Add LoginToken helper class and basic validation

app/src/main/java/dev/garrettmills/starship/hyperlink/Hyperlink.java

@@ -3,7 +3,6 @@ package dev.garrettmills.starship.hyperlink;
 import android.content.SharedPreferences;
 
 public class Hyperlink {
-    public static final int PERMISSION_REQUEST_CAMERA = 0;
     public static final String SHARED_PREFERENCES_NAME = "dev.garrettmills.starship.hyperlink.main";
     public static final String SERVER_ADDR = "dev.garrettmills.starship.hyperlink.server";
     public static final String SERVER_TOKEN = "dev.garrettmills.starship.hyperlink.token.server";
@@ -11,6 +10,7 @@ public class Hyperlink {
     public static final String EXTRA_LOGIN_TOKEN = "dev.garrettmills.starship.hyperlink.extra.login_token";
 
     public static final int REQUEST_LOGIN_TOKEN = 180;
+    public static final int REQUEST_PERMISSION_CAMERA = 181;
 
     public static SharedPreferences preferences;
 }

app/src/main/java/dev/garrettmills/starship/hyperlink/LoginTokenScannerActivity.java

@@ -25,6 +25,8 @@ import java.util.concurrent.ExecutionException;
 
 import dev.garrettmills.starship.hyperlink.scanner.QRCodeImageAnalyzer;
 import dev.garrettmills.starship.hyperlink.scanner.QRCodeListener;
+import dev.garrettmills.starship.hyperlink.util.InvalidLoginTokenException;
+import dev.garrettmills.starship.hyperlink.util.LoginToken;
 
 public class LoginTokenScannerActivity extends AppCompatActivity implements QRCodeListener {
     private PreviewView previewView;
@@ -45,21 +47,22 @@ public class LoginTokenScannerActivity extends AppCompatActivity implements QRCo
         if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
             startCamera();
         } else {
-            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
+            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, Hyperlink.REQUEST_PERMISSION_CAMERA);
-                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, Hyperlink.PERMISSION_REQUEST_CAMERA);
-            } else {
-                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, Hyperlink.PERMISSION_REQUEST_CAMERA);
-            }
         }
     }
 
     @Override
     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
-        if (requestCode == Hyperlink.PERMISSION_REQUEST_CAMERA) {
+        if (requestCode == Hyperlink.REQUEST_PERMISSION_CAMERA) {
             if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                 startCamera();
             } else {
-                Toast.makeText(this, "Camera Permission Denied", Toast.LENGTH_SHORT).show();
+                if ( BuildConfig.DEBUG ) {
+                    Toast.makeText(this, "Camera permission denied", Toast.LENGTH_SHORT).show();
+                }
+
+                // If we denied, go back up to the main activity, w/o any login token
+                finish();
             }
         }
     }
@@ -70,8 +73,12 @@ public class LoginTokenScannerActivity extends AppCompatActivity implements QRCo
                 ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
                 bindCameraPreview(cameraProvider);
             } catch (ExecutionException | InterruptedException e) {
+                if ( BuildConfig.DEBUG ) {
                     Toast.makeText(this, "Error starting camera: " + e.getMessage(), Toast.LENGTH_LONG).show();
                 }
+
+                finish();
+            }
         }, ContextCompat.getMainExecutor(this));
     }
 
@@ -109,6 +116,11 @@ public class LoginTokenScannerActivity extends AppCompatActivity implements QRCo
     public void onQRCodeNotFound() {}
 
     public boolean isValidLoginToken(String token) {
+        try {
+            new LoginToken(token);
             return true;
+        } catch (InvalidLoginTokenException e) {
+            return false;
+        }
     }
 }

app/src/main/java/dev/garrettmills/starship/hyperlink/MainActivity.java

@@ -27,8 +27,10 @@ public class MainActivity extends AppCompatActivity {
 
         if ( resultCode == RESULT_OK && requestCode == Hyperlink.REQUEST_LOGIN_TOKEN ) {
             if ( data.hasExtra(Hyperlink.EXTRA_LOGIN_TOKEN) ) {
+                if ( BuildConfig.DEBUG ) {
                     Toast.makeText(getApplicationContext(), data.getExtras().getString(Hyperlink.EXTRA_LOGIN_TOKEN), Toast.LENGTH_SHORT).show();
                 }
             }
         }
     }
+}

app/src/main/java/dev/garrettmills/starship/hyperlink/util/InvalidLoginTokenException.java

@@ -0,0 +1,4 @@
+package dev.garrettmills.starship.hyperlink.util;
+
+public class InvalidLoginTokenException extends Exception {
+}

app/src/main/java/dev/garrettmills/starship/hyperlink/util/LoginToken.java

@@ -0,0 +1,24 @@
+package dev.garrettmills.starship.hyperlink.util;
+
+public class LoginToken {
+    private String _server;
+    private String _token;
+
+    public LoginToken(String token) throws InvalidLoginTokenException {
+        String[] parts = token.split("\\|");
+        if ( parts.length != 3 || !parts[0].equals("hyperlink")) {
+            throw new InvalidLoginTokenException();
+        }
+
+        this._server = parts[1];
+        this._token = parts[2];
+    }
+
+    public String getServer() {
+        return _server;
+    }
+
+    public String getToken() {
+        return _token;
+    }
+}