/r/DailyProgrammer Challenge 321 Talking Clock

/*
 * No more hiding from your alarm clock! You've decided you
 * want your computer to keep you updated on the time so
 * you're never late again. A talking clock takes a 24-hour
 * time and translates it into words.
 *
 * Input
 *
 * An hour (0-23) followed by a colon followed by the minute (0-59).
 *
 * 00:00
 * 01:30
 * 12:05
 * 14:01
 * 20:29
 * 21:00
 *
 * Output
 *
 * The time in words, using 12-hour format followed by am or pm.
 *
 * It's twelve am
 * It's one thirty am
 * It's twelve oh five pm
 * It's two oh one pm
 * It's eight twenty nine pm
 * It's nine pm
 */

public class Main {
    public static void main(String[] args) {
/*      System.out.println("Hours:");
        for (int i = 0; i < 24; i++) {
            System.out.printf("%s = %s %s%n", i, translateHourIntoWords(i), periodOfHour(i));
        }
        System.out.println();
        System.out.println("Minutes:");
        for (int i = 0; i < 60; i++) {
            System.out.printf("%s %s%n", i, translateMinuteIntoWords(i));
        }*/
        String[] times = {"00:00", "01:30", "12:05", "14:01", "20:29", "21:00"};
        for (String time : times) {
            String timeInWords = translateTimeIntoWords(time);
            System.out.println("It's " + timeInWords);
        }
    }

    public static String translateTimeIntoWords(String time) {
        String[] arr = time.split(":");
        assert arr.length == 2;
        int hour = Integer.parseInt(arr[0]);
        int minute = Integer.parseInt(arr[1]);
        String hourInWords = translateHourIntoWords(hour);
        String period = periodOfHour(hour);
        String minuteInWords = translateMinuteIntoWords(minute);
        if (minuteInWords != null) {
            return hourInWords + " " + minuteInWords + " " + period;
        } else {
            return hourInWords + " " + period;
        }
    }

    public static String periodOfHour(int hour) {
        return hour < 12 ? "am" : "pm";
    }

    public static String translateHourIntoWords(String hour) {
        return translateHourIntoWords(Integer.parseInt(hour));
    }

    public static String translateHourIntoWords(int hour) {
        switch (hour % 12) {
            case 0: return "twelve";
            case 1: return "one";
            case 2: return "two";
            case 3: return "three";
            case 4: return "four";
            case 5: return "five";
            case 6: return "six";
            case 7: return "seven";
            case 8: return "eight";
            case 9: return "nine";
            case 10: return "ten";
            case 11: return "eleven";
            default: throw new RuntimeException();
        }
    }

    public static String translateMinuteIntoWords(String minute) {
        return translateMinuteIntoWords(Integer.parseInt(minute));
    }

    public static String translateMinuteIntoWords(int minute) {
        switch (minute) {
            case 0: return null;
            case 1: return "oh one";
            case 2: return "oh two";
            case 3: return "oh three";
            case 4: return "oh four";
            case 5: return "oh five";
            case 6: return "oh six";
            case 7: return "oh seven";
            case 8: return "oh eight";
            case 9: return "oh nine";
            case 10: return "ten";
            case 11: return "eleven";
            case 12: return "twelve";
            case 13: return "thirteen";
            case 14: return "fourteen";
            case 15: return "fifteen";
            case 16: return "sixteen";
            case 17: return "seventeen";
            case 18: return "eighteen";
            case 19: return "nineteen";
            case 20: return "twenty";
            case 30: return "thirty";
            case 40: return "forty";
            case 50: return "fifty";
            default: switch(minute % 10) {
                case 0: return translateMinuteIntoWords(minute - minute % 10);
                case 1: return translateMinuteIntoWords(minute - minute % 10) + " one";
                case 2: return translateMinuteIntoWords(minute - minute % 10) + " two";
                case 3: return translateMinuteIntoWords(minute - minute % 10) + " three";
                case 4: return translateMinuteIntoWords(minute - minute % 10) + " four";
                case 5: return translateMinuteIntoWords(minute - minute % 10) + " five";
                case 6: return translateMinuteIntoWords(minute - minute % 10) + " six";
                case 7: return translateMinuteIntoWords(minute - minute % 10) + " seven";
                case 8: return translateMinuteIntoWords(minute - minute % 10) + " eight";
                case 9: return translateMinuteIntoWords(minute - minute % 10) + " nine";
                default: throw new RuntimeException();
            }
        }
    }
}