Bridge collapse warning fix (#7992)

Disregards units not actually on a bridge for the collapse warning
indicator
Fixes #7878

Author: HammerGS

megamek/src/megamek/client/ui/clientGUI/boardview/CollapseWarning.java

@@ -40,13 +40,15 @@
 import megamek.client.ui.clientGUI.GUIPreferences;
 import megamek.client.ui.panels.phaseDisplay.DeploymentDisplay;
 import megamek.client.ui.panels.phaseDisplay.MovementDisplay;
+import megamek.common.Hex;
 import megamek.common.board.Board;
 import megamek.common.board.BoardLocation;
 import megamek.common.board.Coords;
 import megamek.common.enums.GamePhase;
 import megamek.common.game.Game;
 import megamek.common.units.Entity;
 import megamek.common.units.IBuilding;
+import megamek.common.units.Terrains;
 import megamek.logging.MMLogger;
 
 /**
@@ -225,11 +227,14 @@ public static List<Coords> findCFWarningsDeployment(Game game, Entity entity, Bo
      * at the hex location that could cause a building to collapse.
      */
     public static double calculateTotalTonnage(Game g, Entity selected, Coords c) {
-        // Calculate total weight of entity and all entities at the location.
+        Hex hex = g.getBoard().getHex(c);
         double totalWeight = selected.getWeight();
         List<Entity> units = g.getEntitiesVector(c, true);
         for (Entity ent : units) {
-            if (CollapseWarning.isEntityPartOfWeight(selected, ent)) {
+            boolean weightCounts = (hex.hasBridge() && isEntityPartOfBridgeWeight(selected, ent,
+                  hex.terrainLevel(Terrains.BRIDGE_ELEV)))
+                  || (!hex.hasBridge() && isEntityPartOfWeight(selected, ent));
+            if (weightCounts) {
                 totalWeight += ent.getWeight();
             }
         }
@@ -240,6 +245,10 @@ private static boolean isEntityPartOfWeight(Entity selected, Entity inHex) {
         return ((selected != inHex) && inHex.isGround() && !inHex.isAirborneVTOLorWIGE());
     }
 
+    private static boolean isEntityPartOfBridgeWeight(Entity selected, Entity inHex, int bridgeElevation) {
+        return isEntityPartOfWeight(selected, inHex) && (inHex.getElevation() == bridgeElevation);
+    }
+
     private CollapseWarning() {
     }
 }

megamek/src/megamek/common/Hex.java

@@ -556,6 +556,14 @@ public boolean hasDepth1WaterOrDeeper() {
         return containsTerrain(Terrains.WATER) && (terrainLevel(Terrains.WATER) >= 1);
     }
 
+    /**
+     * @return True if there is a bridge in this hex. Tests if the hex has Terrains.BRIDGE. When true, the hex will also
+     *       have Terrains.BRIDGE_ELEV and Terrains.BRIDGE_CF.
+     */
+    public boolean hasBridge() {
+        return containsTerrain(Terrains.BRIDGE);
+    }
+
     /**
      * @return the level of the terrain specified, or Terrain.LEVEL_NONE if the terrain is not present in the hex
      */

megamek/unittests/megamek/client/ui/clientGUI/CollapseWarningTest.java

@@ -36,6 +36,7 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -44,6 +45,7 @@
 import java.util.Vector;
 
 import megamek.client.ui.clientGUI.boardview.CollapseWarning;
+import megamek.common.Hex;
 import megamek.common.board.Board;
 import megamek.common.board.Coords;
 import megamek.common.enums.GamePhase;
@@ -118,6 +120,7 @@ void testConstructionFactorWarningFindMovementWarnings() {
         IBuilding bld = createMockBuildingWith(buildingPosition, 20);
 
         Board b = createMockBoardWith(buildingPosition, bld);
+        when(g.getBoard()).thenReturn(b);
 
         List<Coords> warnList = CollapseWarning.findCFWarningsMovement(g, e, b);
 
@@ -216,6 +219,7 @@ void testConstructionFactorWarningFindDeploymentWarnings() {
         when(b.isLegalDeployment(expectedHex, e)).thenReturn(true);
 
         Game g = mock(Game.class);
+        when(g.getBoard()).thenReturn(b);
 
         List<Coords> warnList = CollapseWarning.findCFWarningsDeployment(g, e, b);
 
@@ -347,6 +351,8 @@ void testConstructionFactorWarningCalcTotalWeightWithUnit() {
         entities.add(onBuilding);
 
         when(g.getEntitiesVector(new Coords(3, 7), true)).thenReturn(entities);
+        Board b = createSimpleMockBoard();
+        when(g.getBoard()).thenReturn(b);
 
         double totalWeight = CollapseWarning.calculateTotalTonnage(g, e, new Coords(3, 7));
 
@@ -368,6 +374,8 @@ void testConstructionFactorWarningCalcTotalWeightEntityOnBuilding() {
         entities.add(e);
 
         when(g.getEntitiesVector(new Coords(3, 3), true)).thenReturn(entities);
+        Board b = createSimpleMockBoard();
+        when(g.getBoard()).thenReturn(b);
 
         double totalWeight = CollapseWarning.calculateTotalTonnage(g, e, new Coords(3, 3));
 
@@ -391,6 +399,8 @@ void testConstructionFactorWarningCalcTotalWeightVTOLOverHex() {
         entities.add(vtol);
 
         when(g.getEntitiesVector(new Coords(3, 7), true)).thenReturn(entities);
+        Board b = createSimpleMockBoard();
+        when(g.getBoard()).thenReturn(b);
 
         double totalWeight = CollapseWarning.calculateTotalTonnage(g, e, new Coords(3, 7));
 
@@ -413,6 +423,8 @@ void testConstructionFactorWarningCalcTotalWeightAeroOverHex() {
         entities.add(aero);
 
         when(g.getEntitiesVector(new Coords(3, 7), true)).thenReturn(entities);
+        Board b = createSimpleMockBoard();
+        when(g.getBoard()).thenReturn(b);
 
         double totalWeight = CollapseWarning.calculateTotalTonnage(g, e, new Coords(3, 7));
 
@@ -447,6 +459,16 @@ private IBuilding createMockBuildingWith(Coords pos, int cf) {
     private Board createMockBoardWith(Coords pos, IBuilding bld) {
         Board b = mock(Board.class);
         when(b.getBuildingAt(pos)).thenReturn(bld);
+        Hex hex = mock(Hex.class);
+        when(hex.hasBridge()).thenReturn(false);
+        return b;
+    }
+
+    private Board createSimpleMockBoard() {
+        Board b = mock(Board.class);
+        Hex hex = mock(Hex.class);
+        when(hex.hasBridge()).thenReturn(false);
+        when(b.getHex(any())).thenReturn(hex);
         return b;
     }
 }