smart_printer/smart_printer/ViewController.swift

//
//  ViewController.swift
//  smart_printer
//

import Cocoa

class ViewController: NSViewController {

    private var sidebar: SidebarView!
    private var mainContentView: NSView!
    private var homeContentView: NSView!
    private var scanContentView: NSView!
    private var scanAndHomeContentView: NSView!
    private var settingsContentView: NSView!
    private var contentContainer: NSView!
    private var paywallOverlay: PaywallOverlayView?
    private var photoPreviewOverlay: PhotoPreviewOverlayView?
    private var filePreviewOverlay: FilePreviewOverlayView?
    private var printTextOverlay: PrintTextOverlayView?
    private var printContactsOverlay: PrintContactsOverlayView?
    private var drawPrintOverlay: DrawPrintOverlayView?

    private var headerView: NSView!
    private var contentTopBelowHeader: NSLayoutConstraint!
    private var contentTopBelowWindow: NSLayoutConstraint!

    override func loadView() {
        let container = NSView(frame: NSRect(x: 0, y: 0, width: AppTheme.windowWidth, height: AppTheme.windowHeight))
        container.autoresizingMask = [.width, .height]
        container.wantsLayer = true
        container.layer?.backgroundColor = AppTheme.background.cgColor
        view = container
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        setupLayout()
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(showSettingsFromMenu),
            name: .showSettings,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(appearanceDidChange),
            name: .appearanceDidChange,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(premiumStatusDidChange),
            name: .premiumStatusDidChange,
            object: nil
        )
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    @objc private func showSettingsFromMenu() {
        navigateToSettings()
    }

    @objc private func appearanceDidChange() {
        refreshAppearance()
    }

    @objc private func premiumStatusDidChange() {
        Task { @MainActor in
            paywallOverlay?.refreshStoreState()
        }
    }

    private func refreshAppearance() {
        view.layer?.backgroundColor = AppTheme.background.cgColor
        mainContentView?.layer?.backgroundColor = AppTheme.background.cgColor
        view.window?.backgroundColor = AppTheme.background
        sidebar?.refreshAppearance()
        view.refreshAppearanceRecursively()
        paywallOverlay?.refreshAppearance()
        photoPreviewOverlay?.refreshAppearance()
        filePreviewOverlay?.refreshAppearance()
        printTextOverlay?.refreshAppearance()
        printContactsOverlay?.refreshAppearance()
        drawPrintOverlay?.refreshAppearance()
    }

    func presentPrintText() {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)
        printContactsOverlay?.dismiss(animated: false)
        drawPrintOverlay?.dismiss(animated: false)

        let overlay = PrintTextOverlayView()
        overlay.onDismiss = { [weak self] in
            self?.printTextOverlay = nil
        }
        printTextOverlay = overlay
        overlay.present(in: mainContentView)
    }

    func presentPrintContacts() {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)
        printTextOverlay?.dismiss(animated: false)
        drawPrintOverlay?.dismiss(animated: false)

        if let overlay = printContactsOverlay {
            overlay.present(in: mainContentView)
            return
        }

        let overlay = PrintContactsOverlayView()
        printContactsOverlay = overlay
        overlay.present(in: mainContentView)
    }

    func presentDrawPrint() {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)
        printTextOverlay?.dismiss(animated: false)
        printContactsOverlay?.dismiss(animated: false)

        let overlay = DrawPrintOverlayView()
        overlay.onDismiss = { [weak self] in
            self?.drawPrintOverlay = nil
        }
        drawPrintOverlay = overlay
        overlay.present(in: mainContentView)
    }

    func presentPhotoPreview(urls: [URL]) {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)

        let overlay = PhotoPreviewOverlayView(urls: urls)
        overlay.onDismiss = { [weak self] in
            self?.photoPreviewOverlay = nil
        }
        photoPreviewOverlay = overlay
        overlay.present(in: mainContentView)
    }

    func presentFilePreview(urls: [URL]) {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)

        let overlay = FilePreviewOverlayView(urls: urls)
        overlay.onDismiss = { [weak self] in
            self?.filePreviewOverlay = nil
        }
        filePreviewOverlay = overlay
        overlay.present(in: mainContentView)
    }

    private func setupLayout() {
        sidebar = SidebarView()

        mainContentView = NSView()
        mainContentView.translatesAutoresizingMaskIntoConstraints = false
        mainContentView.wantsLayer = true
        mainContentView.layer?.backgroundColor = AppTheme.background.cgColor

        headerView = makeHeader()

        contentContainer = NSView()
        contentContainer.translatesAutoresizingMaskIntoConstraints = false

        homeContentView = makeHomeContentView()
        scanContentView = makeScanContentView()
        scanAndHomeContentView = makeScanAndHomeContentView()
        settingsContentView = makeSettingsContentView()

        contentContainer.addSubview(homeContentView)
        contentContainer.addSubview(scanContentView)
        contentContainer.addSubview(scanAndHomeContentView)
        contentContainer.addSubview(settingsContentView)

        view.addSubview(sidebar)
        view.addSubview(mainContentView)
        mainContentView.addSubview(contentContainer)
        mainContentView.addSubview(headerView, positioned: .above, relativeTo: contentContainer)

        sidebar.onDestinationSelected = { [weak self] destination in
            self?.showDestination(destination)
        }

        NSLayoutConstraint.activate([
            sidebar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            sidebar.topAnchor.constraint(equalTo: view.topAnchor),
            sidebar.bottomAnchor.constraint(equalTo: view.bottomAnchor),

            mainContentView.leadingAnchor.constraint(equalTo: sidebar.trailingAnchor),
            mainContentView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            mainContentView.topAnchor.constraint(equalTo: view.topAnchor),
            mainContentView.bottomAnchor.constraint(equalTo: view.bottomAnchor),

            headerView.leadingAnchor.constraint(equalTo: mainContentView.leadingAnchor),
            headerView.trailingAnchor.constraint(equalTo: mainContentView.trailingAnchor),
            headerView.topAnchor.constraint(equalTo: mainContentView.topAnchor, constant: AppTheme.headerTopInset),
            headerView.heightAnchor.constraint(equalToConstant: AppTheme.headerHeight),

            contentContainer.leadingAnchor.constraint(equalTo: mainContentView.leadingAnchor),
            contentContainer.trailingAnchor.constraint(equalTo: mainContentView.trailingAnchor),
            contentContainer.bottomAnchor.constraint(equalTo: mainContentView.bottomAnchor),
        ])

        pinContentView(homeContentView)
        pinContentView(scanContentView)
        pinContentView(scanAndHomeContentView)
        pinContentView(settingsContentView)

        contentTopBelowHeader = contentContainer.topAnchor.constraint(
            equalTo: headerView.bottomAnchor,
            constant: AppTheme.contentBelowHeaderGap
        )
        contentTopBelowWindow = contentContainer.topAnchor.constraint(equalTo: mainContentView.topAnchor, constant: 12)
        contentTopBelowHeader.isActive = true

        showDestination(.home)
    }

    private func pinContentView(_ contentView: NSView) {
        NSLayoutConstraint.activate([
            contentView.leadingAnchor.constraint(equalTo: contentContainer.leadingAnchor),
            contentView.trailingAnchor.constraint(equalTo: contentContainer.trailingAnchor),
            contentView.topAnchor.constraint(equalTo: contentContainer.topAnchor),
            contentView.bottomAnchor.constraint(equalTo: contentContainer.bottomAnchor),
        ])
    }

    private func dismissFeatureOverlays() {
        photoPreviewOverlay?.dismiss(animated: false)
        filePreviewOverlay?.dismiss(animated: false)
        printTextOverlay?.dismiss(animated: false)
        printContactsOverlay?.dismiss(animated: false)
        drawPrintOverlay?.dismiss(animated: false)
    }

    private func showDestination(_ destination: SidebarDestination) {
        dismissFeatureOverlays()

        homeContentView.isHidden = destination != .home
        scanContentView.isHidden = destination != .scan
        scanAndHomeContentView.isHidden = destination != .scanAndHome
        settingsContentView.isHidden = destination != .settings

        let isSettings = destination == .settings
        headerView.isHidden = isSettings
        contentTopBelowHeader.isActive = !isSettings
        contentTopBelowWindow.isActive = isSettings

        if destination == .scanAndHome {
            presentPaywall()
        } else {
            dismissPaywall()
        }
    }

    private func presentPaywall() {
        if let paywallOverlay {
            Task { @MainActor in
                await StoreManager.shared.refreshPremiumStatus()
                paywallOverlay.refreshStoreState()
            }
            return
        }
        setTrafficLightsHidden(true)
        let overlay = PaywallOverlayView()
        overlay.onDismiss = { [weak self] in
            self?.setTrafficLightsHidden(false)
            self?.paywallOverlay = nil
            self?.sidebar.select(.home)
            self?.showDestination(.home)
        }
        overlay.present(in: view)
        paywallOverlay = overlay
    }

    private func dismissPaywall() {
        paywallOverlay?.removeFromSuperview()
        paywallOverlay = nil
        setTrafficLightsHidden(false)
    }

    private func setTrafficLightsHidden(_ isHidden: Bool) {
        guard let window = view.window else { return }
        let buttons: [NSWindow.ButtonType] = [.closeButton, .miniaturizeButton, .zoomButton]
        for buttonType in buttons {
            window.standardWindowButton(buttonType)?.isHidden = isHidden
        }
    }

    private func makeHomeContentView() -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false

        let panel = ContentPanelView()
        panel.translatesAutoresizingMaskIntoConstraints = false

        let scrollView = makeScrollView()
        panel.addSubview(scrollView)
        container.addSubview(panel)

        let inset = AppTheme.contentPanelInset
        NSLayoutConstraint.activate([
            panel.leadingAnchor.constraint(equalTo: container.leadingAnchor, constant: inset),
            panel.trailingAnchor.constraint(equalTo: container.trailingAnchor, constant: -inset),
            panel.topAnchor.constraint(equalTo: container.topAnchor),
            panel.bottomAnchor.constraint(equalTo: container.bottomAnchor, constant: -inset),

            scrollView.leadingAnchor.constraint(equalTo: panel.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: panel.trailingAnchor),
            scrollView.topAnchor.constraint(equalTo: panel.topAnchor),
            scrollView.bottomAnchor.constraint(equalTo: panel.bottomAnchor),
        ])

        return container
    }

    private func makeScanContentView() -> NSView {
        makeDestinationScrollView(
            title: "Scan",
            features: [
                FeatureCardData(title: "Scan File", subtitle: "Scan any document", iconKind: .scanFile),
                FeatureCardData(title: "OCR File", subtitle: "Scan and print text from images", iconKind: .ocrFile),
            ]
        )
    }

    private func makeScanAndHomeContentView() -> NSView {
        makeDestinationScrollView(
            title: "Premium",
            features: featureCards(
                FeatureCardData(title: "From Photos", subtitle: "Take a photo from gallery", iconKind: .scanFile),
                FeatureCardData(title: "Scan File", subtitle: "Scan any document", iconKind: .scanFile),
                FeatureCardData(title: "Print Text", subtitle: "Type text and print", iconKind: .printText),
                FeatureCardData(title: "Print Contacts", subtitle: "Print your contacts", iconKind: .printContacts)
            )
        )
    }

    private func makeDestinationScrollView(title: String, features: [FeatureCardData]) -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false
        container.isHidden = true

        let scrollView = NSScrollView()
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.hasVerticalScroller = true
        scrollView.hasHorizontalScroller = false
        scrollView.autohidesScrollers = true
        scrollView.drawsBackground = false
        scrollView.borderType = .noBorder

        let documentView = FlippedDocumentView()
        documentView.translatesAutoresizingMaskIntoConstraints = false

        let sectionTitle = makeSectionTitle(title, icon: .grid)
        let grid = makeFeatureGrid(features: features, columns: AppTheme.featureGridColumns)

        documentView.addSubview(sectionTitle)
        documentView.addSubview(grid)
        scrollView.documentView = documentView
        container.addSubview(scrollView)

        let contentGuide = scrollView.contentView

        NSLayoutConstraint.activate([
            scrollView.leadingAnchor.constraint(equalTo: container.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: container.trailingAnchor),
            scrollView.topAnchor.constraint(equalTo: container.topAnchor),
            scrollView.bottomAnchor.constraint(equalTo: container.bottomAnchor),

            documentView.topAnchor.constraint(equalTo: contentGuide.topAnchor),
            documentView.leadingAnchor.constraint(equalTo: contentGuide.leadingAnchor),
            documentView.trailingAnchor.constraint(equalTo: contentGuide.trailingAnchor),
            documentView.widthAnchor.constraint(equalTo: contentGuide.widthAnchor),

            sectionTitle.leadingAnchor.constraint(equalTo: documentView.leadingAnchor, constant: AppTheme.contentPadding),
            sectionTitle.trailingAnchor.constraint(equalTo: documentView.trailingAnchor, constant: -AppTheme.contentPadding),
            sectionTitle.topAnchor.constraint(equalTo: documentView.topAnchor, constant: 8),

            grid.leadingAnchor.constraint(equalTo: documentView.leadingAnchor, constant: AppTheme.contentPadding),
            grid.trailingAnchor.constraint(equalTo: documentView.trailingAnchor, constant: -AppTheme.contentPadding),
            grid.topAnchor.constraint(equalTo: sectionTitle.bottomAnchor, constant: 16),
            grid.bottomAnchor.constraint(equalTo: documentView.bottomAnchor, constant: -40),
        ])

        return container
    }

    private func makeHeader() -> NSView {
        let header = NSView()
        header.translatesAutoresizingMaskIntoConstraints = false

        let titleLabel = NSTextField.themeLabel("Smart Printer", style: .primary, font: AppTheme.semiboldFont(size: 18))
        titleLabel.alignment = .center
        titleLabel.translatesAutoresizingMaskIntoConstraints = false

        header.addSubview(titleLabel)

        NSLayoutConstraint.activate([
            titleLabel.centerXAnchor.constraint(equalTo: header.centerXAnchor),
            titleLabel.topAnchor.constraint(equalTo: header.topAnchor, constant: 2),
        ])

        return header
    }

    private func makeSettingsContentView() -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false
        let settingsView = SettingsView()
        container.addSubview(settingsView)

        NSLayoutConstraint.activate([
            settingsView.leadingAnchor.constraint(equalTo: container.leadingAnchor),
            settingsView.trailingAnchor.constraint(equalTo: container.trailingAnchor),
            settingsView.topAnchor.constraint(equalTo: container.topAnchor),
            settingsView.bottomAnchor.constraint(equalTo: container.bottomAnchor),
        ])

        return container
    }

    private func navigateToSettings() {
        if paywallOverlay != nil {
            dismissPaywall()
        }
        sidebar.select(.settings)
        showDestination(.settings)
    }

    private func makeScrollView() -> NSScrollView {
        let scrollView = NSScrollView()
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.hasVerticalScroller = true
        scrollView.hasHorizontalScroller = false
        scrollView.autohidesScrollers = true
        scrollView.drawsBackground = false
        scrollView.borderType = .noBorder

        let documentView = FlippedDocumentView()
        documentView.translatesAutoresizingMaskIntoConstraints = false

        let quickStartSection = makeQuickStartSection()
        let createPrintSection = makeCreatePrintSection()

        documentView.addSubview(quickStartSection)
        documentView.addSubview(createPrintSection)
        scrollView.documentView = documentView

        let contentGuide = scrollView.contentView

        NSLayoutConstraint.activate([
            documentView.topAnchor.constraint(equalTo: contentGuide.topAnchor),
            documentView.leadingAnchor.constraint(equalTo: contentGuide.leadingAnchor),
            documentView.trailingAnchor.constraint(equalTo: contentGuide.trailingAnchor),
            documentView.widthAnchor.constraint(equalTo: contentGuide.widthAnchor),

            quickStartSection.leadingAnchor.constraint(equalTo: documentView.leadingAnchor, constant: AppTheme.contentPadding),
            quickStartSection.trailingAnchor.constraint(equalTo: documentView.trailingAnchor, constant: -AppTheme.contentPadding),
            quickStartSection.topAnchor.constraint(equalTo: documentView.topAnchor, constant: 20),

            createPrintSection.leadingAnchor.constraint(equalTo: documentView.leadingAnchor, constant: AppTheme.contentPadding),
            createPrintSection.trailingAnchor.constraint(equalTo: documentView.trailingAnchor, constant: -AppTheme.contentPadding),
            createPrintSection.topAnchor.constraint(equalTo: quickStartSection.bottomAnchor, constant: 36),
            createPrintSection.bottomAnchor.constraint(equalTo: documentView.bottomAnchor, constant: -40),
        ])

        return scrollView
    }

    private enum SectionTitleIcon {
        case none
        case sparkle
        case grid
    }

    private func makeSectionTitle(_ text: String, icon: SectionTitleIcon = .none) -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false

        var leadingAnchor = container.leadingAnchor
        var iconSpacing: CGFloat = 0

        if icon != .none {
            let titleIcon: NSView
            switch icon {
            case .sparkle:
                titleIcon = SparkleIconView()
            case .grid:
                let gridIcon = NSImageView()
                if let image = NSImage(systemSymbolName: "square.grid.2x2", accessibilityDescription: nil) {
                    let config = NSImage.SymbolConfiguration(pointSize: 16, weight: .medium)
                    gridIcon.image = image.withSymbolConfiguration(config)
                }
                gridIcon.contentTintColor = AppTheme.blue
                titleIcon = gridIcon
            case .none:
                titleIcon = NSView()
            }

            titleIcon.translatesAutoresizingMaskIntoConstraints = false
            container.addSubview(titleIcon)

            NSLayoutConstraint.activate([
                titleIcon.leadingAnchor.constraint(equalTo: container.leadingAnchor),
                titleIcon.centerYAnchor.constraint(equalTo: container.centerYAnchor),
                titleIcon.widthAnchor.constraint(equalToConstant: 24),
                titleIcon.heightAnchor.constraint(equalToConstant: 24),
            ])
            leadingAnchor = titleIcon.trailingAnchor
            iconSpacing = 8
        }

        let label = NSTextField.themeLabel(text, style: .primary, font: .systemFont(ofSize: 20, weight: .bold))
        label.translatesAutoresizingMaskIntoConstraints = false
        container.addSubview(label)

        NSLayoutConstraint.activate([
            container.heightAnchor.constraint(equalToConstant: 28),
            label.leadingAnchor.constraint(equalTo: leadingAnchor, constant: iconSpacing),
            label.centerYAnchor.constraint(equalTo: container.centerYAnchor),
            label.trailingAnchor.constraint(equalTo: container.trailingAnchor),
        ])

        return container
    }

    private func makeQuickStartSection() -> NSView {
        let section = NSView()
        section.translatesAutoresizingMaskIntoConstraints = false

        let title = makeSectionTitle("Quick Start", icon: .sparkle)
        section.addSubview(title)

        let cardsStack = NSStackView()
        cardsStack.orientation = .horizontal
        cardsStack.spacing = AppTheme.quickStartSpacing
        cardsStack.distribution = .fillEqually
        cardsStack.translatesAutoresizingMaskIntoConstraints = false

        let cards: [QuickStartCardData] = [
            QuickStartCardData(
                title: "From Photos",
                subtitle: "Select photos from gallery",
                buttonTitle: "Open Gallery",
                accentColor: AppTheme.blue,
                gradientColors: [AppTheme.quickStartBlueLight, NSColor(red: 0.82, green: 0.90, blue: 1.0, alpha: 1)],
                iconKind: .photos
            ),
            QuickStartCardData(
                title: "From Files",
                subtitle: "Select Photos from file manager",
                buttonTitle: "Browse Files",
                accentColor: AppTheme.green,
                gradientColors: [AppTheme.greenLight, NSColor(red: 0.78, green: 0.94, blue: 0.84, alpha: 1)],
                iconKind: .files
            ),
            QuickStartCardData(
                title: "Import File",
                subtitle: "Add files from storage",
                buttonTitle: "Import Now",
                accentColor: AppTheme.orange,
                gradientColors: [AppTheme.orangeLight, NSColor(red: 1.0, green: 0.88, blue: 0.76, alpha: 1)],
                iconKind: .importFile
            ),
        ]

        let pickerKinds: [DocumentPickerKind] = [.photos, .files, .importFile]
        for (index, cardData) in cards.enumerated() {
            let kind = pickerKinds[index]
            let card = QuickStartCardView(data: cardData) { [weak self] in
                DocumentPickerService.present(kind, from: self?.view.window)
            }
            cardsStack.addArrangedSubview(card)
        }

        section.addSubview(cardsStack)

        NSLayoutConstraint.activate([
            title.leadingAnchor.constraint(equalTo: section.leadingAnchor),
            title.topAnchor.constraint(equalTo: section.topAnchor),

            cardsStack.leadingAnchor.constraint(equalTo: section.leadingAnchor),
            cardsStack.trailingAnchor.constraint(equalTo: section.trailingAnchor),
            cardsStack.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 16),
            cardsStack.bottomAnchor.constraint(equalTo: section.bottomAnchor),
        ])

        return section
    }

    private func makeCreatePrintSection() -> NSView {
        let section = NSView()
        section.translatesAutoresizingMaskIntoConstraints = false

        let title = makeSectionTitle("Create & Print", icon: .grid)
        section.addSubview(title)

        let features = featureCards(
            FeatureCardData(title: "Scan File", subtitle: "Scan any document", iconKind: .scanFile),
            FeatureCardData(title: "Print Text", subtitle: "Type text and print", iconKind: .printText),
            FeatureCardData(title: "Print Contacts", subtitle: "Print your contacts", iconKind: .printContacts),
            FeatureCardData(title: "Draw & Print", subtitle: "Add drawings, text and more", iconKind: .drawPrint),
            FeatureCardData(title: "OCR File", subtitle: "Scan and print text from images", iconKind: .ocrFile),
            FeatureCardData(title: "Print Website", subtitle: "Print any website", iconKind: .printWebsite)
        )

        let grid = makeFeatureGrid(features: features, columns: AppTheme.featureGridColumns)

        section.addSubview(grid)

        NSLayoutConstraint.activate([
            title.leadingAnchor.constraint(equalTo: section.leadingAnchor),
            title.topAnchor.constraint(equalTo: section.topAnchor),

            grid.leadingAnchor.constraint(equalTo: section.leadingAnchor),
            grid.trailingAnchor.constraint(equalTo: section.trailingAnchor),
            grid.topAnchor.constraint(equalTo: title.bottomAnchor, constant: 16),
            grid.bottomAnchor.constraint(equalTo: section.bottomAnchor),
        ])

        return section
    }

    private func featureCards(_ cards: FeatureCardData...) -> [FeatureCardData] {
        cards.map { card in
            var updated = card
            if card.iconKind == .printText {
                updated.onActivate = { [weak self] in
                    PrintTextService.present(from: self?.view.window)
                }
            } else if card.iconKind == .printContacts {
                updated.onActivate = { [weak self] in
                    PrintContactsService.present(from: self?.view.window)
                }
            } else if card.iconKind == .drawPrint {
                updated.onActivate = { [weak self] in
                    DrawPrintService.present(from: self?.view.window)
                }
            }
            return updated
        }
    }

    private func makeFeatureGrid(features: [FeatureCardData], columns: Int) -> NSView {
        let grid = NSStackView()
        grid.orientation = .vertical
        grid.spacing = AppTheme.featureGridSpacing
        grid.distribution = .fill
        grid.alignment = .leading
        grid.translatesAutoresizingMaskIntoConstraints = false

        var index = 0
        while index < features.count {
            let row = NSStackView()
            row.orientation = .horizontal
            row.spacing = AppTheme.featureGridSpacing
            row.distribution = .fillEqually
            row.translatesAutoresizingMaskIntoConstraints = false

            let rowCount = min(columns, features.count - index)
            for offset in 0..<rowCount {
                row.addArrangedSubview(FeatureCardView(data: features[index + offset]))
            }
            for _ in 0..<(columns - rowCount) {
                let spacer = NSView()
                spacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
                spacer.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
                row.addArrangedSubview(spacer)
            }

            grid.addArrangedSubview(row)
            row.leadingAnchor.constraint(equalTo: grid.leadingAnchor).isActive = true
            row.trailingAnchor.constraint(equalTo: grid.trailingAnchor).isActive = true
            index += rowCount
        }

        return grid
    }
}

private final class FlippedDocumentView: NSView {
    override var isFlipped: Bool { true }
}

extension Notification.Name {
    static let showSettings = Notification.Name("showSettings")
}