Change group radius management

back/src/Model/Group.ts

@@ -59,6 +59,39 @@ export class Group implements Movable {
         };
     }
 
+    /**
+     * Returns the list of users of the group, ignoring any "followers".
+     * Useful to compute the position of the group if a follower is "trapped" far away from the the leader.
+     */
+    getGroupHeads(): User[] {
+        return Array.from(this.users).filter((user) => user.group?.leader === user || !user.following);
+    }
+
+    /**
+     * Preview the position of the group but don't update it
+     */
+    previewGroupPosition(): { x: number; y: number } | undefined {
+        const users = this.getGroupHeads();
+
+        let x = 0;
+        let y = 0;
+
+        if (users.length === 0) {
+            return undefined;
+        }
+
+        users.forEach((user: User) => {
+            const position = user.getPosition();
+            x += position.x;
+            y += position.y;
+        });
+
+        x /= users.length;
+        y /= users.length;
+
+        return { x, y };
+    }
+
     /**
      * Computes the barycenter of all users (i.e. the center of the group)
      */
@@ -66,19 +99,15 @@ export class Group implements Movable {
         const oldX = this.x;
         const oldY = this.y;
 
-        let x = 0;
-        let y = 0;
         // Let's compute the barycenter of all users.
-        this.users.forEach((user: User) => {
-            const position = user.getPosition();
-            x += position.x;
-            y += position.y;
-        });
-        x /= this.users.size;
-        y /= this.users.size;
-        if (this.users.size === 0) {
-            throw new Error("EMPTY GROUP FOUND!!!");
+        const newPosition = this.previewGroupPosition();
+
+        if (!newPosition) {
+            return;
         }
+
+        const { x, y } = newPosition;
+
         this.x = x;
         this.y = y;
 
@@ -97,10 +126,12 @@ export class Group implements Movable {
         if (!this.currentZone) return;
 
         for (const user of this.positionNotifier.getAllUsersInSquareAroundZone(this.currentZone)) {
+            //  Todo: Merge two groups with a leader
             if (user.group || this.isFull()) return; //we ignore users that are already in a group.
             const distance = GameRoom.computeDistanceBetweenPositions(user.getPosition(), this.getPosition());
             if (distance < this.groupRadius) {
                 this.join(user);
+                this.setOutOfBounds(false);
                 this.updatePosition();
             }
         }
@@ -176,4 +207,8 @@ export class Group implements Movable {
             this.outOfBounds = true;
         }
     }
+
+    get getOutOfBounds() {
+        return this.outOfBounds;
+    }
 }