Update all forge event code, attempt to become loader unaware (#10468)

Introduce a new event handler in the IMinecoloniesAPI, which is backed by an interface containing basic methods for the events we want to send
Event handler is implemented in such a way it could be made loader unaware in the future if needed.
All logic for sending Forge specific events is ripped out in favor of the API event handler

src/main/java/com/minecolonies/api/IMinecoloniesAPI.java

@@ -22,6 +22,7 @@
 import com.minecolonies.api.entity.citizen.happiness.HappinessRegistry;
 import com.minecolonies.api.entity.pathfinding.registry.IPathNavigateRegistry;
 import com.minecolonies.api.equipment.registry.EquipmentTypeEntry;
+import com.minecolonies.api.eventbus.EventBus;
 import com.minecolonies.api.quests.registries.QuestRegistries;
 import com.minecolonies.api.research.IGlobalResearchTree;
 import com.minecolonies.api.research.ModResearchCostTypes.ResearchCostType;
@@ -101,4 +102,6 @@ static IMinecoloniesAPI getInstance()
     void onRegistryNewRegistry(NewRegistryEvent event);
 
     IForgeRegistry<EquipmentTypeEntry> getEquipmentTypeRegistry();
+
+    EventBus getEventBus();
 }

src/main/java/com/minecolonies/api/MinecoloniesAPIProxy.java

@@ -22,6 +22,7 @@
 import com.minecolonies.api.entity.citizen.happiness.HappinessRegistry;
 import com.minecolonies.api.entity.pathfinding.registry.IPathNavigateRegistry;
 import com.minecolonies.api.equipment.registry.EquipmentTypeEntry;
+import com.minecolonies.api.eventbus.EventBus;
 import com.minecolonies.api.quests.registries.QuestRegistries;
 import com.minecolonies.api.research.IGlobalResearchTree;
 import com.minecolonies.api.research.ModResearchCostTypes.ResearchCostType;
@@ -32,7 +33,7 @@
 
 public final class MinecoloniesAPIProxy implements IMinecoloniesAPI
 {
-    private static MinecoloniesAPIProxy ourInstance = new MinecoloniesAPIProxy();
+    private static final MinecoloniesAPIProxy ourInstance = new MinecoloniesAPIProxy();
 
     private IMinecoloniesAPI apiInstance;
 
@@ -235,4 +236,10 @@ public IForgeRegistry<EquipmentTypeEntry> getEquipmentTypeRegistry()
     {
         return apiInstance.getEquipmentTypeRegistry();
     }
+
+    @Override
+    public EventBus getEventBus()
+    {
+        return apiInstance.getEventBus();
+    }
 }

src/main/java/com/minecolonies/api/eventbus/DefaultEventBus.java

@@ -0,0 +1,52 @@
+package com.minecolonies.api.eventbus;
+
+import com.minecolonies.api.util.Log;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Default implementation of the mod event bus.
+ */
+public class DefaultEventBus implements EventBus
+{
+    /**
+     * The map of event handlers.
+     */
+    private final Map<Class<? extends IModEvent>, List<EventHandler<? extends IModEvent>>> eventHandlersPerType = new HashMap<>();
+
+    @Override
+    public <T extends IModEvent> void subscribe(final @NotNull Class<T> eventType, final @NotNull EventHandler<T> handler)
+    {
+        Log.getLogger().debug("Registering event handler for id {}.", eventType.getSimpleName());
+
+        eventHandlersPerType.computeIfAbsent(eventType, (f) -> new ArrayList<>()).add(handler);
+    }
+
+    @Override
+    public void post(final @NotNull IModEvent event)
+    {
+        final List<EventHandler<? extends IModEvent>> eventHandlers = eventHandlersPerType.get(event.getClass());
+        if (eventHandlers == null)
+        {
+            return;
+        }
+
+        Log.getLogger().debug("Sending event '{}' for type '{}'. Sending to {} handlers.", event.getEventId(), event.getClass().getSimpleName(), eventHandlers.size());
+
+        for (final EventHandler<? extends IModEvent> handler : eventHandlers)
+        {
+            try
+            {
+                ((EventHandler<IModEvent>) handler).apply(event);
+            }
+            catch (Exception ex)
+            {
+                Log.getLogger().warn("Sending event '{}' for type '{}'. Error occurred in handler:", event.getEventId(), event.getClass().getSimpleName(), ex);
+            }
+        }
+    }
+}

src/main/java/com/minecolonies/api/eventbus/EventBus.java

@@ -0,0 +1,36 @@
+package com.minecolonies.api.eventbus;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Interface for the mod event bus.
+ */
+public interface EventBus
+{
+    /**
+     * Subscribe to the given event type, providing a handler function.
+     *
+     * @param eventType the event class type.
+     * @param handler   the handler function handling the event logic.
+     * @param <T>       the generic type of the event class.
+     */
+    <T extends IModEvent> void subscribe(final @NotNull Class<T> eventType, final @NotNull EventHandler<T> handler);
+
+    /**
+     * Posts a new event on the event bus for the given type.
+     *
+     * @param event the event to send.
+     */
+    void post(final @NotNull IModEvent event);
+
+    /**
+     * The event handler lambda definition.
+     *
+     * @param <T> the generic type of the event class.
+     */
+    @FunctionalInterface
+    interface EventHandler<T extends IModEvent>
+    {
+        void apply(final @NotNull T event);
+    }
+}

src/main/java/com/minecolonies/api/eventbus/IModEvent.java

@@ -0,0 +1,16 @@
+package com.minecolonies.api.eventbus;
+
+import java.util.UUID;
+
+/**
+ * Default event interface.
+ */
+public interface IModEvent
+{
+    /**
+     * The unique id for this event.
+     *
+     * @return the event id.
+     */
+    UUID getEventId();
+}

src/main/java/com/minecolonies/api/eventbus/events/AbstractModEvent.java

@@ -0,0 +1,30 @@
+package com.minecolonies.api.eventbus.events;
+
+import com.minecolonies.api.eventbus.IModEvent;
+
+import java.util.UUID;
+
+/**
+ * Abstract implementation for this mod bus events.
+ */
+public class AbstractModEvent implements IModEvent
+{
+    /**
+     * The unique id for this event.
+     */
+    private final UUID eventId;
+
+    /**
+     * Default constructor.
+     */
+    protected AbstractModEvent()
+    {
+        this.eventId = UUID.randomUUID();
+    }
+
+    @Override
+    public UUID getEventId()
+    {
+        return eventId;
+    }
+}

src/main/java/com/minecolonies/api/colony/managers/events/ColonyManagerLoadedEvent.java → src/main/java/com/minecolonies/api/eventbus/events/ColonyManagerLoadedModEvent.java

@@ -1,13 +1,12 @@
-package com.minecolonies.api.colony.managers.events;
+package com.minecolonies.api.eventbus.events;
 
 import com.minecolonies.api.colony.IColonyManager;
-import net.minecraftforge.eventbus.api.Event;
 import org.jetbrains.annotations.NotNull;
 
 /**
  * Colony manager loaded event.
  */
-public final class ColonyManagerLoadedEvent extends Event
+public final class ColonyManagerLoadedModEvent extends AbstractModEvent
 {
     /**
      * The colony manager instance.
@@ -18,7 +17,7 @@ public final class ColonyManagerLoadedEvent extends Event
     /**
      * Event for colony manager loaded.
      */
-    public ColonyManagerLoadedEvent(final @NotNull IColonyManager colonyManager)
+    public ColonyManagerLoadedModEvent(final @NotNull IColonyManager colonyManager)
     {
         this.colonyManager = colonyManager;
     }
@@ -28,7 +27,8 @@ public ColonyManagerLoadedEvent(final @NotNull IColonyManager colonyManager)
      *
      * @return the colony manager.
      */
-    public @NotNull IColonyManager getColonyManager()
+    @NotNull
+    public IColonyManager getColonyManager()
     {
         return colonyManager;
     }

src/main/java/com/minecolonies/api/colony/managers/events/ColonyManagerUnloadedEvent.java → src/main/java/com/minecolonies/api/eventbus/events/ColonyManagerUnloadedModEvent.java

@@ -1,13 +1,12 @@
-package com.minecolonies.api.colony.managers.events;
+package com.minecolonies.api.eventbus.events;
 
 import com.minecolonies.api.colony.IColonyManager;
-import net.minecraftforge.eventbus.api.Event;
 import org.jetbrains.annotations.NotNull;
 
 /**
  * Colony manager unloaded event.
  */
-public class ColonyManagerUnloadedEvent extends Event
+public final class ColonyManagerUnloadedModEvent extends AbstractModEvent
 {
     /**
      * The colony manager instance.
@@ -18,7 +17,7 @@ public class ColonyManagerUnloadedEvent extends Event
     /**
      * Event for colony manager loaded.
      */
-    public ColonyManagerUnloadedEvent(final @NotNull IColonyManager colonyManager)
+    public ColonyManagerUnloadedModEvent(final @NotNull IColonyManager colonyManager)
     {
         this.colonyManager = colonyManager;
     }
@@ -28,7 +27,8 @@ public ColonyManagerUnloadedEvent(final @NotNull IColonyManager colonyManager)
      *
      * @return the colony manager.
      */
-    public @NotNull IColonyManager getColonyManager()
+    @NotNull
+    public IColonyManager getColonyManager()
     {
         return colonyManager;
     }

src/main/java/com/minecolonies/core/colony/crafting/CustomRecipesReloadedEvent.java → src/main/java/com/minecolonies/api/eventbus/events/CustomRecipesReloadedEvent.java

@@ -1,10 +1,10 @@
-package com.minecolonies.core.colony.crafting;
+package com.minecolonies.api.eventbus.events;
 
 import net.minecraftforge.eventbus.api.Event;
 
 /**
  * This event is fired on the client side whenever the CustomRecipeManager has been
- * populated.  This occurs once on world load/connect and again whenever datapacks are reloaded.
+ * populated. This occurs once on world load/connect and again whenever data-packs are reloaded.
  */
 public class CustomRecipesReloadedEvent extends Event
 {