/*
 * [TimeInterval.java]
 *
 * Summary: display a number as a time interval in words in milliseconds.
 *
 * 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 initial version.
 */
package com.mindprod.inwords;

/**
 * display a number as a time interval in words in milliseconds.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 1999-01-17 initial version.
 * @since 1999-01-17
 */
public final class TimeInterval implements ToWords
    {
    private static final int FIRST_COPYRIGHT_YEAR = 1999;

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

    private static final String[] pluralGroupName = {
            "milliseconds",
            "centiseconds",
            "tenths of a second",
            "seconds",
            "minutes",
            "hours",
            "days" };

    private static final String[] singularGroupName = {
            "millisecond",
            "centisecond",
            "tenth of a second",
            "second",
            "minute",
            "hour",
            "day" };

    private static final int[] divisor = {
            10, 10, 10, 60, 60, 24, 2147483647 };

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

    /**
     * get time is words e.g. "none" "1 millisecond" "2 milliseconds" "1 hundredth of a second" "2 tenths of a second",
     * "6 seconds", "59 seconds", "1 minute and 10 seconds", "1 hour and 10 minutes" "48 hours", "3 days"
     *
     * @param num time in milliseconds, must be positive.
     *
     * @return approximate time difference in words.
     */
    @SuppressWarnings( { "WeakerAccess" } )
    public String toWords( long num )
        {
        if ( num < 0 )
            {
            return "negative";
            }
        if ( num == 0 )
            {
            return "none";
            }
        String s = "";
        // find highest group we will display
        int highest = 0;
        int lowest;
        long saveNum = num;
        for ( int group = 0; num > 0; group++ )
            {
            int remdr = ( int ) ( num % divisor[ group ] );
            num = num / divisor[ group ];
            if ( remdr != 0 )
                {
                highest = group;
                }
            } // end for
        // find lowest group we will display.
        if ( highest > 3 )
            {
            lowest = highest - 1;
            if ( lowest < 0 )
                {
                lowest = 0;
                }
            }
        else
            {
            lowest = highest;
            }
        num = saveNum;
        for ( int i = 0; num > 0; i++ )
            {
            int remdr = ( int ) ( num % divisor[ i ] );
            num = num / divisor[ i ];
            if ( remdr == 0 )
                {
                continue;
                }
            if ( i < lowest )
                {
                // possibly round up.
                if ( i == lowest - 1 && remdr > divisor[ i ] / 2 )
                    {
                    num++;
                    }
                }
            else
                {
                String t = Integer.toString( remdr );
                boolean plural = ( remdr > 1 );
                boolean needAnd = ( s.length() != 0 );
                s =
                        t
                        + " "
                        + ( plural
                            ? pluralGroupName[ i ]
                            : singularGroupName[ i ] )
                        + ( needAnd ? " and " : "" )
                        + s;
                }
            } // end for
        return s;
        } // end inWords
    } // end TimeInterval