Move session related responsibilities from ChatsFlowFlowCoordinator to UserSessionFlowCoordinator.

Specifically: onboarding, session verification and logout.

ElementX/Sources/Application/Navigation/NavigationTabCoordinator.swift

@@ -17,6 +17,8 @@ import SwiftUI
         let selectedIcon: KeyPath<CompoundIcons, Image>
     }
     
+    // MARK: Tabs
+    
     fileprivate struct TabModule: Identifiable {
         let module: NavigationModule
         let title: String
@@ -58,8 +60,108 @@ import SwiftUI
         }
     }
     
+    // MARK: Sheets
+    
+    fileprivate var sheetModule: NavigationModule? {
+        didSet {
+            if let oldValue {
+                logPresentationChange("Remove sheet", oldValue)
+                oldValue.tearDown()
+            }
+            
+            if let sheetModule {
+                logPresentationChange("Set sheet", sheetModule)
+                sheetModule.coordinator?.start()
+            }
+        }
+    }
+    
+    var presentationDetents: Set<PresentationDetent> = []
+    
+    /// The currently presented sheet coordinator.
+    var sheetCoordinator: (any CoordinatorProtocol)? {
+        sheetModule?.coordinator
+    }
+    
+    /// Present a sheet on top of the stack. If this NavigationStackCoordinator is embedded within a NavigationSplitCoordinator
+    /// then the presentation will be proxied to the split
+    /// - Parameters:
+    ///   - coordinator: the coordinator to display
+    ///   - animated: whether to animate the transition or not. Default is true
+
+    ///   - dismissalCallback: called when the sheet has been dismissed, programatically or otherwise
+    func setSheetCoordinator(_ coordinator: (any CoordinatorProtocol)?, animated: Bool = true, dismissalCallback: (() -> Void)? = nil) {
+        guard let coordinator else {
+            sheetModule = nil
+            return
+        }
+        
+        if sheetModule?.coordinator === coordinator {
+            fatalError("Cannot use the same coordinator more than once")
+        }
+
+        var transaction = Transaction()
+        transaction.disablesAnimations = !animated
+
+        withTransaction(transaction) {
+            sheetModule = NavigationModule(coordinator, dismissalCallback: dismissalCallback)
+        }
+    }
+    
+    // MARK: Full Screen Cover
+    
+    fileprivate var fullScreenCoverModule: NavigationModule? {
+        didSet {
+            if let oldValue {
+                logPresentationChange("Remove fullscreen cover", oldValue)
+                oldValue.tearDown()
+            }
+            
+            if let fullScreenCoverModule {
+                logPresentationChange("Set fullscreen cover", fullScreenCoverModule)
+                fullScreenCoverModule.coordinator?.start()
+            }
+        }
+    }
+    
+    /// The currently presented fullscreen cover coordinator
+    /// Fullscreen covers will be presented through the NavigationSplitCoordinator if provided
+    var fullScreenCoverCoordinator: (any CoordinatorProtocol)? {
+        fullScreenCoverModule?.coordinator
+    }
+    
+    /// Present a fullscreen cover on top of the stack. If this NavigationStackCoordinator is embedded within a NavigationSplitCoordinator
+    /// then the presentation will be proxied to the split
+    /// - Parameters:
+    ///   - coordinator: the coordinator to display
+    ///   - animated: whether to animate the transition or not. Default is true
+    ///   - dismissalCallback: called when the fullscreen cover has been dismissed, programatically or otherwise
+    func setFullScreenCoverCoordinator(_ coordinator: (any CoordinatorProtocol)?, animated: Bool = true, dismissalCallback: (() -> Void)? = nil) {
+        guard let coordinator else {
+            fullScreenCoverModule = nil
+            return
+        }
+        
+        if fullScreenCoverModule?.coordinator === coordinator {
+            fatalError("Cannot use the same coordinator more than once")
+        }
+
+        var transaction = Transaction()
+        transaction.disablesAnimations = !animated
+
+        withTransaction(transaction) {
+            fullScreenCoverModule = NavigationModule(coordinator, dismissalCallback: dismissalCallback)
+        }
+    }
+    
     // MARK: - CoordinatorProtocol
     
+    /// No idea if this is particuarly needed for the TabView but we do this for the NavigationStackCoordinator and NavigationSplitCoordinator so it
+    /// doesn't seem to harm to also do it here.
+    func stop() {
+        tabModules.forEach { $0.module.tearDown() }
+    }
+    
     func toPresentable() -> AnyView {
         AnyView(NavigationTabCoordinatorView(navigationTabCoordinator: self))
     }
@@ -99,5 +201,13 @@ private struct NavigationTabCoordinatorView: View {
                     .id(module.id)
             }
         }
+        .sheet(item: $navigationTabCoordinator.sheetModule) { module in
+            module.coordinator?.toPresentable()
+                .id(module.id)
+        }
+        .fullScreenCover(item: $navigationTabCoordinator.fullScreenCoverModule) { module in
+            module.coordinator?.toPresentable()
+                .id(module.id)
+        }
     }
 }