[FIX] Livechat user registration in another department

app/livechat/server/lib/Livechat.js

@@ -232,7 +232,9 @@ export const Livechat = {
 			updateUser.$set.name = name;
 		}
 
-		if (department) {
+		if (!department) {
+			Object.assign(updateUser, { $unset: { department: 1 } });
+		} else {
 			const dep = LivechatDepartment.findOneByIdOrName(department);
 			updateUser.$set.department = dep && dep._id;
 		}

packages/rocketchat-livechat/.app/client/lib/chatMessages.js

@@ -142,7 +142,7 @@ this.ChatMessages = class ChatMessages {
 			});
 		};
 
-		if (!visitor.getId()) {
+		if (!visitor.getId() || visitor.getDepartment() !== Livechat.department) {
 			const guest = {
 				token: visitor.getToken(),
 			};

packages/rocketchat-livechat/.app/client/views/messages.js

@@ -134,6 +134,7 @@ Template.messages.events({
 				}
 
 				visitor.setId(result.userId);
+				visitor.setData(result.visitor);
 				LivechatVideoCall.request();
 			});
 		} else {

packages/rocketchat-livechat/.app/client/views/register.js

@@ -77,9 +77,7 @@ Template.register.events({
 				}
 			}
 
-			if (departmentId) {
-				Livechat.department = departmentId;
-			}
+			Livechat.department = departmentId;
 
 			const guest = {
 				token: visitor.getToken(),

packages/rocketchat-livechat/.app/imports/client/visitor.js

@@ -60,6 +60,11 @@ export default {
 		return this.token.get();
 	},
 
+	getDepartment() {
+		const data = this.getData();
+		return data && data.department;
+	},
+
 	setToken(token) {
 		if (!token || token === this.token.get()) {
 			return;