Bat/src/main/java/cc/fascinated/bat/common/NumberFormatter.java

package cc.fascinated.bat.common;

import java.text.DecimalFormat;
import java.util.Locale;

/**
 * @author Fascinated (fascinated7)
 */
public class NumberFormatter {
    /**
     * The suffixes for the numbers
     */
    private static final String[] SUFFIXES = new String[] { "K", "M", "B", "T", "Q", "QT", "S", "SP", "O", "N", "D", "UD", "DD", "TD" };
    private static final DecimalFormat FORMAT = new DecimalFormat("###.##");

    /**
     * Format the provided double
     *
     * @param input the value to format
     * @return the formatted double, in the format of xx.xx[suffix]
     */
    public static String format(double input) {
        if (Double.isNaN(input)) {
            return "ERROR";
        }
        if (Double.isInfinite(input) || input == Double.MAX_VALUE) {
            return "∞";
        }
        if (1000 > input) {
            return FORMAT.format(input);
        }
        double power = (int) Math.log10(input);
        int index = (int) Math.floor(power / 3) - 1;
        double factor = input / Math.pow(10, 3 + index * 3);
        if (index >= SUFFIXES.length) {
            return "ERROR";
        }
        return FORMAT.format(factor) + SUFFIXES[index];
    }

    /**
     * Format the provided double with commas
     *
     * @param input the value to format
     * @return the formatted double, in the format of xx,xxx,xxx
     */
    public static String formatCommas(double input) {
        return String.format("%,.0f", input);
    }

    /**
     * Turns a provided string into a double, for example 1M -> 1000000.00
     * Accepts decimal and negative values and is not case-sensitive
     *
     * @param input the string to convert
     * @return the value the string represents
     */
    public static double fromString(String input) {
        if ((input = input.trim()).isEmpty()) {
            return -1D;
        }
        try {
            double value = Double.parseDouble(input); // parse pure numbers
            if (Double.isNaN(value) || Double.isInfinite(value)) {
                return -1;
            }
            return value;
        } catch (NumberFormatException ignored) {
            input = input.toUpperCase(Locale.UK);
            for (int i = SUFFIXES.length - 1; i > 0; i--) {
                String suffix = SUFFIXES[i];
                if (!input.endsWith(suffix)) {
                    continue;
                }
                String amount = input.substring(0, input.length() - suffix.length());
                if (!amount.isEmpty()) {
                    return Double.parseDouble(amount) * Math.pow(10, 3 + i * 3);
                }
            }
        }
        return -1;
    }
}