/*
 * [Octal.java]
 *
 * Summary: Display a number in octal digits.
 *
 * Copyright: (c) 1999-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 1999-01-17 </pre>
 */
package com.mindprod.inwords;

/**
 * Display a number in octal digits.
 * <p/>
 * e.g.
 * -12345 -&gt; 1_777_777_777_777_777_747_707
 * <p/>
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 1999-01-17 </pre>
 * @ </pre>
 * @noinspection UnusedDeclaration
 * @since 1999-01-17
 */
public final class Octal implements ToWords
    {
    private static final int FIRST_COPYRIGHT_YEAR = 1999;

    /**
     * undisplayed copyright notice
     */
    private static final String EMBEDDED_COPYRIGHT =
            "Copyright: (c) 1999-2017 Roedy Green, Canadian Mind Products, http://mindprod.com";

    /**
     * test harness
     *
     * @param args not used
     */
    public static void main( String[] args )
        {
        Test.test( new Octal() );
        } // end main

    /**
     * convert long integer into Octal e.g. -12345 -> 1_777_777_777_777_777_747_707 Handles negative and positive
     * integers on range -Long.MAX_VALUE .. Long.MAX_VALUE; It cannot handle Long.MIN_VALUE;
     *
     * @param num number to convert to words
     *
     * @return words
     */
    @SuppressWarnings( { "WeakerAccess" } )
    public String toWords( long num )
        {
        String h;
        if ( num < 0 )
            {
            h = Long.toString( num & 0x7fffffffffffffffL, 8 );
            // pad out to 21 digits
            h = "000000000000000000000".substring( h.length() ) + h;
            h = Integer.toString( ( int ) ( num >>> 63 ), 8 ) + h;
            }
        else
            {
            h = Long.toString( num, 8 );
            // pad out to 22 digits
            h = "0000000000000000000000".substring( h.length() ) + h;
            }
        // insert decorative underscores every 3 chars to help make it easier to
        // read.
        return h.substring( 0, 1 )
               + '_'
               + h.substring( 1, 4 )
               + '_'
               + h.substring( 4, 7 )
               + '_'
               + h.substring( 7, 10 )
               + '_'
               + h.substring( 10, 13 )
               + '_'
               + h.substring( 13, 16 )
               + '_'
               + h.substring( 16, 19 )
               + '_'
               + h.substring( 19 );
        } // end toWords
    } // end Octal