Automatic theme (#29)

* add "automatic" theme

set the theme and icons based on the system theme

* update the default icons based on system theme

* update pyqt to 6.5.0 to get the colorSchemeChanged callback

* rename style to theme

* remove unused svg files for default theme

* ServerInfoDialog: update feedback colors in dark mode

gotify_tray/gui/themes/__init__.py

@@ -1,5 +1,5 @@
 import logging
-from PyQt6 import QtGui, QtWidgets
+from PyQt6 import QtCore, QtGui, QtWidgets
 from gotify_tray.utils import get_abs_path
 from . import default, dark_purple, light_purple
 from gotify_tray.database import Settings
@@ -9,28 +9,50 @@ settings = Settings("gotify-tray")
 logger = logging.getLogger("gotify-tray")
 
 
-styles = {
+themes = {
     "default": default,
+    "automatic": None,
     "dark purple": dark_purple,
     "light purple": light_purple,
 }
 
 
-def set_theme(app: QtWidgets.QApplication, style: str = "default"):    
-    if style not in styles.keys():
-        logger.error(f"set_style: style {style} is unsupported.")
-        return
+def get_themes():
+    return themes.keys()
+
+
+def is_dark_mode(app: QtWidgets.QApplication) -> bool:
+    return app.styleHints().colorScheme() == QtCore.Qt.ColorScheme.Dark
+
+
+def is_valid_theme(theme: str) -> bool:
+    return theme in get_themes()
+
+
+def set_theme(app: QtWidgets.QApplication, theme: str = "automatic"):
+    if not is_valid_theme(theme):
+        logger.warning(f"set_theme: theme {theme} is unsupported.")
+        theme = "automatic"
+
+    if theme == "automatic":
+        theme = "dark purple" if is_dark_mode(app) else "light purple"
 
     stylesheet = ""
-    with open(get_abs_path(f"gotify_tray/gui/themes/{style.replace(' ', '_')}/style.qss"), "r") as f:
+    with open(get_abs_path(f"gotify_tray/gui/themes/{theme.replace(' ', '_')}/style.qss"), "r") as f:
         stylesheet += f.read()
 
-    app.setPalette(styles[style].get_palette())
+    app.setPalette(themes[theme].get_palette())
     app.setStyleSheet(stylesheet)
 
-def get_themes():
-    return styles.keys()
-    
-def get_theme_file(file: str, theme: str = None) -> str:
+
+def get_theme_file(app: QtWidgets.QApplication, file: str, theme: str = None) -> str:
     theme = settings.value("theme", type=str) if not theme else theme
+
+    if not is_valid_theme(theme):
+        logger.warning(f"set_theme: theme {theme} is unsupported.")
+        theme = "automatic"
+
+    if theme in ("automatic", "default"):
+        theme = "dark purple" if is_dark_mode(app) else "light purple"
+
     return get_abs_path(f"gotify_tray/gui/themes/{theme.replace(' ', '_')}/{file}")