From 963f3f2cd9d020631741e3b9b48cb7d83305f91e Mon Sep 17 00:00:00 2001
From: "Alexander \"PapaTutuWawa" <papatutuwawa@polynom.me>
Date: Wed, 7 Jun 2023 18:41:08 +0200
Subject: [PATCH] feat(core): Check if we can do subscription pre-approval

---
 packages/moxxmpp/lib/moxxmpp.dart             |  1 -
 packages/moxxmpp/lib/src/namespaces.dart      |  1 +
 .../moxxmpp/lib/src/negotiators/manager.dart  |  1 -
 .../lib/src/negotiators/namespaces.dart       |  1 +
 packages/moxxmpp/lib/src/presence.dart        | 30 +++++++++++++++++++
 packages/moxxmpp/test/xmpp_test.dart          | 16 ++++++++++
 6 files changed, 48 insertions(+), 2 deletions(-)
 delete mode 100644 packages/moxxmpp/lib/src/negotiators/manager.dart

diff --git a/packages/moxxmpp/lib/moxxmpp.dart b/packages/moxxmpp/lib/moxxmpp.dart
index e44a60f..944b728 100644
--- a/packages/moxxmpp/lib/moxxmpp.dart
+++ b/packages/moxxmpp/lib/moxxmpp.dart
@@ -18,7 +18,6 @@ export 'package:moxxmpp/src/managers/namespaces.dart';
 export 'package:moxxmpp/src/managers/priorities.dart';
 export 'package:moxxmpp/src/message.dart';
 export 'package:moxxmpp/src/namespaces.dart';
-export 'package:moxxmpp/src/negotiators/manager.dart';
 export 'package:moxxmpp/src/negotiators/namespaces.dart';
 export 'package:moxxmpp/src/negotiators/negotiator.dart';
 export 'package:moxxmpp/src/ping.dart';
diff --git a/packages/moxxmpp/lib/src/namespaces.dart b/packages/moxxmpp/lib/src/namespaces.dart
index eb98e63..d5bd41f 100644
--- a/packages/moxxmpp/lib/src/namespaces.dart
+++ b/packages/moxxmpp/lib/src/namespaces.dart
@@ -9,6 +9,7 @@ const fullStanzaXmlns = 'urn:ietf:params:xml:ns:xmpp-stanzas';
 // RFC 6121
 const rosterXmlns = 'jabber:iq:roster';
 const rosterVersioningXmlns = 'urn:xmpp:features:rosterver';
+const subscriptionPreApprovalXmlns = 'urn:xmpp:features:pre-approval';
 
 // XEP-0004
 const dataFormsXmlns = 'jabber:x:data';
diff --git a/packages/moxxmpp/lib/src/negotiators/manager.dart b/packages/moxxmpp/lib/src/negotiators/manager.dart
deleted file mode 100644
index 8b13789..0000000
--- a/packages/moxxmpp/lib/src/negotiators/manager.dart
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/packages/moxxmpp/lib/src/negotiators/namespaces.dart b/packages/moxxmpp/lib/src/negotiators/namespaces.dart
index 17691ec..e4f30d2 100644
--- a/packages/moxxmpp/lib/src/negotiators/namespaces.dart
+++ b/packages/moxxmpp/lib/src/negotiators/namespaces.dart
@@ -11,3 +11,4 @@ const sasl2Negotiator = 'org.moxxmpp.sasl.sasl2';
 const bind2Negotiator = 'org.moxxmpp.bind2';
 const saslFASTNegotiator = 'org.moxxmpp.sasl.fast';
 const carbonsNegotiator = 'org.moxxmpp.bind2.carbons';
+const presenceNegotiator = 'org.moxxmpp.core.presence';
diff --git a/packages/moxxmpp/lib/src/presence.dart b/packages/moxxmpp/lib/src/presence.dart
index e8fb407..db68ace 100644
--- a/packages/moxxmpp/lib/src/presence.dart
+++ b/packages/moxxmpp/lib/src/presence.dart
@@ -6,14 +6,44 @@ import 'package:moxxmpp/src/managers/data.dart';
 import 'package:moxxmpp/src/managers/handlers.dart';
 import 'package:moxxmpp/src/managers/namespaces.dart';
 import 'package:moxxmpp/src/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/negotiator.dart';
 import 'package:moxxmpp/src/stanza.dart';
 import 'package:moxxmpp/src/stringxml.dart';
+import 'package:moxxmpp/src/types/result.dart';
 
 /// A function that will be called when presence, outside of subscription request
 /// management, will be sent. Useful for managers that want to add [XMLNode]s to said
 /// presence.
 typedef PresencePreSendCallback = Future<List<XMLNode>> Function();
 
+/// A pseudo-negotiator that does not really negotiate anything. Instead, its purpose
+/// is to look for a stream feature indicating that we can pre-approve subscription
+/// requests, shown by [PresenceNegotiator.preApprovalSupported].
+class PresenceNegotiator extends XmppFeatureNegotiatorBase {
+  PresenceNegotiator()
+      : super(11, false, subscriptionPreApprovalXmlns, presenceNegotiator);
+
+  /// Flag indicating whether presence subscription pre-approval is supported
+  bool _supported = false;
+  bool get preApprovalSupported => _supported;
+
+  @override
+  Future<Result<NegotiatorState, NegotiatorError>> negotiate(
+    XMLNode nonza,
+  ) async {
+    _supported = true;
+    return const Result(NegotiatorState.done);
+  }
+
+  @override
+  void reset() {
+    _supported = false;
+
+    super.reset();
+  }
+}
+
 /// A mandatory manager that handles initial presence sending, sending of subscription
 /// request management requests and triggers events for incoming presence stanzas.
 class PresenceManager extends XmppManagerBase {
diff --git a/packages/moxxmpp/test/xmpp_test.dart b/packages/moxxmpp/test/xmpp_test.dart
index 21d80d0..d7fd9d8 100644
--- a/packages/moxxmpp/test/xmpp_test.dart
+++ b/packages/moxxmpp/test/xmpp_test.dart
@@ -794,4 +794,20 @@ void main() {
     expect(fakeSocket.getState(), 9);
     expect(await stanzaFuture != null, true);
   });
+
+  test('Test subscription pre-approval parsing', () async {
+    final rawFeatures = XMLNode.fromString(
+      '''
+<top-level>
+  <test-feature-1 xmlns="invalid:urn:features:1" />
+  <test-feature-2 xmlns="invalid:urn:features:2" />
+  <test-feature-3 xmlns="invalid:urn:features:3" />
+  <test-feature-4 xmlns="invalid:urn:features:4" />
+  <sub xmlns='urn:xmpp:features:pre-approval' />
+</top-level>
+      ''',
+    );
+
+    expect(PresenceNegotiator().matchesFeature(rawFeatures.children), true);
+  });
 }