chore: gracefully shutdown app

Coder Desktop/Coder Desktop/Coder_DesktopApp.swift

@@ -37,6 +37,14 @@ class AppDelegate: NSObject, NSApplicationDelegate {
         }
     }
 
+    func applicationShouldTerminate(_: NSApplication) -> NSApplication.TerminateReply {
+        Task {
+            await vpn.stop()
+            NSApp.reply(toApplicationShouldTerminate: true)
+        }
+        return .terminateLater
+    }
+
     func applicationShouldTerminateAfterLastWindowClosed(_: NSApplication) -> Bool {
         false
     }

Coder Desktop/Coder Desktop/Preview Content/PreviewVPN.swift

@@ -24,27 +24,46 @@ final class PreviewVPN: Coder_Desktop.VPNService {
         self.shouldFail = shouldFail
     }
 
+    var startTask: Task<Void, Never>?
     func start() async {
-        state = .connecting
-        do {
-            try await Task.sleep(for: .seconds(10))
-        } catch {
-            state = .failed(.longTestError)
+        if await startTask?.value != nil {
             return
         }
-        state = shouldFail ? .failed(.longTestError) : .connected
+
+        startTask = Task {
+            state = .connecting
+            do {
+                try await Task.sleep(for: .seconds(5))
+            } catch {
+                state = .failed(.longTestError)
+                return
+            }
+            state = shouldFail ? .failed(.longTestError) : .connected
+        }
+        defer { startTask = nil }
+        await startTask?.value
     }
 
+    var stopTask: Task<Void, Never>?
     func stop() async {
+        await startTask?.value
         guard state == .connected else { return }
-        state = .disconnecting
-        do {
-            try await Task.sleep(for: .seconds(10))
-        } catch {
-            state = .failed(.longTestError)
+        if await stopTask?.value != nil {
             return
         }
-        state = .disabled
+
+        stopTask = Task {
+            state = .disconnecting
+            do {
+                try await Task.sleep(for: .seconds(5))
+            } catch {
+                state = .failed(.longTestError)
+                return
+            }
+            state = .disabled
+        }
+        defer { stopTask = nil }
+        await stopTask?.value
     }
 
     func configureTunnelProviderProtocol(proto _: NETunnelProviderProtocol?) {

Coder Desktop/Coder Desktop/VPNService.swift

@@ -63,20 +63,40 @@ final class CoderVPNService: NSObject, VPNService {
         installSystemExtension()
     }
 
+    var startTask: Task<Void, Never>?
     func start() async {
-        tunnelState = .connecting
-        await enableNetworkExtension()
+        if await startTask?.value != nil {
+            return
+        }
+        startTask = Task {
+            tunnelState = .connecting
+            await enableNetworkExtension()
 
-        // TODO: enable communication with the NetworkExtension to track state and agents. For
-        //       now, just pretend it worked...
-        tunnelState = .connected
+            // TODO: enable communication with the NetworkExtension to track state and agents. For
+            //       now, just pretend it worked...
+            tunnelState = .connected
+        }
+        defer { startTask = nil }
+        await startTask?.value
     }
 
+    var stopTask: Task<Void, Never>?
     func stop() async {
-        tunnelState = .disconnecting
-        await disableNetworkExtension()
-        // TODO: determine when the NetworkExtension is completely disconnected
-        tunnelState = .disabled
+        // Wait for a start operation to finish first
+        await startTask?.value
+        guard state == .connected else { return }
+        if await stopTask?.value != nil {
+            return
+        }
+        stopTask = Task {
+            tunnelState = .disconnecting
+            await disableNetworkExtension()
+
+            // TODO: determine when the NetworkExtension is completely disconnected
+            tunnelState = .disabled
+        }
+        defer { stopTask = nil }
+        await stopTask?.value
     }
 
     func configureTunnelProviderProtocol(proto: NETunnelProviderProtocol?) {

Coder Desktop/Coder Desktop/Views/VPNMenu.swift

@@ -59,10 +59,7 @@ struct VPNMenu<VPN: VPNService, S: Session>: View {
                 }.buttonStyle(.plain)
                 TrayDivider()
                 Button {
-                    Task {
-                        await vpn.stop()
-                        NSApp.terminate(nil)
-                    }
+                    NSApp.terminate(nil)
                 } label: {
                     ButtonRowView {
                         Text("Quit")