package com.ots.common.utils;
import java.math.BigDecimal;
import java.math.RoundingMode;

public class Arith {
    
    private static final int DEF_DIV_SCALE = 10;
    
    private Arith() {
    }
    
    public static double add(double v1, double v2) {
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.add(b2).doubleValue();
    }
    
    public static double sub(double v1, double v2) {
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.subtract(b2).doubleValue();
    }
    
    public static double mul(double v1, double v2) {
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.multiply(b2).doubleValue();
    }
    
    public static double div(double v1, double v2) {
        return div(v1, v2, DEF_DIV_SCALE);
    }
    
    public static double div(double v1, double v2, int scale) {
        if (scale < 0) {
            throw new IllegalArgumentException(
                    "The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        if (b1.compareTo(BigDecimal.ZERO) == 0) {
            return BigDecimal.ZERO.doubleValue();
        }
        return b1.divide(b2, scale, RoundingMode.HALF_UP).doubleValue();
    }
    
    public static double round(double v, int scale) {
        if (scale < 0) {
            throw new IllegalArgumentException(
                    "The scale must be a positive integer or zero");
        }
        BigDecimal b = new BigDecimal(Double.toString(v));
        BigDecimal one = new BigDecimal("1");
        return b.divide(one, scale, RoundingMode.HALF_UP).doubleValue();
    }
}