support TOPIC command

lib/server/chan.ml

@@ -16,6 +16,7 @@ let make ~name =
 
 let name t = t.name
 let topic t = t.topic
+let set_topic t s = t.topic <- s
 let mode t = t.chan_mode
 let set_mode t new_mode = t.chan_mode <- new_mode
 let limit t = t.chan_limit

lib/server/connection.ml

@@ -39,8 +39,13 @@ let reply t (num, params) =
     | Some me -> User.nick me
     | None -> "*"
   in
+  let always_trailing = match num with
+    | "324" | "332" | "353" -> true
+    | _ -> false
+  in
   Outbox.send t.outbox
-    (Msg.make ~prefix num (target :: params))
+    (Msg.make num (target :: params)
+       ~prefix ~always_trailing)
 
 let tryagain cmd          = "263", [cmd; "Please wait a while and try again."]
 let nosuchnick tgt        = "401", [tgt; "No such nick/channel"]
@@ -264,6 +269,41 @@ let on_msg_names t name =
   list_names t chan;
   Ok ()
 
+let get_topic ?(reply_if_missing=true) t chan =
+  match Chan.topic chan with
+  | Some topic ->
+    reply t ("332", [Chan.name chan; topic])
+  (* TODO: RPL_TOPICWHOTIME ? *)
+  | None ->
+    if reply_if_missing then
+      reply t ("331", [Chan.name chan; "No topic is set"])
+
+let set_topic chan topic =
+  Chan.set_topic chan topic
+
+let on_msg_topic t name args =
+  let* me = require_registered t in
+  let* chan =
+    try
+      match name_type name with
+      | `chan -> Ok (Router.find_chan t.router name)
+      | `nick | `invalid -> raise Not_found
+    with Not_found ->
+      Error (nosuchchannel name)
+  in
+  match args with
+  | [] ->
+    (* TODO: if +s then don't send topic to non-members *)
+    get_topic t chan;
+    Ok ()
+  | args ->
+    (* TODO: if +t then only allow +o to set topic *)
+    let topic = String.concat " " args in
+    let msg = Msg.make "TOPIC" [Chan.name chan; topic] ~always_trailing:true in
+    Router.relay msg ~from:me [`to_chan chan; `to_self];
+    set_topic chan (if args = [""] then None else Some topic);
+    Ok ()
+
 let join t user chan =
   (* TODO: check channel mode +k, +l *)
   let msg = Msg.make "JOIN" [Chan.name chan] in
@@ -284,7 +324,10 @@ let on_msg_join t name =
     try
       match name_type name with
       | `chan -> Ok (Router.find_chan t.router name)
-      | _     -> Error (nosuchchannel name)
+      | `nick | `invalid ->
+        (* pretend malformed channel name means the channel doesn't exist and
+           DON'T try to make a new channel *)
+        Error (nosuchchannel name)
     with Not_found ->
       debug (fun m -> m "making new channel %S" name);
       Ok (Chan.make ~name)
@@ -294,7 +337,7 @@ let on_msg_join t name =
     Ok ()
   | exception Not_found ->
     join t me chan;
-    (* TODO: send channel topic *)
+    get_topic t chan ~reply_if_missing:false;
     list_names t chan;
     Ok ()
 
@@ -471,6 +514,7 @@ let dispatch t = function
   | "PRIVMSG", tgt :: msg :: _ -> on_msg_privmsg t tgt msg
   | "JOIN", tgt :: _ when tgt <> "" -> on_msg_join t tgt
   | "NAMES", tgt :: _ when tgt <> "" -> on_msg_names t tgt
+  | "TOPIC", tgt :: args when tgt <> "" -> on_msg_topic t tgt args
   | "PART", tgt :: reason when tgt <> "" -> on_msg_part t tgt reason
   | "MODE", tgt :: args when tgt <> "" -> on_msg_mode t tgt args
   | ("USER" | "JOIN" | "NAMES" | "PART" | "MODE") as cmd, _ ->