Move player mail to MailHandler class

This is so we dont have to save the entire player to the db every time we send mail

src/main/java/emu/grasscutter/game/mail/Mail.java

@@ -1,15 +1,22 @@
 package emu.grasscutter.game.mail;
 
 import dev.morphia.annotations.Entity;
+import dev.morphia.annotations.Id;
+import dev.morphia.annotations.Indexed;
+import dev.morphia.annotations.Transient;
+import emu.grasscutter.database.DatabaseHelper;
 import emu.grasscutter.game.player.Player;
 
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 
-@Entity
-public class Mail {
+import org.bson.types.ObjectId;
 
+@Entity(value = "mail", useDiscriminator = false)
+public class Mail {
+	@Id private ObjectId id;
+	@Indexed private int ownerUid;
     public MailContent mailContent;
     public List<MailItem> itemList;
     public long sendTime;
@@ -18,6 +25,7 @@ public class Mail {
     public boolean isRead;
     public boolean isAttachmentGot;
     public int stateValue;
+    @Transient private boolean shouldDelete;
 
     public Mail() {
         this(new MailContent(), new ArrayList<MailItem>(), (int) Instant.now().getEpochSecond() + 604800); // TODO: add expire time to send mail command
@@ -42,7 +50,19 @@ public class Mail {
         this.stateValue = state; // Different mailboxes, 1 = Default, 3 = Gift-box.
     }
 
-    @Entity
+    public ObjectId getId() {
+		return id;
+	}
+
+	public int getOwnerUid() {
+		return ownerUid;
+	}
+
+	public void setOwnerUid(int ownerUid) {
+		this.ownerUid = ownerUid;
+	}
+
+	@Entity
     public static class MailContent {
         public String title;
         public String content;
@@ -93,4 +113,12 @@ public class Mail {
             this.itemLevel = itemLevel;
         }
     }
+
+	public void save() {
+		if (this.expireTime * 1000 < System.currentTimeMillis()) {
+			DatabaseHelper.deleteMail(this);
+		} else {
+			DatabaseHelper.saveMail(this);
+		}
+	}
 }

src/main/java/emu/grasscutter/game/mail/MailHandler.java

@@ -0,0 +1,104 @@
+package emu.grasscutter.game.mail;
+
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.database.DatabaseHelper;
+import emu.grasscutter.game.player.Player;
+import emu.grasscutter.server.event.player.PlayerReceiveMailEvent;
+import emu.grasscutter.server.packet.send.PacketDelMailRsp;
+import emu.grasscutter.server.packet.send.PacketMailChangeNotify;
+
+public class MailHandler {
+	private final Player player;
+	private final List<Mail> mail;
+	
+	public MailHandler(Player player) {
+		this.player = player;
+		this.mail = new ArrayList<>();
+	}
+
+	public Player getPlayer() {
+		return player;
+	}
+
+	public List<Mail> getMail() {
+		return mail;
+	}
+	
+	// ---------------------MAIL------------------------
+
+	public void sendMail(Mail message) {
+		// Call mail receive event.
+		PlayerReceiveMailEvent event = new PlayerReceiveMailEvent(this.getPlayer(), message); event.call();
+		if(event.isCanceled()) return; message = event.getMessage();
+		
+		message.setOwnerUid(this.getPlayer().getUid());
+		
+		this.mail.add(message);
+		
+		Grasscutter.getLogger().debug("Mail sent to user [" + this.getPlayer().getUid()  + ":" + this.getPlayer().getNickname() + "]!");
+		
+		if (this.getPlayer().isOnline()) {
+			this.getPlayer().sendPacket(new PacketMailChangeNotify(this.getPlayer(), message));
+		} // TODO: setup a way for the mail notification to show up when someone receives mail when they were offline
+	}
+
+	public boolean deleteMail(int mailId) {
+		Mail message = getMailById(mailId);
+
+		if (message != null) {
+			this.getMail().remove(mailId);
+			message.expireTime = 0;
+			message.save();
+			
+			return true;
+		}
+
+		return false;
+	}
+	
+	public void deleteMail(List<Integer> mailList) {
+		List<Integer> sortedMailList = new ArrayList<>();
+		sortedMailList.addAll(mailList);
+		Collections.sort(sortedMailList, Collections.reverseOrder());
+		
+		List<Integer> deleted = new ArrayList<>();
+		
+		for (int id : sortedMailList) {
+			if (this.deleteMail(id)) {
+				deleted.add(id);
+			}
+		}
+		
+		player.getSession().send(new PacketDelMailRsp(player, deleted));
+		player.getSession().send(new PacketMailChangeNotify(player, null, deleted));
+	}
+
+	public Mail getMailById(int index) { return this.mail.get(index); }
+	
+	public int getMailIndex(Mail message) {
+		return this.mail.indexOf(message);
+	}
+
+	public boolean replaceMailByIndex(int index, Mail message) {
+		if(getMailById(index) != null) {
+			this.mail.set(index, message);
+			message.save();
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	public void loadFromDatabase() {
+		List<Mail> mailList = DatabaseHelper.getAllMail(this.getPlayer());
+		
+		for (Mail mail : mailList) {
+			this.getMail().add(mail);
+		}
+	}
+}