chghost, setname, invite-notify capabilities

chghost: advertise the cap. We never rewrite hostnames currently
(everything is "localhost"), so this is a passive declaration that
clients negotiating the cap will see CHGHOST messages if/when host
rewriting lands.

setname: SETNAME :<realname> updates the client's stored realname and,
for every shared-channel member that negotiated the cap, emits the
":nick\!user@host SETNAME :<realname>" notification. Length cap matches
the existing TOPICLEN bound (390); empty/over-length names get
FAIL SETNAME INVALID_REALNAME.

invite-notify: INVITE delivery now also sends the INVITE line to every
channel op (other than inviter/invitee) that negotiated the cap, so
mod tooling can track invites without polling. Uses the same
account-tag-aware delivery as the recipient path.

1 files changed, 62 insertions, 2 deletions

diff --git a/src/papod.clj b/src/papod.clj
index c7dec26..d155b27 100644
--- a/src/papod.clj
+++ b/src/papod.clj
@@ -1388,7 +1388,8 @@
                      " batch labeled-response multi-prefix"
                      " userhost-in-names extended-join"
                      " away-notify utf8only"
-                     " account-notify account-tag"
+                     " account-notify account-tag chghost"
+                     " setname invite-notify"
                      " draft/multiline=max-bytes=4096"
                      ",max-lines=32"
                      " draft/read-marker"
@@ -1402,7 +1403,8 @@
                      " labeled-response multi-prefix"
                      " userhost-in-names extended-join"
                      " away-notify utf8only"
-                     " account-notify account-tag"
+                     " account-notify account-tag chghost"
+                     " setname invite-notify"
                      " draft/multiline draft/read-marker"
                      " draft/message-redaction"
                      " draft/message-editing"
@@ -1419,6 +1421,7 @@
                         "userhost-in-names" "extended-join"
                         "away-notify" "utf8only"
                         "account-notify" "account-tag"
+                        "chghost" "setname" "invite-notify"
                         "draft/multiline" "draft/read-marker"
                         "draft/message-redaction"
                         "draft/message-editing"
@@ -3775,6 +3778,38 @@
           [(numeric-reply client "306"
              ":You have been marked as being away")]))))
 
+(defn- handle-setname
+  [params client components]
+  (let [{:keys [clients channels]} components
+        nick (client-target client)
+        src  (client-prefix client)
+        raw  (when (seq params) (string/join " " params))
+        new-name (when raw
+                   (cond-> raw
+                     (string/starts-with? raw ":") (subs 1)))]
+    (cond
+      (or (string/blank? new-name)
+          (> (count new-name) 390))
+      [(str "FAIL SETNAME INVALID_REALNAME :Invalid realname")]
+
+      :else
+      (let [line (str ":" src " SETNAME :" new-name)]
+        (swap! client assoc-in [:user :realname] new-name)
+        (when (and clients channels)
+          (let [seen (atom #{nick})]
+            (doseq [[ch members] @channels
+                    :when (contains? members nick)
+                    mn members
+                    :when (not (contains? @seen mn))
+                    :let [m (get @clients mn)
+                          ca (:client-atom m)
+                          caps (or (when ca (:caps @ca))
+                                   #{})]
+                    :when (and m (caps "setname"))]
+              (deliver-to-client! (:w m) line)
+              (swap! seen conj mn))))
+        [line]))))
+
 (defn- handle-batch-open!
   [message client components]
   (let [params (clean-params (:params message))
@@ -4136,6 +4171,9 @@
         (= command "AWAY")
         (handle-away params client components)
 
+        (= command "SETNAME")
+        (handle-setname params client components)
+
         (= command "NOTICE")
         (handle-notice params client components)
 
@@ -4969,6 +5007,28 @@
                                tagged-base
                                base)]
                     (deliver-to-client! (:w m) line)))
+                ;; invite-notify: also send the INVITE line
+                ;; to channel ops who negotiated the cap
+                ;; (excluding the inviter and the invitee).
+                (when (and chan-exists? clients
+                           (:ops components))
+                  (let [op-set (or (get @(:ops components)
+                                        handle) #{})]
+                    (doseq [op-nick op-set
+                            :when (and (not= op-nick nick)
+                                       (not= op-nick
+                                             target))
+                            :let [m (get @clients op-nick)
+                                  ca (:client-atom m)
+                                  caps (when ca
+                                         (or (:caps @ca)
+                                             #{}))]
+                            :when (and m
+                                       (caps "invite-notify"))]
+                      (deliver-to-client! (:w m)
+                        (if (and tagged-base
+                                 (caps "account-tag"))
+                          tagged-base base)))))
                 ;; When the channel does not exist, also
                 ;; echo the INVITE back to the inviter
                 ;; (RFC1459 behavior). When it exists,