From cc85859cca97b96b69e9632af3507b4bba89fe29 Mon Sep 17 00:00:00 2001
From: LDA <lda@ari.lt>
Date: Mon, 24 Jun 2024 02:05:11 +0200
Subject: [PATCH] [MOD/WIP] Try doing fallbacks

---
 src/Main.c           |  4 ++--
 src/Parsee/Data.c    | 33 +++++++++++++++++++++++++++++++++
 src/XMPP/Stanza.c    | 17 +++++++++++++++++
 src/include/Parsee.h |  3 +++
 src/include/XMPP.h   |  1 +
 5 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/src/Main.c b/src/Main.c
index 18472c9..6be7a24 100644
--- a/src/Main.c
+++ b/src/Main.c
@@ -19,7 +19,7 @@ static HttpServer *server = NULL;
 static pthread_t xmpp_thr;
 static XMPPComponent *jabber = NULL;
 
-
+extern int ParseeFindDatastart(char *data);
 int
 Main(void)
 {
@@ -38,7 +38,7 @@ Main(void)
 
     ParseeConfigLoad("parsee.json");
     ParseeConfigInit();
-
+    
     /* Write out the config file to a YAML document */
     yaml = StreamOpen("parsee.yaml", "w");
     ParseeExportConfigYAML(yaml);
diff --git a/src/Parsee/Data.c b/src/Parsee/Data.c
index 74dc425..08de33e 100644
--- a/src/Parsee/Data.c
+++ b/src/Parsee/Data.c
@@ -6,6 +6,8 @@
 #include <Cytoplasm/Log.h>
 #include <Cytoplasm/Str.h>
 
+#include <string.h>
+
 #include <Routes.h>
 
 ParseeData *
@@ -99,3 +101,34 @@ ParseeCleanup(void *datp)
     DbListFree(chats);
     /* TODO */
 }
+int
+ParseeFindDatastart(char *data)
+{
+    char *startline;
+    bool found = false;
+    if (!data)
+    {
+        return 0;
+    }
+
+    startline = data;
+    while (startline)
+    {
+        char *endline = strchr(startline, '\n');
+
+        if (*startline != '>')
+        {
+            found = true;
+            break;
+        }
+
+        startline = endline ? endline + 1 : NULL;
+    }
+
+    if (!found)
+    {
+        return 0;
+    }
+
+    return (int) (startline - data);
+}
diff --git a/src/XMPP/Stanza.c b/src/XMPP/Stanza.c
index 73be3ba..6c765b4 100644
--- a/src/XMPP/Stanza.c
+++ b/src/XMPP/Stanza.c
@@ -4,6 +4,7 @@
 #include <Cytoplasm/Str.h>
 #include <Cytoplasm/Log.h>
 
+#include <Parsee.h>
 #include <XML.h>
 
 void
@@ -52,11 +53,27 @@ XMPPSendPlain(XMPPComponent *comp, char *fr, char *to, char *msg, char *type, ch
 
     if (rst && rse)
     {
+        int off = ParseeFindDatastart(msg);
+        char *ostr = StrInt(off);
         XMLElement *reply = XMLCreateTag("reply");
+        XMLElement *fallback = XMLCreateTag("fallback");
+        XMLElement *fall_body = XMLCreateTag("body");
+
         XMLAddAttr(reply, "to", rse);
         XMLAddAttr(reply, "id", rst);
         XMLAddAttr(reply, "xmlns", "urn:xmpp:reply:0");
+
+        XMLAddAttr(fallback, "xmlns", "urn:xmpp:feature-fallback:0");
+        XMLAddAttr(fallback, "for", "urn:xmpp:reply:0");
+
+        XMLAddAttr(fall_body, "start", "0");
+        XMLAddAttr(fall_body, "end", ostr);
+        XMLAddChild(fallback, fall_body);
+
         XMLAddChild(message, reply);
+        XMLAddChild(message, fallback);
+
+        Free(ostr);
     }
 
     XMLAddChild(message, body);
diff --git a/src/include/Parsee.h b/src/include/Parsee.h
index 14cc605..14e832d 100644
--- a/src/include/Parsee.h
+++ b/src/include/Parsee.h
@@ -160,4 +160,7 @@ extern bool ParseeInitialiseSignals(HttpServer *, pthread_t, XMPPComponent *);
 
 /* Job used to cleanup Parsee data that isn't necessary anymore. */
 extern void ParseeCleanup(void *data);
+
+/* Finds the offset of the first line without a '>' at its start. */
+extern int ParseeFindDatastart(char *data);
 #endif
diff --git a/src/include/XMPP.h b/src/include/XMPP.h
index b8cef94..9c3710b 100644
--- a/src/include/XMPP.h
+++ b/src/include/XMPP.h
@@ -60,4 +60,5 @@ extern void XMPPFreeMUCInfo(MUCInfo info);
 
 /* Checks if a stanza has an x-parsee element */
 extern bool XMPPIsParseeStanza(XMLElement *);
+
 #endif