package lang

import (
	"strings"
	"sync"
	"time"
)

const (
	FormatDate     = "yyyy-MM-dd"
	FormatTime     = "HH:mm:ss"
	FormatDatetime = FormatDate + " " + FormatTime
)

// DateFormat 函数用于将时间格式化为指定的字符串格式
func DateFormat(t time.Time, format string) string {
	// 将自定义的格式字符串转换为 Go 的时间格式字符串
	layout := convertToGoLayout(format)
	return t.Format(layout)
}

// DateParse 函数用于解析指定格式的日期字符串
func DateParse(dateStr string, format string) (time.Time, error) {
	// 将自定义的格式字符串转换为 Go 的时间格式字符串
	layout := convertToGoLayout(format)
	return time.Parse(layout, dateStr)
}

type Date struct {
	time time.Time
	lock sync.RWMutex
}

func DateNow() *Date {
	return &Date{
		time: time.Now(),
	}
}

func DateNew(time time.Time) *Date {
	return &Date{
		time: time,
	}
}

// DateStr
// time: 时间 eg: 2024-14-12 12:15:20
// format: 时间格式 eg: yyyy-MM-dd HH:mm:ss OR FormatDatetime
func DateStr(time string, format string) (*Date, error) {
	parse, err := DateParse(time, format)
	if err != nil {
		return nil, err
	}
	return &Date{
		time: parse,
	}, nil
}

func (t *Date) ToString(format string) string {
	return DateFormat(t.time, format)
}

// OffsetYear 函数增加或减少指定的年数
func (t *Date) OffsetYear(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.AddDate(offset, 0, 0)
	return t
}

// OffsetMonth 函数增加或减少指定的月数
func (t *Date) OffsetMonth(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.AddDate(0, offset, 0)
	return t
}

// OffsetDay 函数增加或减少指定的天数
func (t *Date) OffsetDay(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.AddDate(0, 0, offset)
	return t
}

// OffsetHour 函数增加或减少指定的小时数
func (t *Date) OffsetHour(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.Add(time.Duration(offset) * time.Hour)
	return t
}

// OffsetMinute 函数增加或减少指定的分钟数
func (t *Date) OffsetMinute(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.Add(time.Duration(offset) * time.Minute)
	return t
}

// OffsetSecond 函数增加或减少指定的秒数
func (t *Date) OffsetSecond(offset int) *Date {
	t.lock.Lock()
	defer t.lock.Unlock()
	t.time = t.time.Add(time.Duration(offset) * time.Second)
	return t
}

func (t *Date) CompareTimes(time time.Time) int {
	t.lock.RLock()
	defer t.lock.RUnlock()
	if t.time.Before(time) {
		return -1
	} else if t.time.After(time) {
		return 1
	} else if t.time.Equal(time) {
		return 0
	}
	panic("time compare unreachable")
}

// convertToGoLayout 函数将自定义的日期格式转换为 Go 的时间格式
func convertToGoLayout(format string) string {
	// 替换自定义格式为 Go 的时间格式
	layout := format
	layout = strings.Replace(layout, "yyyy", "2006", -1)
	layout = strings.Replace(layout, "MM", "01", -1)
	layout = strings.Replace(layout, "dd", "02", -1)
	layout = strings.Replace(layout, "HH", "15", -1)
	layout = strings.Replace(layout, "hh", "03", -1)
	layout = strings.Replace(layout, "mm", "04", -1)
	layout = strings.Replace(layout, "ss", "05", -1)
	return layout
}