--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/plugins/plugin_xep_0203.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+
+
+# SAT plugin for Delayed Delivery (XEP-0203)
+# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
+# Copyright (C) 2013-2016 Adrien Cossa (souliane@mailoo.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from libervia.backend.core.i18n import _
+from libervia.backend.core.constants import Const as C
+from libervia.backend.core.log import getLogger
+
+log = getLogger(__name__)
+
+from wokkel import disco, iwokkel, delay
+
+try:
+    from twisted.words.protocols.xmlstream import XMPPHandler
+except ImportError:
+    from wokkel.subprotocols import XMPPHandler
+from zope.interface import implementer
+
+
+NS_DD = "urn:xmpp:delay"
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Delayed Delivery",
+    C.PI_IMPORT_NAME: "XEP-0203",
+    C.PI_TYPE: "XEP",
+    C.PI_PROTOCOLS: ["XEP-0203"],
+    C.PI_MAIN: "XEP_0203",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: _("""Implementation of Delayed Delivery"""),
+}
+
+
+class XEP_0203(object):
+    def __init__(self, host):
+        log.info(_("Delayed Delivery plugin initialization"))
+        self.host = host
+
+    def get_handler(self, client):
+        return XEP_0203_handler(self, client.profile)
+
+    def delay(self, stamp, sender=None, desc="", parent=None):
+        """Build a delay element, eventually append it to the given parent element.
+
+        @param stamp (datetime): offset-aware timestamp of the original sending.
+        @param sender (JID): entity that originally sent or delayed the message.
+        @param desc (unicode): optional natural language description.
+        @param parent (domish.Element): add the delay element to this element.
+        @return: the delay element (domish.Element)
+        """
+        elt = delay.Delay(stamp, sender).toElement()
+        if desc:
+            elt.addContent(desc)
+        if parent:
+            parent.addChild(elt)
+        return elt
+
+
+@implementer(iwokkel.IDisco)
+class XEP_0203_handler(XMPPHandler):
+
+    def __init__(self, plugin_parent, profile):
+        self.plugin_parent = plugin_parent
+        self.host = plugin_parent.host
+        self.profile = profile
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_DD)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+        return []