import Cocoa

final class PremiumPlansWindowController: NSWindowController {
    init() {
        let viewController = PremiumPlansViewController()
        let window = NSWindow(contentViewController: viewController)
        window.title = "Premium Plans"
        window.styleMask = [.titled, .closable, .miniaturizable, .resizable]
        window.setContentSize(NSSize(width: 1160, height: 760))
        window.minSize = NSSize(width: 980, height: 680)
        window.center()
        super.init(window: window)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        nil
    }
}

private final class PremiumPlansViewController: NSViewController {
    private struct Plan {
        let id: String
        let title: String
        let subtitle: String
        let price: String
        let period: String
        let billedPill: String
        let billedLine: String
        let crossedPrice: String?
        let savingsText: String?
        let features: [String]
        let iconName: String
        let iconTint: NSColor
        let highlight: Bool
    }

    private enum Theme {
        static let pageStart = NSColor(srgbRed: 249 / 255, green: 252 / 255, blue: 255 / 255, alpha: 1)
        static let pageEnd = NSColor(srgbRed: 238 / 255, green: 244 / 255, blue: 255 / 255, alpha: 1)
        static let cardBackground = NSColor.white
        static let primaryText = NSColor(srgbRed: 27 / 255, green: 38 / 255, blue: 79 / 255, alpha: 1)
        static let secondaryText = NSColor(srgbRed: 108 / 255, green: 120 / 255, blue: 157 / 255, alpha: 1)
        static let cardBorder = NSColor(srgbRed: 198 / 255, green: 216 / 255, blue: 255 / 255, alpha: 1)
        static let accent = NSColor(srgbRed: 55 / 255, green: 128 / 255, blue: 255 / 255, alpha: 1)
        static let accentHover = NSColor(srgbRed: 38 / 255, green: 108 / 255, blue: 232 / 255, alpha: 1)
        static let mutedButtonFill = NSColor(srgbRed: 238 / 255, green: 243 / 255, blue: 252 / 255, alpha: 1)
        static let bottomStrip = NSColor(srgbRed: 244 / 255, green: 248 / 255, blue: 255 / 255, alpha: 1)
        static let divider = NSColor(srgbRed: 218 / 255, green: 228 / 255, blue: 247 / 255, alpha: 1)
        static let successText = NSColor(srgbRed: 21 / 255, green: 154 / 255, blue: 220 / 255, alpha: 1)
        static let iconTint = NSColor(srgbRed: 47 / 255, green: 136 / 255, blue: 255 / 255, alpha: 1)
    }

    private let plans: [Plan] = [
        Plan(
            id: "weekly",
            title: "Weekly",
            subtitle: "Flexible and commitment-free",
            price: "$9.99",
            period: "/ week",
            billedPill: "",
            billedLine: "",
            crossedPrice: nil,
            savingsText: nil,
            features: [
                "All premium features",
                "Perfect for short-term goals",
                "Cancel anytime"
            ],
            iconName: "paperplane.fill",
            iconTint: Theme.iconTint,
            highlight: false
        ),
        Plan(
            id: "monthly",
            title: "Monthly",
            subtitle: "Balanced for regular productivity",
            price: "$19.99",
            period: "/ month",
            billedPill: "Most Popular",
            billedLine: "",
            crossedPrice: nil,
            savingsText: nil,
            features: [
                "All premium features",
                "Best value for regular users",
                "Priority support"
            ],
            iconName: "bolt.fill",
            iconTint: Theme.accent,
            highlight: true
        ),
        Plan(
            id: "yearly",
            title: "Yearly",
            subtitle: "Best value for long-term users",
            price: "$39.99",
            period: "/ year",
            billedPill: "3-day free trial",
            billedLine: "",
            crossedPrice: nil,
            savingsText: nil,
            features: [
                "All premium features",
                "Lowest effective monthly cost",
                "Ideal for long-term use"
            ],
            iconName: "crown.fill",
            iconTint: Theme.successText,
            highlight: false
        )
    ]

    private let pageGradient = CAGradientLayer()
    private lazy var popularGradient: CAGradientLayer = {
        let layer = CAGradientLayer()
        layer.colors = [
            NSColor(srgbRed: 189 / 255, green: 52 / 255, blue: 255 / 255, alpha: 1).cgColor,
            NSColor(srgbRed: 73 / 255, green: 153 / 255, blue: 255 / 255, alpha: 1).cgColor
        ]
        layer.startPoint = CGPoint(x: 0, y: 0.5)
        layer.endPoint = CGPoint(x: 1, y: 0.5)
        return layer
    }()

    override func viewDidLayout() {
        super.viewDidLayout()
        pageGradient.frame = view.bounds
        popularGradient.frame = CGRect(x: 0, y: 0, width: 160, height: 22)
    }

    override func loadView() {
        view = NSView()
        view.wantsLayer = true
        pageGradient.colors = [Theme.pageStart.cgColor, Theme.pageEnd.cgColor]
        pageGradient.startPoint = CGPoint(x: 0, y: 1)
        pageGradient.endPoint = CGPoint(x: 1, y: 0)
        view.layer?.addSublayer(pageGradient)
        setupLayout()
    }

    private func setupLayout() {
        let crownIcon = NSImageView()
        crownIcon.translatesAutoresizingMaskIntoConstraints = false
        crownIcon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 18, weight: .semibold)
        crownIcon.image = NSImage(systemSymbolName: "crown.fill", accessibilityDescription: nil)
        crownIcon.contentTintColor = NSColor(srgbRed: 254 / 255, green: 214 / 255, blue: 92 / 255, alpha: 1)

        let title = NSTextField(labelWithString: "Upgrade to Pro")
        title.font = .systemFont(ofSize: 52, weight: .bold)
        title.textColor = Theme.primaryText
        title.alignment = .center

        let subtitle = NSTextField(labelWithString: "Unlock unlimited access to premium tools and boost your productivity.")
        subtitle.font = .systemFont(ofSize: 15, weight: .medium)
        subtitle.textColor = Theme.secondaryText
        subtitle.alignment = .center

        let cardsRow = NSStackView(views: plans.map(makePricingCard(_:)))
        cardsRow.orientation = .horizontal
        cardsRow.spacing = 14
        cardsRow.alignment = .top
        cardsRow.distribution = .fillEqually
        cardsRow.translatesAutoresizingMaskIntoConstraints = false

        let trustRow = makeTrustRow()
        let footerRow = makeFooterRow()

        let root = NSStackView(views: [crownIcon, title, subtitle, cardsRow, trustRow, footerRow])
        root.orientation = .vertical
        root.spacing = 18
        root.alignment = .centerX
        root.translatesAutoresizingMaskIntoConstraints = false

        view.addSubview(root)
        NSLayoutConstraint.activate([
            root.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 24),
            root.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -24),
            root.topAnchor.constraint(equalTo: view.topAnchor, constant: 20),
            root.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -16),
            cardsRow.widthAnchor.constraint(equalTo: root.widthAnchor),
            cardsRow.heightAnchor.constraint(equalToConstant: 420),
            trustRow.widthAnchor.constraint(equalTo: root.widthAnchor),
            footerRow.widthAnchor.constraint(equalTo: root.widthAnchor),
            crownIcon.heightAnchor.constraint(equalToConstant: 20)
        ])
    }

    private func makePricingCard(_ plan: Plan) -> NSView {
        let card = NSView()
        card.translatesAutoresizingMaskIntoConstraints = false
        card.wantsLayer = true
        card.layer?.backgroundColor = Theme.cardBackground.cgColor
        card.layer?.cornerRadius = 16
        card.layer?.borderWidth = plan.highlight ? 2 : 1
        card.layer?.borderColor = (plan.highlight ? Theme.accent : Theme.cardBorder).cgColor

        let iconWell = NSView()
        iconWell.translatesAutoresizingMaskIntoConstraints = false
        iconWell.wantsLayer = true
        iconWell.layer?.cornerRadius = 10
        iconWell.layer?.backgroundColor = Theme.bottomStrip.cgColor
        iconWell.widthAnchor.constraint(equalToConstant: 24).isActive = true
        iconWell.heightAnchor.constraint(equalToConstant: 24).isActive = true

        let icon = NSImageView()
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 11, weight: .bold)
        icon.image = NSImage(systemSymbolName: plan.iconName, accessibilityDescription: nil)
        icon.contentTintColor = plan.iconTint
        iconWell.addSubview(icon)
        NSLayoutConstraint.activate([
            icon.centerXAnchor.constraint(equalTo: iconWell.centerXAnchor),
            icon.centerYAnchor.constraint(equalTo: iconWell.centerYAnchor)
        ])

        let titleLabel = NSTextField(labelWithString: plan.title)
        titleLabel.font = .systemFont(ofSize: 44, weight: .bold)
        titleLabel.textColor = Theme.primaryText
        titleLabel.alignment = .center

        let subtitleLabel = NSTextField(labelWithString: plan.subtitle)
        subtitleLabel.font = .systemFont(ofSize: 13, weight: .medium)
        subtitleLabel.textColor = Theme.secondaryText
        subtitleLabel.alignment = .center

        let billingPill = pillLabel(text: plan.billedPill, tint: Theme.bottomStrip, textColor: Theme.iconTint)
        billingPill.isHidden = plan.billedPill.isEmpty

        let priceLabel = NSTextField(labelWithString: plan.price)
        priceLabel.font = .systemFont(ofSize: 40, weight: .bold)
        priceLabel.textColor = Theme.primaryText

        let periodLabel = NSTextField(labelWithString: plan.period)
        periodLabel.font = .systemFont(ofSize: 30, weight: .semibold)
        periodLabel.textColor = Theme.secondaryText

        let priceRow = NSStackView(views: [priceLabel, periodLabel])
        priceRow.orientation = .horizontal
        priceRow.spacing = 4
        priceRow.alignment = .firstBaseline

        let billingLabel = NSTextField(labelWithString: plan.billedLine)
        billingLabel.font = .systemFont(ofSize: 13, weight: .medium)
        billingLabel.textColor = Theme.secondaryText
        billingLabel.isHidden = plan.billedLine.isEmpty

        let inlinePriceInfo = inlinePriceInfoLabel(oldPrice: plan.crossedPrice, newPrice: plan.savingsText)
        inlinePriceInfo.isHidden = (plan.crossedPrice == nil || plan.savingsText == nil)

        let divider = NSBox()
        divider.boxType = .separator
        divider.translatesAutoresizingMaskIntoConstraints = false
        divider.borderColor = Theme.divider

        let featuresStack = NSStackView(views: plan.features.map(makeFeatureRow(_:)))
        featuresStack.orientation = .vertical
        featuresStack.spacing = 9
        featuresStack.alignment = .leading

        let selectButton = NSButton(title: "Get \(plan.title)", target: self, action: #selector(didTapSelectPlan))
        selectButton.identifier = NSUserInterfaceItemIdentifier(plan.id)
        selectButton.isBordered = false
        selectButton.bezelStyle = .rounded
        selectButton.font = .systemFont(ofSize: 15, weight: .bold)
        selectButton.contentTintColor = plan.highlight ? .white : Theme.primaryText
        selectButton.wantsLayer = true
        selectButton.layer?.cornerRadius = 12
        selectButton.layer?.borderWidth = 1
        selectButton.layer?.borderColor = (plan.highlight ? Theme.accent : Theme.divider).cgColor
        selectButton.layer?.backgroundColor = (plan.highlight
            ? NSColor(srgbRed: 189 / 255, green: 52 / 255, blue: 255 / 255, alpha: 1)
            : Theme.mutedButtonFill).cgColor
        selectButton.translatesAutoresizingMaskIntoConstraints = false
        selectButton.heightAnchor.constraint(equalToConstant: 58).isActive = true

        let spacer = NSView()
        spacer.setContentHuggingPriority(.defaultLow, for: .vertical)

        let content = NSStackView(views: [iconWell, titleLabel, subtitleLabel, billingPill, priceRow, billingLabel, inlinePriceInfo, divider, featuresStack, spacer, selectButton])
        content.orientation = .vertical
        content.spacing = 10
        content.alignment = .centerX
        content.translatesAutoresizingMaskIntoConstraints = false
        card.addSubview(content)

        NSLayoutConstraint.activate([
            divider.widthAnchor.constraint(equalTo: content.widthAnchor),
            content.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 18),
            content.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -18),
            content.topAnchor.constraint(equalTo: card.topAnchor, constant: 14),
            content.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -16),
            selectButton.widthAnchor.constraint(equalTo: content.widthAnchor)
        ])

        if plan.highlight {
            let badgeHost = NSView()
            badgeHost.translatesAutoresizingMaskIntoConstraints = false
            badgeHost.wantsLayer = true
            badgeHost.layer?.cornerRadius = 14
            badgeHost.layer?.masksToBounds = true
            badgeHost.layer?.addSublayer(popularGradient)

            let sparkle = NSImageView()
            sparkle.translatesAutoresizingMaskIntoConstraints = false
            sparkle.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 10, weight: .semibold)
            sparkle.image = NSImage(systemSymbolName: "sparkles", accessibilityDescription: nil)
            sparkle.contentTintColor = .white

            let badge = NSTextField(labelWithString: "Most Popular")
            badge.font = .systemFont(ofSize: 12, weight: .bold)
            badge.textColor = .white

            badgeHost.addSubview(sparkle)
            badgeHost.addSubview(badge)
            card.addSubview(badgeHost)
            NSLayoutConstraint.activate([
                badgeHost.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -14),
                badgeHost.topAnchor.constraint(equalTo: card.topAnchor, constant: 10),
                badgeHost.widthAnchor.constraint(equalToConstant: 160),
                badgeHost.heightAnchor.constraint(equalToConstant: 22),
                sparkle.leadingAnchor.constraint(equalTo: badgeHost.leadingAnchor, constant: 14),
                sparkle.centerYAnchor.constraint(equalTo: badgeHost.centerYAnchor),
                badge.leadingAnchor.constraint(equalTo: sparkle.trailingAnchor, constant: 6),
                badge.centerYAnchor.constraint(equalTo: badgeHost.centerYAnchor)
            ])
        }

        return card
    }

    private func makeFeatureRow(_ text: String) -> NSView {
        let icon = NSImageView()
        icon.translatesAutoresizingMaskIntoConstraints = false
        icon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 11, weight: .bold)
        icon.image = NSImage(systemSymbolName: "checkmark.circle.fill", accessibilityDescription: nil)
        icon.contentTintColor = Theme.iconTint
        icon.widthAnchor.constraint(equalToConstant: 14).isActive = true

        let label = NSTextField(labelWithString: text)
        label.font = .systemFont(ofSize: 16, weight: .semibold)
        label.textColor = Theme.primaryText

        let row = NSStackView(views: [icon, label])
        row.orientation = .horizontal
        row.spacing = 8
        row.alignment = .centerY
        row.distribution = .fill
        return row
    }

    private func inlinePriceInfoLabel(oldPrice: String?, newPrice: String?) -> NSTextField {
        guard let oldPrice, let newPrice else {
            return NSTextField(labelWithString: "")
        }
        let full = NSMutableAttributedString()
        let oldAttributes: [NSAttributedString.Key: Any] = [
            .font: NSFont.systemFont(ofSize: 12, weight: .semibold),
            .foregroundColor: Theme.secondaryText,
            .strikethroughStyle: NSUnderlineStyle.single.rawValue
        ]
        let newAttributes: [NSAttributedString.Key: Any] = [
            .font: NSFont.systemFont(ofSize: 12, weight: .bold),
            .foregroundColor: Theme.successText
        ]
        full.append(NSAttributedString(string: "\(oldPrice)  ", attributes: oldAttributes))
        full.append(NSAttributedString(string: newPrice, attributes: newAttributes))
        let label = NSTextField(labelWithAttributedString: full)
        return label
    }

    private func pillLabel(text: String, tint: NSColor, textColor: NSColor) -> NSTextField {
        let pill = NSTextField(labelWithString: text)
        pill.font = .systemFont(ofSize: 10, weight: .semibold)
        pill.textColor = textColor
        pill.alignment = .center
        pill.wantsLayer = true
        pill.layer?.backgroundColor = tint.cgColor
        pill.layer?.cornerRadius = 9
        pill.translatesAutoresizingMaskIntoConstraints = false
        pill.heightAnchor.constraint(equalToConstant: 18).isActive = true
        pill.widthAnchor.constraint(greaterThanOrEqualToConstant: 95).isActive = true
        return pill
    }

    private func makeTrustRow() -> NSView {
        let badges = NSStackView(views: [
            trustBadge(icon: "shield.fill", title: "Secure Payments", subtitle: "Your payment is 100% secure."),
            trustBadge(icon: "arrow.counterclockwise", title: "Cancel Anytime", subtitle: "No commitment, cancel anytime."),
            trustBadge(icon: "headphones", title: "24/7 Support", subtitle: "We're here to help you anytime."),
            trustBadge(icon: "lock.fill", title: "Privacy First", subtitle: "Your data is safe with us.")
        ])
        badges.orientation = .horizontal
        badges.alignment = .centerY
        badges.distribution = .fillEqually
        badges.spacing = 12
        badges.edgeInsets = NSEdgeInsets(top: 0, left: 8, bottom: 0, right: 8)
        badges.translatesAutoresizingMaskIntoConstraints = false
        badges.wantsLayer = true
        badges.layer?.backgroundColor = Theme.bottomStrip.cgColor
        badges.layer?.borderColor = Theme.divider.cgColor
        badges.layer?.borderWidth = 1
        badges.layer?.cornerRadius = 10
        badges.setHuggingPriority(.defaultLow, for: .horizontal)
        badges.heightAnchor.constraint(equalToConstant: 72).isActive = true
        return badges
    }

    private func makeFooterRow() -> NSView {
        let items = [
            "Manage Subscription",
            "Restore Purchase",
            "Privacy Policy",
            "Terms of Services",
            "Support"
        ]

        let cells = items.enumerated().map { index, text in
            footerCell(text: text, showsTrailingDivider: index < items.count - 1)
        }

        let links = NSStackView(views: cells)
        links.orientation = .horizontal
        links.distribution = .fillEqually
        links.spacing = 0
        links.alignment = .centerY
        links.translatesAutoresizingMaskIntoConstraints = false
        return links
    }

    private func footerCell(text: String, showsTrailingDivider: Bool) -> NSView {
        let container = NSView()
        container.translatesAutoresizingMaskIntoConstraints = false

        let label = footerLink(text)
        label.translatesAutoresizingMaskIntoConstraints = false
        label.alignment = .center
        container.addSubview(label)

        var constraints = [
            label.centerXAnchor.constraint(equalTo: container.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: container.centerYAnchor)
        ]

        if showsTrailingDivider {
            let divider = footerDivider()
            container.addSubview(divider)
            constraints.append(contentsOf: [
                divider.trailingAnchor.constraint(equalTo: container.trailingAnchor),
                divider.centerYAnchor.constraint(equalTo: container.centerYAnchor)
            ])
        }

        NSLayoutConstraint.activate(constraints)
        return container
    }

    private func trustBadge(icon: String, title: String, subtitle: String) -> NSView {
        let image = NSImageView()
        image.translatesAutoresizingMaskIntoConstraints = false
        image.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 12, weight: .semibold)
        image.image = NSImage(systemSymbolName: icon, accessibilityDescription: nil)
        image.contentTintColor = Theme.primaryText

        let titleLabel = NSTextField(labelWithString: title)
        titleLabel.font = .systemFont(ofSize: 12, weight: .bold)
        titleLabel.textColor = Theme.primaryText
        let subtitleLabel = NSTextField(labelWithString: subtitle)
        subtitleLabel.font = .systemFont(ofSize: 10, weight: .medium)
        subtitleLabel.textColor = Theme.secondaryText

        let textStack = NSStackView(views: [titleLabel, subtitleLabel])
        textStack.orientation = .vertical
        textStack.spacing = 2
        textStack.alignment = .leading

        let stack = NSStackView(views: [image, textStack])
        stack.orientation = .horizontal
        stack.spacing = 8
        stack.alignment = .leading
        stack.edgeInsets = NSEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
        stack.wantsLayer = true
        stack.layer?.backgroundColor = NSColor.clear.cgColor
        return stack
    }

    private func footerLink(_ text: String) -> NSTextField {
        let label = NSTextField(labelWithString: text)
        label.font = .systemFont(ofSize: 12, weight: .medium)
        label.textColor = Theme.secondaryText
        return label
    }

    private func footerDivider() -> NSBox {
        let divider = NSBox()
        divider.boxType = .separator
        divider.borderColor = Theme.divider
        divider.translatesAutoresizingMaskIntoConstraints = false
        divider.widthAnchor.constraint(equalToConstant: 1).isActive = true
        divider.heightAnchor.constraint(equalToConstant: 14).isActive = true
        return divider
    }

    @objc private func didTapSelectPlan(_ sender: NSButton) {
        sender.layer?.backgroundColor = Theme.accentHover.cgColor
        let selectedPlan = sender.identifier?.rawValue ?? sender.title

        let alert = NSAlert()
        alert.messageText = "Premium checkout coming soon"
        alert.informativeText = "Plan selected: \(selectedPlan.capitalized). Payment flow can be connected next."
        alert.alertStyle = .informational
        alert.addButton(withTitle: "OK")
        if let window = view.window {
            alert.beginSheetModal(for: window)
        } else {
            alert.runModal()
        }
    }
}