Show warning dialog when auto-delete timer has changed since starting to compose message

briar-android/src/main/java/org/briarproject/briar/android/view/TextAttachmentController.java

@@ -174,6 +174,7 @@ public class TextAttachmentController extends TextSendController
 	private void onNewUris(boolean restart, List<Uri> newUris) {
 		if (newUris.isEmpty()) return;
 		if (loadingUris) throw new AssertionError();
+		if (textIsEmpty) onStartingMessage();
 		loadingUris = true;
 		if (newUris.size() > MAX_ATTACHMENTS_PER_MESSAGE) {
 			newUris = newUris.subList(0, MAX_ATTACHMENTS_PER_MESSAGE);

briar-android/src/main/java/org/briarproject/briar/android/view/TextSendController.java

@@ -16,6 +16,7 @@ import java.util.List;
 import androidx.annotation.CallSuper;
 import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
+import androidx.appcompat.app.AlertDialog;
 
 import static com.google.android.material.snackbar.Snackbar.LENGTH_SHORT;
 import static java.util.Collections.emptyList;
@@ -32,6 +33,7 @@ public class TextSendController implements TextInputListener {
 	protected boolean textIsEmpty = true;
 	private boolean ready = true;
 	private long currentTimer = NO_AUTO_DELETE_TIMER;
+	private long expectedTimer = NO_AUTO_DELETE_TIMER;
 
 	private final CharSequence defaultHint;
 	private final boolean allowEmptyText;
@@ -49,6 +51,7 @@ public class TextSendController implements TextInputListener {
 	@Override
 	public void onTextIsEmptyChanged(boolean isEmpty) {
 		textIsEmpty = isEmpty;
+		if (!isEmpty) onStartingMessage();
 		updateViewState();
 	}
 
@@ -59,6 +62,15 @@ public class TextSendController implements TextInputListener {
 		}
 	}
 
+	/**
+	 * Call whenever the user starts a new message,
+	 * either by entering text or adding an attachment.
+	 * This updates the expected auto-delete timer to the current value.
+	 */
+	protected void onStartingMessage() {
+		expectedTimer = currentTimer;
+	}
+
 	public void setReady(boolean ready) {
 		this.ready = ready;
 		updateViewState();
@@ -111,6 +123,11 @@ public class TextSendController implements TextInputListener {
 					LENGTH_SHORT).show();
 			return false;
 		}
+		if (expectedTimer != currentTimer) {
+			boolean enabled = currentTimer != NO_AUTO_DELETE_TIMER;
+			showTimerChangedDialog(enabled);
+			return false;
+		}
 		return ready && (canSendEmptyText() || !textIsEmpty);
 	}
 
@@ -118,6 +135,23 @@ public class TextSendController implements TextInputListener {
 		return allowEmptyText;
 	}
 
+	private void showTimerChangedDialog(boolean enabled) {
+		Context ctx = textInput.getContext();
+		int message =
+				enabled ? R.string.auto_delete_changed_warning_message_enabled :
+						R.string.auto_delete_changed_warning_message_disabled;
+		new AlertDialog.Builder(ctx, R.style.BriarDialogTheme)
+				.setTitle(R.string.auto_delete_changed_warning_title)
+				.setMessage(message)
+				.setPositiveButton(R.string.auto_delete_changed_warning_send,
+						(dialog, which) -> {
+							expectedTimer = currentTimer;
+							onSendEvent();
+						})
+				.setNegativeButton(R.string.cancel, null)
+				.show();
+	}
+
 	@Nullable
 	public Parcelable onSaveInstanceState(@Nullable Parcelable superState) {
 		return superState;

briar-android/src/main/res/values/strings.xml

@@ -176,6 +176,10 @@
 	<!-- The second placeholder at the end will add "Tap to learn more." -->
 	<string name="auto_delete_msg_contact_disabled">%1$s\'s messages will not disappear. %2$s</string>
 	<string name="tap_to_learn_more">Tap to learn more.</string>
+	<string name="auto_delete_changed_warning_title">Disappearing messages changed</string>
+	<string name="auto_delete_changed_warning_message_enabled">Since you started composing your message, disappearing messages have been enabled.</string>
+	<string name="auto_delete_changed_warning_message_disabled">Since you started composing your message, disappearing messages have been disabled.</string>
+	<string name="auto_delete_changed_warning_send">Send anyway</string>
 	<string name="delete_all_messages">Delete all messages</string>
 	<string name="dialog_title_delete_all_messages">Confirm Message Deletion</string>
 	<string name="dialog_message_delete_all_messages">Are you sure that you want to delete all messages?</string>