Connect LiveViewCoordinator from NavigationLink (#1201)

* Connect `LiveViewCoordinator` from `NavigationLink`

* Support redirect navigation

* Simplify `redirect` logic

* Revise comment

Author: carson-katri

Sources/LiveViewNative/Coordinators/LiveSessionCoordinator.swift

@@ -78,16 +78,21 @@ public class LiveSessionCoordinator<R: RootRegistry>: ObservableObject {
         })
         $navigationPath.scan(([LiveNavigationEntry<R>](), [LiveNavigationEntry<R>]()), { ($0.1, $1) }).sink { [weak self] prev, next in
             guard let self else { return }
-            if prev.count > next.count {
-                let isDisconnected: Bool
-                if case .notConnected = next.last!.coordinator.state {
-                    isDisconnected = true
-                } else {
-                    isDisconnected = false
-                }
-                if next.last!.coordinator.url != next.last!.url || isDisconnected {
-                    Task {
+            let isDisconnected: Bool
+            if case .notConnected = next.last!.coordinator.state {
+                isDisconnected = true
+            } else {
+                isDisconnected = false
+            }
+            if next.last!.coordinator.url != next.last!.url || isDisconnected {
+                Task {
+                    if prev.count > next.count {
+                        // back navigation
                         try await next.last!.coordinator.connect(domValues: self.domValues, redirect: true)
+                    } else if next.count > prev.count && prev.count > 0 {
+                        // forward navigation (from `redirect` or `<NavigationLink>`)
+                        await prev.last?.coordinator.disconnect()
+                        try await next.last?.coordinator.connect(domValues: self.domValues, redirect: true)
                     }
                 }
             }
@@ -359,7 +364,6 @@ public class LiveSessionCoordinator<R: RootRegistry>: ObservableObject {
     func redirect(_ redirect: LiveRedirect) async throws {
         switch redirect.mode {
         case .replaceTop:
-            await navigationPath.last?.coordinator.disconnect()
             let coordinator = LiveViewCoordinator(session: self, url: redirect.to)
             let entry = LiveNavigationEntry(url: redirect.to, coordinator: coordinator)
             switch redirect.kind {
@@ -368,27 +372,11 @@ public class LiveSessionCoordinator<R: RootRegistry>: ObservableObject {
             case .replace:
                 // If there is nothing to replace, change the root URL.
                 if !navigationPath.isEmpty {
+                    await navigationPath.last?.coordinator.disconnect()
                     navigationPath[navigationPath.count - 1] = entry
+                    try await coordinator.connect(domValues: self.domValues, redirect: true)
                 }
             }
-            try await coordinator.connect(domValues: self.domValues, redirect: true)
-        case .multiplex:
-            switch redirect.kind {
-            case .push:
-                navigationPath.append(.init(
-                    url: redirect.to,
-                    coordinator: LiveViewCoordinator(session: self, url: redirect.to)
-                ))
-            case .replace:
-                // If there is nothing to replace, change the root URL.
-                navigationPath.removeLast()
-                // If we are replacing the current path with the previous one, just pop the URL so the previous one is on top.
-                guard (navigationPath.last?.coordinator.url ?? self.url) != redirect.to else { return }
-                navigationPath.append(.init(
-                    url: redirect.to,
-                    coordinator: LiveViewCoordinator(session: self, url: redirect.to)
-                ))
-            }
         case .patch:
             // patch is like `replaceTop`, but it does not disconnect.
             let coordinator = navigationPath.last!.coordinator

Sources/LiveViewNative/LiveView.swift

@@ -45,18 +45,15 @@ public macro LiveView<Host: LiveViewHost>(
 public struct LiveView<R: RootRegistry>: View {
     @StateObject var session: LiveSessionCoordinator<R>
 
-    @ObservedObject private var rootCoordinator: LiveViewCoordinator<R>
-    
     @StateObject private var liveViewModel = LiveViewModel()
 
     @Environment(\.scenePhase) private var scenePhase
 
     /// Creates a new LiveView attached to the given coordinator.
     ///
     /// - Note: Changing coordinators after the `LiveView` is setup and connected is forbidden.
-    public init(session: LiveSessionCoordinator<R>) {
-        self._session = .init(wrappedValue: session)
-        self.rootCoordinator = session.navigationPath.first!.coordinator
+    public init(session: @autoclosure @escaping () -> LiveSessionCoordinator<R>) {
+        self._session = .init(wrappedValue: session())
     }
 
     public init(_ host: some LiveViewHost, configuration: LiveSessionConfiguration = .init()) {
@@ -66,6 +63,10 @@ public struct LiveView<R: RootRegistry>: View {
     public init(url: URL, configuration: LiveSessionConfiguration = .init()) {
         self.init(session: .init(url, config: configuration))
     }
+    
+    private var rootCoordinator: LiveViewCoordinator<R> {
+        session.navigationPath.first!.coordinator
+    }
 
     public var body: some View {
         SwiftUI.Group {
@@ -77,7 +78,7 @@ public struct LiveView<R: RootRegistry>: View {
                 } else {
                     PhxMain<R>()
                         .environment(\.coordinatorEnvironment, CoordinatorEnvironment(rootCoordinator, document: rootCoordinator.document!))
-                        .environment(\.anyLiveContextStorage, LiveContextStorage(coordinator: rootCoordinator, url: session.url))
+                        .environment(\.anyLiveContextStorage, LiveContextStorage(coordinator: rootCoordinator, url: rootCoordinator.url))
                 }
             default:
                 if R.LoadingView.self == Never.self {
@@ -153,7 +154,7 @@ struct PhxMain<R: RootRegistry>: View {
     @EnvironmentObject private var session: LiveSessionCoordinator<R>
 
     var body: some View {
-        NavStackEntryView(.init(url: session.url, coordinator: context.coordinator))
+        NavStackEntryView(.init(url: context.coordinator.url, coordinator: context.coordinator))
     }
 }
 

Sources/LiveViewNative/Navigation/LiveRedirect.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-struct LiveRedirect {
+struct LiveRedirect: Hashable {
     let kind: Kind
     let to: URL
     let mode: Mode
@@ -32,31 +32,6 @@ struct LiveRedirect {
         /// the top-most ``LiveViewCoordinator/url`` is changed to the new top-most destination.
         case replaceTop
 
-        /// Connects to a separate Phoenix channel with a fresh ``LiveViewCoordinator`` over the same WebSocket.
-        ///
-        /// This works with `NavigationSplitView`. It can also be used with `NavigationStack` to keep the previous pages loaded in the background.
-        ///
-        /// You must send the `native_redirect` event to use this mode:
-        /// ```ex
-        /// push_event(
-        ///   socket,
-        ///   "native_redirect",
-        ///   %{
-        ///     to: "destination",
-        ///     kind: :push,
-        ///     mode: :multiplex
-        ///   }
-        /// )
-        /// ```
-        ///
-        /// When a redirect is received with this mode, the following takes place:
-        ///
-        /// 1. If the kind is ``LiveRedirect/Kind/push``, a new ``LiveViewCoordinator`` is created for the redirect destination.
-        /// A separate Phoenix channel is connected for each coordinator.
-        /// 2. If the kind is ``LiveRedirect/Kind/redirect`` and the destination is the same as the previous path, the current entry is popped and no new ``LiveViewCoordinator`` is connected.
-        /// Otherwise a new ``LiveViewCoordinator`` is created in place of the top-most entry.
-        case multiplex
-        
         /// A `live_patch` style redirect.
         ///
         /// This replaces the URL of the page without reloading anything. It can be a push or replace kind.

Sources/LiveViewNative/Navigation/NavigationCoordinator.swift

@@ -40,12 +40,16 @@ struct NavigationLink<R: RootRegistry>: View {
     #endif
     @Attribute("disabled") private var disabled: Bool
 
+    var url: URL {
+        URL(string: destination, relativeTo: context.coordinator.url)!.appending(path: "").absoluteURL
+    }
+    
     @ViewBuilder
     public var body: some View {
         SwiftUI.NavigationLink(
             value: LiveNavigationEntry(
-                url: URL(string: destination, relativeTo: context.coordinator.url)!.appending(path: "").absoluteURL,
-                coordinator: context.coordinator
+                url: url,
+                coordinator: LiveViewCoordinator(session: context.coordinator.session, url: url)
             )
         ) {
             context.buildChildren(of: element)