Added auth

DemoAndroid/Activities/WakeOnLanActivity.cs

@@ -1,11 +1,51 @@
 using System.Net;
 using System.Net.Sockets;
+using Android.Content;
+using Android.Hardware.Biometrics;
+using Android.OS;
+using Java.Lang;
 
 namespace DemoAndroid;
 
+class BiometricCallback : BiometricPrompt.AuthenticationCallback, IDialogInterfaceOnClickListener
+{
+    private Context _context;
+
+    public BiometricCallback(Context context)
+    {
+        _context = context;
+    }
+    
+    public override void OnAuthenticationError(BiometricErrorCode errorCode, ICharSequence? errString)
+    {
+        Toast.MakeText(_context, $"Authentication error: {errorCode}, {errString?.ToString()}", ToastLength.Long).Show();
+    }
+
+    public override void OnAuthenticationSucceeded(BiometricPrompt.AuthenticationResult? result)
+    {
+        Toast.MakeText(_context, "Authentication succeeded!", ToastLength.Long).Show();
+    }
+
+    public override void OnAuthenticationFailed()
+    {
+        Toast.MakeText(_context, "Authentication failed!", ToastLength.Long).Show();
+    }
+
+    public void OnClick(IDialogInterface? dialog, int which)
+    {
+        Toast.MakeText(_context, "Cancel clicked!", ToastLength.Long).Show();
+    }
+}
+
 [Activity(Label = "WakeOnLanActivity")]
 public class WakeOnLanActivity : Activity
 {
+    private const int BiometricStrong = 0x0000000f;
+    private const int BiometricWeak = 0x000000ff;
+    private const int DeviceCredential = 0x00008000;
+
+    private bool _authenticated = false;
+    
     protected override void OnCreate(Bundle? savedInstanceState)
     {
         base.OnCreate(savedInstanceState);
@@ -16,25 +56,47 @@ public class WakeOnLanActivity : Activity
         var button = FindViewById<Button>(Resource.Id.btnWakeOnLan);
         button.Click += (sender, args) =>
         {
+            if (!_authenticated)
+            {
+                Authenticate();
+                return;
+            }
+            
             WakePc();
         };
     }
 
+    private void Authenticate()
+    {
+        var callback = new BiometricCallback(this);
+
+        var prompt = new BiometricPrompt.Builder(this)
+            .SetNegativeButton("Negative", MainExecutor, callback)
+            .SetTitle("Bewijs jezelf met je vingerafdruk")
+            .SetSubtitle("We willen zeker weten dat je niet Colinde bent")
+            .SetAllowedAuthenticators(BiometricStrong)
+            .Build();
+
+        var cancellation = new CancellationSignal();
+
+        prompt.Authenticate(cancellation, MainExecutor, callback);
+    }
+
     private void WakePc()
     {
-        byte[] macAddress = { 0x2c, 0x4d, 0x54, 0x4d, 0x10, 0x0f };
-        byte[] magicPacket = new byte[102];
+        byte[] macAddress = [0x2c, 0x4d, 0x54, 0x4d, 0x10, 0x0f];
+        var magicPacket = new byte[102];
 
         // Fill first 6 bytes with 0xFF
-        for (int i = 0; i < 6; i++)
+        for (var i = 0; i < 6; i++)
         {
             magicPacket[i] = 0xFF;
         }
 
         // Repeat MAC address 16 times
-        for (int i = 1; i <= 16; i++)
+        for (var i = 1; i <= 16; i++)
         {
-            for (int j = 0; j < 6; j++)
+            for (var j = 0; j < 6; j++)
             {
                 magicPacket[i * 6 + j] = macAddress[j];
             }
@@ -44,10 +106,12 @@ public class WakeOnLanActivity : Activity
         client.EnableBroadcast = true;
         var endpoint = new IPEndPoint(IPAddress.Broadcast, 9); // 255.255.255.255 port 9
 
-        for (int i = 0; i < 5; i++)
+        for (var i = 0; i < 5; i++)
         {
             // Try 5 times
             client.Send(magicPacket, magicPacket.Length, endpoint);
         }
+        
+        Toast.MakeText(this, "Computer started!", ToastLength.Long).Show();
     }
 }