package com.core.common;

import java.math.BigDecimal;
import java.math.RoundingMode;

public class Arith {

    private enum ArithType {
        ADD(0),
        DIVIDE(1),
        SUBTRACT(2),
        MULTIPLY(3);

        private final int value;

        ArithType(int value) {
            this.value = value;
        }

        public int getValue() {
            return value;
        }
    }

    public static double add(int scale, Number... nums) {
        return getAirth(scale, ArithType.ADD.getValue(), nums);
    }

    public static double subtract(int scale, Number... nums) {
        return getAirth(scale, ArithType.SUBTRACT.getValue(), nums);
    }

    public static double multiplys(int scale, Number... nums) {
        return getAirth(scale, ArithType.MULTIPLY.getValue(), nums);
    }

    public static double divides(int scale, Number... nums) {
        return getAirth(scale, ArithType.DIVIDE.getValue(), nums);
    }

    public static int percentage(Number... nums) {
        return (int) (divides(2, nums) * 100);
    }

    public static double remainder(Number... nums) {
        return new BigDecimal(nums[0].toString())
                .remainder(new BigDecimal(String.valueOf(nums[1])))
                .doubleValue();
    }

    private static double getAirth(int scale, int type, Number... nums) {
        if (nums == null || nums.length == 0) {
            return 0D;
        }
        BigDecimal result = new BigDecimal(nums[0].toString());
        for (int i = 1; i < nums.length; i++) {
            BigDecimal current = new BigDecimal(String.valueOf(nums[i]));
            switch (type) {
                case 0:
                    result = result.add(current);
                    break;
                case 1:
                    result = result.divide(current, scale, RoundingMode.HALF_UP);
                    break;
                case 2:
                    result = result.subtract(current);
                    break;
                case 3:
                    result = result.multiply(current);
                    break;
                default:
                    return 0D;
            }
        }
        return result.setScale(scale, RoundingMode.HALF_UP).doubleValue();
    }
}