app_for_reddit/App AI for Reddit/Utilities/AppWindow.swift

import AppKit
import CoreGraphics

enum AppWindow {
    static let width: CGFloat = 1140
    static let height: CGFloat = 720
    static let minWidth: CGFloat = width
    static let minHeight: CGFloat = height

    /// Extra top inset for the sidebar when the window is in macOS full screen.
    static let fullScreenTopInset: CGFloat = 16

    /// Small top breathing room for the embedded Reddit panel.
    static let redditTopInset: CGFloat = 30

    @MainActor
    static func centerOnScreen(_ window: NSWindow) {
        guard !window.styleMask.contains(.fullScreen) else { return }

        let screen = NSScreen.main ?? window.screen
        guard let screen else {
            window.center()
            return
        }

        var frame = window.frame
        frame.size = NSSize(width: width, height: height)

        let visible = screen.visibleFrame
        frame.origin.x = visible.origin.x + ((visible.width - frame.width) / 2)
        frame.origin.y = visible.origin.y + ((visible.height - frame.height) / 2)

        window.setFrame(frame, display: true)
    }
}