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

import Cocoa
import QuartzCore

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 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 linkText = NSColor(calibratedWhite: 0.82, alpha: 1)
    }

    private let contentStack = NSStackView()
    private let documentContainer = NSView()
    private let chromeContainer = NSView()
    private let sidebar = NSStackView()
    private let mainHost = NSView()
    private let mainGradient = NeutralGradientBackgroundView()
    private let mainOverlay = NSStackView()
    private let greetingLabel = NSTextField(labelWithString: "")
    private let subtitleLabel = NSTextField(labelWithString: "")
    private let insightsCard = NSView()
    private let insightsTitleLabel = NSTextField(labelWithString: "")
    private let insightsBodyLabel = NSTextField(labelWithString: "")
    private let insightsLinkButton = NSButton(title: "", target: nil, action: nil)
    private let togglesLabel = NSTextField(labelWithString: "Dashboard Toggles:")
    private let savedToggleButton = NSButton(title: "Saved", target: nil, action: nil)
    private let interviewsToggleButton = NSButton(title: "Interviews", target: nil, action: nil)
    private let sparkleView = NSImageView()
    private let scrollView = NSScrollView()

    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 back, \(data.greetingName)! 👋"
        subtitleLabel.stringValue = data.subtitle
        insightsTitleLabel.stringValue = data.profileInsightsTitle
        insightsBodyLabel.stringValue = data.profileInsightsBody
        insightsLinkButton.title = data.profileInsightsLinkTitle
        configureSidebar(data.sidebarItems)
        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 = .top
        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 = 18
        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

        mainGradient.translatesAutoresizingMaskIntoConstraints = false
        mainGradient.wantsLayer = true
        mainGradient.layer?.cornerRadius = 16
        mainGradient.layer?.masksToBounds = true

        mainHost.addSubview(mainGradient)
        mainHost.addSubview(mainOverlay)

        mainOverlay.orientation = .vertical
        mainOverlay.spacing = 0
        mainOverlay.alignment = .centerX
        mainOverlay.translatesAutoresizingMaskIntoConstraints = false
        mainOverlay.setContentHuggingPriority(.required, 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

        configureInsightsCard()

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

        let headerStack = NSStackView(views: [titleBlock, insightsLinkButton])
        headerStack.orientation = .vertical
        headerStack.spacing = 18
        headerStack.alignment = .centerX

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

        mainOverlay.addArrangedSubview(topInset)
        mainOverlay.addArrangedSubview(headerStack)
        mainOverlay.addArrangedSubview(midSpacer)
        mainOverlay.addArrangedSubview(insightsCard)

        sparkleView.translatesAutoresizingMaskIntoConstraints = false
        sparkleView.symbolConfiguration = NSImage.SymbolConfiguration(pointSize: 22, weight: .regular)
        sparkleView.image = NSImage(systemSymbolName: "sparkle", accessibilityDescription: "Accent")
        sparkleView.contentTintColor = NSColor(calibratedWhite: 0.9, alpha: 0.55)
        mainHost.addSubview(sparkleView)

        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.topAnchor.constraint(equalTo: documentContainer.topAnchor, constant: 18),
            chromeContainer.bottomAnchor.constraint(equalTo: documentContainer.bottomAnchor, constant: -18),
            chromeContainer.centerXAnchor.constraint(equalTo: documentContainer.centerXAnchor),
            chromeContainer.widthAnchor.constraint(lessThanOrEqualToConstant: 1240),
            chromeContainer.widthAnchor.constraint(equalTo: documentContainer.widthAnchor, constant: -36),

            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),

            mainGradient.leadingAnchor.constraint(equalTo: mainHost.leadingAnchor),
            mainGradient.trailingAnchor.constraint(equalTo: mainHost.trailingAnchor),
            mainGradient.topAnchor.constraint(equalTo: mainHost.topAnchor),
            mainGradient.bottomAnchor.constraint(equalTo: mainHost.bottomAnchor),

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

            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),
            insightsLinkButton.leadingAnchor.constraint(equalTo: greetingLabel.leadingAnchor),
            insightsLinkButton.trailingAnchor.constraint(equalTo: greetingLabel.trailingAnchor),

            sparkleView.trailingAnchor.constraint(equalTo: mainHost.trailingAnchor, constant: -28),
            sparkleView.bottomAnchor.constraint(equalTo: mainHost.bottomAnchor, constant: -28)
        ])
    }

    private func configureInsightsCard() {
        insightsCard.wantsLayer = true
        insightsCard.layer?.backgroundColor = Theme.cardBackground.cgColor
        insightsCard.layer?.cornerRadius = 18
        insightsCard.translatesAutoresizingMaskIntoConstraints = false

        insightsTitleLabel.font = .systemFont(ofSize: 20, weight: .semibold)
        insightsTitleLabel.textColor = Theme.primaryText
        insightsTitleLabel.alignment = .center
        insightsTitleLabel.maximumNumberOfLines = 1

        insightsBodyLabel.font = .systemFont(ofSize: 13, weight: .regular)
        insightsBodyLabel.textColor = Theme.secondaryText
        insightsBodyLabel.alignment = .center
        insightsBodyLabel.maximumNumberOfLines = 4
        insightsBodyLabel.lineBreakMode = .byWordWrapping
        insightsBodyLabel.preferredMaxLayoutWidth = 400

        insightsLinkButton.bezelStyle = .inline
        insightsLinkButton.isBordered = false
        insightsLinkButton.font = .systemFont(ofSize: 13, weight: .medium)
        insightsLinkButton.contentTintColor = Theme.linkText
        insightsLinkButton.setButtonType(.momentaryPushIn)

        togglesLabel.font = .systemFont(ofSize: 12, weight: .medium)
        togglesLabel.textColor = Theme.tertiaryText
        togglesLabel.alignment = .center
        togglesLabel.maximumNumberOfLines = 1

        styleToggle(savedToggleButton)
        styleToggle(interviewsToggleButton)

        let toggleRow = NSStackView(views: [savedToggleButton, interviewsToggleButton])
        toggleRow.orientation = .horizontal
        toggleRow.spacing = 10
        toggleRow.alignment = .centerY

        let inner = NSStackView(views: [
            insightsTitleLabel,
            insightsBodyLabel,
            togglesLabel,
            toggleRow
        ])
        inner.orientation = .vertical
        inner.spacing = 14
        inner.alignment = .centerX
        inner.translatesAutoresizingMaskIntoConstraints = false

        insightsCard.addSubview(inner)
        NSLayoutConstraint.activate([
            inner.leadingAnchor.constraint(equalTo: insightsCard.leadingAnchor, constant: 32),
            inner.trailingAnchor.constraint(equalTo: insightsCard.trailingAnchor, constant: -32),
            inner.topAnchor.constraint(equalTo: insightsCard.topAnchor, constant: 28),
            inner.bottomAnchor.constraint(equalTo: insightsCard.bottomAnchor, constant: -28),
            insightsCard.widthAnchor.constraint(equalToConstant: 440)
        ])
    }

    private func styleToggle(_ button: NSButton) {
        button.bezelStyle = .rounded
        button.font = .systemFont(ofSize: 12, weight: .medium)
        button.contentTintColor = Theme.secondaryText
        button.wantsLayer = true
        button.layer?.backgroundColor = Theme.toggleBackground.cgColor
        button.layer?.cornerRadius = 8
        button.translatesAutoresizingMaskIntoConstraints = false
        button.widthAnchor.constraint(equalToConstant: 108).isActive = true
        button.heightAnchor.constraint(equalToConstant: 30).isActive = true
    }

    private func configureSidebar(_ items: [SidebarItem]) {
        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 row = NSStackView()
            row.orientation = .horizontal
            row.spacing = 8
            row.alignment = .centerY
            row.wantsLayer = true
            row.layer?.cornerRadius = 8
            row.edgeInsets = NSEdgeInsets(top: 8, left: 10, bottom: 8, right: 10)
            let isSelected = index == 0
            if isSelected {
                row.layer?.backgroundColor = Theme.selectionFill.cgColor
            }

            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

            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.translatesAutoresizingMaskIntoConstraints = false
                badgeField.widthAnchor.constraint(equalToConstant: 42).isActive = true
                row.addArrangedSubview(NSView())
                row.addArrangedSubview(badgeField)
            }
            sidebar.addArrangedSubview(row)
        }

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

    private func updateDocumentLayout() {
        documentContainer.layoutSubtreeIfNeeded()
        let fittingHeight = max(chromeContainer.fittingSize.height + 36, bounds.height)
        documentContainer.frame = NSRect(x: 0, y: 0, width: bounds.width, height: fittingHeight)
    }
}

// MARK: - Neutral main-area gradient (black / grey only)

private final class NeutralGradientBackgroundView: NSView {
    private let gradientLayer = CAGradientLayer()

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

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

    private func commonInit() {
        wantsLayer = true
        gradientLayer.colors = [
            NSColor(calibratedWhite: 0.12, alpha: 1).cgColor,
            NSColor(calibratedWhite: 0.05, alpha: 1).cgColor,
            NSColor.black.cgColor
        ]
        gradientLayer.locations = [0, 0.42, 1] as [NSNumber]
        gradientLayer.startPoint = CGPoint(x: 0.5, y: 1)
        gradientLayer.endPoint = CGPoint(x: 0.5, y: 0)
        layer?.addSublayer(gradientLayer)
    }

    override func layout() {
        super.layout()
        gradientLayer.frame = bounds
    }
}