package file_copy;

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class Main {

   public static void main(String args[]) {
      
      String dir = "[dir name]";
      
      StringBuffer log = new StringBuffer();
      
      // Define file locations.
      File destination_super = new File("[new dir]");
      File source_super = new File("[old dir]");      
      File destination = new File(destination_super, dir);
      File source = new File(source_super, dir);
         
      if (!destination.exists()) {
         destination.mkdir();
      }
      
      File last_file = null;
      int count = 0;      // Keep track of files copied.
      int fails = 0;      // Let a few failures occur before bailing.
      try {
         if (source.exists()) {
            // Randomize the files in the directory, this will avoid
            hitting
            // bad sectors repeatedly.
            Random random = new Random();
            log.append("Running: " + source.getAbsolutePath() + " " + 
                 source.listFiles().length + " files\n");
            List<File> files = new ArrayList<File>();
            for (File file : source.listFiles()) {
               if (files.size() == 0) {
                  files.add(file);
               }
               else {
                  files.add(random.nextInt(files.size()), file);
               }
            }
            
            // Walk the randomized file list.
            for (File file : files) {
               File target = new File(destination, file.getName());
               // Don't try to go deep, just inform user of a subdirectory.
               
               if (file.isDirectory()) {
                  log.append("Skipped subdirectory: " + 
                       file.getAbsolutePath() + "\n");
               }
               
               last_file = target;
               if (!target.exists()) {
                  try {   
                     count++;         
                     Files.copy(Paths.get(file.getAbsolutePath()), 
                          Paths.get(target.getAbsolutePath()));
                  }
                  catch (Exception e) {
                     log.append("Failed on " + 
                          last_file.getAbsolutePath() + 
                          "\n");
                     fails++;
                     if (fails > 7) {
                        throw e;
                     }
                  }
               }
            }
            log.append("Finished " + source.getAbsolutePath() + " " + 
                 source.listFiles().length + " files\n");   
         }
         else {
            log.append("Could not find: " + source.getAbsolutePath());
         }
      }
      catch (Exception e) {
         log.append("Failed on " + last_file + " " + count + "
         completed\n");
         log.append(e.getMessage());
      }
      

      try {
         PrintWriter writer = new PrintWriter(
               new FileOutputStream(new File("C:\\data\\output.txt")));
         writer.write(log.toString());
         writer.close();
         System.exit(0);
      }
      catch (Exception e) {
         System.exit(1);
      }
   }
   
}