feat: Detect dark theme on Windows

7 files changed, 69 insertions, 1 deletions

diff --git a/README.md b/README.md
index 6a9afbeeb..93f2c580d 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,7 @@
 - [sqlite](https://www.sqlite.org/) (>=3.33.0)
 - [omemo-dr](https://dev.gajim.org/gajim/omemo-dr) (>=1.0.0)
 - [qrcode](https://pypi.org/project/qrcode/) (>=7.3.1)
+- [winsdk](https://pypi.org/project/winsdk/) (Only on Windows)
 
 ### Optional Runtime Requirements
 
diff --git a/gajim/common/winapi/__init__.py b/gajim/common/winapi/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/gajim/common/winapi/__init__.py
diff --git a/gajim/common/winapi/system_style.py b/gajim/common/winapi/system_style.py
new file mode 100644
index 000000000..704dc98d4
--- /dev/null
+++ b/gajim/common/winapi/system_style.py
@@ -0,0 +1,60 @@
+# This file is part of Gajim.
+#
+# Gajim 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; version 3 only.
+#
+# Gajim 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 Gajim. If not, see <http://www.gnu.org/licenses/>.
+
+# Based on https://learn.microsoft.com/en-us/windows/apps/desktop/modernize/apply-windows-themes
+
+from __future__ import annotations
+
+from typing import Callable
+from typing import Optional
+
+import logging
+
+from winsdk.windows.ui import Color
+from winsdk.windows.ui.viewmanagement import UIColorType
+from winsdk.windows.ui.viewmanagement import UISettings
+
+from gajim.common import app
+from gajim.common.events import StyleChanged
+
+log = logging.getLogger('gajim.c.winapi.system_style')
+
+
+class SystemStyleListener:
+    def __init__(self, callback: Callable[..., None]) -> None:
+        self._prefer_dark: Optional[bool] = None
+        self._callback = callback
+
+        self._ui_settings = UISettings()
+        self._ui_settings.add_color_values_changed(
+            self._signal_color_values_changed)
+        foreground_color = self._ui_settings.get_color_value(
+            UIColorType.FOREGROUND)
+        self._prefer_dark = self._is_color_light(foreground_color)
+
+    @staticmethod
+    def _is_color_light(clr: Color) -> bool:
+        return ((5 * clr.g) + (2 * clr.r) + clr.b) > (8 * 128)
+
+    def _signal_color_values_changed(self, ui_settings: UISettings, _) -> None:
+        foreground_color = ui_settings.get_color_value(UIColorType.FOREGROUND)
+        dark_theme = self._is_color_light(foreground_color)
+        if dark_theme != self._prefer_dark:
+            self._prefer_dark = dark_theme
+            self._callback()
+            app.ged.raise_event(StyleChanged())
+
+    @property
+    def prefer_dark(self) -> Optional[bool]:
+        return self._prefer_dark
diff --git a/gajim/gtk/css_config.py b/gajim/gtk/css_config.py
index fe27be51e..a83b9d273 100644
--- a/gajim/gtk/css_config.py
+++ b/gajim/gtk/css_config.py
@@ -36,7 +36,11 @@ from gajim.common import app
 from gajim.common import configpaths
 from gajim.common.const import CSSPriority
 from gajim.common.const import StyleAttr
-from gajim.common.dbus.system_style import SystemStyleListener
+
+if sys.platform == 'win32':
+    from gajim.common.winapi.system_style import SystemStyleListener
+else:
+    from gajim.common.dbus.system_style import SystemStyleListener
 
 from gajim.gtk.const import Theme
 
diff --git a/pyproject.toml b/pyproject.toml
index 553b08ba9..4545e450b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,6 +36,7 @@ dependencies = [
   "PyGObject>=3.42.0",
   "qrcode>=7.3.1",
   "omemo-dr>=0.99.0,<2.0.0",
+  "winsdk ; platform_system == 'Windows'",
 ]
 dynamic = ["version"]
 
diff --git a/win/_base.sh b/win/_base.sh
index 69ce39056..5302c4ef3 100755
--- a/win/_base.sh
+++ b/win/_base.sh
@@ -81,6 +81,7 @@ function install_deps {
         "${MINGW_PACKAGE_PREFIX}"-python-setuptools \
         "${MINGW_PACKAGE_PREFIX}"-python-setuptools-scm \
         "${MINGW_PACKAGE_PREFIX}"-python-six \
+        "${MINGW_PACKAGE_PREFIX}"-python-winsdk \
         "${MINGW_PACKAGE_PREFIX}"-gtk3 \
         "${MINGW_PACKAGE_PREFIX}"-gtksourceview4 \
         "${MINGW_PACKAGE_PREFIX}"-gstreamer \
diff --git a/win/dev_env.sh b/win/dev_env.sh
index 66aa6c873..2d352cd0e 100755
--- a/win/dev_env.sh
+++ b/win/dev_env.sh
@@ -24,6 +24,7 @@ function main {
         ${MINGW_PACKAGE_PREFIX}-python-setuptools \
         ${MINGW_PACKAGE_PREFIX}-python-setuptools-scm \
         ${MINGW_PACKAGE_PREFIX}-python-six \
+        ${MINGW_PACKAGE_PREFIX}-python-winsdk \
         ${MINGW_PACKAGE_PREFIX}-gtk3 \
         ${MINGW_PACKAGE_PREFIX}-gtksourceview4 \
         ${MINGW_PACKAGE_PREFIX}-gstreamer \