Server side partition syncing and packets

src/main/java/net/xevianlight/aphelion/network/PartitionSync.java

@@ -0,0 +1,62 @@
+package net.xevianlight.aphelion.network;
+
+
+import net.minecraft.server.level.ServerPlayer;
+import net.neoforged.bus.api.SubscribeEvent;
+import net.neoforged.fml.common.EventBusSubscriber;
+import net.neoforged.neoforge.event.entity.player.PlayerEvent;
+import net.neoforged.neoforge.event.tick.ServerTickEvent;
+import net.neoforged.neoforge.network.PacketDistributor;
+import net.xevianlight.aphelion.Aphelion;
+import net.xevianlight.aphelion.core.space.SpacePartitionSavedData;
+import net.xevianlight.aphelion.network.packet.PartitionData;
+import net.xevianlight.aphelion.util.SpacePartitionHelper;
+
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+
+@EventBusSubscriber(modid = Aphelion.MOD_ID)
+public final class PartitionSync {
+
+    // send once right after join (safe: delayed to next server tick)
+    private static final Set<UUID> PENDING_JOIN_SEND = new HashSet<>();
+
+    @SubscribeEvent
+    public static void onLogin(PlayerEvent.PlayerLoggedInEvent e) {
+        if (e.getEntity() instanceof ServerPlayer sp) {
+            PENDING_JOIN_SEND.add(sp.getUUID());
+        }
+    }
+
+    private static final java.util.Map<UUID, PartitionData> LAST_SENT = new java.util.HashMap<>();
+
+    @SubscribeEvent
+    public static void onServerTick(ServerTickEvent.Post e) {
+        var server = e.getServer();
+
+//        Aphelion.LOGGER.info("WORKS!!!");
+
+        for (ServerPlayer sp : server.getPlayerList().getPlayers()) {
+            PartitionData now = computePartitionFor(sp); // your logic
+            PartitionData prev = LAST_SENT.get(sp.getUUID());
+
+            if (prev == null || !prev.equals(now)) {
+                PacketDistributor.sendToPlayer(sp, now);
+                LAST_SENT.put(sp.getUUID(), now);
+            }
+        }
+    }
+
+    private static PartitionData computePartitionFor(ServerPlayer sp) {
+        // Example: convert player position to partition coords
+        int px = (int)Math.floor(sp.getX() / SpacePartitionHelper.SIZE);
+        int pz = (int)Math.floor(sp.getZ() / SpacePartitionHelper.SIZE);
+
+        var orbit = SpacePartitionSavedData.get(sp.serverLevel()).getOrbitForPartition(px, pz);
+        String orbitId = (orbit != null) ? orbit.toString() : "aphelion:orbit/default";
+
+        return new PartitionData(orbitId);
+    }
+}