feat: consistent wager outcome table across casino games

1 files changed, 153 insertions, 0 deletions

diff --git a/internal/casino/settlement.go b/internal/casino/settlement.go
new file mode 100644
index 0000000..46d3723
--- /dev/null
+++ b/internal/casino/settlement.go
@@ -0,0 +1,153 @@
+package casino
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Attach receipts to the recipient's final board/menu where possible, so the
+// renderer can place them between the reveal and the next-action prompt.
+// Departing recipients still receive their standalone private receipt.
+func withSettlementReceipts(events, receipts []Event) []Event {
+	for _, receipt := range receipts {
+		attached := false
+		for i := len(events) - 1; i >= 0; i-- {
+			if events[i].PrivateTo == receipt.PrivateTo && events[i].Snapshot != nil && !events[i].Public {
+				events[i].Settlement = receipt.Settlement
+				events[i].SettlementNote = receipt.SettlementNote
+				attached = true
+				break
+			}
+		}
+		if !attached {
+			events = append(events, receipt)
+		}
+	}
+	return events
+}
+
+// profitOdds reduces an exact profit fraction without rounding currency.
+func profitOdds(num, den int) string {
+	if den <= 0 {
+		return "Varies"
+	}
+	a, b := num, den
+	if a < 0 {
+		a = -a
+	}
+	for b != 0 {
+		a, b = b, a%b
+	}
+	if a == 0 {
+		return "0:1"
+	}
+	return fmt.Sprintf("%d:%d", num/a, den/a)
+}
+
+func returnResult(stake, returned int) string {
+	switch {
+	case returned > stake:
+		return "win"
+	case returned < stake:
+		return "loss"
+	default:
+		return "push"
+	}
+}
+
+func rouletteSettlementOdds(w rouletteWager, pocket string) string {
+	if s, ok := w.covers(pocket); ok {
+		return profitOdds(s.num-s.den, s.den)
+	}
+	odds := ""
+	for _, s := range w.shares {
+		next := profitOdds(s.num-s.den, s.den)
+		if odds != "" && odds != next {
+			return "Varies"
+		}
+		odds = next
+	}
+	if odds == "" {
+		return "Varies"
+	}
+	return odds
+}
+
+func baccaratSettlementOdds(spot string, player, banker []card, rules BaccaratConfig) string {
+	rules = rules.Normalize()
+	switch spot {
+	case baccaratSpotPlayer:
+		return "1:1"
+	case baccaratSpotBanker:
+		if rules.Variant == BaccaratSuper6 && baccaratTotal(banker) > baccaratTotal(player) && baccaratTotal(banker) == 6 {
+			return "1:2"
+		}
+		return payoutRatio(rules.BankerPayout)
+	case baccaratSpotTie:
+		return payoutRatio(rules.TiePayout)
+	case "player_pair", "banker_pair":
+		return "11:1"
+	case "dragon_7":
+		return "40:1"
+	case "panda_8":
+		return "25:1"
+	case "super_6":
+		return "12:1"
+	default:
+		return "Varies"
+	}
+}
+
+// For losing or active bets, inspect legal winning outcomes. Variable games
+// (field, horn and variant pass lines) must not advertise one fixed rate.
+func (t *crapsTable) settlementOdds(b *crapsBet) string {
+	odds := ""
+	for _, pair := range t.rollPairs() {
+		done, num, den := t.outcomeFor(b, pair[0], pair[1])
+		if !done || num <= 0 {
+			continue
+		}
+		next := profitOdds(num, den)
+		if odds != "" && odds != next {
+			return "Varies"
+		}
+		odds = next
+	}
+	if odds == "" {
+		odds = "Varies"
+	}
+	if b.kind == "buy" || b.kind == "lay" {
+		odds += " fee"
+	}
+	return odds
+}
+
+// Keep the base bet and its free-odds wager separate, including come-out
+// refunds where the base loses but the odds push.
+func (t *crapsTable) crapsSettlementLines(b *crapsBet, num, den int, refundOdds, active bool) []SettlementLine {
+	base := *b
+	base.odds = Wager{}
+	returned := crapsReturn(&base, num, den, num, false)
+	odds := t.settlementOdds(b)
+	if num > 0 && !active {
+		odds = profitOdds(num, den)
+		if b.kind == "buy" || b.kind == "lay" {
+			odds += " fee"
+		}
+	}
+	lines := []SettlementLine{{Label: crapsBetLabel(b), Odds: odds, Stake: b.stake.Total, Returned: returned, Result: returnResult(b.stake.Total, returned), Unresolved: active}}
+	if b.odds.Total > 0 {
+		x, y := crapsTrueOdds(b.number)
+		if strings.HasPrefix(b.kind, "dont") {
+			x, y = y, x
+		}
+		paid := 0
+		if refundOdds {
+			paid = b.odds.Total
+		} else if num >= 0 {
+			paid = b.odds.Total + b.odds.Total/y*x
+		}
+		lines = append(lines, SettlementLine{Label: crapsBetLabel(b) + " odds", Odds: profitOdds(x, y), Stake: b.odds.Total, Returned: paid, Result: returnResult(b.odds.Total, paid), Unresolved: active})
+	}
+	return lines
+}