1 files changed, 107 insertions, 0 deletions
diff --git a/src/hydrilla/translations.py b/src/hydrilla/translations.py
new file mode 100644
index 0000000..f6e6760
--- /dev/null
+++ b/src/hydrilla/translations.py
@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Handling of gettext for Hydrilla.
+#
+# This file is part of Hydrilla
+#
+# Copyright (C) 2021, 2022 Wojtek Kosior
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use of this
+# code in a proprietary program, I am not going to enforce this in
+# court.
+
+import locale as lcl
+import gettext
+import typing as t
+
+from pathlib import Path
+
+here = Path(__file__).resolve().parent
+
+localedir = here / 'locales'
+
+supported_locales = [f.name for f in localedir.iterdir() if f.is_dir()]
+
+default_locale = 'en_US'
+
+def select_best_locale(supported: t.Sequence[str] = supported_locales) -> str:
+    """
+    ....
+
+    Otherwise, try to determine system's default language and use that.
+    """
+    # TODO: Stop referenceing flask here. Instead, allow other code to register
+    #       custom locale resolvers and register flask-aware resolver during
+    #       runtime from within the flask-related part(s) of the application.
+    try:
+        import flask
+        use_flask = flask.has_request_context()
+    except ModuleNotFoundError:
+        use_flask = False
+
+    if use_flask:
+        best = flask.request.accept_languages.best_match(
+            supported,
+            default = default_locale
+        )
+        assert best is not None
+        return best
+
+    # https://stackoverflow.com/questions/3425294/how-to-detect-the-os-default-language-in-python
+    # I am not going to surrender to Microbugs' nonfree, crappy OS to test it,
+    # so the lines inside try: block may actually fail.
+    locale: t.Optional[str] = lcl.getdefaultlocale()[0]
+    try:
+        from ctypes.windll import kernel32 as windll # type: ignore
+        locale = lcl.windows_locale[windll.GetUserDefaultUILanguage()]
+    except:
+        pass
+
+    if locale is None or locale not in supported:
+        locale = default_locale
+
+    return locale
+
+translations: t.Dict[str, gettext.NullTranslations] = {}
+
+def translation(locale: t.Optional[str] = None) -> gettext.NullTranslations:
+    """
+    Configure translations for domain 'messages' and return the object that
+    represents them. If the requested locale is not available, fall back to
+    'en_US'.
+    """
+    if locale is None:
+        locale = select_best_locale()
+
+    if not (localedir / locale).is_dir():
+        locale = 'en_US'
+
+    if locale not in translations:
+        translations[locale] = gettext.translation(
+            'messages',
+            localedir=localedir,
+            languages=[locale]
+        )
+
+    return translations[locale]
+
+def smart_gettext(msg: str, locale: t.Optional[str] = None) -> str:
+    """...."""
+    return translation(locale).gettext(msg)
+
+_ = smart_gettext