in prog

src/game/rule/operation/suit.go

@@ -0,0 +1,52 @@
+package operation
+
+import (
+	"encoding/json"
+	"local/sandbox/cards/src/entity"
+)
+
+type Suit int
+
+const (
+	_       Suit = iota
+	Heart   Suit = iota
+	Spade   Suit = iota
+	Diamond Suit = iota
+	Club    Suit = iota
+)
+
+var suitStrings = map[string]Suit{
+	"heart":   Heart,
+	"spade":   Spade,
+	"diamond": Diamond,
+	"club":    Club,
+}
+
+func (suit Suit) Is(card entity.Card) bool {
+	return card.Suit == int(suit)
+}
+
+func (suit Suit) MarshalJSON() ([]byte, error) {
+	for k, v := range suitStrings {
+		if suit == v {
+			return json.Marshal(k)
+		}
+	}
+	return json.Marshal("?")
+}
+
+func (suit *Suit) UnmarshalJSON(b []byte) error {
+	var s string
+	err := json.Unmarshal(b, &s)
+	if err != nil {
+		return err
+	}
+	for k, v := range suitStrings {
+		if k == s {
+			*suit = v
+			return nil
+		}
+	}
+	*suit = 0
+	return nil
+}