package common

import (
	"errors"
	"time"
)

var (
	_zero              = time.Time{}
	yearError          = errors.New("年份不能为负数")
	monthError         = errors.New("月份不能大于12或小于1")
	dayError           = errors.New("日期不能大于31或小于1")
	outOfBindTimeError = errors.New("查询时间大于当前系统时间")
)

type TimeDay struct {
	Year  int   `json:"year"`  // 年
	Month uint8 `json:"month"` // 月份
	Day   int   `json:"day"`   // 日期
}

// 根据日期获取每月的开始和结束时间
/**
规则：1、月份大于当前时间抛出异常
     2、当前时间属于当前月份，最后时间返回当前时间的次日0点
	 3、查询月份小于当前月，则返回正常区间
	 4、格式不符合抛出异常，比如年份=0或者<0,月份是0或负数或者大于12
*/
func (day TimeDay) GetMonthWithError() (start time.Time, end time.Time, err error) {
	if day.Year <= 0 {
		return _zero, _zero, yearError
	}
	if day.Month < 1 || day.Month > 12 {
		return _zero, _zero, monthError
	}
	now := time.Now()

	// 月份开始时间，大于当前时间，直接异常
	dateStart := time.Date(day.Year, time.Month(day.Month), 1, 0, 0, 0, 0, time.Local)
	if dateStart.After(now) {
		return _zero, _zero, outOfBindTimeError
	}

	// 月份结束时间，如果大于当前时间，取当前时间的 day+1
	dateEnd := time.Date(day.Year, time.Month(day.Month+1), 1, 0, 0, 0, 0, time.Local)
	if dateEnd.After(now) {
		year, month, day := now.Date()
		return dateStart, time.Date(year, month, day+1, 0, 0, 0, 0, time.Local), nil
	}
	// 正常结束
	return dateStart, dateEnd, nil
}

func (day TimeDay) GetMonthSecWithError() (start int64, end int64, err error) {
	s, e, err := day.GetMonthWithError()
	if err != nil {
		return 0, 0, err
	}
	return Time2Second(s), Time2Second(e), nil
}

// 根据日期获取 每日的开始和结束时间
/**
规则：1、规则不符合抛出异常
	2、Mysql的Between属于左闭右闭，所以保证准确性应该是 2020-09-03 00:00:00 和  2020-09-03 23:59:59
      这里推荐使用Between函数，因为between函数最终解析成了 2020-09-03 00:00:00 <= x <= 2020-09-03 23:59:59
      2020-09-03 返回  2020-09-03 00:00:00 和  2020-09-03 23:59:59
*/
func (day TimeDay) GetDayWithError() (start time.Time, end time.Time, err error) {
	if day.Year <= 0 {
		return _zero, _zero, yearError
	}
	if day.Month < 1 || day.Month > 12 {
		return _zero, _zero, monthError
	}
	if day.Day < 1 || day.Day > 31 {
		return _zero, _zero, dayError
	}
	s := time.Date(day.Year, time.Month(day.Month), day.Day, 0, 0, 0, 0, time.Local)
	e := GetTomorrow(s).Add(-time.Second)
	return s, e, nil
}

func (day TimeDay) GetDaySecWithError() (start int64, end int64, err error) {
	s, e, err := day.GetDayWithError()
	if err != nil {
		return 0, 0, err
	}
	return Time2Second(s), Time2Second(e), nil
}