import java.io.File;
import java.util.Date;
import java.util.ArrayList;

public class Day10
{
    public static int gcd( int m, int n )
    {
        if( n == 0 )
            return m;
        return gcd( n, m % n );
    }

    /*
     * This routine makes lots of extra strings but is otherwise sound.
     */
    /*
    public static boolean isPalindrome( String str )
    {
        if( str.length( ) <= 1 )
            return true;

        if( str.charAt( 0 ) != str.charAt( str.length( ) -1 ) )
            return false;

        return isPalindrome( str.substring( 1, str.length( ) - 1 ) );
    }
     * */

    /**
     * @param str string to check
     * @param beginIdx first index in the view
     * @param endIdx last index in the view
     * @return true if str[beginIdx..endIdx] is a palindrome
     */
    // Private recursive routine with a few extra parameters
    private static boolean isPalindrome( String str, int beginIdx, int endIdx )
    {
        if( endIdx - beginIdx <= 0 ) // view of length 1 or empty view
            return true;

        if( str.charAt( beginIdx ) != str.charAt( endIdx ) )
            return false;

        return isPalindrome( str, beginIdx + 1, endIdx - 1 );
    }

    // Driver routine: for public use
    public static boolean isPalindrome( String str )
    {
        return isPalindrome( str, 0, str.length( ) - 1 );
    }

    public static long totalSize( File d )
    {
        if( !d.isDirectory( ) )
            return d.length( );

        long total = 0;

        for( File f : d.listFiles( ) )
            total += totalSize( f );

        return total;
    }


    public static void listDir( String dirName )
    {
        File d = new File( dirName );
        ArrayList<String> subDirectories = new ArrayList<String>( );


        System.out.println( );
        System.out.println( "Directory of " + d.getAbsolutePath( ) );
        System.out.println( );

        for( File f : d.listFiles( ) )
        {
            boolean isDirectory = false;

            System.out.print( new Date( f.lastModified( ) ) + " " );
            isDirectory = f.isDirectory( );

            if( isDirectory )
                System.out.print( "<DIR> " );
            else
                System.out.print( "      " );

            if( isDirectory )
                System.out.print( "          " );
            else
                System.out.print( String.format(  "%10d", f.length( ) ) );

            if( isDirectory )
                subDirectories.add( f.getAbsolutePath( ) ); // add in f

            System.out.print( " " + f.getName( ) );

            System.out.println( );
        }

        for( String s : subDirectories )
            listDir( s );
    }

    public static void main( String [ ] args )
    {
    //    System.out.println( gcd( 750000, 4500 ) );
    //    System.out.println( isPalindrome( "hannah" ) );
    //    System.out.println( isPalindrome( "abcba" ) );
    //    System.out.println( isPalindrome( "abcca" ) );
    //    System.out.println( isPalindrome( "hanneh" ) );

        final String DIR = ".";

        listDir( DIR );
        System.out.println( "TOTAL BYTES OF ALL FILES " +
                            totalSize( new File( DIR ) ) );
    }

}