From e599bcd3ea9b0aa31ee704fbedb1ad66a82e4cad Mon Sep 17 00:00:00 2001
From: Stephen Paul Weber <singpolyma@singpolyma.net>
Date: Wed, 21 Feb 2024 21:49:45 -0500
Subject: [PATCH] Register with MUC when joining, deregister when leaving

Where allowed, if not allowed just do nothing.
Complex registration forms (requiring more than just nickname) are not
supported for now, we could render them in the UI to allow for "apply
for membership" flows, but no one supports that yet so this gets us the
basics for now.
---
 .../services/XmppConnectionService.java       | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/src/main/java/eu/siacs/conversations/services/XmppConnectionService.java b/src/main/java/eu/siacs/conversations/services/XmppConnectionService.java
index 1ad12ce40761f626a2f556099c6e8a81c02c057d..efe5a8298237faeafcd1c467844c10a40707d104 100644
--- a/src/main/java/eu/siacs/conversations/services/XmppConnectionService.java
+++ b/src/main/java/eu/siacs/conversations/services/XmppConnectionService.java
@@ -2717,6 +2717,71 @@ public class XmppConnectionService extends Service {
         return false;
     }
 
+    public void maybeRegisterWithMuc(Conversation c, String nickArg) {
+        final var nick = nickArg == null ? c.getMucOptions().getSelf().getFullJid().getResource() : nickArg;
+        final IqPacket register = new IqPacket(IqPacket.TYPE.GET);
+        register.query(Namespace.REGISTER);
+        register.setTo(c.getJid().asBareJid());
+        sendIqPacket(c.getAccount(), register, (a, response) -> {
+            if (response.getType() == IqPacket.TYPE.RESULT) {
+                final Element query = response.query(Namespace.REGISTER);
+                String username = query.findChildContent("username", Namespace.REGISTER);
+                if (username == null) username = query.findChildContent("nick", Namespace.REGISTER);
+                if (username != null && username.equals(nick)) {
+                    // Already registered with this nick, done
+                    Log.d(Config.LOGTAG, "Already registered with " + c.getJid().asBareJid() + " as " + username);
+                    return;
+                }
+                Data form = Data.parse(query.findChild("x", Namespace.DATA));
+                if (form != null) {
+                    final var field = form.getFieldByName("muc#register_roomnick");
+                    if (field != null && nick.equals(field.getValue())) {
+                        Log.d(Config.LOGTAG, "Already registered with " + c.getJid().asBareJid() + " as " + field.getValue());
+                        return;
+                    }
+                }
+                if (form == null || !"form".equals(form.getFormType()) || !form.getFields().stream().anyMatch(f -> f.isRequired() && !"muc#register_roomnick".equals(f.getFieldName()))) {
+                    // No form, result form, or no required fields other than nickname, let's just send nickname
+                    if (form == null || !"form".equals(form.getFormType())) {
+                        form = new Data();
+                        form.put("FORM_TYPE", "http://jabber.org/protocol/muc#register");
+                    }
+                    form.put("muc#register_roomnick", nick);
+                    form.submit();
+                    final IqPacket finish = new IqPacket(IqPacket.TYPE.SET);
+                    finish.query(Namespace.REGISTER).addChild(form);
+                    finish.setTo(c.getJid().asBareJid());
+                    sendIqPacket(c.getAccount(), finish, (a2, response2) -> {
+                        if (response.getType() == IqPacket.TYPE.RESULT) {
+                            Log.w(Config.LOGTAG, "Success registering with channel " + c.getJid().asBareJid() + "/" + nick);
+                        } else {
+                            Log.w(Config.LOGTAG, "Error registering with channel: " + response2);
+                        }
+                    });
+                } else {
+                    // TODO: offer registration form to user
+                    Log.d(Config.LOGTAG, "Complex registration form for " + c.getJid().asBareJid() + ": " + response);
+                }
+            } else {
+                // We said maybe. Guess not
+                Log.d(Config.LOGTAG, "Could not register with " + c.getJid().asBareJid() + ": " + response);
+            }
+        });
+    }
+
+    public void deregisterWithMuc(Conversation c) {
+        final IqPacket register = new IqPacket(IqPacket.TYPE.GET);
+        register.query(Namespace.REGISTER).addChild("remove");
+        register.setTo(c.getJid().asBareJid());
+        sendIqPacket(c.getAccount(), register, (a, response) -> {
+            if (response.getType() == IqPacket.TYPE.RESULT) {
+                Log.d(Config.LOGTAG, "deregistered with " + c.getJid().asBareJid());
+            } else {
+                Log.w(Config.LOGTAG, "Could not deregister with " + c.getJid().asBareJid() + ": " + response);
+            }
+        });
+    }
+
     public Conversation findOrCreateConversation(Account account, Jid jid, boolean muc, final boolean async) {
         return this.findOrCreateConversation(account, jid, muc, false, async);
     }
@@ -2829,6 +2894,7 @@ public class XmppConnectionService extends Service {
                         }
                     }
                 }
+                deregisterWithMuc(conversation);
                 leaveMuc(conversation);
             } else {
                 if (conversation.getContact().getOption(Contact.Options.PENDING_SUBSCRIPTION_REQUEST)) {
@@ -3455,6 +3521,8 @@ public class XmppConnectionService extends Service {
                         databaseBackend.updateConversation(conversation);
                     }
 
+                    maybeRegisterWithMuc(conversation, null);
+
                     if (mucOptions.mamSupport()) {
                         getMessageArchiveService().catchupMUC(conversation);
                     }
@@ -3732,6 +3800,8 @@ public class XmppConnectionService extends Service {
             return false;
         }
         if (options.online()) {
+            maybeRegisterWithMuc(conversation, nick);
+
             Account account = conversation.getAccount();
             options.setOnRenameListener(new OnRenameListener() {