93 lines
2.4 KiB
Go
93 lines
2.4 KiB
Go
package timeutil
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import (
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"fmt"
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"regexp"
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"strconv"
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"strings"
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"time"
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)
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const DateLayout = "2006-01-02"
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const LocalDateTimeLayout = "2006-01-02T15:04"
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func LoadLocation(name string) (*time.Location, error) {
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if location, ok := timezoneAliases[name]; ok {
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return location, nil
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}
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if location, ok := parseUTCOffset(name); ok {
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return location, nil
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}
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location, err := time.LoadLocation(name)
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if err == nil {
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return location, nil
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}
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if strings.Contains(name, "/") {
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return nil, fmt.Errorf("load timezone %q: %w", name, err)
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}
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location, chicagoErr := time.LoadLocation("America/" + name)
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if chicagoErr == nil {
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return location, nil
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}
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return nil, fmt.Errorf("load timezone %q: %w", name, err)
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}
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var timezoneAliases = map[string]*time.Location{
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"Chicago": mustLocation("America/Chicago"),
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"Stl": mustLocation("America/Chicago"),
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"EST": time.FixedZone("EST", -5*60*60),
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"EDT": time.FixedZone("EDT", -4*60*60),
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"CST": time.FixedZone("CST", -6*60*60),
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"CDT": time.FixedZone("CDT", -5*60*60),
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"MST": time.FixedZone("MST", -7*60*60),
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"MDT": time.FixedZone("MDT", -6*60*60),
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"PST": time.FixedZone("PST", -8*60*60),
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"PDT": time.FixedZone("PDT", -7*60*60),
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}
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func mustLocation(name string) *time.Location {
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location, err := time.LoadLocation(name)
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if err != nil {
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panic(err)
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}
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return location
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}
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var utcOffsetPattern = regexp.MustCompile(`^([+-])(\d{1,2})(?::?(\d{2}))?$`)
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func parseUTCOffset(value string) (*time.Location, bool) {
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matches := utcOffsetPattern.FindStringSubmatch(value)
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if matches == nil {
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return nil, false
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}
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hours, err := strconv.Atoi(matches[2])
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if err != nil || hours > 23 {
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return nil, false
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}
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minutes := 0
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if matches[3] != "" {
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minutes, err = strconv.Atoi(matches[3])
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if err != nil || minutes > 59 {
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return nil, false
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}
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}
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offset := (hours*60 + minutes) * 60
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if matches[1] == "-" {
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offset = -offset
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}
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return time.FixedZone(value, offset), true
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}
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func LocalDate(now time.Time, location *time.Location) time.Time {
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local := now.In(location)
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return time.Date(local.Year(), local.Month(), local.Day(), 0, 0, 0, 0, location)
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}
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func ParseLocalDate(value string, location *time.Location) (time.Time, error) {
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parsed, err := time.ParseInLocation(DateLayout, value, location)
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if err != nil {
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return time.Time{}, fmt.Errorf("parse date %q as YYYY-MM-DD: %w", value, err)
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}
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return parsed, nil
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}
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