Implement room discovery using the LIST irc command

ref #2472

src/bridge/bridge.cpp

 #include <bridge/bridge.hpp>
 #include <bridge/colors.hpp>
+#include <bridge/list_element.hpp>
 #include <xmpp/xmpp_component.hpp>
 #include <xmpp/xmpp_stanza.hpp>
 #include <irc/irc_message.hpp>
@@ -285,6 +286,43 @@ void Bridge::send_irc_nick_change(const Iid& iid, const std::string& new_nick)
     irc->send_nick_command(new_nick);
 }
 
+void Bridge::send_irc_channel_list_request(const Iid& iid, const std::string& iq_id,
+                                           const std::string& to_jid)
+{
+  IrcClient* irc = this->get_irc_client(iid.get_server());
+
+  if (!irc)
+    return;
+
+  irc->send_list_command();
+  irc_responder_callback_t cb = [this, iid, iq_id, to_jid](const std::string& irc_hostname,
+                                                           const IrcMessage& message) -> bool
+    {
+      static std::vector<ListElement> list;
+
+      if (irc_hostname != iid.get_server())
+        return false;
+      if (message.command == "263" || message.command == "RPL_TRYAGAIN")
+        { // TODO send an error iq
+          return true;
+        }
+      else if (message.command == "322" || message.command == "RPL_LIST")
+        { // Add element to list
+          if (message.arguments.size() == 4)
+            list.emplace_back(message.arguments[1], message.arguments[2],
+                              message.arguments[3]);
+          return false;
+        }
+      else if (message.command == "323" || message.command == "RPL_LISTEND")
+        { // Send the iq response with the content of the list
+          this->xmpp->send_iq_room_list_result(iq_id, to_jid, std::to_string(iid), list);
+          return true;
+        }
+      return false;
+    };
+  this->add_waiting_irc(std::move(cb));
+}
+
 void Bridge::send_irc_kick(const Iid& iid, const std::string& target, const std::string& reason,
                            const std::string& iq_id, const std::string& to_jid)
 {

src/bridge/bridge.hpp

@@ -72,6 +72,8 @@ public:
   void send_irc_version_request(const std::string& irc_hostname, const std::string& target,
                                 const std::string& iq_id, const std::string& to_jid,
                                 const std::string& from_jid);
+  void send_irc_channel_list_request(const Iid& iid, const std::string& iq_id,
+                                     const std::string& to_jid);
   void forward_affiliation_role_change(const Iid& iid, const std::string& nick,
                                        const std::string& affiliation, const std::string& role);
   /**

src/bridge/list_element.hpp

+#ifndef LIST_ELEMENT_HPP_INCLUDED
+#define LIST_ELEMENT_HPP_INCLUDED
+
+#include <string>
+
+struct ListElement
+{
+  ListElement(const std::string& channel, const std::string& nb_users,
+                 const std::string& topic):
+    channel(channel),
+    nb_users(nb_users),
+    topic(topic){}
+
+  std::string channel;
+  std::string nb_users;
+  std::string topic;
+};
+
+#endif /* LIST_ELEMENT_HPP_INCLUDED */

src/irc/irc_client.cpp

@@ -196,6 +196,11 @@ void IrcClient::send_kick_command(const std::string& chan_name, const std::strin
   this->send_message(IrcMessage("KICK", {chan_name, target, reason}));
 }
 
+void IrcClient::send_list_command()
+{
+  this->send_message(IrcMessage("LIST", {}));
+}
+
 void IrcClient::send_topic_command(const std::string& chan_name, const std::string& topic)
 {
   this->send_message(IrcMessage("TOPIC", {chan_name, topic}));

src/irc/irc_client.hpp

@@ -104,6 +104,10 @@ public:
    * Send the KICK irc command
    */
   void send_kick_command(const std::string& chan_name, const std::string& target, const std::string& reason);
+  /**
+   * Send the LIST irc command
+   */
+  void send_list_command();
   void send_topic_command(const std::string& chan_name, const std::string& topic);
   /**
    * Send the QUIT irc command

src/xmpp/xmpp_component.cpp

@@ -4,6 +4,7 @@
 #include <logger/logger.hpp>
 
 #include <xmpp/xmpp_component.hpp>
+#include <bridge/list_element.hpp>
 #include <config/config.hpp>
 #include <xmpp/jid.hpp>
 #include <utils/sha1.hpp>
@@ -556,12 +557,18 @@ void XmppComponent::handle_iq(const Stanza& stanza)
         }
       else if ((query = stanza.get_child("query", DISCO_ITEMS_NS)))
         {
+          Iid iid(to.local);
           const std::string node = query->get_tag("node");
           if (node == ADHOC_NS)
             {
               this->send_adhoc_commands_list(id, from);
               stanza_error.disable();
             }
+          else if (node.empty() && !iid.is_user && !iid.is_channel)
+            { // Disco on an IRC server: get the list of channels
+              bridge->send_irc_channel_list_request(iid, id, from);
+              stanza_error.disable();
+            }
         }
       else if ((query = stanza.get_child("ping", PING_NS)))
         {
@@ -1152,6 +1159,31 @@ void XmppComponent::send_iq_result(const std::string& id, const std::string& to_
   this->send_stanza(iq);
 }
 
+void XmppComponent::send_iq_room_list_result(const std::string& id,
+                                             const std::string to_jid,
+                                             const std::string& from,
+                                             const std::vector<ListElement>& rooms_list)
+{
+  Stanza iq("iq");
+  iq["from"] = from + "@" + this->served_hostname;
+  iq["to"] = to_jid;
+  iq["id"] = id;
+  iq["type"] = "result";
+  XmlNode query("query");
+  query["xmlns"] = DISCO_ITEMS_NS;
+  for (const auto& room: rooms_list)
+    {
+      XmlNode item("item");
+      item["jid"] = room.channel + "%" + from + "@" + this->served_hostname;
+      item.close();
+      query.add_child(std::move(item));
+    }
+  query.close();
+  iq.add_child(std::move(query));
+  iq.close();
+  this->send_stanza(iq);
+}
+
 std::string XmppComponent::next_id()
 {
   char uuid_str[37];

src/xmpp/xmpp_component.hpp

@@ -26,6 +26,8 @@
 #define ADHOC_NS         "http://jabber.org/protocol/commands"
 #define PING_NS          "urn:xmpp:ping"
 
+class ListElement;
+
 /**
  * A callback called when the waited iq result is received (it is matched
  * against the iq id)
@@ -228,6 +230,12 @@ public:
    * Send an empty iq of type result
    */
   void send_iq_result(const std::string& id, const std::string& to_jid, const std::string& from);
+  /**
+   * Send the channels list in one big stanza
+   */
+  void send_iq_room_list_result(const std::string& id, const std::string to_jid,
+                                const std::string& from,
+                                const std::vector<ListElement>& rooms_list);
   /**
    * Handle the various stanza types
    */