package timeutils

import (
	"time"
)

var (
	monthMap = map[string]string{
		"01": "一月",
		"02": "二月",
		"03": "三月",
		"04": "四月",
		"05": "五月",
		"06": "六月",
		"07": "七月",
		"08": "八月",
		"09": "九月",
		"10": "十月",
		"11": "十一月",
		"12": "十二月",
	}

	weekMap = map[string]string{
		"Monday":    "星期一",
		"Tuesday":   "星期二",
		"Wednesday": "星期三",
		"Thursday":  "星期四",
		"Friday":    "星期五",
		"Saturday":  "星期六",
		"Sunday":    "星期日",
	}
)

// ParseLocalDateTime 将日期时间字符串转换为time.Time，dateTime参数如果不是日期时间字符串会panic
func ParseLocalDateTime(dateTime string) *time.Time {
	t, err := time.ParseInLocation(time.DateTime, dateTime, time.Local)
	if err != nil {
		panic(err)
	}

	return &t
}

// ParseLocalDateOnly 将日期字符串转换为time.Time，dateTime参数如果不是日期字符串会panic
func ParseLocalDateOnly(date string) *time.Time {
	t, err := time.ParseInLocation(time.DateOnly, date, time.Local)
	if err != nil {
		panic(err)
	}

	return &t
}

// ParseNowDateOnly 将当前时间转换为time.Time，仅有日期信息
func ParseNowDateOnly() *time.Time {
	return ParseLocalDateOnly(FormatNowDateOnly())
}

// FormatNowDateTime 将当前时间转化为日期时间格式
func FormatNowDateTime() string {
	return time.Now().Format(time.DateTime)
}

// FormatLocalDateTime 将time.Time转化为日期时间格式
func FormatLocalDateTime(t *time.Time) string {
	if t == nil {
		return ""
	}

	return t.Format(time.DateTime)
}

// FormatNowDateOnly 将当前时间转化为日期格式
func FormatNowDateOnly() string {
	return time.Now().Format(time.DateOnly)
}

// FormatLocalDateOnly 将time.Time转化为日期格式
func FormatLocalDateOnly(t *time.Time) string {
	if t == nil {
		return ""
	}

	return t.Format(time.DateOnly)
}

// GetYear 获取time.Time的年
func GetYear(t *time.Time) int {
	if t == nil {
		return 0
	}

	year, _ := t.ISOWeek()
	return year
}

// GetWeek 获取time.Time的星期
func GetWeek(t *time.Time) int {
	if t == nil {
		return 0
	}

	_, week := t.ISOWeek()
	return week
}

// DiffNatureDays 计算两个时间相差的天数
func DiffNatureDays(t1str string, t2str string) int {
	t1 := ParseLocalDateTime(t1str).Unix()
	t2 := ParseLocalDateTime(t2str).Unix()
	var secondsOfDay int64 = 86400

	if t1 == t2 {
		return -1
	}

	if t1 > t2 {
		t1, t2 = t2, t1
	}

	diffDays := 0
	secDiff := t2 - t1
	if secDiff > secondsOfDay {
		tmpDays := int(secDiff / secondsOfDay)
		t1 += int64(tmpDays) * secondsOfDay
		diffDays += tmpDays
	}

	st := time.Unix(t1, 0)
	et := time.Unix(t2, 0)
	dateFormatTpl := "20060102"
	if st.Format(dateFormatTpl) != et.Format(dateFormatTpl) {
		diffDays += 1
	}

	return diffDays
}

// GetChinaMonth 获取中文表示的年
func GetChinaMonth(t *time.Time) string {
	if t == nil {
		return ""
	}

	month := t.Format("01")
	return monthMap[month]
}

// GetChinaWeek 获取中文表示的星期
func GetChinaWeek(t *time.Time) string {
	if t == nil {
		return ""
	}

	week := t.Weekday()
	return weekMap[week.String()]
}