Fixed GDM reinstallation, extracted gresource and update-alternatives logic

scripts/utils/alternatives_updater.py

@@ -0,0 +1,86 @@
+import functools
+import subprocess
+from typing import TypeAlias
+
+from scripts.utils.console import Console
+
+PathString: TypeAlias = str | bytes
+
+class AlternativesUpdater:
+    """
+    Manages update-alternatives for Ubuntu.
+    Ignores errors if update-alternatives not found.
+    """
+
+    @staticmethod
+    def ubuntu_specific(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            try:
+                result = func(*args, **kwargs)
+                return result
+            except FileNotFoundError as e:
+                if not "update-alternatives" in str(e):
+                    raise
+                return None
+
+        return wrapper
+
+    @staticmethod
+    @ubuntu_specific
+    def install_and_set(link: str, name: str, path: PathString, priority: int = 0):
+        AlternativesUpdater.install(link, name, path, priority)
+        AlternativesUpdater.set(name, path)
+
+    @staticmethod
+    @ubuntu_specific
+    def install(link: str, name: str, path: PathString, priority: int = 0):
+        """
+        Add an alternative to the system
+        :param link: Absolute path with file name where the link will be created
+        :param name: Name of the alternative
+        :param path: An absolute path to the file that will be linked
+        :param priority: Priority of the alternative; Higher number means higher priority
+
+        Example:
+            install(/usr/share/gnome-shell/gdm-theme.gresource,
+            gdm-theme.gresource, /usr/share/gnome-shell/gnome-shell-theme.gresource)
+        """
+        subprocess.run([
+            "update-alternatives", "--quiet", "--install",
+            link, name, str(path), str(priority)
+        ], check=True)
+        Console.Line().success(f"Installed {name} alternative.")
+
+    @staticmethod
+    @ubuntu_specific
+    def set(name: str, path: PathString):
+        """
+        Set path as alternative to name in system
+        :param name: Name of the alternative
+        :param path: An absolute path to the file that will be linked
+
+        Example:
+            set(gdm-theme.gresource, /usr/share/gnome-shell/gnome-shell-theme.gresource)
+        """
+        subprocess.run([
+            "update-alternatives", "--quiet", "--set",
+            name, str(path)
+        ], check=True)
+
+    @staticmethod
+    @ubuntu_specific
+    def remove(name: str, path: PathString):
+        """
+        Remove alternative from system
+        :param name: Name of the alternative
+        :param path: An absolute path to the file that will be linked
+
+        Example:
+            remove(gdm-theme.gresource, /usr/share/gnome-shell/gnome-shell-theme.gresource)
+        """
+        subprocess.run([
+            "update-alternatives", "--quiet", "--remove",
+            name, str(path)
+        ], check=True)
+        Console.Line().success(f"Removed {name} alternative.")