package xtime

import (
	"fmt"
	"time"

	"github.com/golang-module/carbon/v2"
)

// 基于Carbon而不是Time
// 默认将 SaoPauloTimezoneOffset 作为时区偏移
// 默认将 WeekStartsAt 作为每周起始
// 注意新加的函数都要基于Now()

// 设置时区
// reverse：给Now()设置时传false，解析系统时区输出的字符串/时间戳时传true
func setLocation(c *carbon.Carbon, offsets ...int) *carbon.Carbon {
	var loc *time.Location
	if len(offsets) > 0 {
		loc = time.FixedZone("CUS", offsets[len(offsets)-1])
	} else {
		loc = time.FixedZone("CST", sysTimezoneOffset)
	}

	return c.SetLocation(loc)
}

func set(c *carbon.Carbon, offsets ...int) *carbon.Carbon {
	// 设置周起始
	c = c.SetWeekStartsAt(WeekStartsAt)
	// 设置时区
	c = setLocation(c, offsets...)
	return c
}

func Now(offsets ...int) (c *carbon.Carbon) {
	c = carbon.Now().AddSeconds(nowOffset)
	c = set(c, offsets...)
	return
}

func ConvertToCarbon[T time.Time | *carbon.Carbon | int64](t T, offsets ...int) *carbon.Carbon {
	var c *carbon.Carbon
	switch v := any(t).(type) {
	case time.Time:
		c = set(carbon.CreateFromStdTime(v), offsets...)
	case *carbon.Carbon:
		c = set(v, offsets...)
	case int64:
		c = set(carbon.CreateFromTimestamp(v), offsets...)
	}
	return c
}

// IsTodayTimestamp 判断该时间戳是否为今天
func IsTodayTimestamp[T int | int64](timestamp T, offsets ...int) bool {
	return IsToday(int64(timestamp), offsets...)
}

// IsToday 判断时间是否为今天
func IsToday[T time.Time | *carbon.Carbon | int64](t T, offsets ...int) bool {
	c := ConvertToCarbon(t, offsets...)

	return c.ToDateString() == Now().ToDateString()
}

// IsBeforeNow 判断时间t是否在现在之前
// example:
//
//	now := time.Now()
//	before := time.Now().Add(-time.Hour)
//	IsBeforeNow(after) // true
func IsBeforeNow[T time.Time | *carbon.Carbon | int64](t T, offsets ...int) bool {
	return !IsAfterNow(t, offsets...)
}

// IsAfterNow 判断时间t是否在现在之后
// example:
//
//	now := time.Now()
//	after := time.Now().Add(time.Hour)
//	IsAfterNow(after) // true
func IsAfterNow[T time.Time | *carbon.Carbon | int64](t T, offsets ...int) bool {
	switch v := any(t).(type) {
	case time.Time:
		return IsAfter(v, time.Now(), offsets...)
	case *carbon.Carbon:
		return IsAfter(v, Now(), offsets...)
	case int64:
		return IsAfter(v, Now().Timestamp())
	default:
		return false
	}
}

// IsBefore 判断时间t1是否在t2之前
// example:
// t1 := time.Now().Add(-time.Hour)
// t2 := time.Now()
// IsBefore(t1,t2) // true
func IsBefore[T time.Time | *carbon.Carbon | int64](t1, t2 T, offsets ...int) bool {
	return !IsAfter(t1, t2, offsets...)
}

// IsAfter 判断时间t1是否在t2之后
// example:
// t1 := time.Now().Add(time.Hour)
// t2 := time.Now()
// IsAfter(t1,t2) // true
func IsAfter[T time.Time | *carbon.Carbon | int64](t1, t2 T, offsets ...int) bool {
	c1, c2 := ConvertToCarbon(t1, offsets...), ConvertToCarbon(t2, offsets...)
	return c1.Gt(c2)
}

// TimestampToTime 将时间戳转为 carbon.Carbon 类型
func TimestampToTime[T int | int64](timestamp T, offsets ...int) *carbon.Carbon {
	return set(carbon.CreateFromTimestamp(int64(timestamp)), offsets...)
}

// IsInDuration 判断某个时间在某个时间段内
func IsInDuration[T time.Time | *carbon.Carbon | int64](t, start, end T, offsets ...int) bool {
	return IsAfter(t, start, offsets...) && IsBefore(t, end, offsets...)
}

// FormatDuration 将起止时间，格式化为 format - format
func FormatDuration[T time.Time | *carbon.Carbon | int64](start, end T, layout string, offsets ...int) string {
	startC, endC := ConvertToCarbon(start, offsets...), ConvertToCarbon(end, offsets...)
	return fmt.Sprintf("%s - %s", startC.StdTime().Format(layout), endC.StdTime().Format(layout))
}

func Yesterday(offsets ...int) *carbon.Carbon {
	return Now(offsets...).SubDay().StartOfDay()
}

func Today(offsets ...int) *carbon.Carbon {
	return Now(offsets...).StartOfDay()
}

func Tomorrow(offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddDay().StartOfDay()
}

func NextNDay(n int, offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddDays(n).StartOfDay()
}

func LastWeek(offsets ...int) *carbon.Carbon {
	return Now(offsets...).SubWeek().StartOfWeek()
}

func ThisWeek(offsets ...int) *carbon.Carbon {
	return Now(offsets...).StartOfWeek()
}

func NextWeek(offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddWeek().StartOfWeek()
}

func NextNWeek(n int, offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddWeeks(n).StartOfWeek()
}

func LastMonth(offsets ...int) *carbon.Carbon {
	return Now(offsets...).SubMonth().StartOfMonth()
}

func ThisMonth(offsets ...int) *carbon.Carbon {
	return Now(offsets...).StartOfMonth()
}

func NextMonth(offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddMonth().StartOfMonth()
}

func NextNMonth(n int, offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddMonths(n).StartOfMonth()
}

func LastQuarter(offsets ...int) *carbon.Carbon {
	return Now(offsets...).SubQuarter().StartOfQuarter()
}

func ThisQuarter(offsets ...int) *carbon.Carbon {
	return Now(offsets...).StartOfQuarter()
}

func NextQuarter(offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddQuarter().StartOfQuarter()
}

func NextNQuarter(n int, offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddQuarters(n).StartOfQuarter()
}

func LastYear(offsets ...int) *carbon.Carbon {
	return Now(offsets...).SubYear().StartOfYear()
}

func ThisYear(offsets ...int) *carbon.Carbon {
	return Now(offsets...).StartOfYear()
}

func NextYear(offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddYear().StartOfYear()
}

func NextNYear(n int, offsets ...int) *carbon.Carbon {
	return Now(offsets...).AddYears(n).StartOfYear()
}