AI tweaks to civ economy management

C7Engine/AI/ChooseProducible.cs

@@ -56,6 +56,11 @@ private static float ScoreInflow(ProducibleStats stats, City city, Player player
 			// I am not sure how civ III does this, although I guess we should consider stuff like
 			// no more buildings to build, reached unit cap, very bad economy with no other options,
 			// the WealthNever and WealthOften flags from RACE, etc
+
+			if (HasWeakEconomy(player)) {
+				return 100 - player.gold;
+			}
+
 			return -1000f;
 		}
 
@@ -134,6 +139,10 @@ private static float ScoreUnit(ProducibleStats stats, City city, Player player,
 			// still in the expansion phase.
 			if (unitSupportCost > 0 && !atWar && !stats.inExpansionPhase) {
 				score -= unitSupportCost / 2;
+
+				if (HasWeakEconomy(player)) {
+					score -= unitSupportCost * 2;
+				}
 			}
 
 			////////////////////////////////////////////////////////////////////
@@ -288,6 +297,11 @@ private static float ScoreBuilding(ProducibleStats stats, City city, Player play
 				score += 20;
 			}
 
+			// Penalize buildings if economy is weak
+			if (HasWeakEconomy(player)) {
+				score -= 10 * building.maintenanceCost;
+			}
+
 			return score;
 		}
 
@@ -374,5 +388,9 @@ private static int NumUnworkedTiles(City city) {
 			}
 			return result;
 		}
+
+		public static bool HasWeakEconomy(Player player) {
+			return player.luxuryRate == 0 && player.scienceRate == 0 && player.gold < 100;
+		}
 	}
 }

C7Engine/AI/PlayerAI.cs

@@ -401,7 +401,7 @@ private static void AdjustSliders(Player player) {
 			// Now max out the science slider and then decrease it (increasing
 			// the tax rate) until we're not losing money.
 			player.scienceRate = MAX_SLIDER_VALUE - player.luxuryRate;
-			while (player.CalculateGoldPerTurn() < 0 && player.scienceRate > 0) {
+			while (player.scienceRate > 0 && !BudgetIsTolerable(player)) {
 				player.scienceRate--;
 				player.taxRate++;
 			}
@@ -441,5 +441,11 @@ private static void FixRemainingUnhappyCities(Player player) {
 				}
 			}
 		}
+
+		public static bool BudgetIsTolerable(Player player) {
+			var gpt = player.CalculateGoldPerTurn();
+			var tolerableDeficit = gpt > player.gold * -0.1;
+			return gpt > 0 || tolerableDeficit;
+		}
 	}
 }

C7Engine/C7GameData/Player.cs

@@ -121,6 +121,8 @@ public int gold {
 			}
 		}
 
+		private int lastGoldPerTurn = 0;
+
 		/// <summary>
 		/// Sets the current gold amount of the player. If the add parameter is true, the gold gets appended.<br/>
 		/// </summary>
@@ -751,7 +753,7 @@ public void DoPerTurnFinanceUpdates(GameData gameData) {
 				}
 
 				// If that wasn't sufficient, go after luxuries.
-				if (scienceRate > 0) {
+				if (luxuryRate > 0) {
 					--luxuryRate;
 					++taxRate;
 					continue;
@@ -761,7 +763,8 @@ public void DoPerTurnFinanceUpdates(GameData gameData) {
 				throw new Exception($"{this} was unable to get the budget under control despite being under the unit support cap and zeroing out the sliders (gold={gold}, gpt={CalculateGoldPerTurn()})");
 			}
 
-			gold += CalculateGoldPerTurn();
+			lastGoldPerTurn = CalculateGoldPerTurn();
+			gold += lastGoldPerTurn;
 		}
 
 		public void HandleCityUpdates(GameData gameData) {