feat: better roulette racetrack graphics and payout table

1 files changed, 109 insertions, 0 deletions

diff --git a/internal/casino/roulette_geometry_test.go b/internal/casino/roulette_geometry_test.go
new file mode 100644
index 0000000..37fec74
--- /dev/null
+++ b/internal/casino/roulette_geometry_test.go
@@ -0,0 +1,109 @@
+package casino
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestRouletteRejectsNonTouchingCombinations(t *testing.T) {
+	for _, tc := range []struct {
+		target string
+		double bool
+	}{
+		{"corner 1 3 4 6", false}, {"corner 1 2 7 8", false},
+		{"corner 1 3 34 36", true}, {"trio 0 1 3", false},
+		{"trio 0 1 3", true}, {"trio 0 2 3", true},
+		{"trio 00 1 2", true}, {"trio 0 00 1", true},
+		{"trio 0 00 3", true}, {"split 0 3", true},
+		{"split 00 1", true},
+	} {
+		if _, mult := rouletteBet(tc.target, tc.double); mult != 0 {
+			t.Errorf("accepted %q (double=%v)", tc.target, tc.double)
+		}
+	}
+	for _, double := range []bool{false, true} {
+		for c := 0; c < 11; c++ {
+			for r := 1; r <= 2; r++ {
+				n := 3*c + r
+				target := fmt.Sprintf("corner %d %d %d %d", n, n+1, n+3, n+4)
+				if _, mult := rouletteBet(target, double); mult != 9 {
+					t.Errorf("rejected %s", target)
+				}
+			}
+		}
+		for _, target := range []string{"split 0 1", "split 0 2", "trio 0 1 2"} {
+			if _, mult := rouletteBet(target, double); mult == 0 {
+				t.Errorf("rejected %s", target)
+			}
+		}
+	}
+	for _, target := range []string{"split 00 2", "split 00 3", "trio 00 2 3", "trio 0 00 2"} {
+		if _, mult := rouletteBet(target, true); mult == 0 {
+			t.Errorf("rejected %s", target)
+		}
+	}
+}
+
+// Sum the return over every equally likely outcome. Ordinary bets return
+// 36 stakes per wheel; the American five-number basket returns only 35.
+func TestRouletteWheelAndExpectedReturns(t *testing.T) {
+	for _, double := range []bool{false, true} {
+		wheel := WheelOrder(double)
+		want := 37
+		if double {
+			want = 38
+		}
+		seen := map[string]bool{}
+		for _, p := range wheel {
+			if _, valid := roulettePocketToken(p, double); !valid || seen[p] {
+				t.Fatalf("invalid wheel pocket %s", p)
+			}
+			seen[p] = true
+		}
+		if len(seen) != want {
+			t.Fatalf("wheel has %d pockets, want %d", len(seen), want)
+		}
+		targets := append(WheelOrder(double), "red", "black", "odd", "even", "low", "high", "1to12", "13to24", "25to36", "row1", "row2", "row3", "split 1 2", "street 1 2 3", "corner 1 2 4 5", "line 1 2 3 4 5 6", "trio 0 1 2", "basket")
+		for _, target := range targets {
+			wager, ok := rouletteWagerFor(target, double, false)
+			if !ok {
+				t.Fatalf("invalid target %s", target)
+			}
+			sum := 0
+			for _, p := range wheel {
+				share, _ := wager.covers(p)
+				payout, err := share.payout(1)
+				if err != nil {
+					t.Fatal(err)
+				}
+				sum += payout
+			}
+			wantReturn := 36
+			if double && target == "basket" {
+				wantReturn = 35
+			}
+			if sum != wantReturn {
+				t.Errorf("%s: total return %d, want %d", target, sum, wantReturn)
+			}
+		}
+	}
+}
+
+func TestRouletteSharePayoutCap(t *testing.T) {
+	shares := []rouletteShare{{36, 1}, {7, 1}, {36, 9}}
+	for _, bet := range rouletteCallBets {
+		for _, share := range bet.wager().shares {
+			shares = append(shares, share)
+		}
+	}
+	for _, share := range shares {
+		limit := ((MaxCredits+1)*share.den - 1) / share.num
+		got, err := share.payout(limit)
+		if err != nil || got > MaxCredits {
+			t.Fatalf("%+v at limit: %d, %v", share, got, err)
+		}
+		if _, err := share.payout(limit + 1); err == nil {
+			t.Fatalf("%+v accepted overflow", share)
+		}
+	}
+}