Check after resolving an ownership conflict that the tile is not an ocean tile with a rank larger than 2

Author: stavrosfa

C7Engine/C7GameData/GameData.cs

@@ -133,8 +133,8 @@ public void UpdateTileOwners() {
 				foreach (Tile t in city.GetTilesWithinBorders()) {
 					// If another city has claim to this tile, we need to resolve
 					// that conflict.
-					if (t.owningCity != null) {
-						t.owningCity = ResolveTileOwnershipConflict(t.owningCity, city, t);
+					if (t.owningCity != null && ResolveTileOwnershipConflict(t.owningCity, city, t, out City winnerCity)) {
+						t.owningCity = winnerCity;
 						t.owningCity.owner.tileKnowledge.AddTilesToKnown(t, recomputeActiveTiles);
 						continue;
 					}
@@ -150,26 +150,29 @@ public void UpdateTileOwners() {
 
 				foreach (Tile t in player.tileKnowledge.knownTiles.Where(t => t.owningCity == null && t.GetEdgeNeighbors().Any(e => e.owningCity != null)).ToList()) {
 					// Law VII
-					if (t.neighbors.TryGetValue(TileDirection.NORTHWEST, out Tile tnw)
-						&& t.neighbors.TryGetValue(TileDirection.SOUTHEAST, out Tile tse)
-						&& tnw.owningCity != null && tse.owningCity != null
-						&& tnw.owningCity.owner == tse.owningCity.owner) {
-						t.owningCity = ResolveTileOwnershipConflict(tnw.owningCity, tse.owningCity, t);
-						t.owningCity.owner.tileKnowledge.AddTilesToKnown(t);
-						continue;
-					}
+					TryResolveOpposingNeighbors(t, TileDirection.NORTHWEST, TileDirection.SOUTHEAST);
+					if (t.owningCity != null) continue;
 					// Law VIII
-					if (t.neighbors.TryGetValue(TileDirection.NORTHEAST, out Tile tne)
-						&& t.neighbors.TryGetValue(TileDirection.SOUTHWEST, out Tile tsw)
-						&& tne.owningCity != null && tsw.owningCity != null
-						&& tne.owningCity.owner == tsw.owningCity.owner) {
-						t.owningCity = ResolveTileOwnershipConflict(tne.owningCity, tsw.owningCity, t);
-						t.owningCity.owner.tileKnowledge.AddTilesToKnown(t);
-					}
+					TryResolveOpposingNeighbors(t, TileDirection.NORTHEAST, TileDirection.SOUTHWEST);
 				}
 			}
 		}
 
+		private void TryResolveOpposingNeighbors(Tile t, TileDirection dirA, TileDirection dirB) {
+			if (!t.neighbors.TryGetValue(dirA, out Tile a) || !t.neighbors.TryGetValue(dirB, out Tile b)) return;
+			if (a.owningCity == null || b.owningCity == null) return;
+			if (a.owningCity.owner != b.owningCity.owner) return;
+			if (!ResolveTileOwnershipConflict(a.owningCity, b.owningCity, t, out City winnerCity)) return;
+
+			// Law II
+			if (t.baseTerrainType.Key == "ocean" && t.rankDistanceTo(winnerCity.location) > 2) {
+				t.owningCity = null;
+				return;
+			}
+			t.owningCity = winnerCity;
+			winnerCity.owner.tileKnowledge.AddTilesToKnown(t);
+		}
+
 		public void UpdateTileOwnersOnCityDestruction(City city) {
 			city.location.owningCity = null;
 
@@ -275,26 +278,27 @@ public void InvalidateCachedTradeNetwork() {
 		}
 
 		// Rules taken from https://forums.civfanatics.com/threads/the-eight-laws-of-border-dynamics.106882/
-		private City ResolveTileOwnershipConflict(City a, City b, Tile t) {
-			if (a.Equals(b)) return a;
+		private bool ResolveTileOwnershipConflict(City a, City b, Tile t, out City owner) {
+			owner = null;
+			if (a.Equals(b)) { owner = a; return true; }
 
 			int aRank = a.location.rankDistanceTo(t);
 			int bRank = b.location.rankDistanceTo(t);
 
 			// Law I
 			// Cities can claim tiles of rank n+1, where n is the city's expansion level
-			if (a.GetBorderExpansionLevel() + 1 < aRank && b.GetBorderExpansionLevel() + 1 >= bRank) return b;
-			if (b.GetBorderExpansionLevel() + 1 < bRank && a.GetBorderExpansionLevel() + 1 >= aRank) return a;
+			if (a.GetBorderExpansionLevel() + 1 < aRank && b.GetBorderExpansionLevel() + 1 >= bRank) { owner = b; return true; }
+			if (b.GetBorderExpansionLevel() + 1 < bRank && a.GetBorderExpansionLevel() + 1 >= aRank) { owner = a; return true; }
 
 			// Law III
 			// The city with the lowest rank claim gets the tile.
-			if (aRank > bRank) return b;
-			if (aRank < bRank) return a;
+			if (aRank > bRank) { owner = b; return true; }
+			if (aRank < bRank) { owner = a; return true; }
 
 			// Law IV
 			// If the ranks are equal, the city with more culture gets the tile.
-			if (a.GetCulture() + a.GetCulturePerTurn() < b.GetCulture() + b.GetCulturePerTurn()) return b;
-			if (a.GetCulture() + a.GetCulturePerTurn() > b.GetCulture() + b.GetCulturePerTurn()) return a;
+			if (a.GetCulture() + a.GetCulturePerTurn() < b.GetCulture() + b.GetCulturePerTurn()) { owner = b; return true; }
+			if (a.GetCulture() + a.GetCulturePerTurn() > b.GetCulture() + b.GetCulturePerTurn()) { owner = a; return true; }
 
 			// Law V
 			// If the cultures are equal the oldest city gets the tile.
@@ -309,9 +313,9 @@ private City ResolveTileOwnershipConflict(City a, City b, Tile t) {
 			for (int r = aRank - 1; r <= aRank; r++) {
 				if (r <= 0) continue;
 				Tile winner = t.FindInRing(r, tile => tile.HasCity && (tile.cityAtTile == a || tile.cityAtTile == b), false);
-				if (winner != null) {
-					return winner.owningCity;
-				}
+				if (winner == null) continue;
+				owner = winner.owningCity;
+				return true;
 			}
 
 			// should never happen, if it does some part of the algorithm has gone wrong