/*
    * This file is part of dependency-check-maven.
    *
    * 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) 2014 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.maven;
  
  import java.util.List;
  import org.apache.maven.project.MavenProject;
  import org.owasp.dependencycheck.analyzer.Analyzer;
  import org.owasp.dependencycheck.analyzer.CPEAnalyzer;
  import org.owasp.dependencycheck.analyzer.FileTypeAnalyzer;
  import org.owasp.dependencycheck.data.nvdcve.DatabaseException;
  import org.owasp.dependencycheck.data.update.exception.UpdateException;
  import org.owasp.dependencycheck.exception.ExceptionCollection;
  import org.owasp.dependencycheck.exception.InitializationException;
  import org.owasp.dependencycheck.utils.Settings;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A modified version of the core engine specifically designed to persist some
   * data between multiple executions of a multi-module Maven project.
   *
   * @author Jeremy Long
   */
  public class MavenEngine extends org.owasp.dependencycheck.Engine {
  
      /**
       * The logger.
       */
      private static final transient Logger LOGGER = LoggerFactory.getLogger(MavenEngine.class);
      /**
       * A key used to persist an object in the MavenProject.
       */
      private static final String CPE_ANALYZER_KEY = "dependency-check-CPEAnalyzer";
      /**
       * The current MavenProject.
       */
      private MavenProject currentProject;
      /**
       * The list of MavenProjects that are part of the current build.
       */
      private List<MavenProject> reactorProjects;
      /**
       * Key used in the MavenProject context values to note whether or not an
       * update has been executed.
       */
      public static final String UPDATE_EXECUTED_FLAG = "dependency-check-update-executed";
  
      /**
       * Creates a new Engine to perform analysis on dependencies.
       *
       * @param project the current Maven project
       * @param reactorProjects the reactor projects for the current Maven
       * execution
       * @throws DatabaseException thrown if there is an issue connecting to the
       * database
       */
      public MavenEngine(MavenProject project, List<MavenProject> reactorProjects) throws DatabaseException {
          this.currentProject = project;
          this.reactorProjects = reactorProjects;
          initializeEngine();
      }
  
      /**
       * Runs the analyzers against all of the dependencies.
       *
       * @throws ExceptionCollection thrown if an exception occurred; contains a
       * collection of exceptions that occurred during analysis.
       */
      @Override
      public void analyzeDependencies() throws ExceptionCollection {
          final MavenProject root = getExecutionRoot();
          if (root != null) {
              LOGGER.debug("Checking root project, {}, if updates have already been completed", root.getArtifactId());
          } else {
              LOGGER.debug("Checking root project, null, if updates have already been completed");
          }
          if (root != null && root.getContextValue(UPDATE_EXECUTED_FLAG) != null) {
              System.setProperty(Settings.KEYS.AUTO_UPDATE, Boolean.FALSE.toString());
          }
          super.analyzeDependencies();
          if (root != null) {
              root.setContextValue(UPDATE_EXECUTED_FLAG, Boolean.TRUE);
          }
      }
 
     /**
      * Runs the update steps of dependency-check.
      *
      * @throws UpdateException thrown if there is an exception
      */
     public void update() throws UpdateException {
         final MavenProject root = getExecutionRoot();
         if (root != null && root.getContextValue(UPDATE_EXECUTED_FLAG) != null) {
             System.setProperty(Settings.KEYS.AUTO_UPDATE, Boolean.FALSE.toString());
         }
         this.doUpdates();
     }
 
     /**
      * This constructor should not be called. Use Engine(MavenProject) instead.
      *
      * @throws DatabaseException thrown if there is an issue connecting to the
      * database
      */
     private MavenEngine() throws DatabaseException {
     }
 
     /**
      * Initializes the given analyzer. This skips the initialization of the
      * CPEAnalyzer if it has been initialized by a previous execution.
      *
      * @param analyzer the analyzer to initialize
      * @return the initialized analyzer
      */
     @Override
     protected Analyzer initializeAnalyzer(Analyzer analyzer) throws InitializationException {
         if (analyzer instanceof CPEAnalyzer) {
             CPEAnalyzer cpe = getPreviouslyLoadedCPEAnalyzer();
             if (cpe != null && cpe.isOpen()) {
                 return cpe;
             }
             cpe = (CPEAnalyzer) super.initializeAnalyzer(analyzer);
             storeCPEAnalyzer(cpe);
         }
         return super.initializeAnalyzer(analyzer);
     }
 
     /**
      * Releases resources used by the analyzers by calling close() on each
      * analyzer.
      */
     @Override
     public void cleanup() {
         super.cleanup();
         if (currentProject == null || reactorProjects == null) {
             return;
         }
         if (this.currentProject == reactorProjects.get(reactorProjects.size() - 1)) {
             final CPEAnalyzer cpe = getPreviouslyLoadedCPEAnalyzer();
             if (cpe != null) {
                 cpe.close();
             }
         }
     }
 
     /**
      * Closes the given analyzer. This skips closing the CPEAnalyzer.
      *
      * @param analyzer the analyzer to close
      */
     @Override
     protected void closeAnalyzer(Analyzer analyzer) {
         if (analyzer instanceof CPEAnalyzer) {
             if (getPreviouslyLoadedCPEAnalyzer() == null) {
                 super.closeAnalyzer(analyzer);
             }
         } else {
             super.closeAnalyzer(analyzer);
         }
     }
 
     /**
      * Gets the CPEAnalyzer from the root Maven Project.
      *
      * @return an initialized CPEAnalyzer
      */
     private CPEAnalyzer getPreviouslyLoadedCPEAnalyzer() {
         CPEAnalyzer cpe = null;
         final MavenProject project = getExecutionRoot();
         if (project != null) {
             final Object obj = project.getContextValue(CPE_ANALYZER_KEY);
             if (obj != null && obj instanceof CPEAnalyzer) {
                 cpe = (CPEAnalyzer) project.getContextValue(CPE_ANALYZER_KEY);
             }
         }
         return cpe;
     }
 
     /**
      * Stores a CPEAnalyzer in the root Maven Project.
      *
      * @param cpe the CPEAnalyzer to store
      */
     private void storeCPEAnalyzer(CPEAnalyzer cpe) {
         final MavenProject p = getExecutionRoot();
         if (p != null) {
             p.setContextValue(CPE_ANALYZER_KEY, cpe);
         }
     }
 
     /**
      * Returns the root Maven Project.
      *
      * @return the root Maven Project
      */
     MavenProject getExecutionRoot() {
         if (reactorProjects == null) {
             return null;
         }
         for (MavenProject p : reactorProjects) {
             if (p.isExecutionRoot()) {
                 return p;
             }
         }
         //the following should  never run, but leaving it as a failsafe.
         if (this.currentProject == null) {
             return null;
         }
         MavenProject p = this.currentProject;
         while (p.getParent() != null) {
             p = p.getParent();
         }
         return p;
     }
 
     /**
      * Resets the file type analyzers so that they can be re-used to scan
      * additional directories. Without the reset the analyzer might be disabled
      * because the first scan/analyze did not identify any files that could be
      * processed by the analyzer.
      */
     public void resetFileTypeAnalyzers() {
         for (FileTypeAnalyzer a : getFileTypeAnalyzers()) {
             a.reset();
         }
     }
 }