package utils

import (
	"time"
)

// 一些计算

// ComputeIndividualIncomeTax 计算个人所得税
func ComputeIndividualIncomeTax(income float64) float64 {
	if income <= 800 {
		return 0
	}

	if income <= 4000 {
		income = income - 800
	}

	// 实际纳税金额
	if income > 4000 {
		income = income * 0.8
	}

	// 税率、速算扣除数
	var taxRate, quickDeduction float64

	if income <= 20000 {
		taxRate = 0.2
		quickDeduction = 0
	} else if income <= 50000 {
		taxRate = 0.3
		quickDeduction = 2000
	} else {
		taxRate = 0.4
		quickDeduction = 7000
	}

	incomeTax := income*taxRate - quickDeduction

	return incomeTax
}

// CalculateAge 计算年龄
func CalculateAge(birthdate string) (int, error) {
	// 解析出生日期字符串
	layout := "2006-01-02"
	birthTime, err := time.Parse(layout, birthdate)
	if err != nil {
		return 0, err
	}

	// 获取当前时间
	now := time.Now()

	// 计算年龄
	years := now.Year() - birthTime.Year()

	// 如果今年的生日还没到，年龄减一
	if now.Month() < birthTime.Month() || (now.Month() == birthTime.Month() && now.Day() < birthTime.Day()) {
		years--
	}

	return years, nil
}