import SwiftUI
import Photos

struct BackupView: View {
    @EnvironmentObject var engine: BackupEngine
    @EnvironmentObject var store: ConnectionStore
    @EnvironmentObject var lanMonitor: LANMonitor
    @EnvironmentObject var statusService: BackupStatusService
    @EnvironmentObject var coordinator: AutoBackupCoordinator
    @StateObject private var vm = BackupViewModel()
    @Environment(\.scenePhase) private var scenePhase

    @State private var showMenu = false
    @State private var showDestinationPicker = false
    @State private var pickerPath: String = "/"
    @State private var ringPage = 0

    private let ringPageCount = 3
    private let ringPageNames = ["BACKUP", "IPHONE STORAGE", "CLEANUP"]

    @State private var deviceTotalGB: Double = 0
    @State private var deviceFreeGB: Double = 0
    @State private var showCleanConfirm = false
    @State private var pullProgress: CGFloat = 0
    @State private var rippleScale: CGFloat = 0.88
    @State private var rippleOpacity: Double = 0
    @State private var pulseDotOpacity: Double = 1.0

    // Counts are the source of truth for final display state.
    // If job ended in .failed but reconciliation shows needBackup == 0, treat as .completed.
    private var resolvedStatus: BackupStatus {
        if case .failed = engine.job.status,
           !statusService.isRefreshing,
           statusService.snapshot.phoneTotal > 0,
           statusService.snapshot.needBackup == 0 {
            return .completed
        }
        return engine.job.status
    }

    var body: some View {
        ZStack(alignment: .topTrailing) {
            AppTheme.background.ignoresSafeArea()

            // ─── Scrollable content with pull-to-refresh ──────────────
            GeometryReader { geo in
                ScrollView(.vertical, showsIndicators: false) {
                    VStack(spacing: 0) {

                        // ─── Brand ────────────────────────────────────
                        VStack(spacing: 10) {
                            Text("kisani.")
                                .font(.system(size: 11, weight: .medium, design: .monospaced))
                                .foregroundStyle(AppTheme.ink)
                                .kerning(2)
                            KisaniLogoMark(size: 66)
                        }
                        .frame(maxWidth: .infinity)
                        .padding(.top, 16)

                        Spacer(minLength: 24).frame(maxHeight: 48)

                        // ─── Per-page content ─────────────────────────
                        if ringPage == 0 {
                            page0Content
                        } else if ringPage == 1 {
                            page1Content
                        } else {
                            page2Content
                        }

                        Spacer(minLength: 0)

                        // ─── Page navigation ──────────────────────────
                        pageNav
                            .padding(.horizontal, AppTheme.hPad)
                            .padding(.bottom, 24)
                    }
                    .frame(minHeight: geo.size.height)
                }
                .refreshable {
                    await statusService.refreshAndWait(force: true)
                    if statusService.snapshot.needBackup == 0 {
                        engine.resolveSuccess()
                    }
                    // handleReconciliationComplete() fires via Combine and will
                    // start auto-backup if needed — no explicit call required here.
                }
            }

            // ─── Menu button — floats above scroll content ─────────────
            Button { showMenu = true } label: {
                Image(systemName: "line.3.horizontal")
                    .font(.system(size: 14, weight: .regular))
                    .foregroundStyle(AppTheme.inkSecondary)
                    .frame(width: 44, height: 44)
                    .contentShape(Rectangle())
            }
            .accessibilityLabel("Activity menu")
            .padding(.top, 4)
            .padding(.trailing, AppTheme.hPad - 4)
        }
        .navigationTitle("")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar(.hidden, for: .navigationBar)
        .sheet(isPresented: $showMenu) {
            AppMenuView()
                .environmentObject(store)
                .environmentObject(lanMonitor)
                .environmentObject(engine)
        }
        .sheet(isPresented: $showDestinationPicker, onDismiss: {
            guard pickerPath != "/", var conn = store.savedConnection else { return }
            conn.remotePath = pickerPath
            store.savedConnection = conn
        }) {
            if let conn = store.savedConnection {
                BrowseView(connection: conn, selectedPath: $pickerPath, isPickerMode: true, initialPath: pickerPath)
            }
        }
        .animation(.spring(response: 0.35, dampingFraction: 0.82), value: engine.job.status == .completed)
        .animation(.spring(response: 0.35, dampingFraction: 0.82), value: vm.photosAuthStatus == .authorized)
        .animation(.spring(response: 0.4, dampingFraction: 0.85), value: ringPage)
        .confirmationDialog(
            "Clean \(String(format: "%.1f", junkGB)) GB from device?",
            isPresented: $showCleanConfirm,
            titleVisibility: .visible
        ) {
            Button("Delete Backed-Up Photos", role: .destructive) { /* TODO: trigger cleanup */ }
            Button("Cancel", role: .cancel) {}
        } message: {
            Text("This removes photos already safely backed up to your NAS.")
        }
        .task {
            coordinator.onActive()
            loadDeviceStorage()
        }
        .onChange(of: scenePhase) { phase in
            // Re-check every time the app returns to the foreground.
            if phase == .active { coordinator.onActive() }
        }
        .onChange(of: store.savedConnection?.remotePath) { _ in
            statusService.refresh(force: true)
        }
        .onChange(of: store.backupFilter) { _ in
            statusService.refresh(force: true)
        }
        .onChange(of: engine.job.status) { status in
            if status == .completed {
                Task {
                    try? await Task.sleep(nanoseconds: 1_000_000_000)
                    statusService.refresh(force: true)
                }
            }
        }
    }

    // MARK: — Logo mark (drawn in code — no asset dependency)


    // MARK: — Ring hero (used inside circleSection — no gesture here)

    private var ringHero: some View {
        ZStack {
            KisaniRingView(
                outerProgress: outerRingProgress,
                innerProgress: innerRingProgressWidget,
                innerColor: innerRingColor
            )
            .accessibilityLabel("Backup progress")
            .accessibilityValue("\(Int(innerRingProgressWidget * 100)) percent")

            VStack(spacing: 4) {
                ringMainView
                    .transition(.opacity.combined(with: .scale(scale: 0.95)))
                    .id(ringContentID)
            }
            .animation(.spring(response: 0.3, dampingFraction: 0.85), value: ringContentID)
        }
        .animation(.spring(response: 0.4, dampingFraction: 0.8), value: engine.job.progress)
    }

    private var ringContentID: String { String(describing: widgetState) }

    @ViewBuilder
    private var ringMainView: some View {
        switch widgetState {
        case .safe:
            VStack(spacing: 6) {
                ringCheckmark
                Text("\(statusService.snapshot.phoneTotal)")
                    .font(.system(size: 46, weight: .ultraLight))
                    .foregroundStyle(AppTheme.positive)
                    .contentTransition(.numericText())
                    .kerning(-2)
                Text("PHOTOS SAFE")
                    .font(.system(size: 8, weight: .regular, design: .monospaced))
                    .foregroundStyle(AppTheme.positive.opacity(0.75))
                    .tracking(2)
            }

        case .checking:
            VStack(spacing: 10) {
                ProgressView()
                    .scaleEffect(0.85)
                    .tint(AppTheme.inkTertiary)
                Text("CHECKING")
                    .font(.system(size: 8, weight: .regular, design: .monospaced))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .tracking(2).opacity(0.75)
            }

        case .running:
            VStack(spacing: 6) {
                Text("\(notBackedUpDisplayCount)")
                    .font(.system(size: 46, weight: .ultraLight))
                    .foregroundStyle(AppTheme.ink)
                    .contentTransition(.numericText())
                    .kerning(-2)
                Text("BACKING UP")
                    .font(.system(size: 8, weight: .regular, design: .monospaced))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .tracking(2).opacity(0.75)
            }

        default: // offline, pending, paused
            VStack(spacing: 6) {
                Text("\(statusService.snapshot.needBackup)")
                    .font(.system(size: 46, weight: .ultraLight))
                    .foregroundStyle(AppTheme.ink)
                    .contentTransition(.numericText())
                    .kerning(-2)
                Text(statusService.snapshot.phoneTotal == 0 ? "NO PHOTOS" : "NEED BACKUP")
                    .font(.system(size: 8, weight: .regular, design: .monospaced))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .tracking(2).opacity(0.75)
            }
        }
    }

    private var ringCheckmark: some View {
        ZStack {
            Circle()
                .stroke(AppTheme.positive, lineWidth: 1)
                .frame(width: 22, height: 22)
            Image(systemName: "checkmark")
                .font(.system(size: 8, weight: .medium))
                .foregroundStyle(AppTheme.positive)
        }
    }

    private var outerRingProgress: CGFloat {
        let nas   = CGFloat(nasArchiveDisplayCount)
        let phone = CGFloat(max(1, statusService.snapshot.phoneTotal))
        return min(nas / (nas + phone), 1)
    }

    private var innerRingProgressWidget: CGFloat {
        switch widgetState {
        case .safe:    return 1.0
        case .running: return CGFloat(engine.job.progress)
        default:       return CGFloat(alreadySafeDisplayCount) / CGFloat(max(1, statusService.snapshot.phoneTotal))
        }
    }

    // MARK: — Compact stats strip

    // Invariant: alreadySafe + needBackup == phoneTotal always.
    // During active backup show optimistic count (only newly uploaded, not skipped —
    // skipped files are already counted inside snapshot.alreadySafe from the last reconcile).
    // Live NAS Archive: grows by 1 with each confirmed upload this session.
    // Skipped files (already on NAS) are NOT added — if nasArchiveTotal came from
    // a directory scan they're already counted; if from manifest they weren't tracked
    // but they're present on disk regardless.
    private var nasArchiveDisplayCount: Int {
        let base = statusService.snapshot.nasArchiveTotal
        if engine.job.status.isActive {
            return base + engine.job.uploadedFiles
        }
        return base
    }

    private var alreadySafeDisplayCount: Int {
        let total = statusService.snapshot.phoneTotal
        guard total > 0 else { return 0 }
        let base = statusService.snapshot.alreadySafe
        if engine.job.status.isActive {
            // Uploaded = newly confirmed on NAS this session.
            // Skipped = fileExists returned true — already on NAS but wasn't in manifest.
            // Both are now confirmed safe; count them both optimistically.
            return min(base + engine.job.uploadedFiles + engine.job.skippedFiles, total)
        }
        return min(base, total)
    }

    private var notBackedUpDisplayCount: Int {
        let total = statusService.snapshot.phoneTotal
        guard total > 0 else { return 0 }
        if engine.job.status.isActive {
            return max(0, total - alreadySafeDisplayCount)
        }
        return statusService.snapshot.needBackup
    }

    private var statsStrip: some View {
        HStack(spacing: 0) {
            compactStat(
                "\(nasArchiveDisplayCount)",
                label: "NAS",
                color: AppTheme.interactive
            )
            thinDivider
            compactStat(
                "\(statusService.snapshot.phoneTotal)",
                label: "IPHONE",
                color: AppTheme.inkSecondary
            )
            thinDivider
            compactStat(
                "\(notBackedUpDisplayCount)",
                label: "PENDING",
                color: Color(red: 1.0, green: 0.62, blue: 0.0)
            )
            thinDivider
            compactStat(
                "\(alreadySafeDisplayCount)",
                label: "SAFE",
                color: AppTheme.positive
            )
        }
        .frame(height: 48)
        .background(AppTheme.surfaceSunken.opacity(0.85))
        .clipShape(RoundedRectangle(cornerRadius: 14, style: .continuous))
    }

    private func compactStat(_ value: String, label: String, color: Color) -> some View {
        VStack(spacing: 2) {
            Text(value)
                .font(.system(size: 15, weight: .semibold))
                .foregroundStyle(color)
                .monospacedDigit()
            Text(label)
                .font(.system(size: 9, weight: .regular))
                .foregroundStyle(AppTheme.inkQuaternary)
                .tracking(0.2)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 6)
    }

    private var thinDivider: some View {
        Rectangle()
            .fill(AppTheme.separator.opacity(0.5))
            .frame(width: 0.5, height: 18)
    }

    // MARK: — Destination row

    private var destinationRow: some View {
        Button(action: {
            pickerPath = store.savedConnection?.remotePath ?? "/"
            showDestinationPicker = true
        }) {
            HStack(spacing: 10) {
                ZStack {
                    Circle()
                        .fill(AppTheme.surfaceSunken)
                        .frame(width: 34, height: 34)
                    Image(systemName: "folder.fill")
                        .font(.system(size: 13, weight: .medium))
                        .foregroundStyle(AppTheme.inkSecondary)
                }

                let path = store.savedConnection?.remotePath ?? "/"
                let folderName = path == "/" ? "Not set" : (path as NSString).lastPathComponent

                VStack(alignment: .leading, spacing: 1) {
                    Text(folderName)
                        .font(AppTheme.headline())
                        .foregroundStyle(path == "/" ? AppTheme.inkTertiary : AppTheme.ink)
                    Text("Backup folder")
                        .font(AppTheme.micro(10))
                        .foregroundStyle(AppTheme.inkTertiary)
                }

                Spacer()

                Image(systemName: "chevron.right")
                    .font(.system(size: 11, weight: .medium))
                    .foregroundStyle(AppTheme.inkQuaternary)
            }
            .padding(.horizontal, 14)
            .padding(.vertical, 12)
            .background(AppTheme.surfaceSunken)
            .clipShape(RoundedRectangle(cornerRadius: AppTheme.radius, style: .continuous))
        }
        .buttonStyle(ScaleButtonStyle())
        .disabled(store.savedConnection == nil)
    }

    private var nasStatusDotColor: Color {
        switch engine.job.status {
        case .running, .preparing, .paused:
            return Color(red: 1.0, green: 0.58, blue: 0.0)
        default:
            switch lanMonitor.nasReachable {
            case true:  return AppTheme.positive
            case false: return AppTheme.destructive
            case nil:   return AppTheme.inkQuaternary
            }
        }
    }

    private var nasStatusLabel: String {
        switch engine.job.status {
        case .running:   return "Backing up"
        case .preparing: return "Preparing"
        case .paused:    return "Paused"
        default:
            return lanMonitor.nasReachable == false ? "Offline" : "Ready"
        }
    }

    // MARK: — NAS status row

    private var nasStatusRow: some View {
        HStack(spacing: 10) {
            ZStack {
                Circle()
                    .fill(AppTheme.surfaceSunken)
                    .frame(width: 34, height: 34)
                Image(systemName: "externaldrive")
                    .font(.system(size: 13, weight: .medium))
                    .foregroundStyle(AppTheme.inkSecondary)
            }

            if let conn = store.savedConnection {
                let friendlyName = conn.displayName == conn.host ? "Home Server" : conn.displayName
                VStack(alignment: .leading, spacing: 1) {
                    Text(friendlyName)
                        .font(AppTheme.headline())
                        .foregroundStyle(AppTheme.ink)
                    Text("\(conn.nasProtocol.rawValue) · \(conn.host)")
                        .font(AppTheme.micro(10))
                        .foregroundStyle(AppTheme.inkTertiary)
                }
            } else {
                Text("No storage connected")
                    .font(AppTheme.body())
                    .foregroundStyle(AppTheme.inkTertiary)
            }

            Spacer()

            VStack(alignment: .trailing, spacing: 2) {
                HStack(spacing: 4) {
                    Circle()
                        .fill(nasStatusDotColor)
                        .frame(width: 6, height: 6)
                        .animation(.spring(response: 0.3, dampingFraction: 0.8), value: nasStatusDotColor == AppTheme.positive)
                    Text(nasStatusLabel)
                        .font(AppTheme.micro())
                        .foregroundStyle(nasStatusDotColor)
                        .animation(.spring(response: 0.3, dampingFraction: 0.8), value: nasStatusLabel)
                }
                if lanMonitor.nasReachable == false {
                    Text(statusService.refreshError ?? "Unreachable")
                        .font(.system(size: 9, weight: .regular))
                        .foregroundStyle(AppTheme.destructive.opacity(0.7))
                        .lineLimit(2)
                        .multilineTextAlignment(.trailing)
                } else if lanMonitor.nasReachable == true && !engine.job.status.isActive {
                    Text("Connected")
                        .font(.system(size: 9, weight: .regular))
                        .foregroundStyle(AppTheme.positive.opacity(0.7))
                }
            }
        }
        .padding(.horizontal, 14)
        .padding(.vertical, 12)
        .background(AppTheme.surfaceSunken)
        .clipShape(RoundedRectangle(cornerRadius: AppTheme.radius, style: .continuous))
    }

    private func startBackup() {
        guard let conn = store.savedConnection else { return }
        Task { _ = try? await engine.run(connection: conn, filter: store.backupFilter) }
    }

    private func etaString(_ seconds: TimeInterval) -> String {
        Int(seconds) / 60 > 0 ? "\(Int(seconds) / 60)m" : "\(Int(seconds))s"
    }

    // MARK: — Widget state

    private enum WidgetState: Equatable {
        case offline, checking, pending, running, safe, paused
    }

    private var widgetState: WidgetState {
        if lanMonitor.nasReachable == false { return .offline }
        switch resolvedStatus {
        case .paused:              return .paused
        case .running, .preparing: return .running
        case .completed:           return .safe
        default: break
        }
        if statusService.isRefreshing || coordinator.phase == .checking { return .checking }
        if statusService.snapshot.needBackup == 0, statusService.snapshot.phoneTotal > 0 { return .safe }
        return .pending
    }

    private var innerRingColor: Color {
        switch widgetState {
        case .offline:  return AppTheme.destructive
        case .checking: return Color(red: 0.58, green: 0.64, blue: 0.73)
        case .pending:  return Color(red: 1.0, green: 0.62, blue: 0.0)
        case .running:  return Color(red: 1.0, green: 0.62, blue: 0.0)
        case .safe:     return AppTheme.positive
        case .paused:   return Color(red: 0.82, green: 0.82, blue: 0.82)
        }
    }

    private var statusLabelText: String {
        switch widgetState {
        case .offline:  return "NAS unreachable"
        case .checking: return "Checking…"
        case .pending:  return "Ready to back up"
        case .running:  return "Backing up"
        case .safe:     return "All safe"
        case .paused:   return "Backup paused"
        }
    }

    private var statusSubText: String {
        switch widgetState {
        case .offline:
            if let date = statusService.snapshot.lastCheckedAt {
                let s = Int(-date.timeIntervalSinceNow)
                return s < 60 ? "last seen \(s) sec ago" : "last seen \(s / 60) min ago"
            }
            return "unable to connect"
        case .checking: return "reconciling with NAS"
        case .pending:  return "pull circle to start"
        case .running:
            if let eta = engine.job.eta { return "\(etaString(eta)) remaining" }
            return "uploading…"
        case .safe:     return "synced with NAS"
        case .paused:   return "pull circle to resume"
        }
    }

    private var dotColor: Color {
        switch widgetState {
        case .offline:  return AppTheme.destructive
        case .checking: return AppTheme.inkTertiary
        case .pending:  return Color(red: 1.0, green: 0.62, blue: 0.0)
        case .running:  return Color(red: 1.0, green: 0.62, blue: 0.0)
        case .safe:     return AppTheme.positive
        case .paused:   return Color(red: 1.0, green: 0.62, blue: 0.0)
        }
    }

    private var dotShouldPulse: Bool {
        widgetState == .offline || widgetState == .pending || widgetState == .paused
    }

    private var showArrows: Bool {
        widgetState == .offline || widgetState == .pending || widgetState == .paused
    }

    private var arrowsColor: Color {
        widgetState == .offline ? AppTheme.destructive : Color(red: 1.0, green: 0.62, blue: 0.0)
    }

    // MARK: — Circle section

    private var circleSection: some View {
        VStack(spacing: 0) {
            pullZone

            ZStack {
                // Ripple expands outward on backup trigger
                Circle()
                    .stroke(AppTheme.positive, lineWidth: 1.5)
                    .frame(width: 258, height: 258)
                    .scaleEffect(rippleScale)
                    .opacity(rippleOpacity)
                    .allowsHitTesting(false)

                ringHero
            }
            .offset(y: min(pullProgress * 0.26, 14))
            .animation(.spring(response: 0.38, dampingFraction: 0.8), value: pullProgress)
            .gesture(pullGesture)
            .padding(.bottom, 4)

            cascadingArrows
                .frame(height: 16)
                .padding(.bottom, 8)

            circleStatusRow
                .padding(.horizontal, AppTheme.hPad)
                .padding(.bottom, 20)
        }
    }

    private var pullZone: some View {
        let pct   = min(pullProgress / 58, 1.0)
        let ready = pullProgress >= 58
        return VStack(spacing: 3) {
            Text("↓")
                .font(.system(size: 13))
                .foregroundStyle(ready ? AppTheme.positive : AppTheme.inkTertiary)
                .rotationEffect(.degrees(ready ? 180 : pct * 160))
                .opacity(min(pct * 2.5, 1))
            Text(ready ? "RELEASE TO BACK UP" : "PULL TO BACK UP")
                .font(.system(size: 8, weight: .regular, design: .monospaced))
                .foregroundStyle(ready ? AppTheme.positive : AppTheme.inkTertiary)
                .tracking(2)
                .opacity(min(pct * 3, 1))
        }
        .padding(.bottom, 6)
        .frame(maxWidth: .infinity, maxHeight: max(0, pullProgress * 0.52), alignment: .bottom)
        .clipped()
    }

    private var cascadingArrows: some View {
        TimelineView(.animation(minimumInterval: 1.0 / 30, paused: !showArrows)) { tl in
            let t = tl.date.timeIntervalSince1970
            HStack(spacing: 3) {
                ForEach(0..<3, id: \.self) { i in
                    let phase = ((t.truncatingRemainder(dividingBy: 1.6) - Double(i) * 0.22) + 1.6)
                        .truncatingRemainder(dividingBy: 1.6) / 1.6
                    Text("↓")
                        .font(.system(size: 10))
                        .foregroundStyle(arrowsColor)
                        .opacity(arrowFlowOpacity(phase))
                        .offset(y: arrowFlowOffset(phase))
                }
            }
        }
        .opacity(showArrows ? 1 : 0)
        .animation(.easeInOut(duration: 0.4), value: showArrows)
    }

    private var circleStatusRow: some View {
        VStack(spacing: 4) {
            HStack(spacing: 6) {
                if widgetState == .checking || widgetState == .running {
                    ProgressView()
                        .scaleEffect(0.55)
                        .tint(AppTheme.inkTertiary)
                        .frame(width: 10, height: 10)
                } else {
                    Circle()
                        .fill(dotColor)
                        .frame(width: 6, height: 6)
                        .opacity(pulseDotOpacity)
                        .onAppear {
                            if dotShouldPulse {
                                withAnimation(.easeInOut(duration: 1.0).repeatForever(autoreverses: true)) {
                                    pulseDotOpacity = 0.3
                                }
                            }
                        }
                        .onChange(of: dotShouldPulse) { pulse in
                            if pulse {
                                withAnimation(.easeInOut(duration: 1.0).repeatForever(autoreverses: true)) {
                                    pulseDotOpacity = 0.3
                                }
                            } else {
                                withAnimation { pulseDotOpacity = 1.0 }
                            }
                        }
                }
                Text(statusLabelText)
                    .font(.system(size: 13, weight: .regular))
                    .foregroundStyle(widgetState == .offline ? AppTheme.destructive : AppTheme.ink)
            }
            Text(statusSubText)
                .font(.system(size: 9, weight: .regular, design: .monospaced))
                .foregroundStyle(AppTheme.inkTertiary)
                .tracking(0.08)
        }
        .multilineTextAlignment(.center)
        .id(widgetState)
        .transition(.opacity.combined(with: .offset(y: 8)))
        .animation(.easeInOut(duration: 0.35), value: widgetState)
    }

    // MARK: — Page switch gesture (used on pages 1 & 2 hero areas)

    private var pageSwitchGesture: some Gesture {
        DragGesture(minimumDistance: 30)
            .onEnded { value in
                let dx = value.translation.width
                guard abs(dx) > abs(value.translation.height) else { return }
                withAnimation(.spring(response: 0.4, dampingFraction: 0.85)) {
                    if dx < 0 {
                        ringPage = (ringPage + 1) % ringPageCount
                    } else {
                        ringPage = (ringPage - 1 + ringPageCount) % ringPageCount
                    }
                }
            }
    }

    // MARK: — Pull gesture

    private var pullGesture: some Gesture {
        DragGesture(minimumDistance: 8)
            .onChanged { value in
                guard value.translation.height > 0 else { return }
                let dy = value.translation.height
                if pullProgress < 58 && dy >= 58 {
                    UIImpactFeedbackGenerator(style: .light).impactOccurred()
                }
                pullProgress = dy
            }
            .onEnded { value in
                let fired = value.translation.height >= 58
                withAnimation(.spring(response: 0.38, dampingFraction: 0.85)) { pullProgress = 0 }
                if fired {
                    UIImpactFeedbackGenerator(style: .medium).impactOccurred()
                    triggerBackupViaPull()
                }
            }
    }

    private func triggerBackupViaPull() {
        rippleScale = 0.88; rippleOpacity = 0.6
        withAnimation(.easeOut(duration: 0.65)) { rippleScale = 1.35; rippleOpacity = 0 }
        if engine.job.status == .paused { engine.resume() } else { startBackup() }
    }

    private func arrowFlowOpacity(_ phase: Double) -> Double {
        if phase < 0.4 { return phase / 0.4 * 0.7 }
        if phase < 0.8 { return (0.8 - phase) / 0.4 * 0.7 }
        return 0
    }

    private func arrowFlowOffset(_ phase: Double) -> CGFloat {
        if phase < 0.4 { return CGFloat(-3 + phase / 0.4 * 3) }
        if phase < 0.8 { return CGFloat((phase - 0.4) / 0.4 * 3) }
        return 3
    }

    // MARK: — Device storage

    private var deviceUsedGB: Double { max(0, deviceTotalGB - deviceFreeGB) }
    private var junkGB: Double { Double(alreadySafeDisplayCount) * 3.5 / 1000 }
    private var usedFraction: CGFloat { CGFloat(deviceUsedGB / max(1, deviceTotalGB)) }
    private var safeFraction: CGFloat { CGFloat(min(junkGB, deviceTotalGB) / max(1, deviceTotalGB)) }
    private var backedUpPhotosGB: Double { Double(alreadySafeDisplayCount) * 3.5 / 1000 }
    private var totalFreeableGB: Double { backedUpPhotosGB }

    private func loadDeviceStorage() {
        let attrs = try? FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory())
        let total = (attrs?[.systemSize] as? Int64) ?? 0
        let free  = (attrs?[.systemFreeSize] as? Int64) ?? 0
        deviceTotalGB = Double(total) / 1_000_000_000
        deviceFreeGB  = Double(free)  / 1_000_000_000
    }

    // MARK: — Page content

    @ViewBuilder
    private var page0Content: some View {
        circleSection
        statsStrip
            .padding(.horizontal, AppTheme.hPad)
            .transition(.opacity.combined(with: .scale(scale: 0.97)))
        Spacer(minLength: 16).frame(maxHeight: 32)
        nasStatusRow
            .padding(.horizontal, AppTheme.hPad)
            .padding(.bottom, 12)
        destinationRow
            .padding(.horizontal, AppTheme.hPad)
        Spacer(minLength: 8).frame(maxHeight: 20)
    }

    @ViewBuilder
    private var page1Content: some View {
        // Storage ring
        ZStack {
            StorageRingView(usedProgress: usedFraction, safeProgress: safeFraction)
            VStack(spacing: 6) {
                Image(systemName: "iphone")
                    .font(.system(size: 14, weight: .ultraLight))
                    .foregroundStyle(AppTheme.inkTertiary)
                Text("\(Int(usedFraction * 100))%")
                    .font(.system(size: 46, weight: .ultraLight))
                    .foregroundStyle(Color(red: 1.0, green: 0.58, blue: 0.0))
                    .kerning(-2)
                Text("STORAGE USED")
                    .font(.system(size: 8, weight: .regular, design: .monospaced))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .tracking(2).opacity(0.75)
            }
        }
        .gesture(pageSwitchGesture)
        .padding(.bottom, 20)

        // 3-col stats
        HStack(spacing: 0) {
            storageStat(String(format: "%.0f GB", deviceUsedGB), label: "USED",
                        color: Color(red: 1.0, green: 0.58, blue: 0.0))
            thinDivider
            storageStat(String(format: "%.0f GB", deviceFreeGB), label: "FREE",
                        color: AppTheme.inkSecondary)
            thinDivider
            storageStat(String(format: "%.1f GB", junkGB), label: "JUNK",
                        color: AppTheme.positive)
        }
        .frame(height: 48)
        .background(AppTheme.surfaceSunken.opacity(0.85))
        .clipShape(RoundedRectangle(cornerRadius: 14, style: .continuous))
        .padding(.horizontal, AppTheme.hPad)
        .padding(.bottom, 12)

        // Legend
        HStack(spacing: 16) {
            storageLegend(color: Color(red: 1.0, green: 0.58, blue: 0.0), label: "used")
            storageLegend(color: AppTheme.positive, label: "safe to delete")
            storageLegend(color: AppTheme.destructive, label: "junk")
        }
        .padding(.horizontal, AppTheme.hPad)
        .padding(.bottom, 20)

        Spacer(minLength: 16).frame(maxHeight: 40)

        Button(action: { showCleanConfirm = true }) {
            Text("HOLD TO CLEAN")
                .font(.system(size: 10, weight: .medium, design: .monospaced))
                .tracking(2)
        }
        .buttonStyle(PrimaryButtonStyle())
        .padding(.horizontal, AppTheme.hPad)
        .simultaneousGesture(
            LongPressGesture(minimumDuration: 0.8).onEnded { _ in showCleanConfirm = true }
        )

        Text(String(format: "%.1f GB RECOVERABLE", junkGB))
            .font(.system(size: 9, weight: .regular, design: .monospaced))
            .foregroundStyle(AppTheme.inkTertiary)
            .tracking(1.5)
            .padding(.top, 6)
            .padding(.bottom, 8)
    }

    @ViewBuilder
    private var page2Content: some View {
        // Freed amount
        HStack(alignment: .lastTextBaseline, spacing: 6) {
            Text(String(format: "%.1f", totalFreeableGB))
                .font(.system(size: 64, weight: .ultraLight))
                .foregroundStyle(AppTheme.positive)
                .kerning(-2)
            Text("GB FREED")
                .font(.system(size: 8, weight: .regular, design: .monospaced))
                .foregroundStyle(AppTheme.inkTertiary)
                .tracking(2)
                .offset(y: -10)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(.horizontal, AppTheme.hPad)
        .padding(.bottom, 20)
        .gesture(pageSwitchGesture)

        // Breakdown
        VStack(spacing: 0) {
            cleanupRow(label: "Backed-up photos", sizeGB: backedUpPhotosGB, color: AppTheme.positive)
            Divider().opacity(0.25).padding(.leading, AppTheme.hPad)
            cleanupRow(label: "Duplicates", sizeGB: 0, color: AppTheme.interactive)
            Divider().opacity(0.25).padding(.leading, AppTheme.hPad)
            cleanupRow(label: "Screenshots", sizeGB: 0,
                       color: Color(red: 1.0, green: 0.58, blue: 0.0))
            Divider().opacity(0.25).padding(.leading, AppTheme.hPad)
            cleanupRow(label: "Large videos", sizeGB: 0, color: AppTheme.inkQuaternary)
        }
        .padding(.horizontal, AppTheme.hPad)
        .padding(.bottom, 24)

        Spacer(minLength: 16).frame(maxHeight: 40)

        Button { withAnimation { ringPage = 0 } } label: { Text("DONE") }
            .buttonStyle(GhostButtonStyle())
            .frame(width: 120)
            .padding(.bottom, 8)
    }

    // MARK: — Page navigation

    private var pageNav: some View {
        HStack {
            Button {
                withAnimation(.spring(response: 0.4, dampingFraction: 0.85)) {
                    ringPage = (ringPage - 1 + ringPageCount) % ringPageCount
                }
            } label: {
                Image(systemName: "chevron.left")
                    .font(.system(size: 10, weight: .medium))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .frame(width: 30, height: 30)
                    .background(AppTheme.surfaceSunken)
                    .clipShape(Circle())
            }

            Spacer()

            Text(ringPageNames[ringPage])
                .font(.system(size: 8, weight: .regular, design: .monospaced))
                .foregroundStyle(AppTheme.inkTertiary)
                .tracking(2)

            Spacer()

            Button {
                withAnimation(.spring(response: 0.4, dampingFraction: 0.85)) {
                    ringPage = (ringPage + 1) % ringPageCount
                }
            } label: {
                Image(systemName: "chevron.right")
                    .font(.system(size: 10, weight: .medium))
                    .foregroundStyle(AppTheme.inkTertiary)
                    .frame(width: 30, height: 30)
                    .background(AppTheme.surfaceSunken)
                    .clipShape(Circle())
            }
        }
    }

    // MARK: — Storage helpers

    private func storageStat(_ value: String, label: String, color: Color) -> some View {
        VStack(spacing: 2) {
            Text(value)
                .font(.system(size: 15, weight: .semibold))
                .foregroundStyle(color)
                .monospacedDigit()
            Text(label)
                .font(.system(size: 9, weight: .regular, design: .monospaced))
                .foregroundStyle(AppTheme.inkQuaternary)
                .tracking(0.5)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 6)
    }

    private func storageLegend(color: Color, label: String) -> some View {
        HStack(spacing: 5) {
            RoundedRectangle(cornerRadius: 1)
                .fill(color)
                .frame(width: 14, height: 2)
            Text(label)
                .font(.system(size: 9, weight: .regular))
                .foregroundStyle(AppTheme.inkTertiary)
        }
    }

    private func cleanupRow(label: String, sizeGB: Double, color: Color) -> some View {
        HStack(spacing: 12) {
            Text(label)
                .font(AppTheme.body(13))
                .foregroundStyle(AppTheme.ink)
            Spacer()
            GeometryReader { geo in
                ZStack(alignment: .leading) {
                    Rectangle().fill(AppTheme.surfaceSunken).frame(height: 2)
                    Rectangle()
                        .fill(color)
                        .frame(
                            width: max(4, geo.size.width * CGFloat(
                                totalFreeableGB > 0 ? min(sizeGB / totalFreeableGB, 1) : 0
                            )),
                            height: 2
                        )
                }
                .frame(maxHeight: .infinity, alignment: .center)
            }
            .frame(height: 2)
            .frame(maxWidth: 140)
            Text(sizeGB > 0.01 ? String(format: "%.1f GB", sizeGB) : "—")
                .font(.system(size: 10, weight: .regular, design: .monospaced))
                .foregroundStyle(AppTheme.inkTertiary)
                .frame(width: 50, alignment: .trailing)
        }
        .padding(.vertical, 12)
    }
}

// MARK: — Ring

private struct KisaniRingView: View {
    let outerProgress: CGFloat
    let innerProgress: CGFloat
    let innerColor: Color

    private let track  = Color(red: 0.76, green: 0.76, blue: 0.76)
    private let nasArc = Color(red: 0.42, green: 0.52, blue: 0.68)

    var body: some View {
        ZStack {
            // Outer track
            Circle().stroke(track, lineWidth: 1).padding(10)
            // Outer NAS progress (blue-slate + glow)
            Circle().trim(from: 0, to: outerProgress)
                .stroke(nasArc, style: StrokeStyle(lineWidth: 1.5, lineCap: .round))
                .shadow(color: nasArc.opacity(0.65), radius: 7, x: 0, y: 0)
                .rotationEffect(.degrees(-90))
                .padding(10)
                .animation(.spring(response: 0.7, dampingFraction: 0.8), value: outerProgress)

            // Middle static ring
            Circle().stroke(Color(red: 0.62, green: 0.62, blue: 0.62), lineWidth: 1).padding(24)

            // Inner track
            Circle().stroke(track, lineWidth: 1.5).padding(38)
            // Inner progress (color-variable)
            Circle().trim(from: 0, to: innerProgress)
                .stroke(innerColor, style: StrokeStyle(lineWidth: 1.5, lineCap: .round))
                .rotationEffect(.degrees(-90))
                .padding(38)
                .animation(.spring(response: 0.7, dampingFraction: 0.8), value: innerProgress)
                .animation(.easeInOut(duration: 0.5), value: innerColor)
        }
        .frame(width: 240, height: 240)
    }
}

private struct StorageRingView: View {
    let usedProgress: CGFloat
    let safeProgress: CGFloat

    private let track = Color(red: 0.92, green: 0.92, blue: 0.92)

    var body: some View {
        ZStack {
            // Outer track + used (orange)
            Circle().stroke(track, lineWidth: 1).padding(10)
            Circle().trim(from: 0, to: usedProgress)
                .stroke(
                    Color(red: 1.0, green: 0.58, blue: 0.0),
                    style: StrokeStyle(lineWidth: 1, lineCap: .round)
                )
                .rotationEffect(.degrees(-90))
                .padding(10)
                .animation(.spring(response: 0.7, dampingFraction: 0.8), value: usedProgress)

            // Middle static ring (gray)
            Circle().stroke(Color(red: 0.78, green: 0.78, blue: 0.78), lineWidth: 1).padding(24)

            // Inner track + safe-to-delete (green)
            Circle().stroke(track, lineWidth: 1.5).padding(38)
            Circle().trim(from: 0, to: safeProgress)
                .stroke(
                    AppTheme.positive,
                    style: StrokeStyle(lineWidth: 1.5, lineCap: .round)
                )
                .rotationEffect(.degrees(-90))
                .padding(38)
                .animation(.spring(response: 0.7, dampingFraction: 0.8), value: safeProgress)
        }
        .frame(width: 240, height: 240)
    }
}