changes to entity load handler keeping it backwards compatible

src/main/java/carpet/mixins/ServerWorld_scarpetMixin.java

@@ -23,6 +23,7 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
 
+import static carpet.script.CarpetEventServer.Event.ENTITY_HANDLER;
 import static carpet.script.CarpetEventServer.Event.ENTITY_LOAD;
 import static carpet.script.CarpetEventServer.Event.EXPLOSION;
 import static carpet.script.CarpetEventServer.Event.LIGHTNING;
@@ -43,24 +44,50 @@ public class ServerWorld_scarpetMixin implements ServerWorldInterface
         if (LIGHTNING.isNeeded()) LIGHTNING.onWorldEventFlag((ServerWorld) (Object)this, blockPos, bl2?1:0);
     }
 
+
+    private ThreadLocal<Boolean> entityJustLoaded = ThreadLocal.withInitial(() -> false);
+
     @Inject(method = "loadEntityUnchecked", at = @At(
             value = "INVOKE",
             target = "Lnet/minecraft/server/world/ServerChunkManager;loadEntity(Lnet/minecraft/entity/Entity;)V"
     ))
             private void onEntityAddedToWorld(Entity entity, CallbackInfo ci)
     {
-        CarpetEventServer.Event event = ENTITY_LOAD.get(entity.getType());
+        boolean justLoaded = entityJustLoaded.get();
+        entityJustLoaded.set(false);
+        CarpetEventServer.Event event = ENTITY_HANDLER.get(entity.getType());
         if (event != null)
         {
             if (event.isNeeded())
             {
-                event.onEntityAction(entity);
+                event.onEntityAction(entity, !justLoaded);
             }
         }
         else
         {
             CarpetSettings.LOG.error("Failed to handle entity "+entity.getType().getTranslationKey());
         }
+
+        // deprecated usage
+        event = ENTITY_LOAD.get(entity.getType());
+        if (event != null)
+        {
+            if (event.isNeeded())
+            {
+                event.onEntityAction(entity, true);
+            }
+        }
+        else
+        {
+            CarpetSettings.LOG.error("Failed to handle entity "+entity.getType().getTranslationKey());
+        }
+    }
+
+    // 1.16only
+    @Inject(method = "loadEntity", at= @At("HEAD"))
+    private void onSideLoaded(Entity entity, CallbackInfoReturnable<Boolean> cir)
+    {
+        entityJustLoaded.set(true);
     }
 
     @Inject(method = "createExplosion", at = @At("HEAD"))

src/main/java/carpet/script/CarpetEventServer.java

@@ -926,18 +926,20 @@ public class CarpetEventServer
             }
         };
 
+        @Deprecated
         public static String getEntityLoadEventName(EntityType<? extends Entity> et)
         {
             return "entity_loaded_" + ValueConversions.of(Registry.ENTITY_TYPE.getId(et)).getString();
         }
 
+        @Deprecated
         public static final Map<EntityType<? extends Entity>, Event> ENTITY_LOAD= new HashMap<EntityType<? extends Entity>, Event>() {{
             EntityType.get("zombie");
             Registry.ENTITY_TYPE.forEach(et -> {
                 put(et, new Event(getEntityLoadEventName(et), 1, true, false)
                 {
                     @Override
-                    public void onEntityAction(Entity entity)
+                    public void onEntityAction(Entity entity, boolean created)
                     {
                         handler.call(
                                 () -> Collections.singletonList(new EntityValue(entity)),
@@ -948,6 +950,28 @@ public class CarpetEventServer
             });
         }};
 
+        public static String getEntityHandlerEventName(EntityType<? extends Entity> et)
+        {
+            return "entity_handler_" + ValueConversions.of(Registry.ENTITY_TYPE.getId(et)).getString();
+        }
+
+        public static final Map<EntityType<? extends Entity>, Event> ENTITY_HANDLER= new HashMap<EntityType<? extends Entity>, Event>() {{
+            EntityType.get("zombie");
+            Registry.ENTITY_TYPE.forEach(et -> {
+                put(et, new Event(getEntityHandlerEventName(et), 2, true, false)
+                {
+                    @Override
+                    public void onEntityAction(Entity entity, boolean created)
+                    {
+                        handler.call(
+                                () -> Arrays.asList(new EntityValue(entity), BooleanValue.of(created)),
+                                () -> CarpetServer.minecraft_server.getCommandSource().withWorld((ServerWorld) entity.world).withLevel(CarpetSettings.runPermissionLevel)
+                        );
+                    }
+                });
+            });
+        }};
+
         // on projectile thrown (arrow from bows, crossbows, tridents, snoballs, e-pearls
 
         public final String name;
@@ -1038,7 +1062,7 @@ public class CarpetEventServer
         public void onBlockPlaced(ServerPlayerEntity player, BlockPos pos, Hand enumhand, ItemStack itemstack) { }
         public void onEntityHandAction(ServerPlayerEntity player, Entity entity, Hand enumhand) { }
         public void onHandAction(ServerPlayerEntity player, Hand enumhand) { }
-        public void onEntityAction(Entity entity) { }
+        public void onEntityAction(Entity entity, boolean created) { }
         public void onDimensionChange(ServerPlayerEntity player, Vec3d from, Vec3d to, RegistryKey<World> fromDim, RegistryKey<World> dimTo) {}
         public void onDamage(Entity target, float amount, DamageSource source) { }
         public void onRecipeSelected(ServerPlayerEntity player, Identifier recipe, boolean fullStack) {}

src/main/java/carpet/script/api/Entities.java

@@ -275,10 +275,21 @@ public class Entities {
             if (funArg.function == null)
             {
                 types.forEach(et -> events.removeBuiltInEvent(CarpetEventServer.Event.getEntityLoadEventName(et), (CarpetScriptHost) c.host));
+                types.forEach(et -> events.removeBuiltInEvent(CarpetEventServer.Event.getEntityHandlerEventName(et), (CarpetScriptHost) c.host));
             }
             else
             {
-                types.forEach(et -> events.addBuiltInEvent(CarpetEventServer.Event.getEntityLoadEventName(et), c.host, funArg.function, funArg.args));
+                ///compat
+                int argno = funArg.function.getArguments().size() - funArg.args.size();
+                if (argno == 1)
+                {
+                    c.host.issueDeprecation("entity_load_handler() with single argument callback");
+                    types.forEach(et -> events.addBuiltInEvent(CarpetEventServer.Event.getEntityLoadEventName(et), c.host, funArg.function, funArg.args));
+                }
+                else
+                {
+                    types.forEach(et -> events.addBuiltInEvent(CarpetEventServer.Event.getEntityHandlerEventName(et), c.host, funArg.function, funArg.args));
+                }
             }
             return new NumericValue(types.size());
         });