ghostty/macos/Sources/Features/Terminal/TerminalToolbar.swift

import Cocoa

// Custom NSToolbar subclass that displays a centered window title,
// in order to accommodate the titlebar tabs feature.
class TerminalToolbar: NSToolbar, NSToolbarDelegate {
    static private let identifier = NSToolbarItem.Identifier("TitleText")
    private let titleTextField = NSTextField(labelWithString: "👻 Ghostty")
    
    var titleText: String {
        get {
            titleTextField.stringValue
        }
        
        set {
            titleTextField.stringValue = newValue
        }
    }
    
    override init(identifier: NSToolbar.Identifier) {
        super.init(identifier: identifier)
        
        delegate = self
        
        if #available(macOS 13.0, *) {
            centeredItemIdentifiers.insert(Self.identifier)
        } else {
            centeredItemIdentifier = Self.identifier
        }
    }
    
    func toolbar(_ toolbar: NSToolbar,
                 itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier,
                 willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? {
        guard itemIdentifier == Self.identifier else { return nil }
        
        let toolbarItem = NSToolbarItem(itemIdentifier: itemIdentifier)
        toolbarItem.isEnabled = true
        toolbarItem.view = self.titleTextField
        return toolbarItem
    }
    
    func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [Self.identifier]
    }
    
    func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
        return [Self.identifier]
    }
}