feat(websocket)!: Implement WebSocket connection and event handling

knockoutwhistweb/app/model/sessions/UserSession.scala

@@ -2,13 +2,19 @@ package model.sessions
 
 import de.knockoutwhist.events.player.{RequestCardEvent, RequestTieChoiceEvent, RequestTrumpSuitEvent}
 import de.knockoutwhist.utils.events.SimpleEvent
+import logic.game.GameLobby
 import model.users.User
+import org.apache.pekko.actor.{Actor, ActorRef}
+import play.api.libs.json.{JsObject, JsValue, Json}
+import util.WebsocketEventMapper
 
 import java.util.UUID
-import java.util.concurrent.locks.{Lock, ReentrantLock}
+import java.util.concurrent.locks.ReentrantLock
+import scala.util.{Failure, Success, Try}
 
-class UserSession(val user: User, val host: Boolean) extends PlayerSession {
+class UserSession(val user: User, val host: Boolean, val gameLobby: GameLobby) extends PlayerSession {
   var canInteract: Option[InteractionType] = None
+  var websocketActor: Option[UserWebsocketActor] = None
   val lock: ReentrantLock = ReentrantLock()
 
   override def updatePlayer(event: SimpleEvent): Unit = {
@@ -31,5 +37,17 @@ class UserSession(val user: User, val host: Boolean) extends PlayerSession {
   def resetCanInteract(): Unit = {
     canInteract = None
   }
+
+  def handleWebResponse(eventType: String, data: JsObject): Unit = {
+    lock.lock()
+    Try {
+      eventType match {
+        case "Ping" =>
+          // No action needed for Ping
+          ()
+      }
+    }
+    lock.unlock()
+  }
   
 }

knockoutwhistweb/app/model/sessions/UserWebsocketActor.scala

@@ -0,0 +1,94 @@
+package model.sessions
+
+import de.knockoutwhist.utils.events.SimpleEvent
+import org.apache.pekko.actor.{Actor, ActorRef}
+import play.api.libs.json.{JsObject, JsValue, Json}
+import util.WebsocketEventMapper
+
+import scala.util.{Failure, Success, Try}
+
+class UserWebsocketActor(
+                          out: ActorRef,
+                          session: UserSession
+                        ) extends Actor {
+
+  if (session.websocketActor.isDefined) {
+    session.websocketActor.foreach(actor => actor.transmitTextToClient("Error: Multiple websocket connections detected. Closing this connection."))
+    context.stop(self)
+  } else {
+    session.websocketActor = Some(this)
+  }
+
+  override def receive: Receive = {
+    case msg: String =>
+      val jsonObject = Try {
+        Json.parse(msg)
+      }
+      Try {
+        jsonObject match {
+          case Success(value) =>
+            handle(value)
+          case Failure(exception) =>
+            transmitTextToClient(s"Error parsing JSON: ${exception.getMessage}")
+        }
+      }.failed.foreach(
+        ex => transmitTextToClient(s"Error handling message: ${ex.getMessage}")
+      )
+    case other =>
+  }
+
+  def transmitEventToClient(event: SimpleEvent): Unit = {
+    val jsonString = WebsocketEventMapper.toJsonString(event)
+    out ! jsonString
+  }
+
+  private def transmitJsonToClient(jsonObj: JsObject): Unit = {
+    out ! jsonObj.toString()
+  }
+
+  private def transmitTextToClient(text: String): Unit = {
+    out ! text
+  }
+
+  private def handle(json: JsValue): Unit = {
+    val idOpt = (json \ "id").asOpt[String]
+    if (idOpt.isEmpty) {
+      transmitJsonToClient(Json.obj(
+        "status" -> "error",
+        "error" -> "Missing 'id' field"
+      ))
+      return
+    }
+    val id = idOpt.get
+    val eventOpt = (json \ "event").asOpt[String]
+    if (eventOpt.isEmpty) {
+      transmitJsonToClient(Json.obj(
+        "id" -> id,
+        "event" -> null,
+        "status" -> "error",
+        "error" -> "Missing 'event' field"
+      ))
+      return
+    }
+    val event = eventOpt.get
+    val data = (json \ "data").asOpt[JsObject].getOrElse(Json.obj())
+    val result = Try {
+      session.handleWebResponse(event, data)
+    }
+    if (result.isSuccess) {
+      transmitJsonToClient(Json.obj(
+        "id" -> id,
+        "event" -> event,
+        "status" -> "success"
+      ))
+    } else {
+      transmitJsonToClient(Json.obj(
+        "id" -> id,
+        "event" -> event,
+        "status" -> "error",
+        "error" -> result.failed.get.getMessage
+      ))
+    }
+  }
+
+}