// This program prompts the user for a file or directory name and shows
// a listing of all files and directories that can be reached from it
// (including subdirectories).

import java.io.*;
import java.util.*;

public class Crawler {
  public static void main(String[] args) {
    Scanner console = new Scanner(System.in);
    System.out.println("Enter the full directory or file name " +
        "(ex: /Users/moorec22/Documents/...)");
    System.out.print("directory or file name? ");
    String name = console.nextLine();
    File f = new File(name);
    if (!f.exists()) {
      System.out.println("That file or directory does not exist");
    } else {
      print(f, 0);
    }
  }

  // pre : f.exists()
  // post: prints a directory listing for the given file using the given
  //       level of indentation.  Prints just the file name for a file.
  //       For a directory, prints the name and a complete listing of all
  //       files/directories under this directory, using indentation to
  //       indicate the level. 
  public static void print(File f, int level) {
    for (int i = 0; i < level; i++) {
      System.out.print("    ");
    }
    System.out.println(f.getName());
    if (f.isDirectory()) {
      for (File subF : f.listFiles()) {
        // can't do level++, or we are reassigning level
        // in this scope as well
        print(subF, level + 1);

      }
    }
  }    

  // alternate version of the above method, showing how to use a String
  // to build up indentation, instead of using an int 
  // would be called with print(f, "")
  public static void print(File f, String indentation) {
    System.out.println(indentation + f.getName());
    if (f.isDirectory()) {
      for (File subF : f.listFiles()) {
        // the equivalent index++ bug for this solution would be
        // reassigning indention = "    " + indentation;
        print(subF, "    " + indentation);
      }
    }
  }
}