package com.thealgorithms.conversions;
import java.util.Map;
public final class IntegerToEnglish {
private static final Map<Integer, String> BASE_NUMBERS_MAP = Map.ofEntries(Map.entry(0, ""), Map.entry(1, "One"), Map.entry(2, "Two"), Map.entry(3, "Three"), Map.entry(4, "Four"), Map.entry(5, "Five"), Map.entry(6, "Six"), Map.entry(7, "Seven"), Map.entry(8, "Eight"), Map.entry(9, "Nine"),
Map.entry(10, "Ten"), Map.entry(11, "Eleven"), Map.entry(12, "Twelve"), Map.entry(13, "Thirteen"), Map.entry(14, "Fourteen"), Map.entry(15, "Fifteen"), Map.entry(16, "Sixteen"), Map.entry(17, "Seventeen"), Map.entry(18, "Eighteen"), Map.entry(19, "Nineteen"), Map.entry(20, "Twenty"),
Map.entry(30, "Thirty"), Map.entry(40, "Forty"), Map.entry(50, "Fifty"), Map.entry(60, "Sixty"), Map.entry(70, "Seventy"), Map.entry(80, "Eighty"), Map.entry(90, "Ninety"), Map.entry(100, "Hundred"));
private static final Map<Integer, String> THOUSAND_POWER_MAP = Map.ofEntries(Map.entry(1, "Thousand"), Map.entry(2, "Million"), Map.entry(3, "Billion"));
private IntegerToEnglish() {
}
private static String convertToWords(int number) {
int remainder = number % 100;
String result;
if (remainder <= 20) {
result = BASE_NUMBERS_MAP.get(remainder);
} else if (BASE_NUMBERS_MAP.containsKey(remainder)) {
result = BASE_NUMBERS_MAP.get(remainder);
} else {
int tensDigit = remainder / 10;
int onesDigit = remainder % 10;
result = String.format("%s %s", BASE_NUMBERS_MAP.get(tensDigit * 10), BASE_NUMBERS_MAP.get(onesDigit));
}
int hundredsDigit = number / 100;
if (hundredsDigit > 0) {
result = String.format("%s %s%s", BASE_NUMBERS_MAP.get(hundredsDigit), BASE_NUMBERS_MAP.get(100), result.isEmpty() ? "" : " " + result);
}
return result;
}
public static String integerToEnglishWords(int number) {
if (number == 0) {
return "Zero";
}
StringBuilder result = new StringBuilder();
int index = 0;
while (number > 0) {
int remainder = number % 1000;
number /= 1000;
if (remainder > 0) {
String subResult = convertToWords(remainder);
if (!subResult.isEmpty()) {
if (!result.isEmpty()) {
result.insert(0, subResult + " " + THOUSAND_POWER_MAP.get(index) + " ");
} else {
if (index > 0) {
result = new StringBuilder(subResult + " " + THOUSAND_POWER_MAP.get(index));
} else {
result = new StringBuilder(subResult);
}
}
}
}
index++;
}
return result.toString();
}
}