Web Go 日期时间示例

// Web Go Get Current Time Examples
// Getting current system time and date with various precision

package main

import (
	"fmt"
	"time"
)

// 1. Basic Current Time

// GetCurrentTime gets current date and time
func GetCurrentTime() time.Time {
	return time.Now()
}

// GetCurrentDate gets current date only
func GetCurrentDate() time.Time {
	now := time.Now()
	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
}

// GetCurrentTimeOnly gets current time only
func GetCurrentTimeOnly() time.Time {
	now := time.Now()
	return time.Date(0, 1, 1, now.Hour(), now.Minute(), now.Second(), now.Nanosecond(), time.UTC)
}

// GetUnixTimestamp gets current Unix timestamp
func GetUnixTimestamp() int64 {
	return time.Now().Unix()
}

// GetUnixTimestampMillis gets current Unix timestamp in milliseconds
func GetUnixTimestampMillis() int64 {
	return time.Now().UnixMilli()
}

// GetUnixTimestampNanos gets current Unix timestamp in nanoseconds
func GetUnixTimestampNanos() int64 {
	return time.Now().UnixNano()
}

// 2. Time with Timezone

// GetUTC gets current UTC time
func GetUTC() time.Time {
	return time.Now().UTC()
}

// GetLocal gets current local time
func GetLocal() time.Time {
	return time.Now()
}

// GetLocationByName gets time in specific location
func GetLocationByName(location string) (time.Time, error) {
	loc, err := time.LoadLocation(location)
	if err != nil {
		return time.Time{}, err
	}
	return time.Now().In(loc), nil
}

// GetTimezoneOffset gets timezone offset in seconds
func GetTimezoneOffset() int {
	_, offset := time.Now().Zone()
	return offset
}

// GetTimezoneName gets timezone name
func GetTimezoneName() string {
	_, name := time.Now().Zone()
	return name
}

// 3. High Precision Time

// GetPrecisionTime gets time with high precision
func GetPrecisionTime() time.Time {
	return time.Now()
}

// GetMonotonicTime gets monotonic time (cannot go backwards)
func GetMonotonicTime() time.Duration {
	start := time.Now()
	// Simulate some work
	return time.Since(start)
}

// 4. Time Components

// GetCurrentYear gets current year
func GetCurrentYear() int {
	return time.Now().Year()
}

// GetCurrentMonth gets current month (1-12)
func GetCurrentMonth() time.Month {
	return time.Now().Month()
}

// GetCurrentDay gets current day of month (1-31)
func GetCurrentDay() int {
	return time.Now().Day()
}

// GetCurrentHour gets current hour (0-23)
func GetCurrentHour() int {
	return time.Now().Hour()
}

// GetCurrentMinute gets current minute (0-59)
func GetCurrentMinute() int {
	return time.Now().Minute()
}

// GetCurrentSecond gets current second (0-59)
func GetCurrentSecond() int {
	return time.Now().Second()
}

// GetCurrentNanosecond gets current nanosecond (0-999999999)
func GetCurrentNanosecond() int {
	return time.Now().Nanosecond()
}

// GetTimeComponents gets all time components as map
func GetTimeComponents() map[string]interface{} {
	now := time.Now()
	return map[string]interface{}{
		"year":       now.Year(),
		"month":      int(now.Month()),
		"day":        now.Day(),
		"hour":       now.Hour(),
		"minute":     now.Minute(),
		"second":     now.Second(),
		"nanosecond": now.Nanosecond(),
		"weekday":    int(now.Weekday()),
	}
}

// 5. Week and Day Information

// GetCurrentWeekday gets current weekday (0=Sunday, 6=Saturday)
func GetCurrentWeekday() time.Weekday {
	return time.Now().Weekday()
}

// GetCurrentISOWeekday gets current ISO weekday (1=Monday, 7=Sunday)
func GetCurrentISOWeekday() int {
	wd := time.Now().Weekday()
	if wd == time.Sunday {
		return 7
	}
	return int(wd)
}

// GetWeekOfYear gets current week of year
func GetWeekOfYear() int {
	_, week := time.Now().ISOWeek()
	return week
}

// GetYearOfWeek gets ISO year
func GetYearOfWeek() int {
	year, _ := time.Now().ISOWeek()
	return year
}

// GetDayOfYear gets current day of year
func GetDayOfYear() int {
	now := time.Now()
	startOfYear := time.Date(now.Year(), 1, 1, 0, 0, 0, 0, now.Location())
	return int(now.Sub(startOfYear).Hours()/24) + 1
}

// GetWeekdayName gets current weekday name
func GetWeekdayName() string {
	return time.Now().Weekday().String()
}

// GetMonthName gets current month name
func GetMonthName() string {
	return time.Now().Month().String()
}

// 6. Time Strings

// GetTimeString gets current time as string
func GetTimeString() string {
	now := time.Now()
	return fmt.Sprintf("%02d:%02d:%02d", now.Hour(), now.Minute(), now.Second())
}

// GetDateString gets current date as string
func GetDateString() string {
	now := time.Now()
	return fmt.Sprintf("%04d-%02d-%02d", now.Year(), now.Month(), now.Day())
}

// GetDateTimeString gets current datetime as string
func GetDateTimeString() string {
	now := time.Now()
	return fmt.Sprintf("%04d-%02d-%02d %02d:%02d:%02d",
		now.Year(), now.Month(), now.Day(),
		now.Hour(), now.Minute(), now.Second())
}

// GetISO8601 gets ISO 8601 formatted time
func GetISO8601() string {
	return time.Now().Format(time.RFC3339)
}

// GetRFC1123 gets RFC 1123 formatted time
func GetRFC1123() string {
	return time.Now().Format(time.RFC1123)
}

// 7. Relative Time

// GetTimeSinceEpoch gets seconds since Unix epoch
func GetTimeSinceEpoch() float64 {
	return float64(time.Now().UnixNano()) / 1e9
}

// GetTimeUntilMidnight gets seconds until midnight
func GetTimeUntilMidnight() float64 {
	now := time.Now()
	midnight := time.Date(now.Year(), now.Month(), now.Day(), 23, 59, 59, 0, now.Location())
	return midnight.Sub(now).Seconds()
}

// GetTimeSinceMidnight gets seconds since midnight
func GetTimeSinceMidnight() float64 {
	now := time.Now()
	midnight := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	return now.Sub(midnight).Seconds()
}

// GetDaysInMonth gets number of days in current month
func GetDaysInMonth() int {
	now := time.Now()
	firstDay := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, time.UTC)
	lastDay := firstDay.AddDate(0, 1, -1)
	return lastDay.Day()
}

// IsLeapYear checks if current year is leap year
func IsLeapYear() bool {
	year := time.Now().Year()
	if year%4 != 0 {
		return false
	} else if year%100 != 0 {
		return true
	} else {
		return year%400 == 0
	}
}

// IsLeapYearFor checks if given year is leap year
func IsLeapYearFor(year int) bool {
	if year%4 != 0 {
		return false
	} else if year%100 != 0 {
		return true
	} else {
		return year%400 == 0
	}
}

// 8. Time Measurements

// StartMeasurement starts time measurement
func StartMeasurement() time.Time {
	return time.Now()
}

// EndMeasurement ends time measurement and returns duration
func EndMeasurement(start time.Time) time.Duration {
	return time.Since(start)
}

// MeasureFunction measures function execution time
func MeasureFunction(fn func()) time.Duration {
	start := time.Now()
	fn()
	return time.Since(start)
}

// 9. Multiple Time Representations

// GetAllTimeFormats gets time in all common formats
func GetAllTimeFormats() map[string]interface{} {
	now := time.Now()
	return map[string]interface{}{
		"unix":        now.Unix(),
		"unix_millis": now.UnixMilli(),
		"unix_nanos":  now.UnixNano(),
		"iso8601":     now.Format(time.RFC3339),
		"rfc1123":     now.Format(time.RFC1123),
		"rfc3339":     now.Format(time.RFC3339),
		"date":        GetDateString(),
		"time":        GetTimeString(),
		"datetime":    GetDateTimeString(),
		"year":        now.Year(),
		"month":       int(now.Month()),
		"day":         now.Day(),
		"hour":        now.Hour(),
		"minute":      now.Minute(),
		"second":      now.Second(),
	}
}

// 10. Time Arithmetic

// AddDays adds days to current time
func AddDays(days int) time.Time {
	return time.Now().AddDate(0, 0, days)
}

// AddMonths adds months to current time
func AddMonths(months int) time.Time {
	return time.Now().AddDate(0, months, 0)
}

// AddYears adds years to current time
func AddYears(years int) time.Time {
	return time.Now().AddDate(years, 0, 0)
}

// AddHours adds hours to current time
func AddHours(hours float64) time.Time {
	return time.Now().Add(time.Duration(hours) * time.Hour)
}

// AddMinutes adds minutes to current time
func AddMinutes(minutes float64) time.Time {
	return time.Now().Add(time.Duration(minutes) * time.Minute)
}

// AddSeconds adds seconds to current time
func AddSeconds(seconds float64) time.Time {
	return time.Now().Add(time.Duration(seconds) * time.Second)
}

// 11. Time Comparison

// IsBefore checks if current time is before given time
func IsBefore(t time.Time) bool {
	return time.Now().Before(t)
}

// IsAfter checks if current time is after given time
func IsAfter(t time.Time) bool {
	return time.Now().After(t)
}

// IsBetween checks if current time is between start and end
func IsBetween(start, end time.Time) bool {
	now := time.Now()
	return now.After(start) && now.Before(end)
}

// Usage Examples
func main() {
	fmt.Println("=== Web Go Get Current Time Examples ===
")

	// 1. Basic time
	fmt.Println("--- 1. Basic Current Time ---")
	fmt.Printf("Current datetime: %v
", GetCurrentTime())
	fmt.Printf("Current date: %v
", GetCurrentDate())
	fmt.Printf("Unix timestamp: %d
", GetUnixTimestamp())
	fmt.Printf("Timestamp (ms): %d
", GetUnixTimestampMillis())

	// 2. Timezone
	fmt.Println("
--- 2. Timezone Information ---")
	fmt.Printf("UTC: %v
", GetUTC())
	fmt.Printf("Local: %v
", GetLocal())
	fmt.Printf("Timezone offset: %d seconds
", GetTimezoneOffset())
	fmt.Printf("Timezone name: %s
", GetTimezoneName())

	// 3. Components
	fmt.Println("
--- 3. Time Components ---")
	fmt.Printf("Components: %v
", GetTimeComponents())

	// 4. Week/Day info
	fmt.Println("
--- 4. Week and Day Information ---")
	fmt.Printf("Weekday: %s
", GetWeekdayName())
	fmt.Printf("Month: %s
", GetMonthName())
	fmt.Printf("Week of year: %d
", GetWeekOfYear())
	fmt.Printf("Day of year: %d
", GetDayOfYear())

	// 5. String formats
	fmt.Println("
--- 5. String Formats ---")
	fmt.Printf("Time: %s
", GetTimeString())
	fmt.Printf("Date: %s
", GetDateString())
	fmt.Printf("DateTime: %s
", GetDateTimeString())
	fmt.Printf("ISO8601: %s
", GetISO8601())
	fmt.Printf("RFC1123: %s
", GetRFC1123())

	// 6. Relative time
	fmt.Println("
--- 6. Relative Time ---")
	fmt.Printf("Until midnight: %.0f seconds
", GetTimeUntilMidnight())
	fmt.Printf("Since midnight: %.0f seconds
", GetTimeSinceMidnight())
	fmt.Printf("Days in month: %d
", GetDaysInMonth())
	fmt.Printf("Is leap year: %t
", IsLeapYear())

	// 7. Time measurement
	fmt.Println("
--- 7. Time Measurement ---")
	start := StartMeasurement()
	time.Sleep(100 * time.Millisecond)
	elapsed := EndMeasurement(start)
	fmt.Printf("Elapsed: %v
", elapsed)

	// 8. All formats
	fmt.Println("
--- 8. All Formats ---")
	formats := GetAllTimeFormats()
	for key, value := range formats {
		fmt.Printf("%s: %v
", key, value)
	}

	// 9. Time arithmetic
	fmt.Println("
--- 9. Time Arithmetic ---")
	fmt.Printf("Tomorrow: %v
", AddDays(1))
	fmt.Printf("Next month: %v
", AddMonths(1))
	fmt.Printf("Next year: %v
", AddYears(1))
	fmt.Printf("In 24 hours: %v
", AddHours(24))

	// 10. Location
	fmt.Println("
--- 10. Time in Different Locations ---")
	if ny, err := GetLocationByName("America/New_York"); err == nil {
		fmt.Printf("New York: %v
", ny)
	}
	if london, err := GetLocationByName("Europe/London"); err == nil {
		fmt.Printf("London: %v
", london)
	}
	if tokyo, err := GetLocationByName("Asia/Tokyo"); err == nil {
		fmt.Printf("Tokyo: %v
", tokyo)
	}

	fmt.Println("
=== All Get Current Time Examples Completed ===")
}

// Web Go Time Formatting Examples
// Converting time.Time objects to formatted strings

package main

import (
	"fmt"
	"time"
)

// 1. Standard Format Codes

// FormatYear formats year in various ways
func FormatYear(t time.Time) map[string]string {
	return map[string]string{
		"full":  fmt.Sprintf("%04d", t.Year()),
		"short": fmt.Sprintf("%02d", t.Year()%100),
	}
}

// FormatMonth formats month in various ways
func FormatMonth(t time.Time) map[string]string {
	return map[string]string{
		"numeric":      fmt.Sprintf("%02d", t.Month()),
		"name":         t.Month().String(),
		"name_short":   t.Format("Jan"),
		"numeric_zero": fmt.Sprintf("%d", t.Month()),
	}
}

// FormatDay formats day in various ways
func FormatDay(t time.Time) map[string]string {
	return map[string]string{
		"numeric": fmt.Sprintf("%02d", t.Day()),
		"with_ordinal": fmt.Sprintf("%d%s", t.Day(),
			getOrdinal(t.Day())),
		"name":    t.Weekday().String(),
		"name_short": t.Format("Mon"),
	}
}

func getOrdinal(day int) string {
	switch day {
	case 1, 21, 31:
		return "st"
	case 2, 22:
		return "nd"
	case 3, 23:
		return "rd"
	default:
		return "th"
	}
}

// FormatTime formats time in various ways
func FormatTime(t time.Time) map[string]string {
	return map[string]string{
		"24h":        fmt.Sprintf("%02d:%02d:%02d", t.Hour(), t.Minute(), t.Second()),
		"12h":        t.Format("03:04:05 PM"),
		"24h_short":  fmt.Sprintf("%02d:%02d", t.Hour(), t.Minute()),
		"12h_short":  t.Format("03:04 PM"),
		"hour_24":    fmt.Sprintf("%02d", t.Hour()),
		"hour_12":    t.Format("3"),
		"minute":     fmt.Sprintf("%02d", t.Minute()),
		"second":     fmt.Sprintf("%02d", t.Second()),
		"period":     t.Format("PM"),
	}
}

// 2. Common Date Formats

// FormatISO8601 formats as ISO 8601
func FormatISO8601(t time.Time) string {
	return t.Format(time.RFC3339)
}

// FormatRFC1123 formats as RFC 1123
func FormatRFC1123(t time.Time) string {
	return t.Format(time.RFC1123)
}

// FormatRFC3339 formats as RFC 3339
func FormatRFC3339(t time.Time) string {
	return t.Format(time.RFC3339)
}

// FormatRFC822 formats as RFC 822
func FormatRFC822(t time.Time) string {
	return t.Format(time.RFC822)
}

// FormatANSIC formats as ANSIC
func FormatANSIC(t time.Time) string {
	return t.Format(time.ANSIC)
}

// FormatUnixDate formats as Unix date
func FormatUnixDate(t time.Time) string {
	return t.Format(time.UnixDate)
}

// 3. Regional Formats

// FormatUSDate formats as US date (MM/DD/YYYY)
func FormatUSDate(t time.Time) string {
	return fmt.Sprintf("%02d/%02d/%04d", t.Month(), t.Day(), t.Year())
}

// FormatEUDate formats as European date (DD/MM/YYYY)
func FormatEUDate(t time.Time) string {
	return fmt.Sprintf("%02d/%02d/%04d", t.Day(), t.Month(), t.Year())
}

// FormatISODate formats as ISO date (YYYY-MM-DD)
func FormatISODate(t time.Time) string {
	return fmt.Sprintf("%04d-%02d-%02d", t.Year(), t.Month(), t.Day())
}

// FormatChineseDate formats as Chinese date (YYYY年MM月DD日)
func FormatChineseDate(t time.Time) string {
	return fmt.Sprintf("%04d年%02d月%02d日", t.Year(), t.Month(), t.Day())
}

// FormatJapaneseDate formats as Japanese date (YYYY年MM月DD日)
func FormatJapaneseDate(t time.Time) string {
	return fmt.Sprintf("%04d年%02d月%02d日", t.Year(), t.Month(), t.Day())
}

// FormatKoreanDate formats as Korean date (YYYY년 MM월 DD일)
func FormatKoreanDate(t time.Time) string {
	return fmt.Sprintf("%04d년 %02d월 %02d일", t.Year(), t.Month(), t.Day())
}

// 4. Custom Formats

// FormatReadable formats in human-readable form
func FormatReadable(t time.Time) string {
	return fmt.Sprintf("%s, %s %d, %s at %02d:%02d %s",
		t.Weekday(),
		t.Month(),
		t.Day(),
		t.Year(),
		t.Hour()%12,
		t.Minute(),
		getAMPM(t))
}

func getAMPM(t time.Time) string {
	if t.Hour() < 12 {
		return "AM"
	}
	return "PM"
}

// FormatCompact formats in compact form
func FormatCompact(t time.Time) string {
	return fmt.Sprintf("%04d%02d%02d_%02d%02d%02d",
		t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second())
}

// FormatWithTimezone formats with timezone info
func FormatWithTimezone(t time.Time) string {
	return fmt.Sprintf("%04d-%02d-%02d %02d:%02d:%02d %s",
		t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second(),
		t.Format("MST"))
}

// FormatFriendly formats in friendly relative form
func FormatFriendly(t time.Time) string {
	now := time.Now()
	diff := now.Sub(t)

	if diff < time.Minute {
		return "just now"
	} else if diff < time.Hour {
		minutes := int(diff.Minutes())
		if minutes == 1 {
			return "1 minute ago"
		}
		return fmt.Sprintf("%d minutes ago", minutes)
	} else if diff < 24*time.Hour {
		hours := int(diff.Hours())
		if hours == 1 {
			return "1 hour ago"
		}
		return fmt.Sprintf("%d hours ago", hours)
	} else if diff < 30*24*time.Hour {
		days := int(diff.Hours() / 24)
		if days == 1 {
			return "1 day ago"
		}
		return fmt.Sprintf("%d days ago", days)
	} else {
		return FormatISODate(t)
	}
}

// 5. Duration Formatting

// FormatDuration formats duration in human-readable form
func FormatDuration(d time.Duration) string {
	hours := int(d.Hours())
	minutes := int(d.Minutes()) % 60
	seconds := int(d.Seconds()) % 60

	if hours > 0 {
		return fmt.Sprintf("%dh %dm %ds", hours, minutes, seconds)
	} else if minutes > 0 {
		return fmt.Sprintf("%dm %ds", minutes, seconds)
	} else {
		return fmt.Sprintf("%ds", seconds)
	}
}

// FormatDurationPrecise formats duration with milliseconds
func FormatDurationPrecise(d time.Duration) string {
	hours := int(d.Hours())
	minutes := int(d.Minutes()) % 60
	seconds := int(d.Seconds()) % 60
	millis := d.Milliseconds() % 1000

	if hours > 0 {
		return fmt.Sprintf("%dh %dm %ds %dms", hours, minutes, seconds, millis)
	} else if minutes > 0 {
		return fmt.Sprintf("%dm %ds %dms", minutes, seconds, millis)
	} else {
		return fmt.Sprintf("%ds %dms", seconds, millis)
	}
}

// 6. Relative Formatting

// FormatRelativeToNow formats datetime relative to now
func FormatRelativeToNow(t time.Time) string {
	now := time.Now()
	var diff time.Duration
	var suffix string

	if t.After(now) {
		diff = t.Sub(now)
		suffix = "from now"
	} else {
		diff = now.Sub(t)
		suffix = "ago"
	}

	if diff < time.Minute {
		seconds := int(diff.Seconds())
		if seconds == 1 {
			return fmt.Sprintf("1 second %s", suffix)
		}
		return fmt.Sprintf("%d seconds %s", seconds, suffix)
	} else if diff < time.Hour {
		minutes := int(diff.Minutes())
		if minutes == 1 {
			return fmt.Sprintf("1 minute %s", suffix)
		}
		return fmt.Sprintf("%d minutes %s", minutes, suffix)
	} else if diff < 24*time.Hour {
		hours := int(diff.Hours())
		if hours == 1 {
			return fmt.Sprintf("1 hour %s", suffix)
		}
		return fmt.Sprintf("%d hours %s", hours, suffix)
	} else if diff < 30*24*time.Hour {
		days := int(diff.Hours() / 24)
		if days == 1 {
			return fmt.Sprintf("1 day %s", suffix)
		}
		return fmt.Sprintf("%d days %s", days, suffix)
	} else if diff < 365*24*time.Hour {
		months := int(diff.Hours() / (24 * 30))
		if months == 1 {
			return fmt.Sprintf("1 month %s", suffix)
		}
		return fmt.Sprintf("%d months %s", months, suffix)
	} else {
		years := int(diff.Hours() / (24 * 365))
		if years == 1 {
			return fmt.Sprintf("1 year %s", suffix)
		}
		return fmt.Sprintf("%d years %s", years, suffix)
	}
}

// 7. Business Date Formats

// FormatQuarter formats as quarter
func FormatQuarter(t time.Time) string {
	quarter := (t.Month()-1)/3 + 1
	return fmt.Sprintf("Q%d %d", quarter, t.Year())
}

// FormatWeekNumber formats with week number
func FormatWeekNumber(t time.Time) string {
	year, week := t.ISOWeek()
	return fmt.Sprintf("%d-W%02d", year, week)
}

// FormatDayOfYear formats with day of year
func FormatDayOfYear(t time.Time) string {
	startOfYear := time.Date(t.Year(), 1, 1, 0, 0, 0, 0, t.Location())
	dayOfYear := int(t.Sub(startOfYear).Hours()/24) + 1
	return fmt.Sprintf("%d-%03d", t.Year(), dayOfYear)
}

// FormatSemester formats as semester
func FormatSemester(t time.Time) string {
	semester := 1
	if t.Month() >= 7 {
		semester = 2
	}
	return fmt.Sprintf("S%d %d", semester, t.Year())
}

// 8. Custom Pattern Formatting

// FormatWithPattern formats with custom pattern
func FormatWithPattern(t time.Time, pattern string) string {
	// Simple pattern replacement
	result := pattern
	result = fmt.Sprintf(result, t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second())
	return result
}

// FormatDateTime formats datetime with custom format
func FormatDateTime(t time.Time, format string) string {
	// Common format placeholders
	layouts := map[string]string{
		"YYYY-MM-DD":     "2006-01-02",
		"DD/MM/YYYY":     "02/01/2006",
		"MM/DD/YYYY":     "01/02/2006",
		"YYYY-MM-DD HH:MM:SS": "2006-01-02 15:04:05",
		"HH:MM":          "15:04",
		"HH:MM:SS":       "15:04:05",
	}

	if layout, ok := layouts[format]; ok {
		return t.Format(layout)
	}
	return t.Format(format)
}

// 9. Format Codes Reference

// GetAllFormatCodes gets all format codes with examples
func GetAllFormatCodes() map[string]string {
	t := time.Date(2025, 12, 31, 14, 30, 45, 0, time.UTC)
	return map[string]string{
		"ANSIC":       t.Format(time.ANSIC),
		"UnixDate":    t.Format(time.UnixDate),
		"RubyDate":    t.Format(time.RubyDate),
		"RFC822":      t.Format(time.RFC822),
		"RFC822Z":     t.Format(time.RFC822Z),
		"RFC850":      t.Format(time.RFC850),
		"RFC1123":     t.Format(time.RFC1123),
		"RFC1123Z":    t.Format(time.RFC1123Z),
		"RFC3339":     t.Format(time.RFC3339),
		"RFC3339Nano": t.Format(time.RFC3339Nano),
		"Kitchen":     t.Format(time.Kitchen),
		"Stamp":       t.Format(time.Stamp),
		"StampMilli":  t.Format(time.StampMilli),
		"StampMicro":  t.Format(time.StampMicro),
		"StampNano":   t.Format(time.StampNano),
	}
}

// 10. Special Formats

// FormatLog formats for logging
func FormatLog(t time.Time) string {
	return t.Format("2006-01-02 15:04:05.000")
}

// FormatFileSafe formats for filenames
func FormatFileSafe(t time.Time) string {
	return fmt.Sprintf("%04d%02d%02d_%02d%02d%02d",
		t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second())
}

// FormatHTTP formats for HTTP headers
func FormatHTTP(t time.Time) string {
	return t.Format(time.RFC1123)
}

// Usage Examples
func main() {
	fmt.Println("=== Web Go Time Formatting Examples ===
")

	now := time.Now()

	// 1. Standard formats
	fmt.Println("--- 1. Standard Format Codes ---")
	fmt.Printf("Month: %v
", FormatMonth(now))
	fmt.Printf("Day: %v
", FormatDay(now))
	fmt.Printf("Time: %v
", FormatTime(now))

	// 2. Common formats
	fmt.Println("
--- 2. Common Date Formats ---")
	fmt.Printf("ISO 8601: %s
", FormatISO8601(now))
	fmt.Printf("RFC 1123: %s
", FormatRFC1123(now))
	fmt.Printf("RFC 3339: %s
", FormatRFC3339(now))

	// 3. Regional formats
	fmt.Println("
--- 3. Regional Formats ---")
	fmt.Printf("US: %s
", FormatUSDate(now))
	fmt.Printf("EU: %s
", FormatEUDate(now))
	fmt.Printf("ISO: %s
", FormatISODate(now))
	fmt.Printf("Chinese: %s
", FormatChineseDate(now))
	fmt.Printf("Japanese: %s
", FormatJapaneseDate(now))

	// 4. Custom formats
	fmt.Println("
--- 4. Custom Formats ---")
	fmt.Printf("Readable: %s
", FormatReadable(now))
	fmt.Printf("Compact: %s
", FormatCompact(now))
	fmt.Printf("Friendly: %s
", FormatFriendly(now))

	// 5. Duration formatting
	fmt.Println("
--- 5. Duration Formatting ---")
	fmt.Printf("1h 30m 45s: %s
", FormatDuration(time.Hour+30*time.Minute+45*time.Second))
	fmt.Printf("Duration precise: %s
", FormatDurationPrecise(90*time.Minute+12345*time.Millisecond))

	// 6. Relative formatting
	fmt.Println("
--- 6. Relative Formatting ---")
	future := now.Add(2 * time.Hour)
	fmt.Printf("2 hours from now: %s
", FormatRelativeToNow(future))
	past := now.Add(-24 * time.Hour)
	fmt.Printf("1 day ago: %s
", FormatRelativeToNow(past))

	// 7. Business formats
	fmt.Println("
--- 7. Business Date Formats ---")
	fmt.Printf("Quarter: %s
", FormatQuarter(now))
	fmt.Printf("Week: %s
", FormatWeekNumber(now))
	fmt.Printf("Day of year: %s
", FormatDayOfYear(now))
	fmt.Printf("Semester: %s
", FormatSemester(now))

	// 8. Format codes reference
	fmt.Println("
--- 8. Format Codes Reference ---")
	codes := GetAllFormatCodes()
	for name, example := range codes {
		fmt.Printf("%s: %s
", name, example)
	}

	// 9. Special formats
	fmt.Println("
--- 9. Special Formats ---")
	fmt.Printf("Log: %s
", FormatLog(now))
	fmt.Printf("File safe: %s
", FormatFileSafe(now))
	fmt.Printf("HTTP: %s
", FormatHTTP(now))

	fmt.Println("
=== All Time Formatting Examples Completed ===")
}

// Web Go Time Parsing Examples
// Converting strings to time.Time objects with various formats

package main

import (
	"fmt"
	"strings"
	"time"
)

// 1. Basic Parsing

// ParseISO8601 parses ISO 8601 format
func ParseISO8601(dateString string) (time.Time, error) {
	return time.Parse(time.RFC3339, dateString)
}

// ParseRFC1123 parses RFC 1123 format
func ParseRFC1123(dateString string) (time.Time, error) {
	return time.Parse(time.RFC1123, dateString)
}

// ParseRFC3339 parses RFC 3339 format
func ParseRFC3339(dateString string) (time.Time, error) {
	return time.Parse(time.RFC3339, dateString)
}

// ParseCustomFormat parses using custom format
func ParseCustomFormat(dateString, layout string) (time.Time, error) {
	return time.Parse(layout, dateString)
}

// 2. Common Format Parsing

// ParseUSDate parses US date (MM/DD/YYYY)
func ParseUSDate(dateString string) (time.Time, error) {
	layouts := []string{
		"01/02/2006",
		"01/02/2006 15:04:05",
		"01-02-2006",
		"01-02-2006 15:04:05",
	}

	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse date: %s", dateString)
}

// ParseEUDate parses European date (DD/MM/YYYY)
func ParseEUDate(dateString string) (time.Time, error) {
	layouts := []string{
		"02/01/2006",
		"02/01/2006 15:04:05",
		"02-01-2006",
		"02-01-2006 15:04:05",
	}

	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse date: %s", dateString)
}

// ParseISODate parses ISO date (YYYY-MM-DD)
func ParseISODate(dateString string) (time.Time, error) {
	layouts := []string{
		"2006-01-02",
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05",
		"2006-01-02T15:04:05Z",
		"20060102",
	}

	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse date: %s", dateString)
}

// 3. Flexible Parsing

// ParseAuto auto-detects and parses format
func ParseAuto(dateString string) (time.Time, error) {
	// Try common layouts in order
	layouts := []string{
		time.RFC3339,
		time.RFC1123,
		time.RFC822,
		time.RFC850,
		time.ANSIC,
		time.UnixDate,
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05",
		"2006-01-02",
		"02/01/2006",
		"01/02/2006",
		"02.01.2006",
		"01.02.2006",
		"02 Jan 2006",
		"02 January 2006",
		"Jan 2, 2006",
		"January 2, 2006",
		"20060102",
		"02/01/06",
		"01/02/06",
	}

	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse date with any known format: %s", dateString)
}

// ParseAutoList parses and returns all possible interpretations
func ParseAutoList(dateString string) []time.Time {
	var results []time.Time

	layouts := []string{
		time.RFC3339,
		"2006-01-02 15:04:05",
		"2006-01-02",
		"02/01/2006",
		"01/02/2006",
		"02.01.2006",
		"01.02.2006",
	}

	seen := make(map[string]bool)
	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			key := t.String()
			if !seen[key] {
				seen[key] = true
				results = append(results, t)
			}
		}
	}

	return results
}

// 4. Time Parsing

// ParseTime parses time string
func ParseTime(timeString string) (time.Time, error) {
	layouts := []string{
		"15:04:05",
		"15:04",
		"3:04:05 PM",
		"3:04 PM",
		"15:04:05.000",
		"3:04:05.000 PM",
	}

	for _, layout := range layouts {
		t, err := time.Parse(layout, timeString)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse time: %s", timeString)
}

// ParseTimestamp parses Unix timestamp
func ParseTimestamp(timestamp int64) time.Time {
	return time.Unix(timestamp, 0)
}

// ParseTimestampMillis parses millisecond timestamp
func ParseTimestampMillis(timestamp int64) time.Time {
	return time.Unix(timestamp/1000, (timestamp%1000)*1000000)
}

// ParseTimestampNanos parses nanosecond timestamp
func ParseTimestampNanos(timestamp int64) time.Time {
	sec := timestamp / 1000000000
	nsec := timestamp % 1000000000
	return time.Unix(sec, nsec)
}

// 5. Relative Time Parsing

// ParseRelative parses relative time strings
func ParseRelative(relativeString string) (time.Time, error) {
	now := time.Now()
	lower := strings.ToLower(relativeString)

	// Match patterns like "in 5 minutes", "2 hours ago", etc.
	if strings.Contains(lower, "ago") {
		// Past
		if strings.Contains(lower, "second") {
			return now, fmt.Errorf("use specific number")
		} else if strings.Contains(lower, "minute") {
			// Parse "X minutes ago"
			var minutes int
			fmt.Sscanf(relativeString, "%d", &minutes)
			return now.Add(-time.Duration(minutes) * time.Minute), nil
		} else if strings.Contains(lower, "hour") {
			var hours int
			fmt.Sscanf(relativeString, "%d", &hours)
			return now.Add(-time.Duration(hours) * time.Hour), nil
		} else if strings.Contains(lower, "day") {
			var days int
			fmt.Sscanf(relativeString, "%d", &days)
			return now.AddDate(0, 0, -days), nil
		}
	} else if strings.Contains(lower, "in ") {
		// Future
		if strings.Contains(lower, "minute") {
			var minutes int
			fmt.Sscanf(relativeString, "in %d", &minutes)
			return now.Add(time.Duration(minutes) * time.Minute), nil
		} else if strings.Contains(lower, "hour") {
			var hours int
			fmt.Sscanf(relativeString, "in %d", &hours)
			return now.Add(time.Duration(hours) * time.Hour), nil
		} else if strings.Contains(lower, "day") {
			var days int
			fmt.Sscanf(relativeString, "in %d", &days)
			return now.AddDate(0, 0, days), nil
		}
	}

	return time.Time{}, fmt.Errorf("cannot parse relative time: %s", relativeString)
}

// 6. Multi-Format Parsing

// TryMultipleFormats tries multiple formats
func TryMultipleFormats(dateString string, layouts []string) (time.Time, error) {
	for _, layout := range layouts {
		t, err := time.Parse(layout, dateString)
		if err == nil {
			return t, nil
		}
	}
	return time.Time{}, fmt.Errorf("none of the formats matched")
}

// 7. Parser with Fallback

// ParseWithFallback parses with fallback on failure
func ParseWithFallback(dateString string, fallback time.Time) time.Time {
	t, err := ParseAuto(dateString)
	if err != nil {
		return fallback
	}
	return t
}

// 8. Validation

// IsValidDate validates date string against format
func IsValidDate(dateString, layout string) bool {
	_, err := time.Parse(layout, dateString)
	return err == nil
}

// GetDetectedFormat detects which format matches
func GetDetectedFormat(dateString string) string {
	layouts := map[string]string{
		"ISO 8601":    "2006-01-02",
		"US Date":     "01/02/2006",
		"EU Date":     "02/01/2006",
		"RFC 3339":    time.RFC3339,
		"RFC 1123":    time.RFC1123,
		"Custom Date": "02-Jan-2006",
	}

	for name, layout := range layouts {
		if IsValidDate(dateString, layout) {
			return name
		}
	}

	return "Unknown"
}

// 9. Extract Date Parts

// ExtractDateParts extracts date parts using string manipulation
func ExtractDateParts(dateString string) map[string]int {
	// Try ISO format first
	var year, month, day int
	if dateString[4] == '-' && dateString[7] == '-' {
		fmt.Sscanf(dateString, "%d-%d-%d", &year, &month, &day)
		return map[string]int{
			"year":  year,
			"month": month,
			"day":   day,
		}
	}

	// Try US format
	if dateString[2] == '/' && dateString[5] == '/' {
		fmt.Sscanf(dateString, "%d/%d/%d", &month, &day, &year)
		return map[string]int{
			"year":  year,
			"month": month,
			"day":   day,
		}
	}

	// Try EU format
	if dateString[2] == '/' && dateString[5] == '/' {
		fmt.Sscanf(dateString, "%d/%d/%d", &day, &month, &year)
		return map[string]int{
			"year":  year,
			"month": month,
			"day":   day,
		}
	}

	return nil
}

// 10. Specialized Parsers

// ParseHTTPDate parses HTTP date format
func ParseHTTPDate(dateString string) (time.Time, error) {
	return time.Parse(time.RFC1123, dateString)
}

// ParseCookieDate parses cookie date format
func ParseCookieDate(dateString string) (time.Time, error) {
	layouts := []string{
		time.RFC1123,
		"Monday, 02-Jan-2006 15:04:05 MST",
		"Mon, 02-Jan-2006 15:04:05 MST",
	}
	return TryMultipleFormats(dateString, layouts)
}

// ParseEmailDate parses email date format
func ParseEmailDate(dateString string) (time.Time, error) {
	return time.Parse(time.RFC1123, dateString)
}

// ParseLogFileDate parses log file timestamp
func ParseLogFileDate(dateString string) (time.Time, error) {
	layouts := []string{
		"2006/01/02 15:04:05",
		"2006-01-02 15:04:05",
		"2006.01.02 15:04:05",
		"01/02/2006 15:04:05",
		"02-Jan-06 15:04:05",
	}
	return TryMultipleFormats(dateString, layouts)
}

// 11. Locale-Specific Parsing

// ParseGermanDate parses German date format
func ParseGermanDate(dateString string) (time.Time, error) {
	layouts := []string{
		"02.01.2006",
		"02.01.06",
		"2.1.2006",
		"2.1.06",
	}
	return TryMultipleFormats(dateString, layouts)
}

// ParseFrenchDate parses French date format
func ParseFrenchDate(dateString string) (time.Time, error) {
	layouts := []string{
		"02/01/2006",
		"02-01-2006",
	}
	return TryMultipleFormats(dateString, layouts)
}

// ParseJapaneseDate parses Japanese date format
func ParseJapaneseDate(dateString string) (time.Time, error) {
	layouts := []string{
		"2006年01月02日",
		"2006/01/02",
	}
	return TryMultipleFormats(dateString, layouts)
}

// Usage Examples
func main() {
	fmt.Println("=== Web Go Time Parsing Examples ===
")

	// 1. Basic parsing
	fmt.Println("--- 1. Basic Parsing ---")
	isoTime := "2025-12-31T14:30:45Z"
	if t, err := ParseISO8601(isoTime); err == nil {
		fmt.Printf("ISO 8601: %v
", t)
	}

	// 2. Common formats
	fmt.Println("
--- 2. Common Format Parsing ---")
	usDate := "12/31/2025"
	if t, err := ParseUSDate(usDate); err == nil {
		fmt.Printf("US date: %v
", t)
	}

	euDate := "31/12/2025"
	if t, err := ParseEUDate(euDate); err == nil {
		fmt.Printf("EU date: %v
", t)
	}

	isoDate := "2025-12-31"
	if t, err := ParseISODate(isoDate); err == nil {
		fmt.Printf("ISO date: %v
", t)
	}

	// 3. Auto-detect
	fmt.Println("
--- 3. Auto-Detection ---")
	testDates := []string{
		"2025-12-31",
		"31/12/2025",
		"12/31/2025",
		"Dec 31, 2025",
	}
	for _, date := range testDates {
		if t, err := ParseAuto(date); err == nil {
			fmt.Printf("'%s' -> %v
", date, t)
		}
	}

	// 4. Time parsing
	fmt.Println("
--- 4. Time Parsing ---")
	times := []string{"14:30:45", "2:30 PM", "14:30"}
	for _, t := range times {
		if parsed, err := ParseTime(t); err == nil {
			fmt.Printf("'%s' -> %v
", t, parsed)
		}
	}

	// 5. Timestamp parsing
	fmt.Println("
--- 5. Timestamp Parsing ---")
	ts := int64(1735667445)
	fmt.Printf("Timestamp %d: %v
", ts, ParseTimestamp(ts))

	// 6. Format detection
	fmt.Println("
--- 6. Format Detection ---")
	fmt.Printf("Detected format for '2025-12-31': %s
", GetDetectedFormat("2025-12-31"))
	fmt.Printf("Detected format for '12/31/2025': %s
", GetDetectedFormat("12/31/2025"))

	// 7. Extract parts
	fmt.Println("
--- 7. Extract Date Parts ---")
	parts := ExtractDateParts("2025-12-31")
	fmt.Printf("Parts: %v
", parts)

	// 8. Multi-format parsing
	fmt.Println("
--- 8. Try Multiple Formats ---")
	layouts := []string{"2006-01-02", "02/01/2006", "01/02/2006"}
	if t, err := TryMultipleFormats("2025-12-31", layouts); err == nil {
		fmt.Printf("Parsed: %v
", t)
	}

	// 9. Locale-specific
	fmt.Println("
--- 9. Locale-Specific Parsing ---")
	german := "31.12.2025"
	if t, err := ParseGermanDate(german); err == nil {
		fmt.Printf("German: %v
", t)
	}

	japanese := "2025年12月31日"
	if t, err := ParseJapaneseDate(japanese); err == nil {
		fmt.Printf("Japanese: %v
", t)
	}

	// 10. Specialized formats
	fmt.Println("
--- 10. Specialized Formats ---")
	httpDate := "Wed, 31 Dec 2025 14:30:45 GMT"
	if t, err := ParseHTTPDate(httpDate); err == nil {
		fmt.Printf("HTTP date: %v
", t)
	}

	logDate := "2025/12/31 14:30:45"
	if t, err := ParseLogFileDate(logDate); err == nil {
		fmt.Printf("Log date: %v
", t)
	}

	fmt.Println("
=== All Time Parsing Examples Completed ===")
}