1 files changed, 67 insertions, 0 deletions
diff --git a/xmpp-vala/src/module/xep/0428_fallback_indication.vala b/xmpp-vala/src/module/xep/0428_fallback_indication.vala
new file mode 100644
index 00000000..6686b0ee
--- /dev/null
+++ b/xmpp-vala/src/module/xep/0428_fallback_indication.vala
@@ -0,0 +1,67 @@
+using Gee;
+
+namespace Xmpp.Xep.FallbackIndication {
+
+    public const string NS_URI = "urn:xmpp:fallback:0";
+
+    public class Fallback {
+        public string ns_uri { get; set; }
+        public FallbackLocation[] locations;
+
+
+        public Fallback(string ns_uri, FallbackLocation[] locations) {
+            this.ns_uri = ns_uri;
+            this.locations = locations;
+        }
+    }
+
+    public class FallbackLocation {
+        public int from_char { get; set; }
+        public int to_char { get; set; }
+
+        public FallbackLocation(int from_char, int to_char) {
+            this.from_char = from_char;
+            this.to_char = to_char;
+        }
+    }
+
+    public static void set_fallback(MessageStanza message, Fallback fallback) {
+        StanzaNode fallback_node = (new StanzaNode.build("fallback", NS_URI))
+                .add_self_xmlns()
+                .put_attribute("for", fallback.ns_uri);
+        foreach (FallbackLocation location in fallback.locations) {
+            fallback_node.put_node(new StanzaNode.build("body", NS_URI)
+                .add_self_xmlns()
+                .put_attribute("start", location.from_char.to_string())
+                .put_attribute("end", location.to_char.to_string()));
+        }
+        message.stanza.put_node(fallback_node);
+    }
+
+    public Gee.List<Fallback> get_fallbacks(MessageStanza message) {
+        var ret = new ArrayList<Fallback>();
+
+        Gee.List<StanzaNode> fallback_nodes = message.stanza.get_subnodes("fallback", NS_URI);
+        if (fallback_nodes.is_empty) return ret;
+
+        foreach (StanzaNode fallback_node in fallback_nodes) {
+            string? ns_uri = fallback_node.get_attribute("for");
+            if (ns_uri == null) continue;
+
+            Gee.List<StanzaNode> body_nodes = fallback_node.get_subnodes("body", NS_URI);
+            if (body_nodes.is_empty) continue;
+
+            var locations = new ArrayList<FallbackLocation>();
+            foreach (StanzaNode body_node in body_nodes) {
+                int start_char = body_node.get_attribute_int("start", -1);
+                int end_char = body_node.get_attribute_int("end", -1);
+                if (start_char == -1 || end_char == -1) continue;
+                locations.add(new FallbackLocation(start_char, end_char));
+            }
+            if (locations.is_empty) continue;
+            ret.add(new Fallback(ns_uri, locations.to_array()));
+        }
+
+        return ret;
+    }
+}
+\ No newline at end of file