Add basic dark & light theme (#18)

gotify_tray/gui/themes/__init__.py

@@ -0,0 +1,38 @@
+import logging
+from PyQt6 import QtGui, QtWidgets
+from gotify_tray.utils import get_abs_path
+from . import default, dark_purple, light_purple
+from gotify_tray.database import Settings
+
+
+settings = Settings("gotify-tray")
+logger = logging.getLogger("gotify-tray")
+
+
+styles = {
+    "default": default,
+    "dark_purple": dark_purple,
+    "light_purple": light_purple,
+}
+
+
+def set_theme(app: QtWidgets.QApplication, style: str = "default"):
+    app.setStyle("fusion")
+    
+    if style not in styles.keys():
+        logger.error(f"set_style: style {style} is unsupported.")
+        return
+
+    stylesheet = ""
+    with open(get_abs_path(f"gotify_tray/gui/themes/{style}/style.qss"), "r") as f:
+        stylesheet += f.read()
+
+    app.setPalette(styles[style].get_palette())
+    app.setStyleSheet(stylesheet)
+
+def get_themes():
+    return styles.keys()
+    
+def get_theme_file(file: str, theme: str = None) -> str:
+    theme = settings.value("theme", type=str) if not theme else theme
+    return get_abs_path(f"gotify_tray/gui/themes/{theme}/{file}")