WIP Safari web extension

src/safari/desktop/ViewController.swift

@@ -1,14 +1,44 @@
 import Cocoa
+import SafariServices.SFSafariApplication
+import SafariServices.SFSafariExtensionManager
+
+let appName = "desktop"
+let extensionBundleIdentifier = "com.bitwarden.desktop.Extension"
 
 class ViewController: NSViewController {
+
+    @IBOutlet var appNameLabel: NSTextField!
+    
     override func viewDidLoad() {
         super.viewDidLoad()
-        // Do any additional setup after loading the view.
-    }
+        self.appNameLabel.stringValue = appName
+        SFSafariExtensionManager.getStateOfSafariExtension(withIdentifier: extensionBundleIdentifier) { (state, error) in
+            guard let state = state, error == nil else {
+                // Insert code to inform the user that something went wrong.
+                return
+            }
 
-    override var representedObject: Any? {
-        didSet {
-            // Update the view, if already loaded.
+            DispatchQueue.main.async {
+                if (state.isEnabled) {
+                    self.appNameLabel.stringValue = "\(appName)'s extension is currently on."
+                } else {
+                    self.appNameLabel.stringValue = "\(appName)'s extension is currently off. You can turn it on in Safari Extensions preferences."
+                }
+            }
         }
     }
+    
+    @IBAction func openSafariExtensionPreferences(_ sender: AnyObject?) {
+        SFSafariApplication.showPreferencesForExtension(withIdentifier: extensionBundleIdentifier) { error in
+            guard error == nil else {
+                // Insert code to inform the user that something went wrong.
+                return
+            }
+
+            DispatchQueue.main.async {
+                NSApplication.shared.terminate(nil)
+            }
+        }
+    }
+
 }