Added GetMailItemReq/Rsp & PacketMailChangeNotify

Mail still doesn't work for whatever reason. I also added a temporary SendMailCommand just to receive PacketMailChangeNotify.
I feel like I'm about to lose my mind.

Grasscutter-Protos @ ba0eab7d

-Subproject commit 0537e9cc4c7856a7c6f88bbbaa908a80c4ee677e
+Subproject commit ba0eab7d629b5adeb145bc430e14ffcb4bdf3d6a

src/main/java/emu/grasscutter/command/commands/SendMailCommand.java

+package emu.grasscutter.command.commands;
+
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.game.GenshinPlayer;
+import emu.grasscutter.server.packet.send.PacketMailChangeNotify;
+
+import java.util.List;
+
+@Command(label = "sendmail", usage = "sendmail")
+public class SendMailCommand implements CommandHandler {
+
+    @Override
+    public void execute(GenshinPlayer sender, List<String> args) {
+        // This is literally so I can test the notification
+        sender.getSession().send(new PacketMailChangeNotify(sender));
+        sender.dropMessage("Check your inbox");
+    }
+}

src/main/java/emu/grasscutter/server/packet/recv/HandlerGetMailItemReq.java

+package emu.grasscutter.server.packet.recv;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.net.packet.Opcodes;
+import emu.grasscutter.net.packet.PacketHandler;
+import emu.grasscutter.net.packet.PacketOpcodes;
+import emu.grasscutter.net.proto.GetMailItemReqOuterClass;
+import emu.grasscutter.server.game.GameSession;
+import emu.grasscutter.server.packet.send.PacketGetAllMailRsp;
+import emu.grasscutter.server.packet.send.PacketGetMailItemRsp;
+
+@Opcodes(PacketOpcodes.GetMailItemReq)
+public class HandlerGetMailItemReq extends PacketHandler {
+
+    @Override
+    public void handle(GameSession session, byte[] header, byte[] payload) throws Exception {
+        Grasscutter.getLogger().info("Mail Item Req");
+        GetMailItemReqOuterClass.GetMailItemReq req = GetMailItemReqOuterClass.GetMailItemReq.parseFrom(payload);
+        session.send(new PacketGetMailItemRsp(session.getPlayer(), req.getMailIdListList()));
+    }
+
+}

src/main/java/emu/grasscutter/server/packet/send/PacketGetAllMailRsp.java

 package emu.grasscutter.server.packet.send;
 
+import com.google.gson.Gson;
+import emu.grasscutter.Grasscutter;
 import emu.grasscutter.game.GenshinPlayer;
 import emu.grasscutter.net.packet.GenshinPacket;
 import emu.grasscutter.net.packet.PacketOpcodes;
+import emu.grasscutter.net.proto.DateTimeDeleteOuterClass;
 import emu.grasscutter.net.proto.GetAllMailRspOuterClass.GetAllMailRsp;
+import emu.grasscutter.net.proto.ItemParamOuterClass;
 import emu.grasscutter.net.proto.MailDataOuterClass.MailData;
+import emu.grasscutter.net.proto.MailItemOuterClass;
 import emu.grasscutter.net.proto.MailTextContentOuterClass.MailTextContent;
-
-import java.time.Instant;
+import emu.grasscutter.net.proto.MaterialDeleteInfoOuterClass;
 
 public class PacketGetAllMailRsp extends GenshinPacket {
 
     public PacketGetAllMailRsp(GenshinPlayer player, boolean isGiftMail) {
         super(PacketOpcodes.GetAllMailRsp);
+        Grasscutter.getLogger().info(String.valueOf(isGiftMail));
 
         GetAllMailRsp.Builder proto = GetAllMailRsp.newBuilder();
 
+        // Dummy data.
         MailTextContent.Builder mailTextContent = MailTextContent.newBuilder();
-        mailTextContent.setTitle("System Message");
-        mailTextContent.setContent("I'm going to kill you...");
-        mailTextContent.setSender("YOU");
+        mailTextContent.setTitle("Hello Traveller..");
+        mailTextContent.setContent("You've called me emergency food for the last time. \n Get ready to die!");
+        mailTextContent.setSender("P·A·I·M·O·N");
+
+        MailItemOuterClass.MailItem.Builder mailItem = MailItemOuterClass.MailItem.newBuilder();
+        ItemParamOuterClass.ItemParam.Builder itemParam = ItemParamOuterClass.ItemParam.newBuilder();
+
+        itemParam.setItemId(1062);
+        itemParam.setCount(1);
+        mailItem.setItemParam(itemParam.build());
 
         MailData.Builder mailData = MailData.newBuilder();
-        mailData.setMailId(0);
+        mailData.setMailId(100);
         mailData.setMailTextContent(mailTextContent.build());
-        mailData.setSendTime((int) Instant.now().getEpochSecond());
-        mailData.setExpireTime(999999999);
+        mailData.addItemList(mailItem.build());
+        mailData.setSendTime(1634100481);
+        mailData.setExpireTime(1664498747);
         mailData.setImportance(1);
         mailData.setIsRead(false);
         mailData.setIsAttachmentGot(false);
-        maildata.
+        mailData.setStateValue(1);
 
         proto.addMailList(mailData.build());
-        proto.setIsTruncated(false);
+        proto.addMailList(mailData.setMailId(101).build());
+        proto.setIsTruncated(true);
+
+        Grasscutter.getLogger().info(Grasscutter.getDispatchServer().getGsonFactory().toJson(proto.build()));
 
-        this.setData(proto);
+        this.setData(proto.build());
     }
 }

src/main/java/emu/grasscutter/server/packet/send/PacketGetMailItemRsp.java

+package emu.grasscutter.server.packet.send;
+
+import emu.grasscutter.game.GenshinPlayer;
+import emu.grasscutter.net.packet.GenshinPacket;
+import emu.grasscutter.net.packet.PacketOpcodes;
+import emu.grasscutter.net.proto.GetMailItemRspOuterClass.GetMailItemRsp;
+import emu.grasscutter.net.proto.ItemParamOuterClass;
+import emu.grasscutter.net.proto.MailItemOuterClass;
+
+import java.util.List;
+
+public class PacketGetMailItemRsp  extends GenshinPacket {
+
+    public PacketGetMailItemRsp(GenshinPlayer player, List<Integer> mailList) {
+        super(PacketOpcodes.GetMailItemRsp);
+
+        //I'm assuming that this is to receive the attachments on the message.
+        // TODO: This.
+
+        //GetMailItemRsp.Builder proto = GetMailItemRsp.newBuilder();
+
+        //MailItemOuterClass.MailItem.Builder mailItem = MailItemOuterClass.MailItem.newBuilder();
+
+        //ItemParamOuterClass.ItemParam.Builder itemParam = ItemParamOuterClass.ItemParam.newBuilder();
+
+        //mailItem.setItemParam(itemParam);
+
+        //proto.addAllMailIdList(mailList);
+        //proto.addItemList();
+    }
+}

src/main/java/emu/grasscutter/server/packet/send/PacketMailChangeNotify.java

+package emu.grasscutter.server.packet.send;
+
+
+import emu.grasscutter.game.GenshinPlayer;
+import emu.grasscutter.net.packet.GenshinPacket;
+import emu.grasscutter.net.packet.PacketOpcodes;
+import emu.grasscutter.net.proto.*;
+
+import java.util.List;
+
+public class PacketMailChangeNotify extends GenshinPacket {
+
+    public PacketMailChangeNotify(GenshinPlayer player) {
+        super(PacketOpcodes.MailChangeNotify);
+
+        MailChangeNotifyOuterClass.MailChangeNotify.Builder proto = MailChangeNotifyOuterClass.MailChangeNotify.newBuilder();
+
+        // Dummy data.
+        MailTextContentOuterClass.MailTextContent.Builder mailTextContent = MailTextContentOuterClass.MailTextContent.newBuilder();
+        mailTextContent.setTitle("System Message");
+        mailTextContent.setContent("I'm going to kill you...");
+        mailTextContent.setSender("YOU");
+
+        MailItemOuterClass.MailItem.Builder mailItem = MailItemOuterClass.MailItem.newBuilder();
+        ItemParamOuterClass.ItemParam.Builder itemParam = ItemParamOuterClass.ItemParam.newBuilder();
+
+        itemParam.setItemId(1062);
+        itemParam.setCount(1);
+        mailItem.setItemParam(itemParam.build());
+
+        MailDataOuterClass.MailData.Builder mailData = MailDataOuterClass.MailData.newBuilder();
+        mailData.setMailId(100);
+        mailData.setMailTextContent(mailTextContent.build());
+        mailData.addItemList(mailItem.build());
+        mailData.setSendTime(1634100481);
+        mailData.setExpireTime(1664498747);
+        mailData.setImportance(1);
+        mailData.setIsRead(false);
+        mailData.setIsAttachmentGot(false);
+        mailData.setStateValue(1);
+
+        proto.addMailList(mailData.build());
+
+        this.setData(proto.build());
+    }
+}
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