import SwiftUI import AVKit import PDFKit import SwiftData struct StudyContainerView: View { @Environment(\.modelContext) private var modelContext @Query private var sessions: [StudySession] let sessionID: String? var body: some View { if let sessionID, let session = sessions.first(where: { $0.id == sessionID }) { StudyView(session: session) } else { ContentUnavailableView( "没有进行中的课程", systemImage: "play.rectangle", description: Text("从首页货架或最近学习打开课程。") ) .navigationTitle("学习") } } } struct StudyView: View { @Environment(\.modelContext) private var modelContext @Environment(\.scenePhase) private var scenePhase @Environment(\.horizontalSizeClass) private var horizontalSizeClass @Environment(\.dismiss) private var dismiss @Bindable var session: StudySession @StateObject private var progressSaver = ProgressSaver() @StateObject private var chatController: StudyChatController @State private var player: AVPlayer? @State private var pdfDocument: PDFDocument? @State private var pdfPage: Int = 1 @State private var splitRatio: Double = 0.55 @State private var orientation: SplitOrientation = .horizontal @State private var layoutOrientation: SplitOrientation = .horizontal @State private var rightMode: StudyRightPanelMode = .hidden @State private var restoreDone = false @State private var dragStartRatio: Double? @State private var showCompactChat = false @State private var clipStart: Double? @State private var clipEnd: Double? @State private var endObserver: NSObjectProtocol? @State private var toastMessage: String? init(session: StudySession) { self.session = session _chatController = StateObject(wrappedValue: StudyChatController( sessionId: session.id, scenario: StudyView.scenario(for: session.mode) )) } private var courseStore: CourseStore { CourseStore(modelContext: modelContext) } private var libraryStore: LibraryStore { LibraryStore(modelContext: modelContext) } private var hasPdf: Bool { switch session.mode { case .singlePdf, .videoPdf, .pdfAudio, .dualPdf: return true default: return false } } private var isSplitMode: Bool { switch session.mode { case .videoPdf, .pdfAudio, .dualVideo, .dualPdf: return true default: return false } } private var isVideoMode: Bool { switch session.mode { case .singleVideo, .videoPdf, .dualVideo: return true default: return false } } private var isAudioMode: Bool { switch session.mode { case .singleAudio, .pdfAudio: return true default: return false } } private var useBottomChrome: Bool { isVideoMode } private var hasNextLesson: Bool { courseStore.hasNextItem(session: session) } private var maxPdfPage: Int { max(1, pdfDocument?.pageCount ?? 1) } private var useRegularLayout: Bool { horizontalSizeClass == .regular } /// PC-style: video study keeps PDF in the right panel, not split in the center stage. private var pdfInRightPanel: Bool { useRegularLayout && session.mode == .videoPdf && orientation == .horizontal } var body: some View { VStack(spacing: 0) { if hasNextLesson { albumAdvanceBar } mainStage } .frame(maxWidth: .infinity, maxHeight: .infinity) .background(isVideoMode && useRegularLayout ? Color.black : Color(.systemBackground)) .navigationBarTitleDisplayMode(.inline) .navigationBarBackButtonHidden(true) .toolbar { studyToolbar } .sheet(isPresented: $showCompactChat) { NavigationStack { StudyAskChatView( controller: chatController, sessionTitle: session.title, showStudyTools: isVideoMode, onPrevSentence: isVideoMode ? { markPrevSentence() } : nil, onCapture: { chatController.attachVideoFrame(from: player) }, onAudioAttach: isAudioMode ? { markClipEnd() } : nil, onVideoAttach: { chatController.attachVideoFrame(from: player) } ) .navigationTitle("AI 助手") .toolbar { ToolbarItem(placement: .cancellationAction) { Button("关闭") { showCompactChat = false } } } } } .onAppear(perform: setup) .onDisappear { chatController.flush() chatController.stopSpeaking() persist(force: true) removeEndObserver() } .onChange(of: scenePhase) { _, phase in if phase != .active { chatController.flush() persist(force: true) } } .onChange(of: pdfPage) { _, _ in persist(force: true) } .onReceive(Timer.publish(every: 60, on: .main, in: .common).autoconnect()) { _ in persist(force: true) } .overlay(alignment: .top) { if let toastMessage { Text(toastMessage) .font(.caption) .padding(.horizontal, 12) .padding(.vertical, 8) .background(.ultraThinMaterial, in: Capsule()) .padding(.top, 8) .onAppear { DispatchQueue.main.asyncAfter(deadline: .now() + 2.5) { self.toastMessage = nil } } } } } @ToolbarContentBuilder private var studyToolbar: some ToolbarContent { ToolbarItem(placement: .topBarLeading) { Button { chatController.flush() persist(force: true) dismiss() } label: { Image(systemName: "chevron.backward") } .accessibilityLabel("返回") } ToolbarItemGroup(placement: .topBarTrailing) { if isVideoMode && !useRegularLayout { Button { openChat() } label: { Image(systemName: "message") } .accessibilityLabel("AI 对话") } if isSplitMode && !pdfInRightPanel { Button { toggleOrientation() } label: { Image(systemName: orientation == .horizontal ? "rectangle.portrait.rotate" : "rectangle.landscape.rotate") } .accessibilityLabel("切换方向") } if hasPdf && (!pdfInRightPanel || rightMode == .pdf) { Button { goPdfPage(-1) } label: { Image(systemName: "chevron.left") } .disabled(pdfPage <= 1) Button { goPdfPage(1) } label: { Image(systemName: "chevron.right") } .disabled(pdfPage >= maxPdfPage) } if useRegularLayout && (isVideoMode || hasPdf) { Button { cycleRightPanel() } label: { Image(systemName: rightPanelIcon) } .accessibilityLabel("切换右侧面板") } } } private var rightPanelIcon: String { switch rightMode { case .hidden: return "sidebar.right" case .chat: return "sidebar.right" case .pdf: return "doc.richtext" } } private var albumAdvanceBar: some View { HStack { Text("还有下一课") .font(.subheadline) .foregroundStyle(.secondary) Spacer() Button("下一课") { advanceLesson() } .buttonStyle(.borderedProminent) } .padding(.horizontal, 16) .padding(.vertical, 8) .background(Color(.secondarySystemBackground)) } @ViewBuilder private var mainStage: some View { if useRegularLayout && (isVideoMode || (!useBottomChrome && hasPdf)) { HStack(spacing: 0) { stageContent .frame(maxWidth: .infinity, maxHeight: .infinity) if rightMode != .hidden { Divider() trailingPanel .frame(minWidth: 320, idealWidth: 380, maxWidth: 480) .background(Color.white) } } } else { stageContent } } @ViewBuilder private var trailingPanel: some View { switch rightMode { case .chat: StudyAskChatView( controller: chatController, sessionTitle: session.title, showStudyTools: isVideoMode, onCollapse: { collapseChatPanel() }, onPrevSentence: isVideoMode ? { markPrevSentence() } : nil, onCapture: { if isVideoMode { chatController.attachVideoFrame(from: player) } else { chatController.attachPdfPage(from: pdfDocument, page: pdfPage) } }, onAudioAttach: isAudioMode || isVideoMode ? { markClipEnd() } : nil, onVideoAttach: isVideoMode ? { chatController.attachVideoFrame(from: player) } : nil ) case .pdf: if let pdfDocument { StudyPdfPanelView(document: pdfDocument, pageIndex: $pdfPage) } else { ContentUnavailableView("无 PDF", systemImage: "doc") } case .hidden: EmptyView() } } @ViewBuilder private var stageContent: some View { GeometryReader { geo in let autoLayout: SplitOrientation = geo.size.width >= geo.size.height ? .horizontal : .vertical Group { switch session.mode { case .singleVideo, .singleAudio: mediaPane case .singlePdf: pdfPane case .videoPdf: if pdfInRightPanel { mediaPane } else { split(orientation: effectiveOrientation(auto: autoLayout), geo: geo) { mediaPane } secondary: { pdfPane } } case .pdfAudio: split(orientation: effectiveOrientation(auto: autoLayout), geo: geo) { pdfPane } secondary: { mediaPane } case .dualVideo, .dualPdf: ContentUnavailableView( "模式暂未产品化", systemImage: "rectangle.split.2x1", description: Text("dual_* 已可登记，MVP Study UI 未启用。") ) } } .onAppear { layoutOrientation = autoLayout } .onChange(of: geo.size) { _, size in layoutOrientation = size.width >= size.height ? .horizontal : .vertical } } } private func effectiveOrientation(auto: SplitOrientation) -> SplitOrientation { if session.mode == .videoPdf || session.mode == .pdfAudio { return orientation } return auto } private var mediaPane: some View { Group { if let player { if session.mode == .singleAudio || session.mode == .pdfAudio { VStack { Image(systemName: "waveform") .font(.system(size: 48)) .foregroundStyle(.secondary) VideoPlayer(player: player) .frame(height: 80) } .frame(maxWidth: .infinity, maxHeight: .infinity) .background(Color.black.opacity(0.04)) } else { ZStack(alignment: .bottom) { Color.black VideoPlayer(player: player) if useBottomChrome { StudyBottomChromeView( chat: chatController, player: player, onCapture: { chatController.attachVideoFrame(from: player) } ) } } } } else { ContentUnavailableView("无法加载媒体", systemImage: "exclamationmark.triangle") } } } private var pdfPane: some View { Group { if let pdfDocument { PDFKitView(document: pdfDocument, pageIndex: $pdfPage) } else { ContentUnavailableView("无法加载 PDF", systemImage: "doc.richtext") } } .simultaneousGesture( DragGesture(minimumDistance: 24) .onChanged { _ in persist(force: false) } ) } @ViewBuilder private func split( orientation: SplitOrientation, geo: GeometryProxy, @ViewBuilder primary: () -> Primary, @ViewBuilder secondary: () -> Secondary ) -> some View { let primaryView = primary() let secondaryView = secondary() if orientation == .horizontal { let total = geo.size.width let gap: CGFloat = 10 let first = total * splitRatio let second = total - first - gap HStack(spacing: 0) { primaryView.frame(width: max(120, first)) divider(axis: .horizontal, total: total) secondaryView.frame(width: max(120, second)) } } else { let total = geo.size.height let gap: CGFloat = 10 let first = total * splitRatio let second = total - first - gap VStack(spacing: 0) { primaryView.frame(height: max(120, first)) divider(axis: .vertical, total: total) secondaryView.frame(height: max(120, second)) } } } private func divider(axis: Axis, total: CGFloat) -> some View { let barThickness: CGFloat = 10 return ZStack { Color.clear RoundedRectangle(cornerRadius: 2) .fill(Color.secondary.opacity(0.45)) .frame( width: axis == .horizontal ? 4 : 48, height: axis == .vertical ? 4 : 48 ) } .frame( width: axis == .horizontal ? barThickness : nil, height: axis == .vertical ? barThickness : nil ) .frame(maxWidth: axis == .vertical ? .infinity : nil, maxHeight: axis == .horizontal ? .infinity : nil) .contentShape(Rectangle()) .gesture( DragGesture(minimumDistance: 0) .onChanged { value in if dragStartRatio == nil { dragStartRatio = splitRatio } let delta = axis == .horizontal ? value.translation.width : value.translation.height let next = (dragStartRatio ?? splitRatio) + Double(delta / max(total, 1)) splitRatio = min(0.8, max(0.2, next)) } .onEnded { _ in dragStartRatio = nil persist(force: true) } ) .accessibilityLabel("拖拽调整分屏") } private func setup() { guard !restoreDone else { return } restoreDone = true pdfPage = max(1, session.pdfPage) splitRatio = session.splitRatio orientation = session.orientation layoutOrientation = session.orientation chatController.loadHistory() let videoURL = resolveURL(session.videoId) let audioURL = resolveURL(session.audioId) let mediaURL = videoURL ?? audioURL if let mediaURL { let item = AVPlayerItem(url: mediaURL) let av = AVPlayer(playerItem: item) player = av let time = CMTime(seconds: session.mediaTime, preferredTimescale: 600) av.seek(to: time) installEndObserver(for: item) } if let pdfURL = resolveURL(session.pdfId) { pdfDocument = PDFDocument(url: pdfURL) } if isVideoMode && useRegularLayout { rightMode = .chat } } private func installEndObserver(for item: AVPlayerItem) { removeEndObserver() endObserver = NotificationCenter.default.addObserver( forName: .AVPlayerItemDidPlayToEndTime, object: item, queue: .main ) { _ in handleMediaEnded() } } private func removeEndObserver() { if let endObserver { NotificationCenter.default.removeObserver(endObserver) self.endObserver = nil } } private func handleMediaEnded() { guard hasNextLesson else { return } switch session.mode { case .singleVideo, .singleAudio: advanceLesson(auto: true) default: break } } private func advanceLesson(auto: Bool = false) { do { try courseStore.advanceToNextItem(session: session) reloadSessionMedia() if auto { toastMessage = "已自动进入下一课" } } catch { toastMessage = error.localizedDescription } } private func reloadSessionMedia() { removeEndObserver() player?.pause() player = nil pdfDocument = nil pdfPage = max(1, session.pdfPage) splitRatio = session.splitRatio orientation = session.orientation let videoURL = resolveURL(session.videoId) let audioURL = resolveURL(session.audioId) if let mediaURL = videoURL ?? audioURL { let item = AVPlayerItem(url: mediaURL) let av = AVPlayer(playerItem: item) player = av installEndObserver(for: item) } if let pdfURL = resolveURL(session.pdfId) { pdfDocument = PDFDocument(url: pdfURL) } } private func openChat() { if useRegularLayout { rightMode = .chat } else { showCompactChat = true } } private func toggleChatPanel() { rightMode = rightMode == .chat ? .hidden : .chat } private func collapseChatPanel() { rightMode = .hidden } private func cycleRightPanel() { if isVideoMode { switch rightMode { case .hidden: rightMode = pdfInRightPanel && pdfDocument != nil ? .pdf : .chat case .pdf: rightMode = .chat case .chat: rightMode = .hidden } return } switch rightMode { case .hidden: rightMode = hasPdf ? .pdf : .chat case .pdf: rightMode = .chat case .chat: rightMode = .hidden } } private func toggleOrientation() { orientation = orientation == .horizontal ? .vertical : .horizontal if pdfInRightPanel && rightMode == .pdf { rightMode = .chat } persist(force: true) } private func markPrevSentence() { player?.pause() let t = player?.currentTime().seconds ?? 0 let start = max(0, t - 10) chatController.setAudioClip(start: start, end: t) chatController.attachVideoFrame(from: player) if chatController.question.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty { chatController.question = "这段话是什么意思？里面男声、女声分别说了什么？和前文有什么关系？" } toastMessage = String(format: "已标记上一句 %.1f–%.1fs", start, t) } private func markClipEnd() { let t = player?.currentTime().seconds ?? 0 if clipStart == nil { clipStart = t toastMessage = String(format: "已标记开始 %.1fs", t) } else { clipEnd = t chatController.setAudioClip(start: clipStart ?? 0, end: t) toastMessage = String(format: "已附加片段 %.1f–%.1fs", clipStart ?? 0, t) clipStart = nil clipEnd = nil } } private func goPdfPage(_ delta: Int) { let next = min(maxPdfPage, max(1, pdfPage + delta)) guard next != pdfPage else { return } pdfPage = next persist(force: true) } private func resolveURL(_ resourceId: String?) -> URL? { guard let resourceId else { return nil } if let courseId = session.courseId { return try? CourseLibrary.resolveMediaURL(courseId: courseId, resourceId: resourceId) } return libraryStore.fileURL(forResourceId: resourceId) } private func persist(force: Bool) { let mediaTime = player?.currentTime().seconds ?? session.mediaTime let safeTime = mediaTime.isFinite ? mediaTime : 0 progressSaver.save( session: session, mediaTime: safeTime, pdfPage: pdfPage, splitRatio: splitRatio, orientation: orientation, force: force, store: libraryStore ) } private static func scenario(for mode: StudyMode) -> StudyAskScenario { switch mode { case .singleVideo, .videoPdf, .dualVideo: return .video case .singleAudio, .pdfAudio: return .audio case .singlePdf, .dualPdf: return .pdf } } }