Implement trial activities

src/main/java/emu/nebula/game/activity/GameActivity.java

@@ -0,0 +1,65 @@
+package emu.nebula.game.activity;
+
+import dev.morphia.annotations.Entity;
+import emu.nebula.Nebula;
+import emu.nebula.data.resources.ActivityDef;
+import emu.nebula.game.player.Player;
+import emu.nebula.proto.ActivityDetail.ActivityMsg;
+import emu.nebula.proto.Public.Activity;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Entity(useDiscriminator = true)
+public abstract class GameActivity {
+    private int id;
+    
+    @Setter private transient ActivityManager manager;
+    @Setter private transient ActivityDef data;
+    
+    @Deprecated // Morhpia only
+    public GameActivity() {
+        
+    }
+    
+    public GameActivity(ActivityManager manager, ActivityDef data) {
+        this.id = data.getId();
+        this.manager = manager;
+        this.data = data;
+    }
+    
+    public Player getPlayer() {
+        return this.getManager().getPlayer();
+    }
+    
+    public void save() {
+        Nebula.getGameDatabase().update(
+            this.getManager(),
+            this.getManager().getPlayerUid(),
+            "activities." + this.getId(), 
+            this
+        );
+    }
+    
+    // Proto
+    
+    public Activity toProto() {
+        var proto = Activity.newInstance()
+                .setId(this.getId())
+                .setStartTime(1)
+                .setEndTime(Integer.MAX_VALUE);
+        
+        return proto;
+    }
+    
+    public ActivityMsg toMsgProto() {
+        var proto = ActivityMsg.newInstance()
+                .setId(this.getId());
+        
+        this.encodeActivityMsg(proto);
+        
+        return proto;
+    }
+    
+    public abstract void encodeActivityMsg(ActivityMsg msg);
+}