ghostty/macos/Sources/Features/Terminal/Window Styles/TabsTitlebarTerminalWindow.swift

import AppKit
import SwiftUI

class TabsTitlebarTerminalWindow: TerminalWindow, NSToolbarDelegate {
    override func awakeFromNib() {
        super.awakeFromNib()

        // We must hide the title since we're going to be moving tabs into
        // the titlebar which have their own title.
        titleVisibility = .hidden

        // Create a toolbar
        let toolbar = NSToolbar(identifier: "TerminalToolbar")
        toolbar.delegate = self
        toolbar.centeredItemIdentifiers.insert(.title)
        self.toolbar = toolbar
        //toolbarStyle = .unifiedCompact
    }

    // MARK: NSToolbarDelegate

    func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [.title, .flexibleSpace, .space]
    }

    func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [.flexibleSpace, .title, .flexibleSpace]
    }

    func toolbar(_ toolbar: NSToolbar,
                 itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier,
                 willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? {
        switch itemIdentifier {
        case .title:
            let item = NSToolbarItem(itemIdentifier: .title)
            item.view = NSHostingView(rootView: TitleItem())
            item.visibilityPriority = .user
            item.isEnabled = true
            return item
        default:
            return NSToolbarItem(itemIdentifier: itemIdentifier)
        }
    }

}

extension NSToolbarItem.Identifier {
    /// Displays the title of the window
    static let title = NSToolbarItem.Identifier("Title")
}

extension TabsTitlebarTerminalWindow {
    struct TitleItem: View {
        var body: some View {
            Text("HELLO THIS IS A PRETTY LONG TITLE")
        }
    }
}