Return the language for a reply post

So that replies are by default in the same language

daemon.py

@@ -264,6 +264,7 @@ from shares import shares_catalog_account_endpoint
 from shares import shares_catalog_csv_endpoint
 from categories import set_hashtag_category
 from categories import update_hashtag_categories
+from languages import get_reply_language
 from languages import load_default_post_languages
 from languages import set_default_post_language
 from languages import get_actor_languages
@@ -15772,12 +15773,22 @@ class PubServer(BaseHTTPRequestHandler):
 
             custom_submit_text = get_config_param(base_dir, 'customSubmitText')
 
+            default_post_language = self.server.system_language
+            if self.server.default_post_language.get(nickname):
+                default_post_language = \
+                    self.server.default_post_language[nickname]
+
             post_json_object = None
             if in_reply_to_url:
                 reply_post_filename = \
                     locate_post(base_dir, nickname, domain, in_reply_to_url)
                 if reply_post_filename:
                     post_json_object = load_json(reply_post_filename)
+                    if post_json_object:
+                        reply_language = \
+                            get_reply_language(base_dir, post_json_object)
+                        if reply_language:
+                            default_post_language = reply_language
 
             bold_reading = False
             if self.server.bold_reading.get(nickname):
@@ -15790,10 +15801,6 @@ class PubServer(BaseHTTPRequestHandler):
                                          self.server.domain_full,
                                          self.server.person_cache)
 
-            default_post_language = self.server.system_language
-            if self.server.default_post_language.get(nickname):
-                default_post_language = \
-                    self.server.default_post_language[nickname]
             msg = \
                 html_new_post(edit_post_params, media_instance,
                               translate,

languages.py

@@ -369,3 +369,20 @@ def load_default_post_languages(base_dir: str) -> {}:
                 print('EX: Unable to read default post language ' +
                       default_post_language_filename)
     return result
+
+
+def get_reply_language(base_dir: str,
+                       post_json_object: {}) -> str:
+    """Returns the language that te given post was written in
+    """
+    post_obj = post_json_object
+    if has_object_dict(post_json_object):
+        post_obj = post_json_object['object']
+    if not post_obj.get('contentMap'):
+        return None
+    for lang, content in post_obj['contentMap'].items():
+        lang_filename = base_dir + '/translations/' + lang + '.json'
+        if not os.path.isfile(lang_filename):
+            continue
+        return lang
+    return None

tests.py

@@ -176,6 +176,7 @@ from mastoapiv1 import get_nickname_from_masto_api_v1id
 from webapp_post import prepare_html_post_nickname
 from speaker import speaker_replace_links
 from markdown import markdown_to_html
+from languages import get_reply_language
 from languages import set_actor_languages
 from languages import get_actor_languages
 from languages import get_links_from_content
@@ -7608,6 +7609,35 @@ def _test_emoji_in_actor_name(base_dir: str) -> None:
     assert actor_json['tag'][0]['name'] == ':verified:'
 
 
+def _test_reply_language(base_dir: str) -> None:
+    print('reply_language')
+
+    post_json_object = {
+        'object': {
+            'contentMap': {
+                'en': 'This is some content'
+            }
+        }
+    }
+    assert get_reply_language(base_dir, post_json_object) == 'en'
+
+    post_json_object = {
+        'object': {
+            'contentMap': {
+                'xx': 'This is some content',
+                'de': 'This is some content'
+            }
+        }
+    }
+    assert get_reply_language(base_dir, post_json_object) == 'de'
+
+    post_json_object = {
+        'object': {
+        }
+    }
+    assert not get_reply_language(base_dir, post_json_object)
+
+
 def run_all_tests():
     base_dir = os.getcwd()
     print('Running tests...')
@@ -7625,6 +7655,7 @@ def run_all_tests():
     _test_checkbox_names()
     _test_thread_functions()
     _test_functions()
+    _test_reply_language(base_dir)
     _test_emoji_in_actor_name(base_dir)
     _test_uninvert()
     _test_hashtag_maps()