unit test on connect is working, lets start the worst ....

back/src/Model/Group.ts

@@ -1,15 +1,26 @@
 import {MessageUserPosition} from "./Websocket/MessageUserPosition";
 import { World } from "./World";
+import { UserInterface } from "./UserInterface";
+
 export class Group {
     static readonly MAX_PER_GROUP = 4;
     
-    users: MessageUserPosition[];
+    private users: UserInterface[];
+    private connectCallback: (user1: string, user2: string) => void;
+    private disconnectCallback: (user1: string, user2: string) => void;
 
-    constructor(users: MessageUserPosition[]) {
-        this.users = users;
+
+    constructor(users: UserInterface[], connectCallback: (user1: string, user2: string) => void, disconnectCallback: (user1: string, user2: string) => void) {
+        this.users = [];
+        this.connectCallback = connectCallback;
+        this.disconnectCallback = disconnectCallback;
+        
+        users.forEach((user: UserInterface) => {
+            this.join(user);
+        });
     }
 
-    getUsers(): MessageUserPosition[] {
+    getUsers(): UserInterface[] {
         return this.users;
     }
 
@@ -17,12 +28,22 @@ export class Group {
         return this.users.length >= Group.MAX_PER_GROUP;
     }
 
-    isPartOfGroup(user: MessageUserPosition): boolean
+    join(user: UserInterface): void
+    {
+        // Broadcast on the right event
+        this.users.forEach((groupUser: UserInterface) => {
+            this.connectCallback(user.id, groupUser.id);
+        });
+        this.users.push(user);
+        user.group = this;
+    }
+
+    isPartOfGroup(user: UserInterface): boolean
     {
         return this.users.indexOf(user) !== -1;
     }
 
-    isStillIn(user: MessageUserPosition): boolean
+    isStillIn(user: UserInterface): boolean
     {
         if(!this.isPartOfGroup(user)) {
             return false;
@@ -30,7 +51,7 @@ export class Group {
         let stillIn = true;
         for(let i = 0; i <= this.users.length; i++) {
             let userInGroup = this.users[i];
-            let distance = World.computeDistance(user.position, userInGroup.position);
+            let distance = World.computeDistance(user, userInGroup);
             if(distance > World.MIN_DISTANCE) {
                 stillIn = false;
                 break;
@@ -39,7 +60,7 @@ export class Group {
         return stillIn;
     }
 
-    removeFromGroup(users: MessageUserPosition[]): void
+    removeFromGroup(users: UserInterface[]): void
     {
         for(let i = 0; i < users.length; i++) {
             let user = users[i];