import AppKit

@MainActor
final class AppDelegate: NSObject, NSApplicationDelegate, NSTableViewDataSource, NSTableViewDelegate {
    private var window: NSWindow!
    private var sidebarItems = ["First sidebar row", "Second row", "Third row", "Fourth row", "Fifth row"]
    private var contentDataSources: [ContentListDataSource] = []
    private let initialWindowSize = NSSize(width: 1180, height: 820)
    private let requestedAccessoryHeight: CGFloat = 36

    func applicationDidFinishLaunching(_ notification: Notification) {
        NSApp.setActivationPolicy(.regular)

        window = NSWindow(
            contentRect: NSRect(origin: .zero, size: initialWindowSize),
            styleMask: [.titled, .closable, .resizable, .miniaturizable, .fullSizeContentView],
            backing: .buffered,
            defer: false
        )
        window.isRestorable = false
        window.minSize = NSSize(width: 980, height: 680)
        window.title = "Accessory Repro"
        window.titleVisibility = .hidden
        window.toolbar = NSToolbar(identifier: "MainToolbar")
        window.toolbarStyle = .unified

        let splitViewController = NSSplitViewController()
        let sidebarItem = NSSplitViewItem(sidebarWithViewController: makeSidebarController())
        sidebarItem.minimumThickness = 240
        sidebarItem.maximumThickness = 240
        sidebarItem.canCollapse = false

        let titlebarContentItem = NSSplitViewItem(viewController: makeContentController(
            title: "Content below window titlebar accessory",
            rowPrefix: "Titlebar accessory content row"
        ))
        titlebarContentItem.minimumThickness = 430

        let splitContentItem = NSSplitViewItem(viewController: makeContentController(
            title: "Content below split-view accessory",
            rowPrefix: "Split accessory content row"
        ))
        splitContentItem.minimumThickness = 430
        splitContentItem.addTopAlignedAccessoryViewController(makeSplitAccessoryController())

        splitViewController.addSplitViewItem(sidebarItem)
        splitViewController.addSplitViewItem(titlebarContentItem)
        splitViewController.addSplitViewItem(splitContentItem)
        window.contentViewController = splitViewController
        splitViewController.splitView.setPosition(240, ofDividerAt: 0)
        splitViewController.splitView.setPosition(710, ofDividerAt: 1)

        window.addTitlebarAccessoryViewController(makeTitlebarAccessoryController())
        applyInitialWindowFrame()
        window.makeKeyAndOrderFront(nil)
        NSApp.activate(ignoringOtherApps: true)
    }

    func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
        true
    }

    private func makeSidebarController() -> NSViewController {
        let tableView = NSTableView()
        tableView.headerView = nil
        tableView.rowSizeStyle = .large
        tableView.dataSource = self
        tableView.delegate = self

        let column = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("SidebarColumn"))
        tableView.addTableColumn(column)

        let scrollView = NSScrollView()
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.documentView = tableView
        scrollView.hasVerticalScroller = true
        scrollView.drawsBackground = false

        let viewController = NSViewController()
        viewController.view = NSView()
        viewController.view.addSubview(scrollView)

        NSLayoutConstraint.activate([
            scrollView.leadingAnchor.constraint(equalTo: viewController.view.safeAreaLayoutGuide.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: viewController.view.safeAreaLayoutGuide.trailingAnchor),
            scrollView.topAnchor.constraint(equalTo: viewController.view.safeAreaLayoutGuide.topAnchor),
            scrollView.bottomAnchor.constraint(equalTo: viewController.view.safeAreaLayoutGuide.bottomAnchor),
        ])

        return viewController
    }

    private func makeContentController(title: String, rowPrefix: String) -> NSViewController {
        let dataSource = ContentListDataSource(title: title, rowPrefix: rowPrefix)
        contentDataSources.append(dataSource)

        let tableView = NSTableView()
        tableView.headerView = nil
        tableView.rowHeight = 58
        tableView.intercellSpacing = .zero
        tableView.style = .plain
        tableView.backgroundColor = .controlBackgroundColor
        tableView.columnAutoresizingStyle = .uniformColumnAutoresizingStyle
        tableView.autoresizingMask = [.width]
        tableView.dataSource = dataSource
        tableView.delegate = dataSource

        let column = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("ContentColumn"))
        column.resizingMask = .autoresizingMask
        tableView.addTableColumn(column)

        let scrollView = NSScrollView()
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.documentView = tableView
        scrollView.hasVerticalScroller = true
        scrollView.drawsBackground = true
        scrollView.backgroundColor = .controlBackgroundColor

        let viewController = NSViewController()
        viewController.view = scrollView
        return viewController
    }

    private func applyInitialWindowFrame() {
        let visibleFrame = window.screen?.visibleFrame ?? NSScreen.main?.visibleFrame ?? NSRect(x: 0, y: 0, width: 1180, height: 820)
        let width = min(initialWindowSize.width, visibleFrame.width - 40)
        let height = min(initialWindowSize.height, visibleFrame.height - 40)
        let frame = NSRect(
            x: visibleFrame.midX - width / 2,
            y: visibleFrame.midY - height / 2,
            width: width,
            height: height
        )
        window.setFrame(frame, display: true)
    }

    private func makeTitlebarAccessoryController() -> NSTitlebarAccessoryViewController {
        let titlebarAccessory = NSTitlebarAccessoryViewController()
        titlebarAccessory.view = makeAccessoryBar(title: "NSTitlebarAccessoryViewController")
        titlebarAccessory.fullScreenMinHeight = titlebarAccessory.view.fittingSize.height
        if #available(macOS 26.1, *) {
            titlebarAccessory.preferredScrollEdgeEffectStyle = .hard
        }
        return titlebarAccessory
    }

    private func makeSplitAccessoryController() -> NSSplitViewItemAccessoryViewController {
        let splitAccessory = NSSplitViewItemAccessoryViewController()
        splitAccessory.view = makeAccessoryBar(title: "NSSplitViewItemAccessoryViewController")
        splitAccessory.automaticallyAppliesContentInsets = true
        if #available(macOS 26.1, *) {
            splitAccessory.preferredScrollEdgeEffectStyle = .hard
        }
        return splitAccessory
    }

    private func makeAccessoryBar(title: String) -> NSView {
        let view = AccessoryHeightDebugView(title: title, requestedHeight: requestedAccessoryHeight)
        view.frame = NSRect(x: 0, y: 0, width: 540, height: requestedAccessoryHeight)
        return view
    }

    func numberOfRows(in tableView: NSTableView) -> Int {
        sidebarItems.count
    }

    func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
        let textField = NSTextField(labelWithString: sidebarItems[row])
        textField.font = .preferredFont(forTextStyle: .body)

        let cellView = NSTableCellView()
        cellView.addSubview(textField)
        textField.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            textField.leadingAnchor.constraint(equalTo: cellView.leadingAnchor, constant: 18),
            textField.trailingAnchor.constraint(equalTo: cellView.trailingAnchor, constant: -12),
            textField.centerYAnchor.constraint(equalTo: cellView.centerYAnchor),
        ])

        return cellView
    }
}

@MainActor
final class AccessoryHeightDebugView: NSView {
    private let requestedHeight: CGFloat
    private let heightLabel = NSTextField(labelWithString: "")

    init(title: String, requestedHeight: CGFloat) {
        self.requestedHeight = requestedHeight
        super.init(frame: NSRect(x: 0, y: 0, width: 540, height: requestedHeight))
        wantsLayer = true
        layer?.backgroundColor = NSColor.systemRed.withAlphaComponent(0.1).cgColor

        let titleLabel = NSTextField(labelWithString: title)
        titleLabel.font = .preferredFont(forTextStyle: .body)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false

        heightLabel.font = .monospacedSystemFont(ofSize: 11, weight: .regular)
        heightLabel.textColor = .secondaryLabelColor
        heightLabel.translatesAutoresizingMaskIntoConstraints = false

        let spacer = NSView()
        spacer.translatesAutoresizingMaskIntoConstraints = false

        let stackView = NSStackView(views: [titleLabel, spacer, heightLabel])
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.orientation = .horizontal
        stackView.alignment = .centerY
        stackView.spacing = 12
        stackView.edgeInsets = NSEdgeInsets(top: 6, left: 12, bottom: 6, right: 12)

        addSubview(stackView)

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

        updateHeightLabel()
    }

    required init?(coder: NSCoder) {
        nil
    }

    override var intrinsicContentSize: NSSize {
        NSSize(width: 540, height: requestedHeight)
    }

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

    private func updateHeightLabel() {
        heightLabel.stringValue = String(format: "requested %.0f pt, actual %.1f pt", requestedHeight, bounds.height)
    }

}

@MainActor
final class ContentListDataSource: NSObject, NSTableViewDataSource, NSTableViewDelegate {
    private let title: String
    private let rowPrefix: String

    init(title: String, rowPrefix: String) {
        self.title = title
        self.rowPrefix = rowPrefix
    }

    func numberOfRows(in tableView: NSTableView) -> Int {
        91
    }

    func tableView(_ tableView: NSTableView, heightOfRow row: Int) -> CGFloat {
        row == 0 ? 44 : 58
    }

    func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
        if row == 0 {
            return makeRowView(primaryText: title, secondaryText: "Full-width table row header", row: row, isHeader: true)
        }

        let index = row
        let secondaryText = index <= 3 ? "Top row marker - scroll to watch this pass under the accessory" : "Scrollable list item"
        return makeRowView(primaryText: "\(rowPrefix) \(index)", secondaryText: secondaryText, row: row, isHeader: false)
    }

    private func makeRowView(primaryText: String, secondaryText: String, row: Int, isHeader: Bool) -> NSView {
        let primaryLabel = NSTextField(labelWithString: primaryText)
        primaryLabel.font = isHeader
            ? .preferredFont(forTextStyle: .headline)
            : .monospacedSystemFont(ofSize: 14, weight: row <= 3 ? .bold : .regular)
        primaryLabel.translatesAutoresizingMaskIntoConstraints = false

        let secondaryLabel = NSTextField(labelWithString: secondaryText)
        secondaryLabel.font = .preferredFont(forTextStyle: .caption1)
        secondaryLabel.textColor = .secondaryLabelColor
        secondaryLabel.translatesAutoresizingMaskIntoConstraints = false

        let stackView = NSStackView(views: [primaryLabel, secondaryLabel])
        stackView.translatesAutoresizingMaskIntoConstraints = false
        stackView.orientation = .vertical
        stackView.alignment = .leading
        stackView.spacing = 2

        let cellView = NSTableCellView()
        cellView.addSubview(stackView)

        NSLayoutConstraint.activate([
            stackView.leadingAnchor.constraint(equalTo: cellView.leadingAnchor, constant: 20),
            stackView.trailingAnchor.constraint(equalTo: cellView.trailingAnchor, constant: -20),
            stackView.centerYAnchor.constraint(equalTo: cellView.centerYAnchor),
        ])

        return cellView
    }
}