Update services.
      *
      * @throws DatabaseException thrown if there is an error connecting to the database
      */
     protected final void initializeEngine() throws DatabaseException {
         ConnectionFactory.initialize();
         loadAnalyzers();
     }
 
     /**
      * Properly cleans up resources allocated during analysis.
      */
     public void cleanup() {
         ConnectionFactory.cleanup();
     }
 
     /**
      * Loads the analyzers specified in the configuration file (or system properties).
      */
     private void loadAnalyzers() {
         if (!analyzers.isEmpty()) {
             return;
         }
         for (AnalysisPhase phase : AnalysisPhase.values()) {
             analyzers.put(phase, new ArrayList<Analyzer>());
         }
 
         final AnalyzerService service = new AnalyzerService(serviceClassLoader);
         final List<Analyzer> iterator = service.getAnalyzers();
         for (Analyzer a : iterator) {
             analyzers.get(a.getAnalysisPhase()).add(a);
             if (a instanceof FileTypeAnalyzer) {
                 this.fileTypeAnalyzers.add((FileTypeAnalyzer) a);
             }
         }
     }
 
     /**
      * Get the List of the analyzers for a specific phase of analysis.
      *
      * @param phase the phase to get the configured analyzers.
      * @return the analyzers loaded
      */
     public List<Analyzer> getAnalyzers(AnalysisPhase phase) {
         return analyzers.get(phase);
     }
 
     /**
      * Get the dependencies identified.
      *
      * @return the dependencies identified
      */
     public List<Dependency> getDependencies() {
         return dependencies;
     }
 
     /**
      * Sets the dependencies.
      *
      * @param dependencies the dependencies
      */
     public void setDependencies(List<Dependency> dependencies) {
         this.dependencies = dependencies;
     }
 
     /**
      * Scans an array of files or directories. If a directory is specified, it will be scanned recursively. Any dependencies
      * identified are added to the dependency collection.
      *
      * @param paths an array of paths to files or directories to be analyzed
      * @return the list of dependencies scanned
      * @since v0.3.2.5
      */
     public List<Dependency> scan(String[] paths) {
         final List<Dependency> deps = new ArrayList<Dependency>();
         for (String path : paths) {
             final List<Dependency> d = scan(path);
             if (d != null) {
                 deps.addAll(d);
             }
         }
         return deps;
     }
 
     /**
      * Scans a given file or directory. If a directory is specified, it will be scanned recursively. Any dependencies identified
      * are added to the dependency collection.
      *
      * @param path the path to a file or directory to be analyzed
      * @return the list of dependencies scanned
      */
     public List<Dependency> scan(String path) {
         final File file = new File(path);
         return scan(file);
     }
 
     /**
      * Scans an array of files or directories. If a directory is specified, it will be scanned recursively. Any dependencies
      * identified are added to the dependency collection.
      *
      * @param files an array of paths to files or directories to be analyzed.
      * @return the list of dependencies
      * @since v0.3.2.5
      */
     public List<Dependency> scan(File[] files) {
         final List<Dependency> deps = new ArrayList<Dependency>();
         for (File file : files) {
             final List<Dependency> d = scan(file);
             if (d != null) {
                 deps.addAll(d);
             }
         }
         return deps;
     }
 
     /**
      * Scans a collection of files or directories. If a directory is specified, it will be scanned recursively. Any dependencies
      * identified are added to the dependency collection.
      *
      * @param files a set of paths to files or directories to be analyzed
      * @return the list of dependencies scanned
      * @since v0.3.2.5
      */
     public List<Dependency> scan(Collection<File> files) {
         final List<Dependency> deps = new ArrayList<Dependency>();
         for (File file : files) {
             final List<Dependency> d = scan(file);
             if (d != null) {
                 deps.addAll(d);
             }
         }
         return deps;
     }
 
     /**
      * Scans a given file or directory. If a directory is specified, it will be scanned recursively. Any dependencies identified
      * are added to the dependency collection.
      *
      * @param file the path to a file or directory to be analyzed
      * @return the list of dependencies scanned
      * @since v0.3.2.4
      */
     public List<Dependency> scan(File file) {
         if (file.exists()) {
             if (file.isDirectory()) {
                 return scanDirectory(file);
             } else {
                 final Dependency d = scanFile(file);
                 if (d != null) {
                     final List<Dependency> deps = new ArrayList<Dependency>();
                     deps.add(d);
                     return deps;
                 }
             }
         }
         return null;
     }
 
     /**
      * Recursively scans files and directories. Any dependencies identified are added to the dependency collection.
      *
      * @param dir the directory to scan
      * @return the list of Dependency objects scanned
      */
     protected List<Dependency> scanDirectory(File dir) {
         final File[] files = dir.listFiles();
         final List<Dependency> deps = new ArrayList<Dependency>();
         if (files != null) {
             for (File f : files) {
                 if (f.isDirectory()) {
                     final List<Dependency> d = scanDirectory(f);
                     if (d != null) {
                         deps.addAll(d);
                     }
                 } else {
                     final Dependency d = scanFile(f);
                     deps.add(d);
                 }
             }
         }
         return deps;
     }
 
     /**
      * Scans a specified file. If a dependency is identified it is added to the dependency collection.
      *
      * @param file The file to scan
      * @return the scanned dependency
      */
     protected Dependency scanFile(File file) {
         Dependency dependency = null;
         if (file.isFile()) {
             if (accept(file)) {
                 dependency = new Dependency(file);
                 dependencies.add(dependency);
             }
         } else {
             LOGGER.debug("Path passed to scanFile(File) is not a file: {}. Skipping the file.", file);
         }
         return dependency;
     }
 
     /**
      * Runs the analyzers against all of the dependencies. Since the mutable dependencies list is exposed via
      * {@link #getDependencies()}, this method iterates over a copy of the dependencies list. Thus, the potential for
      * {@link java.util.ConcurrentModificationException}s is avoided, and analyzers may safely add or remove entries from the
      * dependencies list.
      */
     public void analyzeDependencies() {
         boolean autoUpdate = true;
         try {
             autoUpdate = Settings.getBoolean(Settings.KEYS.AUTO_UPDATE);
         } catch (InvalidSettingException ex) {
             LOGGER.debug("Invalid setting for auto-update; using true.");
         }
         if (autoUpdate) {
             doUpdates();
         }
 
         //need to ensure that data exists
         try {
             ensureDataExists();
         } catch (NoDataException ex) {
             LOGGER.error("{}\n\nUnable to continue dependency-check analysis.", ex.getMessage());
             LOGGER.debug("", ex);
             return;
         } catch (DatabaseException ex) {
             LOGGER.error("{}\n\nUnable to continue dependency-check analysis.", ex.getMessage());
             LOGGER.debug("", ex);
             return;
 
         }
 
         LOGGER.debug("\n----------------------------------------------------\nBEGIN ANALYSIS\n----------------------------------------------------");
         LOGGER.info("Analysis Starting");
         final long analysisStart = System.currentTimeMillis();
 
         // analysis phases
         for (AnalysisPhase phase : AnalysisPhase.values()) {
             final List<Analyzer> analyzerList = analyzers.get(phase);
 
             for (Analyzer a : analyzerList) {
                 a = initializeAnalyzer(a);
 
                 /* need to create a copy of the collection because some of the
                  * analyzers may modify it. This prevents ConcurrentModificationExceptions.
                  * This is okay for adds/deletes because it happens per analyzer.
                  */
                 LOGGER.debug("Begin Analyzer '{}'", a.getName());
                 final Set<Dependency> dependencySet = new HashSet<Dependency>(dependencies);
                 for (Dependency d : dependencySet) {
                     boolean shouldAnalyze = true;
                     if (a instanceof FileTypeAnalyzer) {
                         final FileTypeAnalyzer fAnalyzer = (FileTypeAnalyzer) a;
                         shouldAnalyze = fAnalyzer.accept(d.getActualFile());
                     }
                     if (shouldAnalyze) {
                         LOGGER.debug("Begin Analysis of '{}'", d.getActualFilePath());
                         try {
                             a.analyze(d, this);
                         } catch (AnalysisException ex) {
                             LOGGER.warn("An error occurred while analyzing '{}'.", d.getActualFilePath());
                             LOGGER.debug("", ex);
                         } catch (Throwable ex) {
                             //final AnalysisException ax = new AnalysisException(axMsg, ex);
                             LOGGER.warn("An unexpected error occurred during analysis of '{}'", d.getActualFilePath());
                             LOGGER.debug("", ex);
                         }
                     }
                 }
             }
         }
         for (AnalysisPhase phase : AnalysisPhase.values()) {
             final List<Analyzer> analyzerList = analyzers.get(phase);
 
             for (Analyzer a : analyzerList) {
                 closeAnalyzer(a);
             }
         }
 
         LOGGER.debug("\n----------------------------------------------------\nEND ANALYSIS\n----------------------------------------------------");
         LOGGER.info("Analysis Complete ({} ms)", System.currentTimeMillis() - analysisStart);
     }
 
     /**
      * Initializes the given analyzer.
      *
      * @param analyzer the analyzer to initialize
      * @return the initialized analyzer
      */
     protected Analyzer initializeAnalyzer(Analyzer analyzer) {
         try {
             LOGGER.debug("Initializing {}", analyzer.getName());
             analyzer.initialize();
         } catch (Throwable ex) {
             LOGGER.error("Exception occurred initializing {}.", analyzer.getName());
             LOGGER.debug("", ex);
             try {
                 analyzer.close();
             } catch (Throwable ex1) {
                 LOGGER.trace("", ex1);
             }
         }
         return analyzer;
     }
 
     /**
      * Closes the given analyzer.
      *
      * @param analyzer the analyzer to close
      */
     protected void closeAnalyzer(Analyzer analyzer) {
         LOGGER.debug("Closing Analyzer '{}'", analyzer.getName());
         try {
             analyzer.close();
         } catch (Throwable ex) {
             LOGGER.trace("", ex);
         }
     }
 
     /**
      * Cycles through the cached web data sources and calls update on all of them.
      */
     public void doUpdates() {
         LOGGER.info("Checking for updates");
         final long updateStart = System.currentTimeMillis();
         final UpdateService service = new UpdateService(serviceClassLoader);
         final Iterator<CachedWebDataSource> iterator = service.getDataSources();
         while (iterator.hasNext()) {
             final CachedWebDataSource source = iterator.next();
             try {
                 source.update();
             } catch (UpdateException ex) {
                 LOGGER.warn(
                         "Unable to update Cached Web DataSource, using local data instead. Results may not include recent vulnerabilities.");
                 LOGGER.debug("Unable to update details for {}", source.getClass().getName(), ex);
             }
         }
         LOGGER.info("Check for updates complete ({} ms)", System.currentTimeMillis() - updateStart);
     }
 
     /**
      * Returns a full list of all of the analyzers. This is useful for reporting which analyzers where used.
      *
      * @return a list of Analyzers
      */
     public List<Analyzer> getAnalyzers() {
         final List<Analyzer> ret = new ArrayList<Analyzer>();
         for (AnalysisPhase phase : AnalysisPhase.values()) {
             final List<Analyzer> analyzerList = analyzers.get(phase);
             ret.addAll(analyzerList);
         }
         return ret;
     }
 
     /**
      * Checks all analyzers to see if an extension is supported.
      *
      * @param file a file extension
      * @return true or false depending on whether or not the file extension is supported
      */
     @Override
     public boolean accept(File file) {
         if (file == null) {
             return false;
         }
         boolean scan = false;
         for (FileTypeAnalyzer a : this.fileTypeAnalyzers) {
             /* note, we can't break early on this loop as the analyzers need to know if
              they have files to work on prior to initialization */
             scan |= a.accept(file);
         }
         return scan;
     }
 
     /**
      * Returns the set of file type analyzers.
      *
      * @return the set of file type analyzers
      */
     public Set<FileTypeAnalyzer> getFileTypeAnalyzers() {
         return this.fileTypeAnalyzers;
     }
 
     /**
      * Checks the CPE Index to ensure documents exists. If none exist a NoDataException is thrown.
      *
      * @throws NoDataException thrown if no data exists in the CPE Index
      * @throws DatabaseException thrown if there is an exception opening the database
      */
     private void ensureDataExists() throws NoDataException, DatabaseException {
         final CveDB cve = new CveDB();
         try {
             cve.open();
             if (!cve.dataExists()) {
                 throw new NoDataException("No documents exist");
             }
         } catch (DatabaseException ex) {
             throw new NoDataException(ex.getMessage(), ex);
         } finally {
             cve.close();
         }
     }
 }