1 files changed, 39 insertions, 4 deletions
diff --git a/internal/casino/big_six.go b/internal/casino/big_six.go
index 6d16bbc..b17bde4 100644
--- a/internal/casino/big_six.go
+++ b/internal/casino/big_six.go
@@ -34,9 +34,43 @@ func bigSixHouseEdge(_ TableConfig, bet string) HouseEdge {
 func bigSixTarget(s string) string {
 	return strings.TrimPrefix(strings.ToUpper(strings.TrimSpace(s)), "$")
 }
+
+// bigSixResolveTarget maps a written target to a betting symbol. An exact
+// label always wins over a longer label that shares its prefix, so "1" is the
+// $1 symbol and never an ambiguous prefix of $10. Otherwise an unambiguous
+// prefix is accepted, so "SW", "SWO" and "SWORD" all name the sword and "SH"
+// names the shield. DOUBLE is not a betting target, so "DO" resolves to
+// nothing. It reports false when nothing or more than one symbol matches.
+func bigSixResolveTarget(s string) (string, bool) {
+	t := bigSixTarget(s)
+	if t == "" {
+		return "", false
+	}
+	match := ""
+	for _, spot := range BigSixSpots() {
+		if spot.Pays <= 0 {
+			continue
+		}
+		if spot.Label == t {
+			return spot.Label, true
+		}
+		if strings.HasPrefix(spot.Label, t) {
+			if match != "" {
+				return "", false
+			}
+			match = spot.Label
+		}
+	}
+	return match, match != ""
+}
+
 func bigSixPayout(s string) int {
+	target, ok := bigSixResolveTarget(s)
+	if !ok {
+		return 0
+	}
 	for _, spot := range BigSixSpots() {
-		if spot.Label == bigSixTarget(s) && spot.Pays > 0 {
+		if spot.Label == target {
 			return spot.Pays + 1
 		}
 	}
@@ -225,10 +259,11 @@ func (t *bigSixTable) bet(name, spot string, amount int, w Wallet) []Event {
 	if spot == "" {
 		spot = p.lastSpot
 	}
-	spot = bigSixTarget(spot)
-	if bigSixPayout(spot) == 0 {
-		return []Event{t.private(name, "Bet on 1, 2, 5, 10, 20, SWORD or SHIELD. DOUBLE is automatic, not a bet.")}
+	resolved, ok := bigSixResolveTarget(spot)
+	if !ok {
+		return []Event{t.private(name, "Bet on 1, 2, 5, 10, 20, SWORD or SHIELD — an unambiguous prefix is fine. DOUBLE is automatic, not a bet.")}
 	}
+	spot = resolved
 	if amount < t.Config.MinBet || amount > t.Config.MaxBet {
 		return []Event{t.private(name, "Big 6 bets must be "+betRangeText(t.Config.MinBet, t.Config.MaxBet)+".")}
 	}