From 06c5b94570e6ce0cbdf7e9876c348aff34c30c50 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20D=C5=82ugosz?=
 <pawel.dlugosz@erlang-solutions.com>
Date: Wed, 21 Jun 2023 13:41:00 +0200
Subject: [PATCH] Update XEP-0050: Ad-Hoc Commands to version 1.3.0

---
 src/adhoc.erl | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/adhoc.erl b/src/adhoc.erl
index ca1d9c0466..c0f6da7f9b 100644
--- a/src/adhoc.erl
+++ b/src/adhoc.erl
@@ -25,7 +25,7 @@
 
 -module(adhoc).
 -author('henoch@dtek.chalmers.se').
--xep([{xep, 50}, {version, "1.2"}]).
+-xep([{xep, 50}, {version, "1.3"}]).
 -export([parse_request/1,
          produce_response/2,
          produce_response/4,
@@ -126,21 +126,34 @@ ensure_correct_session_id(_) ->
 -spec maybe_actions_element([binary()], binary()) -> [exml:element()].
 maybe_actions_element([], _DefaultAction) ->
     [];
+maybe_actions_element(Actions, <<>>) ->
+    % If the "execute" attribute is absent, it defaults to "next".
+    AllActions = ensure_default_action_present(Actions, <<"next">>),
+    [#xmlel{
+        name = <<"actions">>,
+        children = [#xmlel{name = Action} || Action <- AllActions]
+    }];
 maybe_actions_element(Actions, DefaultAction) ->
-    ActionsElAttrs = case DefaultAction of
-        <<"">> -> [];
-        _ -> [{<<"execute">>, DefaultAction}]
-    end,
+    % A form which has an <actions/> element and an "execute" attribute
+    % which evaluates to an action which is not allowed is invalid.
+    AllActions = ensure_default_action_present(Actions, DefaultAction),
     [#xmlel{
         name = <<"actions">>,
-        attrs = ActionsElAttrs,
-        children = [#xmlel{name = Action} || Action <- Actions]
+        attrs = [{<<"execute">>, DefaultAction}],
+        children = [#xmlel{name = Action} || Action <- AllActions]
     }].
 
+-spec ensure_default_action_present([binary()], binary()) -> [exml:element()].
+ensure_default_action_present(Actions, DefaultAction) ->
+    case lists:member(Actions, DefaultAction) of
+        true -> Actions;
+        false -> [DefaultAction | Actions]
+    end.
+
 -spec note_to_xmlel({binary(), iodata()}) -> exml:element().
 note_to_xmlel({Type, Text}) ->
     #xmlel{
         name = <<"note">>,
         attrs = [{<<"type">>, Type}],
         children = [#xmlcdata{content = Text}]
-    }.
\ No newline at end of file
+    }.