Fixes #3727 Magma crust breakthrough and liquid magma damage not working as expected

megamek/i18n/megamek/common/report-messages.properties

@@ -201,6 +201,7 @@
 2395=<newline><data> (<data>) breaks through magma crust on a 6+, rolls <data>.
 2396=<newline><data> (<data>) breaks through magma crust on a 4+, rolls <data>.
 2400=<data> (<data>) falls into liquid magma, and is instantly destroyed!
+2404=<data> (<data>) takes additional damage from beginning and ending movement in a magma hex!
 2405=<data> (<data>) is damaged by the extreme heat of liquid magma!
 2410=<data> (<data>) breaks through ice from below
 2415=<data> collapes due to nuclear explosion ground zero.

megamek/src/megamek/server/GameManager.java

@@ -4921,6 +4921,7 @@ else if ((target instanceof Infantry) && (bldg != null)) {
             // note that this must sequentially occur before the next 'entering liquid magma' check
             // otherwise, magma crust won't have a chance to break
             ServerHelper.checkAndApplyMagmaCrust(nextHex, nextElevation, entity, curPos, false, vPhaseReport, this);
+            ServerHelper.checkEnteringMagma(nextHex, nextElevation, entity, this);
 
             // is the next hex a swamp?
             PilotingRollData rollTarget = entity.checkBogDown(step, moveType, nextHex, curPos, nextPos,
@@ -5923,6 +5924,7 @@ private void processMovement(Entity entity, MovePath md, Map<EntityTargetPair,
         // okay, proceed with movement calculations
         Coords lastPos = entity.getPosition();
         Coords curPos = entity.getPosition();
+        Hex firstHex = game.getBoard().getHex(curPos); // Used to check for start/end magma damage
         int curFacing = entity.getFacing();
         int curVTOLElevation = entity.getElevation();
         int curElevation;
@@ -6129,6 +6131,10 @@ private void processMovement(Entity entity, MovePath md, Map<EntityTargetPair,
                 break;
             }
 
+            // Extra damage if first and last hex are magma
+            if (firstStep) {
+                firstHex = game.getBoard().getHex(curPos);
+            }
             // stop if the entity already killed itself
             if (entity.isDestroyed() || entity.isDoomed()) {
                 break;
@@ -7293,7 +7299,20 @@ private void processMovement(Entity entity, MovePath md, Map<EntityTargetPair,
 
             // check for breaking magma crust unless we are jumping over the hex
             if (stepMoveType != EntityMovementType.MOVE_JUMP) {
-                ServerHelper.checkAndApplyMagmaCrust(curHex, step.getElevation(), entity, curPos, false, vPhaseReport, this);
+                if (!curPos.equals(lastPos)) {
+                    ServerHelper.checkAndApplyMagmaCrust(curHex, step.getElevation(), entity, curPos, false, vPhaseReport, this);
+                    ServerHelper.checkEnteringMagma(curHex, step.getElevation(), entity, this);
+                }
+            }
+
+            // check for last move ending in magma TODO: build report for end of move
+            if (!i.hasMoreElements() && curHex.terrainLevel(Terrains.MAGMA) == 2
+                    && firstHex.terrainLevel(Terrains.MAGMA) == 2) {
+                r = new Report(2404);
+                r.addDesc(entity);
+                r.subject = entity.getId();
+                addReport(r);
+                doMagmaDamage(entity, false);
             }
 
             // check if we've moved into a swamp
@@ -8431,6 +8450,7 @@ else if ((step.getElevation() + entity.height()) == 0) {
             // Don't interact with terrain when jumping onto a building or a bridge
             if (entity.getElevation() == 0) {
                 ServerHelper.checkAndApplyMagmaCrust(curHex, entity.getElevation(), entity, curPos, true, vPhaseReport, this);
+                ServerHelper.checkEnteringMagma(curHex, entity.getElevation(), entity, this);
 
                 // jumped into swamp? maybe stuck!
                 if (curHex.getBogDownModifier(entity.getMovementMode(),
@@ -12052,6 +12072,7 @@ private Vector<Report> doEntityDisplacement(Entity entity, Coords src,
         }
 
         ServerHelper.checkAndApplyMagmaCrust(destHex, entity.getElevation(), entity, dest, false, vPhaseReport, this);
+        ServerHelper.checkEnteringMagma(destHex, entity.getElevation(), entity, this);
 
         Entity violation = Compute.stackingViolation(game, entity.getId(), dest);
         if (violation == null) {

megamek/src/megamek/server/ServerHelper.java

@@ -445,12 +445,24 @@ public static void checkAndApplyMagmaCrust(Hex hex, int elevation, Entity entity
                 hex.addTerrain(new Terrain(Terrains.MAGMA, 2));
                 gameManager.sendChangedHex(curPos);
                 for (Entity en : entity.getGame().getEntitiesVector(curPos)) {
-                    gameManager.doMagmaDamage(en, false);
+                    if (en != entity) {
+                        gameManager.doMagmaDamage(en, false);
+                    }
                 }
             }
         }
     }
 
+    /**
+     * Check for movement into magma hex and apply damage. TODO: If first and last step are in magma double it.
+     */
+    public static void checkEnteringMagma(Hex hex, int elevation, Entity entity, GameManager gameManager) {
+
+        if ((hex.terrainLevel(Terrains.MAGMA) == 2) && (elevation == 0) && (entity.getMovementMode() != EntityMovementMode.HOVER)) {
+            gameManager.doMagmaDamage(entity, false);
+        }
+    }
+
     /**
      * Loops through all active entities in the game and performs mine detection
      */