1 files changed, 54 insertions, 0 deletions
diff --git a/src/main/java/de/hysky/skyblocker/utils/RomanNumerals.java b/src/main/java/de/hysky/skyblocker/utils/RomanNumerals.java
new file mode 100644
index 00000000..007cb0b1
--- /dev/null
+++ b/src/main/java/de/hysky/skyblocker/utils/RomanNumerals.java
@@ -0,0 +1,54 @@
+package de.hysky.skyblocker.utils;
+
+public class RomanNumerals {
+	private RomanNumerals() {
+	}
+	private static int getDecimalValue(char romanChar) {
+		return switch (romanChar) {
+			case 'I' -> 1;
+			case 'V' -> 5;
+			case 'X' -> 10;
+			case 'L' -> 50;
+			case 'C' -> 100;
+			case 'D' -> 500;
+			case 'M' -> 1000;
+			default -> 0;
+		};
+	}
+
+	/**
+	 * Checks if a string is a valid roman numeral.
+	 * It's the caller's responsibility to clean up the string before calling this method (such as trimming it).
+	 * @param romanNumeral The roman numeral to check.
+	 * @return True if the string is a valid roman numeral, false otherwise.
+	 * @implNote This will only check if the string contains valid roman numeral characters. It won't check if the numeral is well-formed.
+	 */
+	public static boolean isValidRomanNumeral(String romanNumeral) {
+		if (romanNumeral == null || romanNumeral.isEmpty()) return false;
+		for (int i = 0; i < romanNumeral.length(); i++) {
+			if (getDecimalValue(romanNumeral.charAt(i)) == 0) return false;
+		}
+		return true;
+	}
+
+	/**
+	 * Converts a roman numeral to a decimal number.
+	 *
+	 * @param romanNumeral The roman numeral to convert.
+	 * @return The decimal number, or 0 if the roman numeral string has non-roman characters in it, or if the string is empty or null.
+	 */
+	public static int romanToDecimal(String romanNumeral) {
+		if (romanNumeral == null || romanNumeral.isEmpty()) return 0;
+		romanNumeral = romanNumeral.trim().toUpperCase();
+		int decimal = 0;
+		int lastNumber = 0;
+		for (int i = romanNumeral.length() - 1; i >= 0; i--) {
+			char ch = romanNumeral.charAt(i);
+			int number = getDecimalValue(ch);
+			if (number == 0) return 0; //Malformed roman numeral
+			decimal = number >= lastNumber ? decimal + number : decimal - number;
+			lastNumber = number;
+		}
+		return decimal;
+	}
+}