GODT-1329: Dark mode, with macOS autodetect.

internal/frontend/theme/detect_windows.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge 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.
+//
+// ProtonMail Bridge 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 ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+//go:build windows
+// +build windows
+
+package theme
+
+import (
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows/registry"
+)
+
+func detectSystemTheme() Theme {
+	log := logrus.WithField("pkg", "theme")
+	k, err := registry.OpenKey(
+		registry.CURRENT_USER,
+		`SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize`,
+		registry.QUERY_VALUE,
+	)
+
+	if err != nil {
+		log.WithError(err).Error("Not able to open register")
+		return Light
+	}
+	defer k.Close()
+
+	i, _, err := k.GetIntegerValue("AppsUseLightTheme")
+	if err != nil {
+		log.WithError(err).Error("Cannot get value")
+		return Light
+	}
+
+	if i == 0 {
+		return Dark
+	}
+
+	return Light
+}