Fix double-counting of commerce in treasury flows (#864)

C7/UIElements/Advisors/DomesticAdvisor.cs

@@ -224,7 +224,7 @@ public void ShowAdvisor() {
 			scienceStatus.Text = playerController.SummarizeScience(gameData);
 			treasury.Text = $"Treasury: {playerController.gold}";
 
-			incomeDetails.Text = $"From cities: +{totalIncome.CityInflows()}\nFrom taxmen: +{totalIncome.taxmenTaxes}\nFrom other civs: +{totalIncome.fromOtherCivs}\nFrom interest: +{totalIncome.interest}";
+			incomeDetails.Text = $"From cities: +{totalIncome.taxes + totalIncome.wealthProduction}\nFrom taxmen: +{totalIncome.taxmenTaxes}\nFrom other civs: +{totalIncome.fromOtherCivs}\nFrom interest: +{totalIncome.interest}";
 			expenseDetails.Text = $"-{totalIncome.beakers}: Science\n-{totalIncome.happiness}: Entertainment\n-{totalIncome.corrupted}: Corruption\n-{totalIncome.maintenance}: Maintenance\n-{totalIncome.unitSupport}: Unit costs\n-{totalIncome.toOtherCivs}: To other civs";
 			incomeSummary.Text = $"Income: {totalIncome.Inflows()}";
 			expenseSummary.Text = $"Expenses: {totalIncome.Outflows()}";

C7Engine/C7GameData/Player.cs

@@ -25,19 +25,24 @@ public struct PlayerCommerceBreakdown {
 		public int unitSupport;         // Expenses due to unit support costs
 		public int wealthProduction;    // Amount of extra commerce from "building" an Inflow that produces commerce
 
+		// The total treasury gold coming in each turn. Corruption, science and
+		// entertainment are allocations of a city's commerce, not income.
 		public int Inflows() {
-			return corrupted + taxes + taxmenTaxes + beakers + happiness + fromOtherCivs + interest + wealthProduction;
+			return taxes + taxmenTaxes + fromOtherCivs + interest + wealthProduction;
 		}
 
+		// The total treasury gold going out each turn.
 		public int Outflows() {
-			return corrupted + beakers + happiness + toOtherCivs + maintenance + unitSupport;
+			return toOtherCivs + maintenance + unitSupport;
 		}
 
 		public int Netflows() {
 			return Inflows() - Outflows();
 		}
 
-		public int CityInflows() {
+		// The total commerce generated by a player's cities before it is split
+		// between corruption, science, entertainment and taxes.
+		public int CommerceTotal() {
 			return corrupted + taxes + beakers + happiness + wealthProduction;
 		}
 	}

EngineTests/GameData/PlayerCommerceBreakdownTest.cs

@@ -0,0 +1,54 @@
+using C7GameData;
+using Xunit;
+
+namespace EngineTests.GameData;
+
+public class PlayerCommerceBreakdownTest {
+	private static PlayerCommerceBreakdown MakeBreakdown() {
+		return new PlayerCommerceBreakdown {
+			corrupted = 3,
+			taxes = 4,
+			taxmenTaxes = 2,
+			beakers = 5,
+			happiness = 6,
+			fromOtherCivs = 1,
+			toOtherCivs = 2,
+			interest = 3,
+			maintenance = 4,
+			unitSupport = 5,
+			wealthProduction = 6,
+		};
+	}
+
+	[Fact]
+	public void InflowsIncludesOnlyTreasuryGoldIncome() {
+		PlayerCommerceBreakdown breakdown = MakeBreakdown();
+
+		// corrupted, beakers and happiness are allocations of city commerce,
+		// not income, so they must not appear in the treasury inflow number.
+		Assert.Equal(4 + 2 + 1 + 3 + 6, breakdown.Inflows());
+	}
+
+	[Fact]
+	public void OutflowsIncludesOnlyTreasuryGoldExpenses() {
+		PlayerCommerceBreakdown breakdown = MakeBreakdown();
+
+		// Science, entertainment and corruption are not treasury expenses.
+		Assert.Equal(2 + 4 + 5, breakdown.Outflows());
+	}
+
+	[Fact]
+	public void NetflowsIsInflowsMinusOutflows() {
+		PlayerCommerceBreakdown breakdown = MakeBreakdown();
+
+		Assert.Equal(breakdown.Inflows() - breakdown.Outflows(), breakdown.Netflows());
+		Assert.Equal(5, breakdown.Netflows());
+	}
+
+	[Fact]
+	public void CommerceTotalIncludesAllCityCommerce() {
+		PlayerCommerceBreakdown breakdown = MakeBreakdown();
+
+		Assert.Equal(3 + 4 + 5 + 6 + 6, breakdown.CommerceTotal());
+	}
+}