Show transition on account switch (#1086)

Mlem.xcodeproj/project.pbxproj

@@ -48,6 +48,8 @@
 		036CC3AF2B8145C30098B6A1 /* AppState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 036CC3AE2B8145C30098B6A1 /* AppState.swift */; };
 		037386472BDAFE81007492B5 /* LemmyMarkdownUI in Frameworks */ = {isa = PBXBuildFile; productRef = 037386462BDAFE81007492B5 /* LemmyMarkdownUI */; };
 		037658DF2BE7D9EF00F4DD4D /* Community1Providing+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 037658DE2BE7D9EF00F4DD4D /* Community1Providing+Extensions.swift */; };
+		0380965F2C10AA80003ED1D8 /* AppState+Transition.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0380965E2C10AA80003ED1D8 /* AppState+Transition.swift */; };
+		038096612C10AAD8003ED1D8 /* TransitionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 038096602C10AAD8003ED1D8 /* TransitionView.swift */; };
 		0382A7F02C09F0F800C79DDA /* PersonView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0382A7EF2C09F0F800C79DDA /* PersonView.swift */; };
 		0382A7F22C0A758E00C79DDA /* ProfileDateView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0382A7F12C0A758E00C79DDA /* ProfileDateView.swift */; };
 		0382A7F42C0A76A900C79DDA /* Date+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0382A7F32C0A76A900C79DDA /* Date+Extensions.swift */; };
@@ -203,6 +205,8 @@
 		0369B35A2BFB86E3001EFEDF /* Account.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Account.swift; sourceTree = "<group>"; };
 		036CC3AE2B8145C30098B6A1 /* AppState.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppState.swift; sourceTree = "<group>"; };
 		037658DE2BE7D9EF00F4DD4D /* Community1Providing+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Community1Providing+Extensions.swift"; sourceTree = "<group>"; };
+		0380965E2C10AA80003ED1D8 /* AppState+Transition.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AppState+Transition.swift"; sourceTree = "<group>"; };
+		038096602C10AAD8003ED1D8 /* TransitionView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TransitionView.swift; sourceTree = "<group>"; };
 		0382A7EF2C09F0F800C79DDA /* PersonView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PersonView.swift; sourceTree = "<group>"; };
 		0382A7F12C0A758E00C79DDA /* ProfileDateView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileDateView.swift; sourceTree = "<group>"; };
 		0382A7F32C0A76A900C79DDA /* Date+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Date+Extensions.swift"; sourceTree = "<group>"; };
@@ -633,6 +637,7 @@
 				6363D5C627EE196700E34822 /* ContentView.swift */,
 				6363D5C427EE196700E34822 /* MlemApp.swift */,
 				B157E0C32A507B8000B02C8B /* FlowRoot.swift */,
+				038096602C10AAD8003ED1D8 /* TransitionView.swift */,
 				CDA1E81A2B8FC39A007953EF /* Onboarding */,
 				6363D5F427EE1BAE00E34822 /* Tabs */,
 			);
@@ -781,6 +786,7 @@
 			children = (
 				CD4D58B22B86BFD400B82964 /* AccountsTracker.swift */,
 				036CC3AE2B8145C30098B6A1 /* AppState.swift */,
+				0380965E2C10AA80003ED1D8 /* AppState+Transition.swift */,
 				CD317D4B2BE97FED008F63E2 /* Palette.swift */,
 				CD4D58A42B86BD1B00B82964 /* PersistenceRepository.swift */,
 				CD4ED8462BF110FA00EFA0A2 /* TabReselectTracker.swift */,
@@ -1079,6 +1085,7 @@
 				CD1446212A5B328E00610EF1 /* Privacy Policy.swift in Sources */,
 				03FE140C2BF953B000A8377F /* HandleError.swift in Sources */,
 				CD1446272A5B36DA00610EF1 /* EULA.swift in Sources */,
+				038096612C10AAD8003ED1D8 /* TransitionView.swift in Sources */,
 				0382A7F42C0A76A900C79DDA /* Date+Extensions.swift in Sources */,
 				03D2A63B2C010B7500ED4FF2 /* GuestAccount.swift in Sources */,
 				CD4ED84A2BF1113800EFA0A2 /* View+TabReselectConsumer.swift in Sources */,
@@ -1163,6 +1170,7 @@
 				CD4D58F82B87B0D100B82964 /* InternetSpeed.swift in Sources */,
 				0382A7F02C09F0F800C79DDA /* PersonView.swift in Sources */,
 				CDBFCB6C2C054AA7008CD468 /* TilePostView.swift in Sources */,
+				0380965F2C10AA80003ED1D8 /* AppState+Transition.swift in Sources */,
 				CD4D58932B86BA5C00B82964 /* StandardPalette.swift in Sources */,
 				03D2A63F2C010DBF00ED4FF2 /* GuestSession.swift in Sources */,
 				030FF6812BC859FD00F6BFAC /* CustomTabViewHostingController.swift in Sources */,

Mlem/App/Constants/Icons.swift

@@ -228,4 +228,6 @@ enum Icons {
     static let noFile: String = "questionmark.folder"
     static let forward: String = "chevron.right"
     static let imageDetails: String = "doc.badge.ellipsis"
+    static let accountSwitchReload: String = "arrow.2.circlepath"
+    static let accountSwitchKeepPlace: String = "checkmark.diamond"
 }

Mlem/App/Globals/Definitions/AppState+transition.swift

@@ -0,0 +1,38 @@
+//
+//  AppState+Transition.swift
+//  Mlem
+//
+//  Created by Sjmarf on 05/06/2024.
+//
+
+import SwiftUI
+
+extension AppState {
+    func transition(_ account: any Account) {
+        Task { @MainActor in
+            let transition = TransitionView(account: account)
+            guard let transitionView = UIHostingController(rootView: transition).view,
+                  let window = UIApplication.shared.firstKeyWindow else {
+                return
+            }
+
+            transitionView.alpha = 0
+            window.addSubview(transitionView)
+            UIView.animate(withDuration: 0.15) {
+                transitionView.alpha = 1
+            }
+
+            transitionView.translatesAutoresizingMaskIntoConstraints = false
+            transitionView.heightAnchor.constraint(equalTo: window.heightAnchor).isActive = true
+            transitionView.widthAnchor.constraint(equalTo: window.widthAnchor).isActive = true
+
+            DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
+                UIView.animate(withDuration: 0.3) {
+                    transitionView.alpha = 0
+                } completion: { _ in
+                    transitionView.removeFromSuperview()
+                }
+            }
+        }
+    }
+}

Mlem/App/Globals/Definitions/AppState.swift

@@ -8,30 +8,61 @@
 import Dependencies
 import Foundation
 import MlemMiddleware
-import Observation
+import SwiftUI
 
 @Observable
 class AppState {
-    private(set) var guestSession: GuestSession!
-    private(set) var activeSessions: [UserSession] = []
+    private(set) var guestSession: GuestSession! {
+        didSet {
+            if oldValue != guestSession {
+                oldValue?.deactivate()
+            }
+        }
+    }
+
+    private(set) var activeSessions: [UserSession] = [] {
+        didSet {
+            if oldValue != activeSessions {
+                for session in Set(oldValue).subtracting(activeSessions) {
+                    session.deactivate()
+                }
+            }
+        }
+    }
+
+    /// ``ContentView`` watches this for changes. When it is toggled, the app is refreshed.
+    var appRefreshToggle: Bool = true
 
     private init() {
         self.guestSession = .init(account: AccountsTracker.main.defaultGuestAccount)
-        changeAccount(to: AccountsTracker.main.defaultAccount, deactivateOldGuest: false)
+        setAccount(to: AccountsTracker.main.defaultAccount)
     }
 
-    func changeAccount(to account: any Account) {
-        changeAccount(to: account, deactivateOldGuest: true)
+    /// If `keepPlace` is `nil`, use the value from `UserDefaults`.
+    func changeAccount(to account: any Account, keepPlace: Bool? = nil) {
+        @AppStorage("accounts.keepPlace") var keepPlaceSetting = false
+        let keepPlace = keepPlace ?? keepPlaceSetting
+        if keepPlace {
+            ToastModel.main.add(.account(account))
+            setAccount(to: account)
+        } else {
+            transition(account)
+            // The delays between these events are necessary to stop SwiftUIIntrospect from causing a lag spike.
+            // That library seems to not like us adding subviews to the window directly. For some reason adding
+            // these delays fixes that.
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
+                self.appRefreshToggle = false
+            }
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.6) {
+                self.setAccount(to: account)
+            }
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.7) {
+                self.appRefreshToggle = true
+            }
+        }
     }
 
-    private func changeAccount(to account: any Account, deactivateOldGuest: Bool) {
-        ToastModel.main.add(.account(account))
-
-        activeSessions.forEach { $0.deactivate() }
-        if deactivateOldGuest {
-            guestSession?.deactivate()
-        }
-
+    private func setAccount(to account: any Account) {
         // Save because we updated `lastUsed` in the above `deactivate()` calls
         AccountsTracker.main.saveAccounts(ofType: .all)
 

Mlem/App/Logic/HandleError.swift

@@ -18,28 +18,18 @@ func handleError(
     #if DEBUG
         print("☠️ ERROR ☠️")
         print("📝 -> \(error.localizedDescription)")
+        if let error = error as? ApiClientError {
+            print("     \(error.description)")
+        }
         print("📂 -> \(file) | \(function) | line: \(line)")
     #endif
 
     switch error {
     // TODO: Modify MlemMiddleware to attach the ApiClient throwing the error to ApiClientError.invalidSession, so that we can access the relevant UserStub in a multi-account context
     case ApiClientError.invalidSession:
-        if let user = AppState.main.firstSession.account as? UserAccount {
-            for layer in NavigationModel.main.layers {
-                switch layer.path.first {
-                case let .login(page):
-                    switch page {
-                    case .reauth:
-                        return
-                    default:
-                        break
-                    }
-                default:
-                    break
-                }
-            }
-            NavigationModel.main.openSheet(.login(.reauth(user)))
-        }
+        showReauthSheet()
+    case ApiClientError.cancelled:
+        print("Cancellation error")
     default:
         if let errorDetails {
             errorDetails.wrappedValue = .init(error: error)
@@ -48,3 +38,22 @@ func handleError(
         }
     }
 }
+
+private func showReauthSheet() {
+    if let user = AppState.main.firstSession.account as? UserAccount {
+        for layer in NavigationModel.main.layers {
+            switch layer.path.first {
+            case let .login(page):
+                switch page {
+                case .reauth:
+                    return
+                default:
+                    break
+                }
+            default:
+                break
+            }
+        }
+        NavigationModel.main.openSheet(.login(.reauth(user)))
+    }
+}

Mlem/App/Models/ErrorDetails.swift

@@ -6,6 +6,7 @@
 //
 
 import Combine
+import MlemMiddleware
 import SwiftUI
 import UniformTypeIdentifiers
 
@@ -31,4 +32,11 @@ struct ErrorDetails: Hashable {
     static func == (lhs: ErrorDetails, rhs: ErrorDetails) -> Bool {
         lhs.hashValue == rhs.hashValue
     }
+
+    var errorText: String {
+        if let error = error as? ApiClientError {
+            return error.description
+        }
+        return error?.localizedDescription ?? ""
+    }
 }

Mlem/App/Views/Root/ContentView.swift

@@ -23,26 +23,28 @@ struct ContentView: View {
     var navigationModel: NavigationModel { .main }
 
     var body: some View {
-        content
-            .onReceive(timer) { _ in
-                appState.cleanCaches()
-            }
-            .sheet(isPresented: Binding(
-                get: { !(navigationModel.layers.first?.isFullScreenCover ?? true) },
-                set: { if !$0 { navigationModel.layers.removeAll() } }
-            )) {
-                NavigationLayerView(layer: navigationModel.layers[0], hasSheetModifiers: true)
-            }
-            .fullScreenCover(isPresented: Binding(
-                get: { navigationModel.layers.first?.isFullScreenCover ?? false },
-                set: { if !$0 { navigationModel.layers.removeAll() } }
-            )) {
-                NavigationLayerView(layer: navigationModel.layers[0], hasSheetModifiers: true)
-            }
-            .tint(palette.accent)
-            .environment(palette)
-            .environment(tabReselectTracker)
-            .environment(appState)
+        if appState.appRefreshToggle {
+            content
+                .onReceive(timer) { _ in
+                    appState.cleanCaches()
+                }
+                .sheet(isPresented: Binding(
+                    get: { !(navigationModel.layers.first?.isFullScreenCover ?? true) },
+                    set: { if !$0 { navigationModel.layers.removeAll() } }
+                )) {
+                    NavigationLayerView(layer: navigationModel.layers[0], hasSheetModifiers: true)
+                }
+                .fullScreenCover(isPresented: Binding(
+                    get: { navigationModel.layers.first?.isFullScreenCover ?? false },
+                    set: { if !$0 { navigationModel.layers.removeAll() } }
+                )) {
+                    NavigationLayerView(layer: navigationModel.layers[0], hasSheetModifiers: true)
+                }
+                .tint(palette.accent)
+                .environment(palette)
+                .environment(tabReselectTracker)
+                .environment(appState)
+        }
     }
 
     var shouldDisplayToasts: Bool {

Mlem/App/Views/Root/Onboarding/LandingPage.swift

@@ -112,7 +112,9 @@ struct LandingPage: View {
 //
 //            let newAccount = try await authenticatedApiClient.loadUser()
 //
-//            // MARK: Save the account's credentials into the keychain
+
+    // MARK: Save the account's credentials into the keychain
+
 //
 //            AppConstants.keychain["\(newAccount.id)_accessToken"] = response.jwt
 //            AccountsTracker.main.addAccount(account: newAccount)

Mlem/App/Views/Root/Tabs/Feeds/FeedsView.swift

@@ -78,13 +78,6 @@ struct MinimalPostFeedView: View {
                     }
                 }
             }
-            .task(id: appState.firstApi) {
-                do {
-                    try await postTracker.loadMoreItems()
-                } catch {
-                    handleError(error)
-                }
-            }
             .task(id: appState.firstApi) {
                 do {
                     try await postTracker.changeFeedType(to: .aggregateFeed(appState.firstApi, type: .subscribed))

Mlem/App/Views/Root/Tabs/Settings/AccountListSettingsView.swift

@@ -11,12 +11,20 @@ import SwiftUI
 struct AccountListSettingsView: View {
     @Environment(AppState.self) var appState
 
+    @AppStorage("accounts.keepPlace") var keepPlace: Bool = false
+
     var accounts: [UserAccount] { AccountsTracker.main.userAccounts }
 
     var body: some View {
         Form {
             headerView
             AccountListView()
+            Section {
+                Toggle(
+                    "Reload on Switch",
+                    isOn: Binding(get: { !keepPlace }, set: { keepPlace = !$0 })
+                )
+            }
         }
     }
 

Mlem/App/Views/Root/TransitionView.swift

@@ -0,0 +1,30 @@
+//
+//  AccountTransitionView.swift
+//  Mlem
+//
+//  Created by Eric Andrews on 2023-10-02.
+//
+
+import Foundation
+import SwiftUI
+
+struct TransitionView: View {
+    let account: any Account
+    @State var accountNameOpacity: CGFloat = .zero
+
+    var body: some View {
+        VStack(spacing: 24) {
+            Text(account is UserAccount ? "Welcome" : "Welcome to")
+                .onAppear {
+                    withAnimation(.easeIn(duration: 0.5)) {
+                        accountNameOpacity = 1.0
+                    }
+                }
+            Text(account.nickname)
+                .opacity(accountNameOpacity)
+        }
+        .font(.largeTitle)
+        .bold()
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+    }
+}

Mlem/App/Views/Shared/Avatar/AvatarView.swift

@@ -36,7 +36,7 @@ struct AvatarView: View {
             .aspectRatio(1, contentMode: .fill)
             .clipShape(Circle())
             .background {
-                if url != nil, loading {
+                if url != nil, loading, showLoadingPlaceholder {
                     ProgressView()
                 } else if url == nil {
                     DefaultAvatarView(avatarType: type)