/*
    * Copyright (c) 2006 JMockit developers
    * This file is subject to the terms of the MIT license (see LICENSE.txt).
    */
   package mockit.coverage.data;
   
   import edu.umd.cs.findbugs.annotations.NonNull;
   import edu.umd.cs.findbugs.annotations.Nullable;
   
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.OutputStream;
  import java.io.Serializable;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  import mockit.coverage.CoveragePercentage;
  import mockit.internal.util.Utilities;
  
  import org.checkerframework.checker.index.qual.NonNegative;
  
  /**
   * Coverage data captured for all source files exercised during a test run.
   */
  public final class CoverageData implements Serializable {
      private static final long serialVersionUID = -4860004226098360259L;
      @NonNull
      private static final CoverageData instance = new CoverageData();
  
      @NonNull
      public static CoverageData instance() {
          return instance;
      }
  
      private boolean withCallPoints;
  
      @NonNull
      private final Map<String, FileCoverageData> fileToFileData = new LinkedHashMap<>();
      @NonNull
      private final List<FileCoverageData> indexedFileData = new ArrayList<>(100);
  
      public boolean isWithCallPoints() {
          return withCallPoints;
      }
  
      public void setWithCallPoints(boolean withCallPoints) {
          this.withCallPoints = withCallPoints;
      }
  
      @NonNull
      public Map<String, FileCoverageData> getFileToFileData() {
          return fileToFileData;
      }
  
      @NonNull
      public FileCoverageData getOrAddFile(@NonNull String file, @Nullable String kindOfTopLevelType) {
          FileCoverageData fileData = fileToFileData.get(file);
  
          // For a class with nested/inner classes, a previous class in the same source file may already have been added.
          if (fileData == null) {
              int fileIndex = indexedFileData.size();
              fileData = new FileCoverageData(fileIndex, kindOfTopLevelType);
              indexedFileData.add(fileData);
              fileToFileData.put(file, fileData);
          } else if (kindOfTopLevelType != null) {
              fileData.kindOfTopLevelType = kindOfTopLevelType;
          }
  
          return fileData;
      }
  
      @NonNull
      public FileCoverageData getFileData(@NonNull String file) {
          return fileToFileData.get(file);
      }
  
      @NonNull
      public FileCoverageData getFileData(@NonNegative int fileIndex) {
          return indexedFileData.get(fileIndex);
      }
  
      public boolean isEmpty() {
          return fileToFileData.isEmpty();
      }
  
      public void clear() {
          fileToFileData.clear();
     }
 
     /**
      * Computes the coverage percentage over a subset of the available source files.
      *
      * @param fileNamePrefix
      *            a regular expression for matching the names of the source files to be considered, or <code>null</code>
      *            to consider <em>all</em> files
      *
      * @return the computed percentage from <code>0</code> to <code>100</code> (inclusive), or <code>-1</code> if no
      *         meaningful value could be computed
      */
     public int getPercentage(@Nullable String fileNamePrefix) {
         int coveredItems = 0;
         int totalItems = 0;
 
         for (Entry<String, FileCoverageData> fileAndFileData : fileToFileData.entrySet()) {
             String sourceFile = fileAndFileData.getKey();
 
             if (fileNamePrefix == null || sourceFile.startsWith(fileNamePrefix)) {
                 FileCoverageData fileData = fileAndFileData.getValue();
                 coveredItems += fileData.getCoveredItems();
                 totalItems += fileData.getTotalItems();
             }
         }
 
         return CoveragePercentage.calculate(coveredItems, totalItems);
     }
 
     /**
      * Finds the source file with the smallest coverage percentage.
      *
      * @return the percentage value for the file found, or <code>Integer.MAX_VALUE</code> if no file is found with a
      *         meaningful percentage
      */
     @NonNegative
     public int getSmallestPerFilePercentage() {
         int minPercentage = Integer.MAX_VALUE;
 
         for (FileCoverageData fileData : fileToFileData.values()) {
             if (!fileData.wasLoadedAfterTestCompletion()) {
                 int percentage = fileData.getCoveragePercentage();
 
                 if (percentage >= 0 && percentage < minPercentage) {
                     minPercentage = percentage;
                 }
             }
         }
 
         return minPercentage;
     }
 
     public void fillLastModifiedTimesForAllClassFiles() {
         for (Iterator<Entry<String, FileCoverageData>> itr = fileToFileData.entrySet().iterator(); itr.hasNext();) {
             Entry<String, FileCoverageData> fileAndFileData = itr.next();
             long lastModified = getLastModifiedTimeForClassFile(fileAndFileData.getKey());
 
             if (lastModified > 0L) {
                 FileCoverageData fileCoverageData = fileAndFileData.getValue();
                 fileCoverageData.lastModified = lastModified;
                 continue;
             }
 
             itr.remove();
         }
     }
 
     private long getLastModifiedTimeForClassFile(@NonNull String sourceFilePath) {
         String sourceFilePathNoExt = sourceFilePath.substring(0, sourceFilePath.lastIndexOf('.'));
         String className = sourceFilePathNoExt.replace('/', '.');
 
         Class<?> coveredClass = findCoveredClass(className);
 
         if (coveredClass == null) {
             return 0L;
         }
 
         String locationPath = Utilities.getClassFileLocationPath(coveredClass);
 
         if (locationPath.endsWith(".jar")) {
             try {
                 return getLastModifiedTimeFromJarEntry(sourceFilePathNoExt, locationPath);
             } catch (IOException ignore) {
                 return 0L;
             }
         }
 
         String pathToClassFile = locationPath + sourceFilePathNoExt + ".class";
 
         return Path.of(pathToClassFile).toFile().lastModified();
     }
 
     private static long getLastModifiedTimeFromJarEntry(@NonNull String sourceFilePathNoExt,
             @NonNull String locationPath) throws IOException {
 
         try (JarFile jarFile = new JarFile(locationPath)) {
             JarEntry classEntry = jarFile.getJarEntry(sourceFilePathNoExt + ".class");
             return classEntry.getTime();
         }
     }
 
     @Nullable
     private Class<?> findCoveredClass(@NonNull String className) {
         ClassLoader currentCL = getClass().getClassLoader();
         Class<?> coveredClass = loadClass(className, currentCL);
 
         if (coveredClass == null) {
             ClassLoader systemCL = ClassLoader.getSystemClassLoader();
 
             if (systemCL != currentCL) {
                 coveredClass = loadClass(className, systemCL);
             }
 
             if (coveredClass == null) {
                 ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
 
                 if (contextCL != null && contextCL != systemCL) {
                     coveredClass = loadClass(className, contextCL);
                 }
             }
         }
 
         return coveredClass;
     }
 
     @Nullable
     private static Class<?> loadClass(@NonNull String className, @Nullable ClassLoader loader) {
         try {
             return Class.forName(className, false, loader);
         } catch (ClassNotFoundException | NoClassDefFoundError ignore) {
             return null;
         }
     }
 
     /**
      * Reads a serialized <code>CoverageData</code> object from the given file (normally, a "<code>coverage.ser</code>"
      * file generated at the end of a previous test run).
      *
      * @param dataFile
      *            the ".ser" file containing a serialized <code>CoverageData</code> instance
      *
      * @return a new object containing all coverage data resulting from a previous test run
      */
     @NonNull
     public static CoverageData readDataFromFile(@NonNull File dataFile) throws IOException {
         try (ObjectInputStream input = new ObjectInputStream(
                 new BufferedInputStream(Files.newInputStream(dataFile.toPath())))) {
             return (CoverageData) input.readObject();
         } catch (ClassNotFoundException e) {
             throw new RuntimeException(
                     "Serialized class in coverage data file \"" + dataFile + "\" not found in classpath", e);
         }
     }
 
     public void writeDataToFile(@NonNull File dataFile) throws IOException {
         try (OutputStream outputStream = Files.newOutputStream(dataFile.toPath());
                 BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream);
                 ObjectOutputStream output = new ObjectOutputStream(bufferedOutputStream)) {
             output.writeObject(this);
         }
     }
 
     public void merge(@NonNull CoverageData previousData) {
         withCallPoints |= previousData.withCallPoints;
 
         for (Entry<String, FileCoverageData> previousFileAndFileData : previousData.fileToFileData.entrySet()) {
             String previousFile = previousFileAndFileData.getKey();
             FileCoverageData previousFileData = previousFileAndFileData.getValue();
             FileCoverageData fileData = fileToFileData.get(previousFile);
 
             if (fileData == null) {
                 fileToFileData.put(previousFile, previousFileData);
             } else if (fileData.lastModified > 0 && previousFileData.lastModified == fileData.lastModified) {
                 fileData.mergeWithDataFromPreviousTestRun(previousFileData);
             }
         }
     }
 }