new x/jsonx season type

x/jsonx/jsonx.go

@@ -1,11 +1,17 @@
 package jsonx
 
-import "bytes"
+import (
+	"bytes"
+	"errors"
+)
 
 var (
 	quoteLiteral    = '"'
 	emptyQuoteBytes = []byte(`""`)
 	nullLiteral     = []byte("null")
+
+	// ErrInvalid is returned when the value is invalid.
+	ErrInvalid = errors.New("invalid")
 )
 
 func isNull(b []byte) bool {

x/jsonx/season.go

@@ -0,0 +1,123 @@
+package jsonx
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// GetSeasonByDate returns the season based on the given date.
+func GetSeasonByDate(date SimpleDate) Season {
+	month := date.ToTime().Month()
+
+	switch month {
+	case time.December, time.January, time.February:
+		return Winter
+	case time.March, time.April, time.May:
+		return Spring
+	case time.June, time.July, time.August:
+		return Summer
+	case time.September, time.October, time.November:
+		return Autumn
+	default:
+		return 0 // Should never happen.
+	}
+}
+
+// Season is a bitmask of seasons
+// Winter, Spring, Summer, Autumn.
+// It is used to represent the seasons of a year.
+// It is a bitmask so that multiple seasons can be set at once.
+// It has methods to check if a season is set, add a season,
+// remove a season, and get a string representation of the seasons.
+type Season int
+
+const (
+	// December, January, February.
+	Winter Season = 1 << iota // 1 << 0 = 1
+	// March, April, May.
+	Spring // 1 << 1 = 2
+	// June, July, August.
+	Summer // 1 << 2 = 4
+	// September, October, November.
+	Autumn // 1 << 3 = 8
+
+	// AllSeasons is a bitmask of all seasons.
+	// It's the number 15 because it's the sum of all seasons.
+	AllSeasons = Winter | Spring | Summer | Autumn // 1 + 2 + 4 + 8 = 15
+)
+
+// IsValid checks if the season is valid.
+func (s Season) IsValid() bool {
+	return s&AllSeasons == s
+}
+
+// Is checks if the season is set in the bitmask.
+func (s Season) Is(season Season) bool {
+	return s&season != 0
+}
+
+// Add adds a season to the bitmask.
+func (s *Season) Add(season Season) {
+	*s |= season
+}
+
+// Remove removes a season from the bitmask.
+func (s *Season) Remove(season Season) {
+	*s &= ^season
+}
+
+// String returns the string representation of the season(s).
+func (s Season) String() string {
+	var seasons []string
+
+	if s.Is(Winter) {
+		seasons = append(seasons, "Winter")
+	}
+	if s.Is(Spring) {
+		seasons = append(seasons, "Spring")
+	}
+	if s.Is(Summer) {
+		seasons = append(seasons, "Summer")
+	}
+	if s.Is(Autumn) {
+		seasons = append(seasons, "Autumn")
+	}
+
+	if len(seasons) == 0 {
+		return "None"
+	}
+
+	return strings.Join(seasons, ", ")
+}
+
+// MarshalJSON marshals the season to JSON.
+// It marshals the season as a string.
+func (s *Season) UnmarshalJSON(data []byte) error {
+	if isNull(data) {
+		return nil
+	}
+
+	data = trimQuotes(data)
+	if len(data) == 0 {
+		return nil
+	}
+
+	str := string(data)
+	constantAsInt, err := strconv.Atoi(str)
+	if err != nil {
+		return err
+	}
+
+	if constantAsInt == 0 { // if 0 is passed, it means All seasons.
+		constantAsInt = int(AllSeasons)
+	}
+
+	*s = Season(constantAsInt)
+	if !s.IsValid() {
+		return fmt.Errorf("%w: season: %s", ErrInvalid, str)
+	}
+
+	return nil
+}