1 files changed, 55 insertions, 0 deletions
diff --git a/internal/casino/house_edge_pai_gow.go b/internal/casino/house_edge_pai_gow.go
new file mode 100644
index 0000000..82cff09
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+++ b/internal/casino/house_edge_pai_gow.go
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+package casino
+
+// Main-game reference estimates: published house-way play, not a solver for
+// this implementation's house way or a player's chosen arrangement. Sources:
+// https://wizardofodds.com/games/pai-gow-poker/
+// https://wizardofodds.com/games/ez-pai-gow-poker/
+// https://wizardofodds.com/games/face-up-pai-gow-poker/
+// The wheel convention can change individual results; these rounded reference
+// estimates do not resolve its small effect on the full strategy distribution.
+func paiGowHouseEdge(c TableConfig, bet string) HouseEdge {
+	r := c.PaiGow.Normalize()
+	switch bet {
+	case "main":
+		switch r.Variant {
+		case PaiGowClassic:
+			return edge(.027212)
+		case PaiGowEZ:
+			return edge(.0254)
+		case PaiGowFaceUp:
+			return edge(.0181)
+		case PaiGowNoPush:
+			// No published table for our tiebreaker variant. Use published classic
+			// win/loss/push frequencies, remove commission, then price tied extra
+			// cards as dealer wins. Five ace-valued cards (including joker), 12x4
+			// other ranks. Card-removal correlation is ignored in this estimate.
+			return edge(.303847 - .291195 + .404958*(5.0*4+12*4*3)/(53*52))
+		}
+	case "fortune":
+		profit := -121694196.0
+		for i, row := range FortunePayTable(r.Envy) {
+			profit += float64(row.Odds * fortuneCombinations[i])
+		}
+		return edge(-profit / 154143080)
+	case "pushace":
+		if rates, ok := r.pushAceRates(); ok {
+			// Published event probabilities (both ace-high, joker, plain ace-high).
+			return edge(1 - (.008700*float64(rates[2]+1) + .004100*float64(rates[1]+1) + .080800*float64(rates[0]+1)))
+		}
+	}
+	return unknownEdge("unrecognized pai gow wager")
+}
+
+// Fortune table 8 category counts, also pinned by pai_gow_test.go.
+var fortuneCombinations = []int{32, 72, 196, 1128, 26020, 184644, 307472, 4188528, 6172088, 7672500, 11034204, 2862000}
+
+func fortuneEnvyReturn(others, stake int) float64 {
+	if stake < 5 {
+		return 0
+	}
+	total := 0.0
+	for i, row := range FortunePayTable(true) {
+		total += float64(row.Envy * fortuneCombinations[i])
+	}
+	return total / 154143080 * float64(others) / float64(stake)
+}