--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/plugins/plugin_exp_lang_detect.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+
+
+# SAT plugin to detect language (experimental)
+# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.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 _, D_
+from libervia.backend.core.constants import Const as C
+from libervia.backend.core.log import getLogger
+
+log = getLogger(__name__)
+from libervia.backend.core import exceptions
+
+try:
+    from langid.langid import LanguageIdentifier, model
+except ImportError:
+    raise exceptions.MissingModule(
+        'Missing module langid, please download/install it with "pip install langid")'
+    )
+
+identifier = LanguageIdentifier.from_modelstring(model, norm_probs=False)
+
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Language detection plugin",
+    C.PI_IMPORT_NAME: "EXP-LANG-DETECT",
+    C.PI_TYPE: "EXP",
+    C.PI_PROTOCOLS: [],
+    C.PI_DEPENDENCIES: [],
+    C.PI_MAIN: "LangDetect",
+    C.PI_HANDLER: "no",
+    C.PI_DESCRIPTION: _("""Detect and set message language when unknown"""),
+}
+
+CATEGORY = D_("Misc")
+NAME = "lang_detect"
+LABEL = D_("language detection")
+PARAMS = """
+    <params>
+    <individual>
+    <category name="{category_name}">
+        <param name="{name}" label="{label}" type="bool" value="true" />
+    </category>
+    </individual>
+    </params>
+    """.format(
+    category_name=CATEGORY, name=NAME, label=_(LABEL)
+)
+
+
+class LangDetect(object):
+    def __init__(self, host):
+        log.info(_("Language detection plugin initialization"))
+        self.host = host
+        host.memory.update_params(PARAMS)
+        host.trigger.add("message_received", self.message_received_trigger)
+        host.trigger.add("sendMessage", self.message_send_trigger)
+
+    def add_language(self, mess_data):
+        message = mess_data["message"]
+        if len(message) == 1 and list(message.keys())[0] == "":
+            msg = list(message.values())[0].strip()
+            if msg:
+                lang = identifier.classify(msg)[0]
+                mess_data["message"] = {lang: msg}
+        return mess_data
+
+    def message_received_trigger(self, client, message_elt, post_treat):
+        """ Check if source is linked and repeat message, else do nothing  """
+
+        lang_detect = self.host.memory.param_get_a(
+            NAME, CATEGORY, profile_key=client.profile
+        )
+        if lang_detect:
+            post_treat.addCallback(self.add_language)
+        return True
+
+    def message_send_trigger(self, client, data, pre_xml_treatments, post_xml_treatments):
+        lang_detect = self.host.memory.param_get_a(
+            NAME, CATEGORY, profile_key=client.profile
+        )
+        if lang_detect:
+            self.add_language(data)
+        return True