feat: additional baca and bj rules variants

1 files changed, 66 insertions, 0 deletions

diff --git a/internal/casino/blackjack_rules.go b/internal/casino/blackjack_rules.go
new file mode 100644
index 0000000..8bf63a8
--- /dev/null
+++ b/internal/casino/blackjack_rules.go
@@ -0,0 +1,66 @@
+package casino
+
+import (
+	"fmt"
+	"strings"
+)
+
+// BlackjackRulesText is the table's rule card, built from effective defaults.
+// Keep fixed engine rules here too: players should not have to guess them.
+func (c TableConfig) BlackjackRulesText() string {
+	c = c.Normalize()
+	b := c.Blackjack
+	yesNo := func(v bool) string {
+		if v {
+			return "Yes"
+		}
+		return "No"
+	}
+	dealer := "stands on"
+	if b.DealerHitsSoft17() {
+		dealer = "hits"
+	}
+	surrender := "Not offered"
+	if b.AllowsSurrender() {
+		surrender = "Late (original two-card hand only)"
+	}
+	split := "Identical ranks only"
+	if b.AllowsUnlikeTenSplit() {
+		split = "Identical ranks or any two ten-valued cards"
+	}
+	return strings.Join([]string{
+		fmt.Sprintf("Blackjack table %s — rules", c.ID),
+		fmt.Sprintf("Number of decks: %d", b.Decks),
+		"Blackjack pays " + payoutRatio(b.BlackjackPayout),
+		"Dealer " + dealer + " soft 17",
+		"Dealer hole card / peek: Yes; blackjack checked before player actions (after insurance)",
+		"Ordinary wins pay 1:1; ties push; player and dealer blackjack push",
+		"Double down: Any initial two cards; one additional card only",
+		"Double after split: " + yesNo(b.AllowsDoubleAfterSplit()),
+		fmt.Sprintf("Maximum split hands: %d (including original hand)", b.MaxSplitHands),
+		"Re-splitting: " + yesNo(b.MaxSplitHands > 2) + " (within maximum hands)",
+		"Re-splitting aces: " + yesNo(b.AllowsResplitAces()) + " (within maximum hands)",
+		"Split pairs: " + split,
+		"Split aces: One card per ace; no hitting or doubling",
+		"Split-hand 21 pays 1:1, except the optional bonus below",
+		"Split-and-doubled 21 receives blackjack payout: " + yesNo(b.CountsDoubleSplitBlackjack()),
+		"Surrender: " + surrender,
+		"Insurance: Offered against an ace; costs half the original bet; pays " + payoutRatio(b.InsurancePayout),
+		"Fractional credits: Rounded down (including insurance stake and surrender return)",
+		fmt.Sprintf("Shuffle threshold: %g%% of shoe remaining; may shuffle earlier for round coverage", b.ShuffleAt*100),
+		"Shoe exhaustion: Reshuffle mid-round if necessary",
+		"Bet limits: " + betRangeText(c.MinBet, c.MaxBet) + " credits",
+		fmt.Sprintf("Seats: %d; betting window: %d ticks; action window: %d ticks", c.MaxPlayers, c.BettingTicks, b.ActionTicks),
+	}, "\n")
+}
+
+func payoutRatio(p float64) string {
+	switch p {
+	case 1.5:
+		return "3:2"
+	case 1.2:
+		return "6:5"
+	default:
+		return fmt.Sprintf("%g:1", p)
+	}
+}