[Feature] New Helper to handle config files from Datapacks

src/main/java/org/betterx/worlds/together/util/DatapackConfigs.java

@@ -0,0 +1,100 @@
+package org.betterx.worlds.together.util;
+
+import org.betterx.bclib.BCLib;
+
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.PackType;
+import net.minecraft.server.packs.resources.Resource;
+import net.minecraft.server.packs.resources.ResourceManager;
+
+import net.fabricmc.fabric.api.resource.ResourceManagerHelper;
+import net.fabricmc.fabric.api.resource.SimpleSynchronousResourceReloadListener;
+
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+
+import java.io.Reader;
+import java.util.HashMap;
+import java.util.Map;
+
+public class DatapackConfigs {
+    @FunctionalInterface
+    public interface DatapackConfigReloadHandler {
+        void onReload(ResourceLocation id, JsonObject root);
+    }
+
+    @FunctionalInterface
+    public interface DatapackConfigReloadPrepare {
+        void onReload();
+    }
+
+    private static DatapackConfigs INSTANCE = new DatapackConfigs();
+
+    public static DatapackConfigs instance() {
+        return INSTANCE;
+    }
+
+    private Map<ResourceLocation, DatapackConfigReloadHandler> handlers = new HashMap<>();
+
+    public void register(
+            String modID,
+            String fileName,
+            DatapackConfigReloadHandler handler
+    ) {
+        register(
+                modID, fileName, () -> {
+                    //nothing to do
+                }, handler
+        );
+    }
+
+    public void register(
+            String modID,
+            String fileName,
+            DatapackConfigReloadPrepare prepare,
+            DatapackConfigReloadHandler handler
+    ) {
+        final ResourceLocation handlerID = new ResourceLocation(
+                modID,
+                "config_manager_" + fileName.replaceAll("/", "_").replaceAll(".", "_")
+        );
+        ResourceManagerHelper
+                .get(PackType.SERVER_DATA)
+                .registerReloadListener(new SimpleSynchronousResourceReloadListener() {
+                    @Override
+                    public ResourceLocation getFabricId() {
+                        return handlerID;
+                    }
+
+                    @Override
+                    public void onResourceManagerReload(ResourceManager manager) {
+                        prepare.onReload();
+                        runForResources(manager, modID, fileName, handler);
+                    }
+                });
+    }
+
+    public void runForResources(
+            ResourceManager manager,
+            String modID,
+            String fileName,
+            DatapackConfigReloadHandler handler
+    ) {
+        for (Map.Entry<ResourceLocation, Resource> entry : manager.listResources(
+                "config",
+                id -> id.getNamespace().equals(modID) &&
+                        id.getPath().endsWith(fileName)
+        ).entrySet()) {
+            try (Reader reader = entry.getValue().openAsReader()) {
+                final JsonObject obj = JsonParser.parseReader(reader).getAsJsonObject();
+                if (obj != null)
+                    handler.onReload(entry.getKey(), obj);
+            } catch (Exception e) {
+                BCLib.LOGGER.error(
+                        "Error occurred while loading resource json " + entry.getKey(),
+                        e
+                );
+            }
+        }
+    }
+}