Reimplement gacha (#32)

* Fix some grammar warning

* Reimplement gacha

* Update GachaResult#toSpinResp declaration

---------

Co-authored-by: Yostarcc <lubenwei7758258@gmail.com>

src/main/java/emu/nebula/server/handlers/HandlerGachaNewbieSaveReq.java

@@ -0,0 +1,25 @@
+package emu.nebula.server.handlers;
+
+import emu.nebula.Nebula;
+import emu.nebula.net.GameSession;
+import emu.nebula.net.HandlerId;
+import emu.nebula.net.NetHandler;
+import emu.nebula.net.NetMsgId;
+import emu.nebula.proto.GachaNewbieSave.GachaNewbieSaveReq;
+
+@HandlerId(NetMsgId.gacha_newbie_save_req)
+public class HandlerGachaNewbieSaveReq extends NetHandler {
+
+    @Override
+    public byte[] handle(GameSession session, byte[] message) throws Exception {
+        var req = GachaNewbieSaveReq.parseFrom(message);
+        Integer index = req.hasIdx() ? req.getIdx() : null;
+        boolean succeeded = Nebula.getGameContext().getGachaModule().saveNewbie(session.getPlayer(), req.getId(), index);
+        if (!succeeded) {
+            return session.encodeMsg(NetMsgId.gacha_newbie_save_failed_ack);
+        }
+
+        return session.encodeMsg(NetMsgId.gacha_newbie_save_succeed_ack);
+    }
+
+}