initial commit

internal/game/cards.go

@@ -0,0 +1,111 @@
+package game
+
+import "math/rand"
+
+type Rank int
+
+const (
+	RankAce Rank = iota
+	Rank2
+	Rank3
+	Rank4
+	Rank5
+	Rank6
+	Rank7
+	Rank8
+	Rank9
+	Rank10
+	RankJack
+	RankQueen
+	RankKing
+)
+
+func (r Rank) String() string {
+	switch r {
+	case RankAce:
+		return "A"
+	case Rank2:
+		return "2"
+	case Rank3:
+		return "3"
+	case Rank4:
+		return "4"
+	case Rank5:
+		return "5"
+	case Rank6:
+		return "6"
+	case Rank7:
+		return "7"
+	case Rank8:
+		return "8"
+	case Rank9:
+		return "9"
+	case Rank10:
+		return "10"
+	case RankJack:
+		return "J"
+	case RankQueen:
+		return "Q"
+	case RankKing:
+		return "K"
+	}
+	return "?"
+}
+
+type Suit int
+
+const (
+	SuitClubs Suit = iota
+	SuitDiamonds
+	SuitHearts
+	SuitSpades
+)
+
+func (s Suit) String() string {
+	switch s {
+	case SuitClubs:
+		return "♣"
+	case SuitDiamonds:
+		return "♦"
+	case SuitHearts:
+		return "♥"
+	case SuitSpades:
+		return "♠"
+	}
+	return "?"
+}
+
+type Card struct {
+	Rank Rank
+	Suit Suit
+}
+
+func NewDeck() []Card {
+	var deck []Card
+	for suit := SuitClubs; suit <= SuitSpades; suit++ {
+		for rank := RankAce; rank <= RankKing; rank++ {
+			deck = append(deck, Card{Rank: rank, Suit: suit})
+		}
+	}
+	return deck
+}
+
+func Shuffle(deck []Card) []Card {
+	result := make([]Card, len(deck))
+	copy(result, deck)
+	for i := len(result) - 1; i > 0; i-- {
+		j := rand.Intn(i + 1)
+		result[i], result[j] = result[j], result[i]
+	}
+	return result
+}
+
+var faceCards = map[Rank]bool{
+	RankJack:  true,
+	RankQueen: true,
+	RankKing:  true,
+}
+
+func IsFaceCard(r Rank) bool {
+	return faceCards[r]
+}