[ADD/WIP] Two-way replies

Call me Seija Kijin the way I apply my Reverse Ideology.

src/Events.c

@@ -192,3 +192,14 @@ MatrixCreateReact(char *event, char *body)
     return map;
 
 }
+void
+MatrixSetReply(HashMap *map, char *event)
+{
+    if (!map || !event)
+    {
+        return;
+    }
+    JsonValueFree(JsonSet(map, JsonValueString(event),
+        3, "m.relates_to", "m.in_reply_to", "event_id"
+    ));
+}

src/XMPP/Stanza.c

@@ -268,3 +268,14 @@ XMPPGetReplacedID(XMLElement *stanza)
     );
     return replace ? HashMapGet(replace->attrs, "id") : NULL;
 }
+char *
+XMPPGetReply(XMLElement *elem)
+{
+    XMLElement *rep = XMLookForTKV(elem, "reply", "xmlns", "urn:xmpp:reply:0");
+    if (!rep)
+    {
+        return NULL;
+    }
+
+    return HashMapGet(rep->attrs, "id");
+}

src/XMPPThread.c

@@ -90,6 +90,7 @@ MessageStanza(ParseeData *args, XMLElement *stanza)
         char *id_str    = HashMapGet(stanza->attrs, "id");
         char *event_id  = NULL;
         char *replaced  = XMPPGetReplacedID(stanza);
+        char *reply_to  = XMPPGetReply(stanza);
 
         if (ParseeVerifyStanza(args, chat_id, s_id_str) && !replaced)
         {
@@ -145,9 +146,23 @@ MessageStanza(ParseeData *args, XMLElement *stanza)
             }
             else
             {
+                /* TODO: Use HTML-formatted bodies, and respect the fallback 
+                 * trims the stanza provides us if possible. Element does 
+                 * not like raw bodies on replies. Go figure. */
+                size_t off = 
+                    reply_to ? ParseeFindDatastart(data->data) : 0;
+                HashMap *ev = MatrixCreateMessage(data->data + off);
+                if (reply_to)
+                {
+                    char *reply_id = ParseeEventFromSID(
+                        args, chat_id, reply_to
+                    );
+                    MatrixSetReply(ev, reply_id);
+                    Free(reply_id);
+                }
                 event_id = ASSend(
                     args->config, mroom_id, encoded, 
-                    "m.room.message", MatrixCreateMessage(data->data)
+                    "m.room.message", ev
                 );
             }
             ParseePushStanza(args, chat_id, s_id_str, id_str, event_id, from);

src/include/Matrix.h

@@ -26,6 +26,9 @@ extern HashMap * MatrixCreateNameState(char *name);
 /* Creates a join membership with a specific nickname */
 extern HashMap * MatrixCreateNickChange(char *nick);
 
+/* Modifies a hashmap to create a reply event */
+extern void MatrixSetReply(HashMap *e, char *event);
+
 /* Get the event ID of the reply if existent */
 extern char * MatrixGetReply(HashMap *event);
 extern char * MatrixGetEdit(HashMap *event);

src/include/XMPP.h

@@ -70,4 +70,7 @@ extern char * XMPPGetOriginID(XMLElement *);
  * is a replacement notice */
 extern char * XMPPGetReplacedID(XMLElement *);
 
+/* Get the replied-to stanza ID, if existent. */
+extern char * XMPPGetReply(XMLElement *elem);
+
 #endif