initial commit

README.md

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+# clocktime
+
+clocktime provides a type that holds a calendar-independent time of day value in 24-hour format.

clocktime.go

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+package clocktime
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"io"
+	"time"
+)
+
+// ClockTime represents a time of day without a date component in 24-hour format.
+// It is used to represent times in a way that is independent of any specific date.
+type ClockTime struct {
+	Hour   int `json:"hour"`
+	Minute int `json:"minute"`
+	Second int `json:"second"`
+}
+
+// NewClockTime creates a new ClockTime instance.
+func NewClockTime(hour, minute, second int) ClockTime {
+	return ClockTime{
+		Hour:   hour,
+		Minute: minute,
+		Second: second,
+	}
+}
+
+// ClockTimeFromString parses a ClockTime from a string in the format "HH:MM:SS" (Subset of RFC 8601).
+func ClockTimeFromString(s string) (ClockTime, error) {
+	var hour, minute, second int
+	n, err := fmt.Sscanf(s, "%d:%d:%d", &hour, &minute, &second)
+	if err != nil || n != 3 {
+		return ClockTime{}, fmt.Errorf("invalid time format: %s", s)
+	}
+	if hour < 0 || hour > 23 || minute < 0 || minute > 59 || second < 0 || second > 59 {
+		return ClockTime{}, fmt.Errorf("time out of range: %s", s)
+	}
+	return NewClockTime(hour, minute, second), nil
+}
+
+// ClockTimeFromTime converts a time.Time to a ClockTime.
+func ClockTimeFromTime(t time.Time) ClockTime {
+	return NewClockTime(t.Hour(), t.Minute(), t.Second())
+}
+
+// String returns the string representation of the ClockTime in "HH:MM:SS" format.
+func (t ClockTime) String() string {
+	return fmt.Sprintf("%02d:%02d:%02d", t.Hour, t.Minute, t.Second)
+}
+
+// Time returns a time.Time representation of the ClockTime.
+// It uses a fixed date (January 1, 1970) to create a time.Time object.
+func (t ClockTime) Time() time.Time {
+	return time.Date(1970, 1, 1, t.Hour, t.Minute, t.Second, 0, time.UTC)
+}
+
+// MarshalJSON implements the json.Marshaler interface for ClockTime.
+func (t ClockTime) MarshalJSON() ([]byte, error) {
+	return json.Marshal(t.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for ClockTime.
+func (t *ClockTime) UnmarshalJSON(data []byte) error {
+	var timeString string
+	if err := json.Unmarshal(data, &timeString); err != nil {
+		return err
+	}
+	parsedTime, err := ClockTimeFromString(timeString)
+	if err != nil {
+		return err
+	}
+	*t = parsedTime
+	return nil
+}
+
+// MarshalGQL implements the graphql.Marshaler interface for ClockTime.
+func (t ClockTime) MarshalGQL(w io.Writer) {
+	fmt.Fprint(w, t.String())
+}
+
+// UnmarshalGQL implements the graphql.Unmarshaler interface for ClockTime.
+func (t *ClockTime) UnmarshalGQL(value any) error {
+	if value == nil {
+		*t = ClockTime{}
+		return nil
+	}
+	str, ok := value.(string)
+	if !ok {
+		return fmt.Errorf("ClockTime must be a string, got %T", value)
+	}
+	parsedTime, err := ClockTimeFromString(str)
+	if err != nil {
+		return err
+	}
+	*t = parsedTime
+	return nil
+}
+
+// Value implements the database/sql/driver.Valuer interface for ClockTime.
+// Marshals the ClockTime to a time.Time for database storage.
+func (t ClockTime) Value() (driver.Value, error) {
+	return t.Time(), nil
+}
+
+// Scan implements the database/sql.Scanner interface for ClockTime.
+func (t *ClockTime) Scan(value any) error {
+	if value == nil {
+		*t = ClockTime{}
+		return nil
+	}
+	rawTime, ok := value.(time.Time)
+	if !ok {
+		return fmt.Errorf("ClockTime must be a time.Time, got %T", value)
+	}
+	*t = ClockTimeFromTime(rawTime)
+	return nil
+}

go.mod

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+module gitea.auvem.com/go-toolkit/clocktime
+
+go 1.24.0