Epic: create and join rooms - Start Chat (#680)

* add start chat flow with UI

* add feature flag for start chat

* add changelog

* fix naming and tests

* fix empty display name in user cell

* Update ElementX/Sources/Application/AppSettings.swift

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

* add screenshots from UI test

* fix swiftFormat and add identifiers

* fix warnings

---------

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

ElementX/Sources/Services/UserSession/UserSessionFlowCoordinator.swift

@@ -102,6 +102,10 @@ class UserSessionFlowCoordinator: CoordinatorProtocol {
             case (.feedbackScreen, .dismissedFeedbackScreen, .roomList):
                 break
                 
+            case (.roomList, .showStartChatScreen, .startChatScreen):
+                self.presentStartChat()
+            case (.startChatScreen, .dismissedStartChatScreen, .roomList):
+                break
             default:
                 fatalError("Unknown transition: \(context)")
             }
@@ -133,6 +137,8 @@ class UserSessionFlowCoordinator: CoordinatorProtocol {
                 self.stateMachine.processEvent(.feedbackScreen)
             case .presentSessionVerificationScreen:
                 self.stateMachine.processEvent(.showSessionVerificationScreen)
+            case .presentStartChatScreen:
+                self.stateMachine.processEvent(.showStartChatScreen)
             case .signOut:
                 self.callback?(.signOut)
             }
@@ -235,6 +241,30 @@ class UserSessionFlowCoordinator: CoordinatorProtocol {
             self?.stateMachine.processEvent(.dismissedSessionVerificationScreen)
         }
     }
+    
+    // MARK: Start Chat
+    
+    private func presentStartChat() {
+        let startChatNavigationStackCoordinator = NavigationStackCoordinator()
+        
+        let userIndicatorController = UserIndicatorController(rootCoordinator: startChatNavigationStackCoordinator)
+        
+        let parameters = StartChatCoordinatorParameters(userSession: userSession)
+        let coordinator = StartChatCoordinator(parameters: parameters)
+        coordinator.callback = { [weak self] action in
+            guard let self else { return }
+            switch action {
+            case .close:
+                self.navigationSplitCoordinator.setSheetCoordinator(nil)
+            }
+        }
+
+        startChatNavigationStackCoordinator.setRootCoordinator(coordinator)
+        
+        navigationSplitCoordinator.setSheetCoordinator(userIndicatorController) { [weak self] in
+            self?.stateMachine.processEvent(.dismissedStartChatScreen)
+        }
+    }
         
     // MARK: Bug reporting
     

ElementX/Sources/Services/UserSession/UserSessionFlowCoordinatorStateMachine.swift

@@ -34,6 +34,9 @@ class UserSessionFlowCoordinatorStateMachine {
         
         /// Showing the settings screen
         case settingsScreen(selectedRoomId: String?)
+        
+        /// Showing the start chat screen
+        case startChatScreen(selectedRoomId: String?)
     }
 
     /// Events that can be triggered on the AppCoordinator state machine
@@ -61,6 +64,11 @@ class UserSessionFlowCoordinatorStateMachine {
         case showSessionVerificationScreen
         /// Session verification has finished
         case dismissedSessionVerificationScreen
+        
+        /// Request the start of the start chat flow
+        case showStartChatScreen
+        /// Start chat has been dismissed
+        case dismissedStartChatScreen
     }
     
     private let stateMachine: StateMachine<State, Event>
@@ -74,6 +82,7 @@ class UserSessionFlowCoordinatorStateMachine {
         configure()
     }
 
+    // swiftlint:disable:next cyclomatic_complexity
     private func configure() {
         stateMachine.addRoutes(event: .start, transitions: [.initial => .roomList(selectedRoomId: nil)])
 
@@ -99,6 +108,10 @@ class UserSessionFlowCoordinatorStateMachine {
             case (.dismissedSessionVerificationScreen, .sessionVerificationScreen(let selectedRoomId)):
                 return .roomList(selectedRoomId: selectedRoomId)
                 
+            case (.showStartChatScreen, .roomList(let selectedRoomId)):
+                return .startChatScreen(selectedRoomId: selectedRoomId)
+            case (.dismissedStartChatScreen, .startChatScreen(let selectedRoomId)):
+                return .roomList(selectedRoomId: selectedRoomId)
             default:
                 return nil
             }