Function to setup global shortcuts in MacOS apps - somewhat incomplete, written before moving to HotKeys

GlobalShortcutMacOS.swift

    /// Sets up the global shortcuts (currently, just Cmd+Shift+ç)
    ///
    /// References:
    /// https://developer.apple.com/forums/thread/707680?answerId=716892022#716892022
    /// https://developer.apple.com/documentation/coregraphics/cgevent/1454426-tapcreate
    /// https://stackoverflow.com/a/55617464/28296770
    func setupGlobalShortcuts() -> CFMachPort? {
        // TODO: store in UserSettings if it is the first time the user is opening the app
        // if it is, use CGRequestListenEventAccess, otherwise, just check with Preflight
        let keyDownEventMask = CGEventMask(1 << CGEventType.keyDown.rawValue)
        let eventTap = CGEvent.tapCreate(
            tap: .cgSessionEventTap,
            place: .headInsertEventTap,
            options: .listenOnly,
            eventsOfInterest: keyDownEventMask,
            callback: {
                _, type, event, refcon in
                // If the userInfo (i.e. self) was not passed, don't even try to handle the event
                guard let refcon else { return Unmanaged.passUnretained(event)}

                // If the event is not a key-down event, don't handle it
                guard type == .keyDown else { return Unmanaged.passUnretained(event) }

                // Convert the raw flags into NSEvent.ModifierFlags
                // and intersect with deviceIndependentFlagsMask to extract things like Cmd+Shift
                let modifierFlags = NSEvent.ModifierFlags(rawValue: UInt(event.flags.rawValue)).intersection(NSEvent.ModifierFlags.deviceIndependentFlagsMask)
                // Get the event keycode (finding out the correct keycode is pure chaos)
                let keyCode = event.getIntegerValueField(.keyboardEventKeycode)
                // 41 is the magic keycode for ç
                if keyCode == 41 && modifierFlags == [.shift, .command] {
                    // takeUnretained doesn't lower the refcount here, which is practical
                    // since we don't want to be responsible for releasing the object later
                    let appDelegate = Unmanaged<AppDelegate>.fromOpaque(refcon).takeUnretainedValue()
                    appDelegate.showWindowIfPossible()
                }
                return nil
            },
            // passRetained "increases" the refcount of self, keeping it alive
            userInfo: Unmanaged<AppDelegate>.passRetained(self).toOpaque()
        )
        
        if let eventTap {
            let runLoopSource = CFMachPortCreateRunLoopSource(nil, eventTap, 0)
            CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, .commonModes)
            CGEvent.tapEnable(tap: eventTap, enable: true)
        } else {
            // Show a modal explaining to the user that we need the permissions
            let alert = NSAlert()
            alert.messageText = "Application requires Accessibility permissions to setup global shortcuts"
            alert.alertStyle = .warning
            alert.runModal()
                
            // If the user restarted the app, this doesn't run
            // if the user didn't restart the app, this runs and the shortcut is not set
            return nil
        }
        
        return eventTap
    }