//
//  DashboardView.swift
//  App for Indeed
//

import Cocoa

final class DashboardView: NSView {
    private enum Theme {
        static let pageBackground = NSColor(calibratedWhite: 0.02, alpha: 1)
        static let chromeBackground = NSColor(calibratedWhite: 0.04, alpha: 1)
        static let sidebarBackground = NSColor(calibratedWhite: 0.07, alpha: 1)
        static let mainHostBackground = NSColor(calibratedWhite: 0.06, alpha: 1)
        static let selectionFill = NSColor(calibratedWhite: 1, alpha: 0.1)
        static let cardBackground = NSColor(calibratedWhite: 0.11, alpha: 1)
        static let toggleBackground = NSColor(calibratedWhite: 0.16, alpha: 1)
        static let primaryText = NSColor(calibratedWhite: 0.96, alpha: 1)
        static let secondaryText = NSColor(calibratedWhite: 0.62, alpha: 1)
        static let tertiaryText = NSColor(calibratedWhite: 0.48, alpha: 1)
        static let proCardFill = NSColor(calibratedRed: 0.1, green: 0.09, blue: 0.12, alpha: 1)
        static let proCardBorder = NSColor(calibratedWhite: 1, alpha: 0.09)
        static let proAccent = NSColor(calibratedRed: 0.98, green: 0.82, blue: 0.38, alpha: 1)
        static let proCTABackground = NSColor(calibratedWhite: 0.97, alpha: 1)
        static let proCTAText = NSColor(calibratedWhite: 0.05, alpha: 1)
    }

    private let contentStack = NSStackView()
    private let documentContainer = NSView()
    private let chromeContainer = NSView()
    private let sidebar = NSStackView()
    private let mainHost = NSView()
    private let mainOverlay = NSStackView()
    private let greetingLabel = NSTextField(labelWithString: "")
    private let subtitleLabel = NSTextField(labelWithString: "")
    private let searchCard = NSView()
    private let searchIcon = NSImageView()
    private let searchField = NSTextField()
    private let scrollView = NSScrollView()

    private var currentSidebarItems: [SidebarItem] = []
    private var selectedSidebarIndex: Int = 0

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        setupLayout()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupLayout()
    }

    override func layout() {
        super.layout()
        updateDocumentLayout()
    }

    func render(_ data: DashboardData) {
        greetingLabel.stringValue = "Welcome"
        subtitleLabel.stringValue = data.subtitle
        currentSidebarItems = data.sidebarItems
        if selectedSidebarIndex >= currentSidebarItems.count {
            selectedSidebarIndex = max(0, currentSidebarItems.count - 1)
        }
        configureSidebar()
        updateDocumentLayout()
    }

    private func setupLayout() {
        wantsLayer = true
        layer?.backgroundColor = Theme.pageBackground.cgColor

        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.hasVerticalScroller = true
        scrollView.drawsBackground = false
        addSubview(scrollView)

        contentStack.orientation = .horizontal
        contentStack.spacing = 20
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        contentStack.alignment = .height
        contentStack.edgeInsets = NSEdgeInsets(top: 24, left: 24, bottom: 24, right: 24)

        documentContainer.translatesAutoresizingMaskIntoConstraints = true
        documentContainer.autoresizingMask = [.width]
        documentContainer.frame = NSRect(x: 0, y: 0, width: 1040, height: 900)
        chromeContainer.translatesAutoresizingMaskIntoConstraints = false
        chromeContainer.wantsLayer = true
        chromeContainer.layer?.backgroundColor = Theme.chromeBackground.cgColor
        chromeContainer.layer?.cornerRadius = 0
        documentContainer.addSubview(chromeContainer)
        chromeContainer.addSubview(contentStack)
        scrollView.documentView = documentContainer

        sidebar.orientation = .vertical
        sidebar.spacing = 10
        sidebar.distribution = .fill
        sidebar.alignment = .leading
        sidebar.wantsLayer = true
        sidebar.layer?.backgroundColor = Theme.sidebarBackground.cgColor
        sidebar.layer?.cornerRadius = 16
        sidebar.edgeInsets = NSEdgeInsets(top: 18, left: 14, bottom: 18, right: 14)
        sidebar.translatesAutoresizingMaskIntoConstraints = false

        mainHost.translatesAutoresizingMaskIntoConstraints = false
        mainHost.wantsLayer = true
        mainHost.layer?.backgroundColor = Theme.mainHostBackground.cgColor
        mainHost.layer?.cornerRadius = 16
        mainHost.layer?.masksToBounds = true

        mainHost.addSubview(mainOverlay)

        mainOverlay.orientation = .vertical
        mainOverlay.spacing = 0
        mainOverlay.alignment = .centerX
        mainOverlay.distribution = .fill
        mainOverlay.translatesAutoresizingMaskIntoConstraints = false
        mainOverlay.setContentHuggingPriority(.defaultLow, for: .vertical)

        greetingLabel.font = .systemFont(ofSize: 32, weight: .bold)
        greetingLabel.textColor = Theme.primaryText
        greetingLabel.alignment = .center
        greetingLabel.maximumNumberOfLines = 1

        subtitleLabel.font = .systemFont(ofSize: 15, weight: .regular)
        subtitleLabel.textColor = Theme.secondaryText
        subtitleLabel.alignment = .center
        subtitleLabel.maximumNumberOfLines = 2

        let topInset = NSView()
        topInset.translatesAutoresizingMaskIntoConstraints = false
        topInset.heightAnchor.constraint(equalToConstant: 32).isActive = true

        configureSearchCard()

        let titleBlock = NSStackView(views: [greetingLabel, subtitleLabel])
        titleBlock.orientation = .vertical
        titleBlock.spacing = 10
        titleBlock.alignment = .centerX

        let midSpacer = NSView()
        midSpacer.translatesAutoresizingMaskIntoConstraints = false
        midSpacer.heightAnchor.constraint(equalToConstant: 20).isActive = true

        let overlayBottomSpacer = NSView()
        overlayBottomSpacer.translatesAutoresizingMaskIntoConstraints = false
        overlayBottomSpacer.setContentHuggingPriority(.defaultLow, for: .vertical)
        overlayBottomSpacer.setContentCompressionResistancePriority(.defaultLow, for: .vertical)

        mainOverlay.addArrangedSubview(topInset)
        mainOverlay.addArrangedSubview(titleBlock)
        mainOverlay.addArrangedSubview(midSpacer)
        mainOverlay.addArrangedSubview(searchCard)
        mainOverlay.addArrangedSubview(overlayBottomSpacer)

        contentStack.addArrangedSubview(sidebar)
        contentStack.addArrangedSubview(mainHost)

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

            chromeContainer.leadingAnchor.constraint(equalTo: documentContainer.leadingAnchor),
            chromeContainer.trailingAnchor.constraint(equalTo: documentContainer.trailingAnchor),
            chromeContainer.topAnchor.constraint(equalTo: documentContainer.topAnchor),
            chromeContainer.bottomAnchor.constraint(equalTo: documentContainer.bottomAnchor),

            contentStack.leadingAnchor.constraint(equalTo: chromeContainer.leadingAnchor),
            contentStack.trailingAnchor.constraint(equalTo: chromeContainer.trailingAnchor),
            contentStack.topAnchor.constraint(equalTo: chromeContainer.topAnchor),
            contentStack.bottomAnchor.constraint(equalTo: chromeContainer.bottomAnchor),

            sidebar.widthAnchor.constraint(equalToConstant: 225),
            mainHost.widthAnchor.constraint(greaterThanOrEqualToConstant: 720),

            mainOverlay.leadingAnchor.constraint(equalTo: mainHost.leadingAnchor),
            mainOverlay.trailingAnchor.constraint(equalTo: mainHost.trailingAnchor),
            mainOverlay.topAnchor.constraint(equalTo: mainHost.topAnchor),
            mainOverlay.bottomAnchor.constraint(equalTo: mainHost.bottomAnchor, constant: -24),

            searchCard.widthAnchor.constraint(equalTo: mainOverlay.widthAnchor, multiplier: 0.82),

            greetingLabel.leadingAnchor.constraint(equalTo: mainOverlay.leadingAnchor, constant: 24),
            greetingLabel.trailingAnchor.constraint(equalTo: mainOverlay.trailingAnchor, constant: -24),
            subtitleLabel.leadingAnchor.constraint(equalTo: greetingLabel.leadingAnchor),
            subtitleLabel.trailingAnchor.constraint(equalTo: greetingLabel.trailingAnchor)
        ])
    }

    private func configureSearchCard() {
        searchCard.wantsLayer = true
        searchCard.layer?.backgroundColor = Theme.cardBackground.cgColor
        searchCard.layer?.cornerRadius = 14
        searchCard.layer?.borderWidth = 1
        searchCard.layer?.borderColor = NSColor(calibratedWhite: 1, alpha: 0.06).cgColor
        searchCard.translatesAutoresizingMaskIntoConstraints = false
        searchCard.setContentHuggingPriority(.defaultHigh, for: .vertical)

        searchIcon.translatesAutoresizingMaskIntoConstraints = false
        searchIcon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 15, weight: .medium)
        searchIcon.image = NSImage(systemSymbolName: "magnifyingglass", accessibilityDescription: "Search")
        searchIcon.contentTintColor = Theme.secondaryText

        searchField.translatesAutoresizingMaskIntoConstraints = false
        searchField.isBordered = false
        searchField.drawsBackground = false
        searchField.focusRingType = .none
        searchField.font = .systemFont(ofSize: 14, weight: .regular)
        searchField.textColor = Theme.primaryText
        searchField.placeholderAttributedString = NSAttributedString(
            string: "Search jobs, companies, or locations",
            attributes: [
                .foregroundColor: Theme.tertiaryText,
                .font: NSFont.systemFont(ofSize: 14, weight: .regular)
            ]
        )
        searchField.cell?.usesSingleLineMode = true
        searchField.cell?.wraps = false
        searchField.cell?.isScrollable = true
        searchField.target = self
        searchField.action = #selector(didSubmitSearch)

        searchCard.addSubview(searchIcon)
        searchCard.addSubview(searchField)

        NSLayoutConstraint.activate([
            searchCard.heightAnchor.constraint(equalToConstant: 48),

            searchIcon.leadingAnchor.constraint(equalTo: searchCard.leadingAnchor, constant: 16),
            searchIcon.centerYAnchor.constraint(equalTo: searchCard.centerYAnchor),
            searchIcon.widthAnchor.constraint(equalToConstant: 18),
            searchIcon.heightAnchor.constraint(equalToConstant: 18),

            searchField.leadingAnchor.constraint(equalTo: searchIcon.trailingAnchor, constant: 10),
            searchField.trailingAnchor.constraint(equalTo: searchCard.trailingAnchor, constant: -16),
            searchField.centerYAnchor.constraint(equalTo: searchCard.centerYAnchor)
        ])
    }

    @objc private func didSubmitSearch() {
        // Hook up search submission here when wiring up real data.
    }

    private func configureSidebar() {
        let items = currentSidebarItems
        sidebar.arrangedSubviews.forEach {
            sidebar.removeArrangedSubview($0)
            $0.removeFromSuperview()
        }

        let brand = NSTextField(labelWithString: "Indeed AI\nJob Finder")
        brand.font = .systemFont(ofSize: 18, weight: .bold)
        brand.textColor = Theme.primaryText
        brand.alignment = .left
        sidebar.addArrangedSubview(brand)

        let titleToMenuSpacer = NSView()
        titleToMenuSpacer.translatesAutoresizingMaskIntoConstraints = false
        titleToMenuSpacer.heightAnchor.constraint(equalToConstant: 24).isActive = true
        sidebar.addArrangedSubview(titleToMenuSpacer)

        items.enumerated().forEach { index, item in
            let isSelected = index == selectedSidebarIndex

            let rowHost = SidebarNavRowView { [weak self] in
                self?.selectSidebarItem(at: index)
            }
            rowHost.translatesAutoresizingMaskIntoConstraints = false
            rowHost.wantsLayer = true
            rowHost.layer?.cornerRadius = 8
            if isSelected {
                rowHost.layer?.backgroundColor = Theme.selectionFill.cgColor
            }
            rowHost.setAccessibilityLabel(item.title)
            rowHost.setAccessibilityRole(.button)
            rowHost.setAccessibilitySelected(isSelected)

            let row = NSStackView()
            row.orientation = .horizontal
            row.spacing = 8
            row.alignment = .centerY
            row.translatesAutoresizingMaskIntoConstraints = false

            let icon = NSImageView()
            icon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 13, weight: .medium)
            icon.image = NSImage(systemSymbolName: item.systemImage, accessibilityDescription: item.title)
            icon.contentTintColor = isSelected ? Theme.primaryText : Theme.secondaryText

            let text = NSTextField(labelWithString: item.title)
            text.font = .systemFont(ofSize: 14, weight: .medium)
            text.textColor = isSelected ? Theme.primaryText : Theme.secondaryText
            text.refusesFirstResponder = true

            row.addArrangedSubview(icon)
            row.addArrangedSubview(text)

            if let badge = item.badge {
                let badgeField = NSTextField(labelWithString: badge)
                badgeField.font = .systemFont(ofSize: 11, weight: .semibold)
                badgeField.textColor = Theme.primaryText
                badgeField.wantsLayer = true
                badgeField.layer?.backgroundColor = Theme.toggleBackground.cgColor
                badgeField.layer?.cornerRadius = 8
                badgeField.alignment = .center
                badgeField.maximumNumberOfLines = 1
                badgeField.lineBreakMode = .byClipping
                badgeField.refusesFirstResponder = true
                badgeField.translatesAutoresizingMaskIntoConstraints = false
                badgeField.widthAnchor.constraint(equalToConstant: 42).isActive = true
                row.addArrangedSubview(NSView())
                row.addArrangedSubview(badgeField)
            }

            rowHost.addSubview(row)
            NSLayoutConstraint.activate([
                row.leadingAnchor.constraint(equalTo: rowHost.leadingAnchor, constant: 10),
                row.trailingAnchor.constraint(equalTo: rowHost.trailingAnchor, constant: -10),
                row.topAnchor.constraint(equalTo: rowHost.topAnchor, constant: 8),
                row.bottomAnchor.constraint(equalTo: rowHost.bottomAnchor, constant: -8)
            ])
            sidebar.addArrangedSubview(rowHost)
        }

        let sidebarBottomSpacer = NSView()
        sidebarBottomSpacer.translatesAutoresizingMaskIntoConstraints = false
        sidebarBottomSpacer.setContentHuggingPriority(.defaultLow, for: .vertical)
        sidebarBottomSpacer.setContentCompressionResistancePriority(.defaultLow, for: .vertical)
        sidebar.addArrangedSubview(sidebarBottomSpacer)

        let upgradeCard = NSView()
        upgradeCard.translatesAutoresizingMaskIntoConstraints = false
        upgradeCard.wantsLayer = true
        upgradeCard.layer?.backgroundColor = Theme.proCardFill.cgColor
        upgradeCard.layer?.cornerRadius = 14
        upgradeCard.layer?.borderWidth = 1
        upgradeCard.layer?.borderColor = Theme.proCardBorder.cgColor
        upgradeCard.layer?.masksToBounds = true

        let accentBar = NSView()
        accentBar.translatesAutoresizingMaskIntoConstraints = false
        accentBar.wantsLayer = true
        accentBar.layer?.backgroundColor = Theme.proAccent.cgColor

        let inner = NSStackView()
        inner.translatesAutoresizingMaskIntoConstraints = false
        inner.orientation = .vertical
        inner.spacing = 10
        inner.alignment = .leading

        let proIcon = NSImageView()
        proIcon.translatesAutoresizingMaskIntoConstraints = false
        proIcon.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 13, weight: .semibold)
        proIcon.image = NSImage(systemSymbolName: "sparkles", accessibilityDescription: nil)
        proIcon.contentTintColor = Theme.proAccent

        let proEyebrow = NSTextField(labelWithString: "Premium")
        proEyebrow.font = .systemFont(ofSize: 11, weight: .heavy)
        proEyebrow.textColor = Theme.proAccent
        proEyebrow.alignment = .left

        let eyebrowRow = NSStackView(views: [proIcon, proEyebrow])
        eyebrowRow.orientation = .horizontal
        eyebrowRow.spacing = 6
        eyebrowRow.alignment = .centerY

        let headline = NSTextField(labelWithString: "Upgrade to Pro")
        headline.font = .systemFont(ofSize: 16, weight: .bold)
        headline.textColor = Theme.primaryText
        headline.alignment = .left

        let upgradeDescription = NSTextField(wrappingLabelWithString: "Unlimited AI matches, smart alerts, and interview prep—all in one place.")
        upgradeDescription.font = .systemFont(ofSize: 12, weight: .regular)
        upgradeDescription.textColor = Theme.secondaryText
        upgradeDescription.preferredMaxLayoutWidth = 165

        let upgradeButton = NSButton(title: "Upgrade to Pro", target: self, action: #selector(didTapUpgradeToPro))
        upgradeButton.isBordered = false
        upgradeButton.bezelStyle = .rounded
        upgradeButton.font = .systemFont(ofSize: 13, weight: .bold)
        upgradeButton.contentTintColor = Theme.proCTAText
        upgradeButton.wantsLayer = true
        upgradeButton.layer?.backgroundColor = Theme.proCTABackground.cgColor
        upgradeButton.layer?.cornerRadius = 20
        upgradeButton.translatesAutoresizingMaskIntoConstraints = false
        upgradeButton.heightAnchor.constraint(equalToConstant: 40).isActive = true

        inner.addArrangedSubview(eyebrowRow)
        inner.addArrangedSubview(headline)
        inner.addArrangedSubview(upgradeDescription)
        inner.addArrangedSubview(upgradeButton)

        upgradeCard.addSubview(accentBar)
        upgradeCard.addSubview(inner)

        let cardWidth: CGFloat = 197
        NSLayoutConstraint.activate([
            upgradeCard.widthAnchor.constraint(equalToConstant: cardWidth),

            accentBar.topAnchor.constraint(equalTo: upgradeCard.topAnchor),
            accentBar.leadingAnchor.constraint(equalTo: upgradeCard.leadingAnchor),
            accentBar.trailingAnchor.constraint(equalTo: upgradeCard.trailingAnchor),
            accentBar.heightAnchor.constraint(equalToConstant: 2),

            inner.leadingAnchor.constraint(equalTo: upgradeCard.leadingAnchor, constant: 14),
            inner.trailingAnchor.constraint(equalTo: upgradeCard.trailingAnchor, constant: -14),
            inner.topAnchor.constraint(equalTo: accentBar.bottomAnchor, constant: 12),
            inner.bottomAnchor.constraint(equalTo: upgradeCard.bottomAnchor, constant: -14),

            upgradeButton.widthAnchor.constraint(equalTo: inner.widthAnchor)
        ])

        sidebar.addArrangedSubview(upgradeCard)
    }

    @objc private func didTapUpgradeToPro() {
        guard let url = URL(string: "https://www.indeed.com") else { return }
        NSWorkspace.shared.open(url)
    }

    private func selectSidebarItem(at index: Int) {
        guard index >= 0, index < currentSidebarItems.count, index != selectedSidebarIndex else { return }
        selectedSidebarIndex = index
        configureSidebar()
    }

    private func updateDocumentLayout() {
        documentContainer.layoutSubtreeIfNeeded()
        let fittingHeight = max(chromeContainer.fittingSize.height, bounds.height)
        documentContainer.frame = NSRect(x: 0, y: 0, width: bounds.width, height: fittingHeight)
    }
}

/// Captures clicks for the full sidebar pill so icon, label, and padding behave as one tab.
private final class SidebarNavRowView: NSView {
    private let onSelect: () -> Void

    init(onSelect: @escaping () -> Void) {
        self.onSelect = onSelect
        super.init(frame: .zero)
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func hitTest(_ point: NSPoint) -> NSView? {
        guard let superview else { return super.hitTest(point) }
        let local = convert(point, from: superview)
        return bounds.contains(local) ? self : nil
    }

    override func mouseDown(with event: NSEvent) {
        onSelect()
    }

    override func updateTrackingAreas() {
        super.updateTrackingAreas()
        trackingAreas.forEach { removeTrackingArea($0) }
        addTrackingArea(NSTrackingArea(
            rect: bounds,
            options: [.activeInKeyWindow, .mouseEnteredAndExited, .inVisibleRect],
            owner: self,
            userInfo: nil
        ))
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        NSCursor.pointingHand.push()
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        NSCursor.pop()
    }
}