Implement DNI, EI Interface, and Damage Interrupt Circuit support

megamek/src/megamek/client/ui/entityreadout/ReadoutUtils.java

@@ -248,9 +248,15 @@ private static void addBayAmmoList(WeaponMounted mounted, TableElement wpnTable)
 
     static boolean hideMisc(MiscMounted mounted, Entity entity) {
         String name = mounted.getName();
+        // Check if this is a cockpit modification that should always be shown (e.g., DNI, EI Interface)
+        boolean isCockpitModification = mounted.getType().hasFlag(MiscType.F_DNI_COCKPIT_MOD)
+              || mounted.getType().hasFlag(MiscType.F_EI_INTERFACE)
+              || mounted.getType().hasFlag(MiscType.F_DAMAGE_INTERRUPT_CIRCUIT);
         return (((mounted.getLocation() == Entity.LOC_NONE)
               // Meks can have zero-slot equipment in LOC_NONE that needs to be shown.
-              && (!(entity instanceof Mek) || mounted.getNumCriticalSlots() > 0)))
+              // Also show cockpit modifications for all unit types.
+              && (!(entity instanceof Mek) || mounted.getNumCriticalSlots() > 0)
+              && !isCockpitModification))
               || name.contains("Jump Jet")
               || (name.contains("CASE") && !name.contains("II") && entity.isClan())
               || (name.contains("Heat Sink") && !name.contains("Radical"))

megamek/src/megamek/common/cost/MekCostCalculator.java

@@ -45,7 +45,7 @@
 public class MekCostCalculator {
 
     public static double calculateCost(Mek mek, CalculationReport costReport, boolean ignoreAmmo) {
-        double[] costs = new double[18 + mek.locations()];
+        double[] costs = new double[17 + mek.locations()];
         int i = 0;
 
         double cockpitCost = switch (mek.getCockpitType()) {
@@ -119,12 +119,6 @@ public static double calculateCost(Mek mek, CalculationReport costReport, boolea
         // cost of sinks
         costs[i++] = sinkCost * (mek.heatSinks() - freeSinks);
         costs[i++] = mek.hasFullHeadEject() ? 1725000 : 0;
-        // Damage Interrupt Circuit (IO p.39) costs 150 C-bills per pilot seat
-        int dicCost = 0;
-        if (mek.hasDamageInterruptCircuit() && (mek.getCrew() != null)) {
-            dicCost = 150 * mek.getCrew().getCrewType().getCrewSlots();
-        }
-        costs[i++] = dicCost;
         // armored components
         int armoredCrits = 0;
         for (int j = 0; j < mek.locations(); j++) {

megamek/src/megamek/common/equipment/MiscType.java

@@ -1058,6 +1058,13 @@ public double getCost(Entity entity, boolean isArmored, int loc, double size) {
                 costValue = size * 10000;
             } else if (hasFlag(F_RAM_PLATE)) {
                 costValue = getTonnage(entity, loc) * 10000;
+            } else if (hasFlag(F_DAMAGE_INTERRUPT_CIRCUIT)) {
+                // DIC costs 150 C-bills per pilot seat (IO p.39)
+                if (entity.getCrew() != null) {
+                    costValue = 150 * entity.getCrew().getCrewType().getCrewSlots();
+                } else {
+                    costValue = 150; // Default to 1 seat if no crew assigned
+                }
             }
 
             if (isArmored) {
@@ -4726,7 +4733,8 @@ public static MiscType createDNICockpitModification() {
               .setISAdvancement(3052, 3055, DATE_NONE, DATE_NONE, DATE_NONE)
               .setISApproximate(false, false, false, false, false)
               .setPrototypeFactions(Faction.FS)
-              .setProductionFactions(Faction.WB);
+              .setProductionFactions(Faction.WB)
+              .setStaticTechLevel(SimpleTechLevel.ADVANCED);
         return misc;
     }
 
@@ -4742,7 +4750,7 @@ public static MiscType createDamageInterruptCircuit() {
 
         misc.tonnage = 0;
         misc.criticalSlots = 0;
-        misc.cost = 150; // 150 C-bills per pilot seat (handled in cost calculator)
+        misc.cost = EquipmentType.COST_VARIABLE; // 150 C-bills per pilot seat (IO p.39)
         misc.hittable = false;
         misc.flags = misc.flags.or(F_MEK_EQUIPMENT, F_DAMAGE_INTERRUPT_CIRCUIT);
 
@@ -4754,7 +4762,8 @@ public static MiscType createDamageInterruptCircuit() {
               .setAvailability(AvailabilityValue.X, AvailabilityValue.X, AvailabilityValue.F, AvailabilityValue.F)
               .setISAdvancement(3055, DATE_NONE, DATE_NONE, DATE_NONE, DATE_NONE)
               .setISApproximate(true, false, false, false, false)
-              .setPrototypeFactions(Faction.LC);
+              .setPrototypeFactions(Faction.LC)
+              .setStaticTechLevel(SimpleTechLevel.EXPERIMENTAL);
         return misc;
     }
 

megamek/src/megamek/common/interfaces/ITechManager.java

@@ -110,18 +110,22 @@ && unofficialNoYear()) {
         Faction faction = getTechFaction();
         boolean clanTech = useClanTechBase();
 
+        // Use getGameYear() for availability checks - this respects the "Use Game Year" setting
+        // which allows equipment available by the configured game year, not just the unit's intro year
+        int yearForAvailability = getGameYear();
+
         int isIntroDate = tech.getIntroductionDate(false);
         int clanIntroDate = tech.getIntroductionDate(true);
-        boolean introducedIS = (isIntroDate != ITechnology.DATE_NONE) && (isIntroDate <= getTechIntroYear());
-        boolean introducedClan = (clanIntroDate != ITechnology.DATE_NONE) && (clanIntroDate <= getTechIntroYear());
-        boolean extinctIS = tech.isExtinct(getTechIntroYear(), false);
-        boolean extinctClan = tech.isExtinct(getTechIntroYear(), true);
+        boolean introducedIS = (isIntroDate != ITechnology.DATE_NONE) && (isIntroDate <= yearForAvailability);
+        boolean introducedClan = (clanIntroDate != ITechnology.DATE_NONE) && (clanIntroDate <= yearForAvailability);
+        boolean extinctIS = tech.isExtinct(yearForAvailability, false);
+        boolean extinctClan = tech.isExtinct(yearForAvailability, true);
         // A little bit of hard-coded universe detail
         if ((faction == Faction.CS)
               && extinctIS && (isIntroDate != ITechnology.DATE_NONE)
-              && (tech.getBaseAvailability(ITechnology.getTechEra(getTechIntroYear())).getIndex()
+              && (tech.getBaseAvailability(ITechnology.getTechEra(yearForAvailability)).getIndex()
               < AvailabilityValue.X.getIndex())
-              && isIntroDate <= getTechIntroYear()) {
+              && isIntroDate <= yearForAvailability) {
             // ComStar has access to Star League tech that is otherwise extinct in the Inner Sphere as if TH,
             // unless it has an availability of X (which is SLDF Royal equipment).
             extinctIS = false;
@@ -138,7 +142,7 @@ && unofficialNoYear()) {
         if (useMixedTech()) {
             if ((!introducedIS && !introducedClan)
                   || (!showExtinct()
-                  && (tech.isExtinct(getTechIntroYear())))) {
+                  && (tech.isExtinct(yearForAvailability)))) {
                 return false;
             } else if (useVariableTechLevel()) {
                 // If using tech progression with mixed tech, we pass if either IS or Clan meets the required level

megamek/src/megamek/common/loaders/BLKAeroSpaceFighterFile.java

@@ -208,6 +208,7 @@ public Entity getEntity() throws EntityLoadingException {
 
         a.setArmorTonnage(a.getArmorWeight());
         loadQuirks(a);
+        loadSlotlessEquipment(a);
         return a;
     }
 

megamek/src/megamek/common/loaders/BLKBattleArmorFile.java

@@ -175,6 +175,7 @@ public Entity getEntity() throws EntityLoadingException {
         }
         t.setArmorTonnage(t.getArmorWeight());
         loadQuirks(t);
+        loadSlotlessEquipment(t);
         return t;
     }
 

megamek/src/megamek/common/loaders/BLKConvFighterFile.java

@@ -169,6 +169,7 @@ public Entity getEntity() throws EntityLoadingException {
 
         a.setArmorTonnage(a.getArmorWeight());
         loadQuirks(a);
+        loadSlotlessEquipment(a);
         return a;
     }
 

megamek/src/megamek/common/loaders/BLKFile.java

@@ -97,6 +97,7 @@ public class BLKFile {
     private static final int TECH_CLAN_BASE = 1 << 1;
 
     static final String BLK_EXTRA_SEATS = "extra_seats";
+    static final String BLK_SLOTLESS_EQUIPMENT = "slotless_equipment";
 
     /**
      * If a vehicular grenade launcher does not have a facing provided, assign a default facing. The vehicle location
@@ -346,6 +347,44 @@ protected void loadEquipment(Entity t, String sName, int nLoc) throws EntityLoad
         }
     }
 
+    /**
+     * Loads slotless equipment (equipment at LOC_NONE) such as cockpit modifications.
+     * This equipment has no location but still needs to be saved and loaded.
+     *
+     * @param t the entity to load equipment into
+     * @throws EntityLoadingException if the equipment cannot be loaded
+     */
+    protected void loadSlotlessEquipment(Entity t) throws EntityLoadingException {
+        String[] saEquip = dataFile.getDataAsString(BLK_SLOTLESS_EQUIPMENT);
+        if (saEquip == null) {
+            return;
+        }
+
+        String prefix = t.isClan() ? "Clan " : "IS ";
+
+        for (String s : saEquip) {
+            if (s == null || s.isBlank()) {
+                continue;
+            }
+            String equipName = s.trim();
+
+            EquipmentType etype = EquipmentType.get(equipName);
+            if (etype == null) {
+                etype = EquipmentType.get(prefix + equipName);
+            }
+
+            if (etype != null) {
+                try {
+                    t.addEquipment(etype, Entity.LOC_NONE);
+                } catch (LocationFullException ex) {
+                    throw new EntityLoadingException(ex.getMessage());
+                }
+            } else if (!equipName.isBlank()) {
+                t.addFailedEquipment(equipName);
+            }
+        }
+    }
+
     protected void loadSVArmor(Entity sv) throws EntityLoadingException {
         boolean patchworkArmor = dataFile.exists("armor_type") &&
               dataFile.getDataAsInt("armor_type")[0] == EquipmentType.T_ARMOR_PATCHWORK;
@@ -875,6 +914,19 @@ public static BuildingBlock getBlock(Entity t) throws EntitySavingException {
         for (int i = 0; i < numLocs; i++) {
             blk.writeBlockData(t.getLocationName(i) + " Equipment", eq.get(i));
         }
+
+        // Write slotless equipment (LOC_NONE) - e.g., cockpit modifications like DNI
+        Vector<String> slotlessEquipment = new Vector<>();
+        for (Mounted<?> m : t.getEquipment()) {
+            if (m.getLocation() == Entity.LOC_NONE && !m.isWeaponGroup() && !m.isAPMMounted()
+                  && !(m.getType() instanceof InfantryAttack)
+                  && !(m.getType() instanceof BayWeapon)) {
+                slotlessEquipment.add(encodeEquipmentLine(m));
+            }
+        }
+        if (!slotlessEquipment.isEmpty()) {
+            blk.writeBlockData(BLK_SLOTLESS_EQUIPMENT, slotlessEquipment);
+        }
         if (!t.hasPatchworkArmor() && ArmorType.forEntity(t).hasFlag(MiscType.F_SUPPORT_VEE_BAR_ARMOR)) {
             blk.writeBlockData("barrating", t.getBARRating(1));
         }

megamek/src/megamek/common/loaders/BLKFixedWingSupportFile.java

@@ -171,6 +171,7 @@ public Entity getEntity() throws EntityLoadingException {
         }
 
         loadQuirks(a);
+        loadSlotlessEquipment(a);
         return a;
     }
 

megamek/src/megamek/common/loaders/BLKLargeSupportTankFile.java

@@ -207,6 +207,7 @@ public Entity getEntity() throws EntityLoadingException {
             }
         }
         loadQuirks(t);
+        loadSlotlessEquipment(t);
 
         resetCrew(t);
 

megamek/src/megamek/common/loaders/BLKSupportTankFile.java

@@ -206,6 +206,7 @@ public Entity getEntity() throws EntityLoadingException {
             }
         }
         loadQuirks(t);
+        loadSlotlessEquipment(t);
 
         resetCrew(t);
 

megamek/src/megamek/common/loaders/BLKSupportVTOLFile.java

@@ -197,6 +197,7 @@ public Entity getEntity() throws EntityLoadingException {
             t.setBaseChassisFireConWeight((dataFile.getDataAsDouble("baseChassisFireConWeight")[0]));
         }
         loadQuirks(t);
+        loadSlotlessEquipment(t);
         return t;
     }
 

megamek/src/megamek/common/loaders/BLKTankFile.java

@@ -271,6 +271,7 @@ public Entity getEntity() throws EntityLoadingException {
         }
         t.recalculateTechAdvancement();
         loadQuirks(t);
+        loadSlotlessEquipment(t);
 
         resetCrew(t);
 

megamek/src/megamek/common/loaders/BLKVTOLFile.java

@@ -192,6 +192,7 @@ public Entity getEntity() throws EntityLoadingException {
             t.setBaseChassisSponsonPintleWeight(dataFile.getDataAsDouble("baseChassisSponsonPintleWeight")[0]);
         }
         loadQuirks(t);
+        loadSlotlessEquipment(t);
         return t;
     }
 }

megamek/src/megamek/common/templates/AeroTROView.java

@@ -43,6 +43,7 @@
 import megamek.common.Messages;
 import megamek.common.equipment.AmmoMounted;
 import megamek.common.equipment.AmmoType;
+import megamek.common.equipment.EquipmentType;
 import megamek.common.equipment.MiscType;
 import megamek.common.equipment.Mounted;
 import megamek.common.equipment.WeaponMounted;
@@ -327,4 +328,15 @@ protected void addCrewEntry(String stringKey, int count) {
         }
     }
 
+    @Override
+    protected boolean skipMount(Mounted<?> mount, boolean includeAmmo) {
+        if (mount.getLocation() == Entity.LOC_NONE) {
+            // Skip armor, structure, and CASE. Show cockpit modifications like DNI.
+            return mount.getType().hasFlag(MiscType.F_CASE)
+                  || EquipmentType.isArmorType(mount.getType())
+                  || EquipmentType.isStructureType(mount.getType());
+        }
+        return super.skipMount(mount, includeAmmo);
+    }
+
 }

megamek/src/megamek/common/templates/BattleArmorTROView.java

@@ -167,9 +167,17 @@ private int addBAEquipment() {
         int nameWidth = 30;
         for (final Mounted<?> m : ba.getEquipment()) {
             if (m.isAPMMounted() || (m.getType() instanceof InfantryAttack)
-                  || (m.getType() == armor) || (m.getLocation() == BattleArmor.LOC_NONE)) {
+                  || (m.getType() == armor)) {
                 continue;
             }
+            // Skip LOC_NONE equipment except for cockpit modifications like DNI and EI
+            if (m.getLocation() == BattleArmor.LOC_NONE) {
+                if (!(m.getType() instanceof MiscType) ||
+                      (!m.getType().hasFlag(MiscType.F_DNI_COCKPIT_MOD) &&
+                       !m.getType().hasFlag(MiscType.F_EI_INTERFACE))) {
+                    continue;
+                }
+            }
             if ((m.getType() instanceof MiscType) && m.getType().hasFlag(MiscType.F_BA_MANIPULATOR)) {
                 continue;
             }

megamek/src/megamek/common/templates/SupportVeeTROView.java

@@ -268,4 +268,15 @@ protected int addEquipment(Entity entity, boolean includeAmmo) {
         return nameWidth;
     }
 
+    @Override
+    protected boolean skipMount(Mounted<?> mount, boolean includeAmmo) {
+        if (mount.getLocation() == Entity.LOC_NONE) {
+            // Skip armor, structure, and CASE. Show cockpit modifications like DNI.
+            return mount.getType().hasFlag(MiscType.F_CASE)
+                  || EquipmentType.isArmorType(mount.getType())
+                  || EquipmentType.isStructureType(mount.getType());
+        }
+        return super.skipMount(mount, includeAmmo);
+    }
+
 }

megamek/src/megamek/common/templates/VehicleTROView.java

@@ -39,7 +39,9 @@
 import java.util.Map;
 
 import megamek.common.Messages;
+import megamek.common.equipment.EquipmentType;
 import megamek.common.equipment.GunEmplacement;
+import megamek.common.equipment.MiscType;
 import megamek.common.equipment.Mounted;
 import megamek.common.equipment.Transporter;
 import megamek.common.units.Entity;
@@ -211,4 +213,15 @@ protected int addEquipment(Entity entity, boolean includeAmmo) {
         }
         return retVal;
     }
+
+    @Override
+    protected boolean skipMount(Mounted<?> mount, boolean includeAmmo) {
+        if (mount.getLocation() == Entity.LOC_NONE) {
+            // Skip armor, structure, and CASE. Show cockpit modifications like DNI.
+            return mount.getType().hasFlag(MiscType.F_CASE)
+                  || EquipmentType.isArmorType(mount.getType())
+                  || EquipmentType.isStructureType(mount.getType());
+        }
+        return super.skipMount(mount, includeAmmo);
+    }
 }