push_screens_v1 (#29)

Co-authored-by: Nick <[email protected]>

Sources/SwiftfulRouting/Core/AnyRouter.swift

@@ -8,34 +8,81 @@
 import Foundation
 import SwiftUI
 
+// Note (possible SwiftUI bug?):
+// Do not conform to Equatable here. It causes the @State property wrapper to monitor Equatable value instead of Hashable value
+// so didSegue changing value does not update the View (I think)
+public struct AnyRoute: Identifiable {
+    public let id = UUID().uuidString
+    let segue: SegueOption
+    let destination: (AnyRouter) -> any View
+
+    public init(_ segue: SegueOption, destination: @escaping (AnyRouter) -> any View) {
+        self.segue = segue
+        self.destination = destination
+    }
+
+    static var root: AnyRoute = {
+        var route = AnyRoute(.push) { router in
+            AnyView(Text("Root"))
+        }
+        return route
+    }()
+}
+
 /// Type-erased Router with convenience methods.
 public struct AnyRouter: Router {
     private let object: any Router
-    
+
     public init(object: any Router) {
         self.object = object
     }
 
-    public var screens: [AnyDestination] {
-        object.screens
-    }
-
     /// Show any screen via Push (NavigationLink), Sheet, or FullScreenCover.
     public func showScreen<T>(_ option: SegueOption, @ViewBuilder destination: @escaping (AnyRouter) -> T) where T : View {
-        object.showScreen(option, destination: destination)
+        object.showScreens([AnyRoute(option, destination: destination)])
+    }
+
+    /// Show any screen via Push (NavigationLink), Sheet, or FullScreenCover.
+    public func showScreen(_ route: AnyRoute) {
+        object.showScreens([route])
+    }
+
+    /// Show a flow of screens, segueing to the first route immediately. The following routes can be accessed via 'showNextScreen()'.
+    public func showScreens(_ routes: [AnyRoute]) {
+        object.showScreens(routes)
+    }
+
+    /// Shows the next screen set in the current screen flow. This would have been set previously via showScreens().
+    public func showNextScreen() throws {
+        try object.showNextScreen()
+    }
+
+    /// If there is a next screen in the current screen flow, go to it. Otherwise, flow is complete and dismiss the environment.
+    public func showNextScreenOrDismissEnvironment() {
+        do {
+            try showNextScreen()
+        } catch {
+            dismissEnvironment()
+        }
+    }
+
+    /// Dismiss the top-most presented environment (this would be the top-most sheet or fullScreenCover).
+    public func dismissEnvironment() {
+        object.dismissEnvironment()
     }
 
     /// Dismiss the top-most presented screen in the current Environment. Same as calling presentationMode.wrappedValue.dismiss().
     public func dismissScreen() {
         object.dismissScreen()
     }
 
-    /// Dismiss all NavigationLinks in NavigationStack heirarchy.
+    /// Push a stack of screens and show the last one immediately.
     @available(iOS 16, *)
-    public func pushScreens(destinations: [(AnyRouter) -> any View]) {
-        object.pushScreens(destinations: destinations)
+    public func pushScreenStack(destinations: [(AnyRouter) -> any View]) {
+        object.pushScreenStack(destinations: destinations)
     }
 
+    /// Show a resizeable sheet on top of the current context.
     @available(iOS 16, *)
     public func showResizableSheet<V>(sheetDetents: Set<PresentationDetentTransformable>, selection: Binding<PresentationDetentTransformable>?, showDragIndicator: Bool, destination: @escaping (AnyRouter) -> V) where V : View {
         object.showResizableSheet(sheetDetents: sheetDetents, selection: selection, showDragIndicator: showDragIndicator, destination: destination)
@@ -45,8 +92,8 @@ public struct AnyRouter: Router {
     ///
     ///  WARNING: Does not dismiss Sheet or FullScreenCover.
     @available(iOS 16, *)
-    public func popToRoot() {
-        object.popToRoot()
+    public func dismissScreenStack() {
+        object.dismissScreenStack()
     }
 
     /// Show any Alert or ConfirmationDialog.

Sources/SwiftfulRouting/Core/Router.swift

@@ -9,15 +9,16 @@ import SwiftUI
 import Combine
 
 public protocol Router {
-    var screens: [AnyDestination] { get }
-    func showScreen<V:View>(_ option: SegueOption, @ViewBuilder destination: @escaping (AnyRouter) -> V)
+    func showScreens(_ routes: [AnyRoute])
+    func showNextScreen() throws
     func dismissScreen()
+    func dismissEnvironment()
+    @available(iOS 16, *)
+    func dismissScreenStack()
 
     @available(iOS 16, *)
-    func pushScreens(destinations: [(AnyRouter) -> any View])
+    func pushScreenStack(destinations: [(AnyRouter) -> any View])
 
-    @available(iOS 16, *)
-    func popToRoot()
 
     @available(iOS 16, *)
     func showResizableSheet<V:View>(sheetDetents: Set<PresentationDetentTransformable>, selection: Binding<PresentationDetentTransformable>?, showDragIndicator: Bool, @ViewBuilder destination: @escaping (AnyRouter) -> V)

Sources/SwiftfulRouting/Core/RouterView.swift

@@ -38,13 +38,20 @@ public struct RouterView<T:View>: View, Router {
     let addNavigationView: Bool
     let content: (AnyRouter) -> T
 
+    // Routable methods
+    @State private var route: AnyRoute
+
     // Segues
     @State private var segueOption: SegueOption = .push
     @State public var screens: [AnyDestination] = []
+    @State private var previousScreens: [AnyDestination] = []
 
+    /// routes are all routes set on heirarchy, included ones that are in front of current screen
+    @State private var routes: [[AnyRoute]]
+    @State private var environmentRouter: Router?
+
     // Binding to view stack from previous RouterViews
     @Binding private var screenStack: [AnyDestination]
-    @State private var screenStackCount: Int = 0
 
     // Configuration for resizable sheet on iOS 16+
     // TODO: Move resizable sheet modifiers into a struct "SheetConfiguration"
@@ -61,11 +68,21 @@ public struct RouterView<T:View>: View, Router {
     @State private var modalConfiguration: ModalConfiguration = .default
     @State private var modal: AnyDestination? = nil
 
-    public init(addNavigationView: Bool = true, screens: (Binding<[AnyDestination]>)? = nil, @ViewBuilder content: @escaping (AnyRouter) -> T) {
+    public init(addNavigationView: Bool = true, screens: (Binding<[AnyDestination]>)? = nil, route: AnyRoute? = nil, routes: [[AnyRoute]]? = nil, environmentRouter: Router? = nil, @ViewBuilder content: @escaping (AnyRouter) -> T) {
         self.addNavigationView = addNavigationView
         self._screenStack = screens ?? .constant([])
-        self._screenStackCount = State(wrappedValue: (screens?.wrappedValue.count ?? 0))
+
+        if let route {
+            self._route = State(wrappedValue: route)
+            self._routes = State(wrappedValue: routes ?? [])
+        } else {
+            let root = AnyRoute.root
+            self._route = State(wrappedValue: root)
+            self._routes = State(wrappedValue: [[root]])
+        }
+        self._environmentRouter = State(wrappedValue: environmentRouter)
         self.content = content
+
     }
 
     public var body: some View {
@@ -78,21 +95,92 @@ public struct RouterView<T:View>: View, Router {
                     sheetDetents: sheetDetents,
                     sheetSelection: sheetSelection,
                     sheetSelectionEnabled: sheetSelectionEnabled,
-                    showDragIndicator: showDragIndicator)
+                    showDragIndicator: showDragIndicator
+                )
+                .onFirstAppear(perform: setEnvironmentRouterIfNeeded)
         }
         .showingAlert(option: alertOption, item: $alert)
         .showingModal(configuration: modalConfiguration, item: $modal)
     }
 
-    public func showScreen<V:View>(_ option: SegueOption, @ViewBuilder destination: @escaping (AnyRouter) -> V) {
-        self.segueOption = option
+    private func setEnvironmentRouterIfNeeded() {
+        // If this is a new environnent (ie. .sheet or .fullScreenCover) then no previous environmentRouter will be passed in
+        // Therefore, this is the start of a new environment and this router will be the environmentRouter
+        // The first screen should not have one
+        if environmentRouter == nil {
+            environmentRouter = self
+        }
+    }
+
+    /// Show a flow of screens, segueing to the first route immediately. The following routes can be accessed via 'showNextScreen()'.
+    public func showScreens(_ newRoutes: [AnyRoute]) {
+        guard let route = newRoutes.first else {
+            assertionFailure("SwiftfulRouting: No routes found.")
+            return
+        }
+
+        routes.append(newRoutes)
+
+        let destination = { router in
+            AnyView(route.destination(router))
+        }
+
+        showScreen(route, destination: destination)
+    }
+
+    public func dismissEnvironment() {
+        if let environmentRouter {
+            environmentRouter.dismissScreen()
+        } else {
+            dismissScreen()
+        }
+    }
+
+    private enum RoutableError: LocalizedError {
+        case noNextScreenSet
+    }
+
+    public func showNextScreen() throws {
+        guard
+            let currentFlow = routes.last(where: { flow in
+                return flow.contains(where: { $0.id == route.id })
+            }),
+            let nextRoute = currentFlow.firstAfter(route)
+        else {
+            throw RoutableError.noNextScreenSet
+        }
+
+        let destination = { router in
+            AnyView(nextRoute.destination(router))
+        }
+
+        showScreen(nextRoute, destination: destination)
+    }
+
+    private func removeRoutes(route: AnyRoute) {
+        // After segueing, remove that flow from local routes
+        // Loop backwards, if have not yet found the current flow...
+        // it's a future flow or the current flow and should be removed now
+        for (index, item) in routes.enumerated().reversed() {
+            routes.remove(at: index)
+
+            if item.contains(where: { $0.id == route.id }) {
+                return
+            }
+        }
+    }
+
+    // if isEnvironmentRouter & screens no longer includes this screen, then environment did dismiss?
+
+    private func showScreen<V:View>(_ route: AnyRoute, @ViewBuilder destination: @escaping (AnyRouter) -> V) {
+        self.segueOption = route.segue
 
-        if option != .push {
+        if route.segue != .push {
             // Add new Navigation
-            // Sheet and FullScreenCover enter new Environments and require a new Navigation to be added.
+            // Sheet and FullScreenCover enter new Environments and require a new Navigation to be added, and don't need an environmentRouter because they will host the environment.
             self.sheetDetents = [.large]
             self.sheetSelectionEnabled = false
-            self.screens.append(AnyDestination(RouterView<V>(addNavigationView: true, screens: nil, content: destination)))
+            self.screens.append(AnyDestination(RouterView<V>(addNavigationView: true, screens: nil, route: route, routes: routes, environmentRouter: nil, content: destination)))
         } else {
             // Using existing Navigation
             // Push continues in the existing Environment and uses the existing Navigation
@@ -102,22 +190,24 @@ public struct RouterView<T:View>: View, Router {
             if #available(iOS 16, *) {
                 if screenStack.isEmpty {
                     // We are in the root Router and should start building on $screens
-                    self.screens.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: $screens, content: destination)))
+                    self.screens.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: $screens, route: route, routes: routes, environmentRouter: environmentRouter, content: destination)))
                 } else {
                     // We are not in the root Router and should continue off of $screenStack
-                    self.screenStack.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: $screenStack, content: destination)))
+                    self.screenStack.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: $screenStack, route: route, routes: routes, environmentRouter: environmentRouter, content: destination)))
                 }
 
             // iOS 14/15 uses NavigationView and can only push 1 view at a time
             } else {
                 // Push a new screen and don't pass view stack to child view (screens == nil)
-                self.screens.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: nil, content: destination)))
+                self.screens.append(AnyDestination(RouterView<V>(addNavigationView: false, screens: nil, route: route, routes: routes, environmentRouter: environmentRouter, content: destination)))
             }
         }
+
+        removeRoutes(route: route)
     }
 
     @available(iOS 16, *)
-    public func pushScreens(destinations: [(AnyRouter) -> any View]) {
+    public func pushScreenStack(destinations: [(AnyRouter) -> any View]) {
         // iOS 16 supports NavigationStack, which can push a stack of views and increment an existing view stack
         self.segueOption = .push
 
@@ -127,14 +217,20 @@ public struct RouterView<T:View>: View, Router {
 
         var localStack: [AnyDestination] = []
         let bindingStack = screenStack.isEmpty ? $screens : $screenStack
+        var localRoutes: [AnyRoute] = []
 
         destinations.forEach { destination in
-            let view = AnyDestination(RouterView<AnyView>(addNavigationView: false, screens: bindingStack, content: { router in
+            let route = AnyRoute(.push, destination: destination)
+            localRoutes.append(route)
+
+            let allRoutes: [[AnyRoute]] = routes + [localRoutes]
+
+            let view = AnyDestination(RouterView<AnyView>(addNavigationView: false, screens: bindingStack, route: route, routes: allRoutes, environmentRouter: environmentRouter, content: { router in
                 AnyView(destination(router))
             }))
             localStack.append(view)
         }
-        
+
         if screenStack.isEmpty {
             self.screens.append(contentsOf: localStack)
         } else {
@@ -156,15 +252,15 @@ public struct RouterView<T:View>: View, Router {
             self.sheetSelectionEnabled = false
         }
 
-        self.screens.append(AnyDestination(RouterView<V>(addNavigationView: true, screens: nil, content: destination)))
+        self.screens.append(AnyDestination(RouterView<V>(addNavigationView: true, screens: nil, route: route, routes: routes, environmentRouter: environmentRouter, content: destination)))
     }
 
     public func dismissScreen() {
         self.presentationMode.wrappedValue.dismiss()
     }
 
     @available(iOS 16, *)
-    public func popToRoot() {
+    public func dismissScreenStack() {
         self.screens = []
         self.screenStack = []
     }
@@ -231,7 +327,8 @@ extension View {
         sheetDetents: Set<PresentationDetentTransformable>,
         sheetSelection: Binding<PresentationDetentTransformable>,
         sheetSelectionEnabled: Bool,
-        showDragIndicator: Bool) -> some View {
+        showDragIndicator: Bool
+    ) -> some View {
             if #available(iOS 14, *) {
                 self
                     .modifier(NavigationLinkViewModifier(
@@ -279,12 +376,4 @@ extension View {
         modifier(ModalViewModifier(configuration: configuration, item: item))
     }
 
-    @ViewBuilder func onChangeIfiOS15<E:Equatable>(of value: E, perform: @escaping (E) -> Void) -> some View {
-        if #available(iOS 15, *) {
-            self
-                .onChange(of: value, perform: perform)
-        } else {
-            self
-        }
-    }
 }