package date

import (
	"errors"
	"fmt"
	"time"
)

// Format 根据特定格式格式化日期
func (td *DateTime) Format(date time.Time, format string) (string, error) {
	if _, ok := formatMap[format]; !ok {
		return "", errors.New("unsupported format")
	}
	return date.Format(formatMap[format]), nil
}

// Parse 将日期字符串转换为Time
func (td *DateTime) Parse(dateStr, format string) (time.Time, error) {
	if _, ok := formatMap[format]; !ok {
		return time.Time{}, errors.New("unsupported format")
	}
	return time.Parse(formatMap[format], dateStr)
}

// Offset 时间偏移
func (td *DateTime) Offset(date time.Time, format string) (time.Time, error) {
	pd, err := time.ParseDuration(format)
	if err != nil {
		return date, err
	}
	return date.Add(pd), nil
}

// OffsetDay 时间日期偏移
func (td *DateTime) OffsetDay(date time.Time, day int) (time.Time, error) {
	return td.Offset(date, fmt.Sprintf("%dh", day*24))
}

// OffsetHour 按小时偏移
func (td *DateTime) OffsetHour(date time.Time, hour int) (time.Time, error) {
	return td.Offset(date, fmt.Sprintf("%dh", hour))
}

// OffsetMinute 按分钟偏移
func (td *DateTime) OffsetMinute(date time.Time, minute int) (time.Time, error) {
	return td.Offset(date, fmt.Sprintf("%dm", minute))
}

// OffsetSecond 按秒偏移
func (td *DateTime) OffsetSecond(date time.Time, second int) (time.Time, error) {
	return td.Offset(date, fmt.Sprintf("%ds", second))
}

// OffsetMillisecond 按毫秒偏移
func (td *DateTime) OffsetMillisecond(date time.Time, ms int) (time.Time, error) {
	return td.Offset(date, fmt.Sprintf("%dms", ms))
}

// SubDays 日期差
func (td *DateTime) SubDays(date1, date2 time.Time) int {
	return int(date1.Sub(date2).Hours() / 24)
}

// SubHours 小时差
func (td *DateTime) SubHours(date1, date2 time.Time) int {
	return int(date1.Sub(date2).Hours())
}

// SubMinutes 分钟差
func (td *DateTime) SubMinutes(date1, date2 time.Time) int {
	return int(date1.Sub(date2).Minutes())
}

// SubSeconds 秒差
func (td *DateTime) SubSeconds(date1, date2 time.Time) int {
	return int(date1.Sub(date2).Seconds())
}

// SubMilliseconds 毫秒差
func (td *DateTime) SubMilliseconds(date1, date2 time.Time) int {
	return int(date1.Sub(date2).Milliseconds())
}