Implement +b channel ban mode with glob mask matching

- Track per-channel ban masks in :chan-bans atom
- MODE +b <mask> adds, -b removes (case-insensitive)
- MODE +b without mask returns RPL_BANLIST + RPL_ENDOFBANLIST
- JOIN checks ban list and returns ERR_BANNEDFROMCHAN (474)
- Update CHANMODES isupport to b,k,l,nt

1 files changed, 73 insertions, 3 deletions

diff --git a/src/papod.clj b/src/papod.clj
index 316b65a..8e1851c 100644
--- a/src/papod.clj
+++ b/src/papod.clj
@@ -1064,7 +1064,7 @@
                          (numeric-reply client "005"
                            (str "AWAYLEN=200 CASEMAPPING=ascii"
                                 " CHANLIMIT=#:100"
-                                " CHANMODES=,,l,nt"
+                                " CHANMODES=b,k,l,nt"
                                 " CHANNELLEN=64 CHANTYPES=#"
                                 " ELIST= HOSTLEN=64"
                                 " KICKLEN=300 MAXLIST=b:50"
@@ -2236,6 +2236,34 @@
         (get @(:chan-modes components) handle))
       "+nt"))
 
+(defn- glob-pattern
+  [^String mask]
+  (re-pattern
+   (str "^"
+        (->> mask
+             (map (fn [c]
+                    (case c
+                      \* ".*"
+                      \? "."
+                      (java.util.regex.Pattern/quote
+                       (str c)))))
+             (apply str))
+        "$")))
+
+(defn- nuh-mask
+  [nick]
+  (str nick "!" nick "@localhost"))
+
+(defn- ban-matches?
+  [bans nick]
+  (let [nuh (nuh-mask nick)]
+    (some (fn [mask]
+            (boolean
+             (re-matches (glob-pattern
+                          (string/lower-case mask))
+                         (string/lower-case nuh))))
+          bans)))
+
 (defn- chan-symbol
   [components handle]
   (let [m (chan-modes-for components handle)]
@@ -2304,6 +2332,16 @@
          (str handle
               " :Cannot join channel (+l)"))]
 
+      ;; +b: banned
+      (and existing?
+           (not (contains? (get @channels handle) nick))
+           (let [bans-atom (:chan-bans components)
+                 bans (when bans-atom
+                        (get @bans-atom handle #{}))]
+             (and (seq bans) (ban-matches? bans nick))))
+      [(numeric-reply client "474"
+         (str handle " :Cannot join channel (+b)"))]
+
       :else
       (let [db          (when conn (d/db conn))
             channel-eid (when db (resolve-channel db handle))
@@ -3811,10 +3849,41 @@
                            (:w m) line)))
                       [])))
 
+                ;; +b/-b with mask: add/remove ban
+                (and (= \b mode-char) mode-arg)
+                (let [bans-atom (:chan-bans components)
+                      mask     mode-arg
+                      mask-key (string/lower-case mask)
+                      line     (str ":" nick " MODE " target
+                                    " " mode-str " " mask)]
+                  (when bans-atom
+                    (if adding?
+                      (swap! bans-atom update target
+                             (fnil conj #{}) mask-key)
+                      (swap! bans-atom update target
+                             (fnil disj #{}) mask-key)))
+                  (when (and clients channels)
+                    (doseq [mn (get @channels target)
+                            :let [m (get @clients mn)]
+                            :when m]
+                      (deliver-to-client! (:w m) line)))
+                  [])
+
                 ;; +b: ban list query
                 (and (= \b mode-char) (nil? mode-arg))
-                [(numeric-reply client "368"
-                   (str target " :End of channel ban list"))]
+                (let [bans-atom (:chan-bans components)
+                      cur-bans (when bans-atom
+                                 (get @bans-atom target #{}))]
+                  (concat
+                   (mapv (fn [mask]
+                           (numeric-reply client "367"
+                             (str target " " mask " " nick
+                                  " " (quot
+                                       (System/currentTimeMillis)
+                                       1000))))
+                         (sort cur-bans))
+                   [(numeric-reply client "368"
+                      (str target " :End of channel ban list"))]))
 
                 :else []))))
 
@@ -4495,6 +4564,7 @@
      :chan-modes  (atom {})
      :chan-keys   (atom {})
      :chan-limits (atom {})
+     :chan-bans   (atom {})
      :invites     (atom {})
      :whowas       (atom [])
      :max-users    (atom 0)