fix: resolve confirmed bugs from the open iOS issues

Core/Core/Domain/Model/CourseBlockModel.swift

@@ -7,11 +7,10 @@
 
 import Foundation
 
+// Equality is memberwise on purpose. SwiftUI skips redrawing a view whose inputs compare
+// equal, so an id-only `==` kept the outline showing stale completion, due dates and
+// progress until the course screen was opened again.
 public struct CourseStructure: Equatable, Sendable {
-    public static func == (lhs: CourseStructure, rhs: CourseStructure) -> Bool {
-        return lhs.id == rhs.id
-    }
-
     public let id: String
     public let graded: Bool
     public let completion: Double
@@ -101,7 +100,7 @@ public struct CourseImage: Decodable, Sendable, Equatable {
     }
 }
 
-public struct CourseProgress: Sendable {
+public struct CourseProgress: Sendable, Equatable {
     public let totalAssignmentsCount: Int?
     public let assignmentsCompleted: Int?
 
@@ -112,11 +111,6 @@ public struct CourseProgress: Sendable {
 }
 
 public struct CourseChapter: Identifiable, Sendable, Equatable {
-    public static func == (lhs: CourseChapter, rhs: CourseChapter) -> Bool {
-        lhs.id == rhs.id &&
-        lhs.blockId == rhs.blockId
-    }
-
     public let blockId: String
     public let id: String
     public let displayName: String
@@ -139,11 +133,6 @@ public struct CourseChapter: Identifiable, Sendable, Equatable {
 }
 
 public struct CourseSequential: Identifiable, Sendable, Equatable {
-    public static func == (lhs: CourseSequential, rhs: CourseSequential) -> Bool {
-        lhs.id == rhs.id &&
-        lhs.blockId == rhs.blockId
-    }
-
     public let blockId: String
     public let id: String
     public let displayName: String
@@ -231,7 +220,7 @@ public struct SubtitleUrl: Equatable, Sendable {
     }
 }
 
-public struct SequentialProgress: Sendable {
+public struct SequentialProgress: Sendable, Equatable {
     public let assignmentType: String?
     public let numPointsEarned: Int?
     public let numPointsPossible: Int?

Core/Core/Extensions/DateExtension.swift

@@ -14,8 +14,10 @@ public extension Date {
         var date: Date
         var dateFormatter: DateFormatter?
         dateFormatter = DateFormatter()
-        dateFormatter?.locale = .current
-
+        // A fixed-format API date must not follow the user's locale: with the 24-hour
+        // time switch overridden, `HH` stops matching hours past noon (Apple QA1480).
+        dateFormatter?.locale = Locale(identifier: "en_US_POSIX")
+
         date = formats.compactMap { format -> Date? in
             dateFormatter?.dateFormat = format
             guard let formattedDate = dateFormatter?.date(from: iso8601) else { return nil }

Core/Core/Network/DownloadManager.swift

@@ -204,6 +204,7 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
     private let appStorage: CoreStorage
     private let connectivity: ConnectivityProtocol
     private let filePathProvider: InstanceFilePathProvider
+    private let session: Session
     private var downloadRequest: DownloadRequest?
     nonisolated
     private let currentDownloadEventPublisher: PassthroughSubject<DownloadManagerEvent, Never> = .init()
@@ -230,12 +231,14 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
         persistence: CorePersistenceProtocol,
         appStorage: CoreStorage,
         connectivity: ConnectivityProtocol,
-        filePathProvider: InstanceFilePathProvider
+        filePathProvider: InstanceFilePathProvider,
+        session: Session = AF
     ) {
         self.persistence = persistence
         self.appStorage = appStorage
         self.connectivity = connectivity
         self.filePathProvider = filePathProvider
+        self.session = session
         if let userId = appStorage.user?.id {
             persistence.set(userId: userId)
         }
@@ -606,9 +609,9 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
         }
 
         if let resumeData = download.resumeData {
-            downloadRequest = AF.download(resumingWith: resumeData, to: destination)
+            downloadRequest = session.download(resumingWith: resumeData, to: destination).validate()
         } else {
-            downloadRequest = AF.download(url, to: destination)
+            downloadRequest = session.download(url, to: destination).validate()
         }
 
         downloadRequest?.downloadProgress { @Sendable [weak self] prog in
@@ -636,6 +639,21 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
         currentDownloadEventPublisher.send(.started(download))
     }
 
+    /// Drops a download the server refused or that broke for a reason other than the
+    /// connection, so `newDownload()` moves on instead of picking it up again, and leaves
+    /// it to be reported with the others once the queue is done. `file` is whatever the
+    /// server sent instead, such as an error page, which must not stay on disk.
+    private func failDownload(_ download: DownloadDataTask, file: URL?) {
+        if let file {
+            try? FileManager.default.removeItem(at: file)
+        }
+        failedDownloads.append(download)
+        try? cancelDownloading(task: download)
+        Task {
+            try? await self.newDownload()
+        }
+    }
+
     private func setCurrentTask(with task: DownloadDataTask?) async {
         currentDownloadTask = task
     }
@@ -646,10 +664,7 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
             if error.isInternetError {
                 state = .waiting
             } else if error.asAFError?.isExplicitlyCancelledError == false {
-                self.failedDownloads.append(download)
-                Task {
-                    try? await self.newDownload()
-                }
+                failDownload(download, file: response.fileURL)
                 return
             }
         }
@@ -697,9 +712,9 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
         currentDownloadTask = download
         currentDownloadTask?.state = .inProgress
         if let resumeData = download.resumeData {
-            downloadRequest = AF.download(resumingWith: resumeData, to: destination)
+            downloadRequest = session.download(resumingWith: resumeData, to: destination).validate()
         } else {
-            downloadRequest = AF.download(url, to: destination)
+            downloadRequest = session.download(url, to: destination).validate()
         }
         downloadRequest?.downloadProgress { [weak self] prog in
             guard let self else { return }
@@ -729,8 +744,7 @@ public actor DownloadManager: DownloadManagerProtocol, @unchecked Sendable {
     private func completeHTMLDownload(with response: AFDownloadResponse<URL>, for download: DownloadDataTask) async {
         if let error = response.error {
             if error.asAFError?.isExplicitlyCancelledError == false {
-                failedDownloads.append(download)
-                try? await self.newDownload()
+                failDownload(download, file: response.fileURL)
                 return
             }
         }

Core/Core/View/Base/Webview/Models/ColorInversionInjection.swift

@@ -22,6 +22,12 @@ public struct ColorInversionInjection: WebViewScriptInjectionProtocol, CSSInject
                 img, video, iframe {
                     filter: invert(100%) hue-rotate(180deg) !important;
                 }
+                img {
+                    /* Course figures are often PNGs with dark text on a transparent
+                       background. Give them the white page they were drawn for; the
+                       double inversion above keeps it white. */
+                    background-color: #ffffff;
+                }
             }
         """
         return cssScript(with: css)

Core/CoreTests/DownloadManager/DownloadManagerTests.swift

@@ -7,6 +7,7 @@
 
 import XCTest
 import Combine
+import Alamofire
 @testable import Core
 
 @MainActor
@@ -15,6 +16,7 @@ final class DownloadManagerTests: XCTestCase {
     var persistence: CorePersistenceProtocolMock!
     var storage: CoreStorageMock!
     var connectivity: ConnectivityProtocolMock!
+    var cancellables = Set<AnyCancellable>()
 
     override func setUp() {
         super.setUp()
@@ -120,6 +122,42 @@ final class DownloadManagerTests: XCTestCase {
         XCTAssertEqual(currentDownloadTask?.id, mockTask.id)
     }
 
+    func testNewDownload_WhenServerRefusesTheFile_ReportsItAsFailedNotDownloaded() async throws {
+        // Given
+        let task = createMockDownloadTask()
+        persistence.getDownloadDataTasksHandler = { [task] }
+        connectivity.isMobileData = false
+        let configuration = URLSessionConfiguration.af.default
+        configuration.protocolClasses = [ForbiddenURLProtocol.self]
+
+        let downloadManager = DownloadManager(
+            persistence: persistence,
+            appStorage: storage,
+            connectivity: connectivity,
+            filePathProvider: InstanceFilePathProvider(instanceStore: InstanceProviderMock()),
+            session: Session(configuration: configuration)
+        )
+        var finishedCount = 0
+        await downloadManager.eventPublisher()
+            .sink { event in
+                if case .finished = event {
+                    finishedCount += 1
+                }
+            }
+            .store(in: &cancellables)
+        let reported = expectation(forNotification: .showDownloadFailed, object: nil) { notification in
+            (notification.object as? [DownloadDataTask])?.map(\.id) == [task.id]
+        }
+
+        // When
+        try await downloadManager.resumeDownloading()
+
+        // Then
+        await fulfillment(of: [reported], timeout: 10)
+        XCTAssertEqual(finishedCount, 0)
+        XCTAssertEqual(persistence.deleteDownloadDataTasksCallCount, 1)
+    }
+
     // MARK: - Test Cancel Downloads
 
     func testCancelDownloading_ForSpecificTask_ShouldRemoveFileAndTask() async throws {
@@ -366,3 +404,24 @@ final class DownloadManagerTests: XCTestCase {
         )
     }
 }
+
+/// Answers every request the way a CDN answers a link it refuses: 403 with an XML body.
+private final class ForbiddenURLProtocol: URLProtocol {
+    override class func canInit(with request: URLRequest) -> Bool { true }
+    override class func canonicalRequest(for request: URLRequest) -> URLRequest { request }
+
+    override func startLoading() {
+        guard let url = request.url,
+              let response = HTTPURLResponse(
+                url: url,
+                statusCode: 403,
+                httpVersion: "HTTP/1.1",
+                headerFields: ["Content-Type": "application/xml"]
+              ) else { return }
+        client?.urlProtocol(self, didReceive: response, cacheStoragePolicy: .notAllowed)
+        client?.urlProtocol(self, didLoad: Data("<Error><Code>AccessDenied</Code></Error>".utf8))
+        client?.urlProtocolDidFinishLoading(self)
+    }
+
+    override func stopLoading() {}
+}

Course/Course/Presentation/Container/CourseContainerView.swift

@@ -70,6 +70,8 @@ public struct CourseContainerView: View {
         self.courseDatesViewModel = courseDatesViewModel
         self.courseProgressViewModel = courseProgressViewModel
         Task {
+            // Without access the server has no content to give; don't ask for it.
+            guard viewModel.isActive != false else { return }
             await withTaskGroup(of: Void.self) { group in
                 group.addTask {
                     await viewModel.getCourseBlocks(courseID: courseID)
@@ -95,6 +97,9 @@ public struct CourseContainerView: View {
         .onChange(of: viewModel.selection, perform: didSelect)
         .onChange(of: coordinate, perform: collapseHeader)
         .background(Theme.Colors.background)
+        .sheet(isPresented: $viewModel.isDownloadsListPresented) {
+            DownloadsView(router: viewModel.router, courseHelper: viewModel.courseHelper)
+        }
     }
 
     @ViewBuilder
@@ -112,6 +117,8 @@ public struct CourseContainerView: View {
                     viewHeight: $viewHeight,
                     dateTabIndex: CourseTab.dates.rawValue
                 )
+            } else if viewModel.isActive == false {
+                noAccessContent
             } else {
                 ZStack(alignment: .top) {
                     tabs
@@ -161,6 +168,22 @@ public struct CourseContainerView: View {
         }
     }
 
+    private var noAccessContent: some View {
+        VStack(spacing: 0) {
+            NavigationBar(
+                title: title,
+                leftButtonAction: { viewModel.router.back() }
+            )
+            FullScreenErrorView(
+                type: .noContent(
+                    CourseLocalization.Error.courseAccessUnavailable,
+                    image: CoreAssets.lockIcon.swiftUIImage
+                )
+            )
+        }
+        .background(Theme.Colors.background.ignoresSafeArea())
+    }
+
     private func showDatesSuccessView(title: String, message: String) -> some View {
         return DatesSuccessView(
             title: title,