* Added message "Can t invite yourself to game"

* Fixed possible backend crash with game

back/volume/src/pong/pong.gateway.ts

@@ -20,6 +20,7 @@ import { MatchmakingQueue } from './game/MatchmakingQueue'
 import { MatchmakingDtoValidated } from './dtos/MatchmakingDtoValidated'
 import { PongService } from './pong.service'
 import { UsersService } from 'src/users/users.service'
+import type User from 'src/users/entity/user.entity'
 
 @WebSocketGateway({
   cors: { origin: new RegExp(`^(http|ws)://${process.env.HOST ?? 'localhost'}(:\\d+)?$`) }
@@ -65,8 +66,33 @@ export class PongGateway implements OnGatewayConnection, OnGatewayDisconnect {
       @MessageBody('socketKey') socketKey: StringDtoValidated
   ): Promise<{ event: string, data: boolean }> {
     let succeeded: boolean = false
-    const user = await this.usersService.findUserByName(playerName.value)
-    // console.log(socketKey.value, user?.socketKey)
+    let user: User | null = null
+    try {
+      user = await this.usersService.findUserByName(playerName.value)
+    } catch (e) {
+      console.log('Failed to register player', playerName.value)
+    }
+
+    // Check that socket key is not already registered
+    for (const [socket, name] of this.socketToPlayerName) {
+      try {
+        const _user: User = await this.usersService.findUserByName(name)
+        if (_user.socketKey === socketKey.value) {
+          console.log('Failed to register player', playerName.value, '(socket key already registered)')
+        }
+      } catch (e) {
+        // User does not exist anymore, unregister it
+        console.log('Disconnected player', name)
+        this.socketToPlayerName.delete(socket)
+        const game: Game | undefined = this.games.playerGame(name)
+        if (game !== undefined) {
+          game.stop(name)
+        }
+        this.matchmakingQueue.removePlayer(name)
+        this.socketToPlayerName.delete(client)
+      }
+    }
+
     if (
       user !== null &&
       user.socketKey === socketKey.value &&

front/volume/src/components/Pong/GameCreation.svelte

@@ -10,6 +10,7 @@
   import type { GameCreationDto } from "./dtos/GameCreationDto";
   import { store } from "../../Auth";
   import type { Socket } from "socket.io-client";
+  import { show_popup } from "../Alert/content";
 
   export let socket: Socket;
   export let invitedUsername: string;
@@ -19,6 +20,10 @@
   let initialBallSpeedY: number = DEFAULT_BALL_INITIAL_SPEED.y;
 
   function createGame() {
+    if ($store.username === invitedUsername) {
+      show_popup("You can't invite yourself to a game.", false);
+      return;
+    }
     const data: GameCreationDto = {
       playerNames: [$store.username, invitedUsername],
       map,

front/volume/src/components/Pong/Pong.svelte

@@ -12,13 +12,17 @@
   import { io, Socket } from "socket.io-client";
   import type { GameUpdate } from "./dtos/GameUpdate";
   import type { GameInfo } from "./dtos/GameInfo";
-  import { popup } from "../Alert/content";
+  import { popup, show_popup } from "../Alert/content";
   import Alert from "../Alert/Alert.svelte";
   import { bind } from 'svelte-simple-modal';
 
   export function inviteToGame(event: CustomEvent<string>) {
-    setAppState(APPSTATE.CREATE_GAME);
     invitedUsername = event.detail;
+    if ($store.username ===  invitedUsername) {
+      show_popup("You can't invite yourself to a game.", false);
+    } else {
+      setAppState(APPSTATE.CREATE_GAME);
+    }
   }
 
   export function resetGameConnection() {