SingleFileApp.swift

import Cocoa
import AVFoundation

// MARK: - Automation Logic

struct Automation {
    static func selectHeadPointerCamera(named cameraName: String) {
        let scriptSource = """
        tell application "System Settings" to activate
        open location "x-apple.systempreferences:com.apple.Accessibility-Settings.extension?PointerControl"
        tell application "System Events"
            tell application process "System Settings"
                repeat until exists (window "Pointer Control")
                    delay 0.5
                end repeat
                tell window "Pointer Control"
                    try
                        set rightGroup to group 1 of scroll area 1 of group 1 of splitter group 1 of group 1
                        set foundRow to missing value
                        repeat with uiGroup in groups of rightGroup
                            if (exists static text "Head pointer" of uiGroup) then
                                set foundRow to uiGroup
                                exit repeat
                            end if
                        end repeat
                        if foundRow is missing value then
                            display dialog "Could not find 'Head pointer' settings row." buttons {"OK"} default button "OK"
                            return
                        end if
                        click button 1 of foundRow
                        repeat until exists sheet 1
                            delay 0.1
                        end repeat
                        tell sheet 1
                            if (exists button "Camera Options…" of group 1 of scroll area 1) then
                                click button "Camera Options…" of group 1 of scroll area 1
                                delay 0.5
                            end if
                            set foundPopup to missing value
                            try
                                set foundPopup to pop up button "Camera" of group 1 of scroll area 1
                            on error
                                try
                                    set foundPopup to pop up button 1 of group 1 of scroll area 1
                                end try
                            end try
                            if foundPopup is not missing value then
                                click foundPopup
                                delay 0.2
                                click menu item "\(cameraName)" of menu 1 of foundPopup
                            else
                                display dialog "Could not find Camera selection menu."
                            end if
                            if exists button "OK" then
                                click button "OK"
                            else if exists button "Done" then
                                click button "Done"
                            end if
                        end tell
                    on error errMsg
                        display dialog "Automation Error: " & errMsg
                    end try
                end tell
            end tell
        end tell
        """
        
        var error: NSDictionary?
        if let scriptObject = NSAppleScript(source: scriptSource) {
            scriptObject.executeAndReturnError(&error)
        }
        if let err = error {
            print("AppleScript Exec Error: \(err)")
        }
    }
}

// MARK: - App Delegate & Main

class AppDelegate: NSObject, NSApplicationDelegate {
    var statusItem: NSStatusItem!
    var cameraDiscovery: AVCaptureDevice.DiscoverySession!

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
        if let button = statusItem.button {
            button.image = NSImage(systemSymbolName: "video.fill", accessibilityDescription: "Camera Switcher")
        }

        cameraDiscovery = AVCaptureDevice.DiscoverySession(
            deviceTypes: [.builtInWideAngleCamera, .externalUnknown],
            mediaType: .video,
            position: .unspecified
        )

        constructMenu()
        
        NotificationCenter.default.addObserver(self, selector: #selector(deviceChanged), name: .AVCaptureDeviceWasConnected, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(deviceChanged), name: .AVCaptureDeviceWasDisconnected, object: nil)
    }

    @objc func deviceChanged() {
        DispatchQueue.main.async {
            self.constructMenu()
        }
    }

    func constructMenu() {
        let menu = NSMenu()
        menu.addItem(NSMenuItem(title: "Head Pointer Camera", action: nil, keyEquivalent: ""))
        menu.addItem(NSMenuItem.separator())

        let devices = cameraDiscovery.devices
        
        if devices.isEmpty {
            menu.addItem(NSMenuItem(title: "No Cameras Found", action: nil, keyEquivalent: ""))
        } else {
            for device in devices {
                let item = NSMenuItem(title: device.localizedName, action: #selector(cameraSelected(_:)), keyEquivalent: "")
                item.target = self
                item.representedObject = device.localizedName
                menu.addItem(item)
            }
        }

        menu.addItem(NSMenuItem.separator())
        menu.addItem(NSMenuItem(title: "Quit", action: #selector(quitApp), keyEquivalent: "q"))

        statusItem.menu = menu
    }

    @objc func cameraSelected(_ sender: NSMenuItem) {
        guard let cameraName = sender.representedObject as? String else { return }
        print("Switching to camera: \(cameraName)")
        
        DispatchQueue.global(qos: .userInitiated).async {
            Automation.selectHeadPointerCamera(named: cameraName)
        }
    }

    @objc func quitApp() {
        NSApplication.shared.terminate(self)
    }
}

// Application Entry Point
let app = NSApplication.shared
let delegate = AppDelegate()
app.delegate = delegate
_ = NSApplicationMain(CommandLine.argc, CommandLine.unsafeArgv)