Allow overriding directories via args

You can now specify directories via args when calling ammo from bash.
All of these arguments are optional.

`--downloads`
    this defaults to `~/Downloads`

`--conf`
    this defaults to `~/.local/share/ammo`.
    If you are overriding this, note that this is the configuration
    for ALL games, not just one. Ammo will still make/expect
    game-specific folders under this directory, and conf for each game
    will be stored inside of that game's folder.

`--mods`
    this defaults to `~/.local/share/ammo/<game name>/mods`.
    If you are overriding this, note that this is the directory that
    contains the actual source files of mods for a specific game. Due to
    the way ammo uses symlinks, it is not recommended to toggle this
    back and forth when running against the same game, as ammo will
    detect when a game's symlinks don't point back to source files in
    this folder (which will cause it to deactivate mods you had
    previously configured).

    I do not recommend using ammo alongside another mod organizer, but I
    suppose this might be useful in those cases.

With these changes, you can now get some semblance of profile support
(though if you're switching between profiles, you will need to
reactivate your mods and plugins then commit):

- Manage all games with default profile:
    `ammo`
- Manage all games with arbitrary profile:
    `ammo --conf Documents/ammo_alt_profile`

ammo/game_controller.py

@@ -33,7 +33,8 @@ class GameController(Controller):
     with the selected game and runs it under the UI.
     """
 
-    def __init__(self):
+    def __init__(self, args):
+        self.args = args
         self.ids = {
             "Skyrim Special Edition": "489830",
             "Oblivion": "22330",
@@ -43,7 +44,8 @@ def __init__(self):
             "Enderal Special Edition": "976620",
             "Starfield": "1716740",
         }
-        self.downloads = Path.home() / "Downloads"
+        self.downloads = self.args.downloads.resolve(strict=True)
+
         self.steam = Path.home() / ".local/share/Steam/steamapps"
         self.flatpak = (
             Path.home()
@@ -139,8 +141,8 @@ def _manage_game(self, index: int) -> None:
         )
         data = directory / "Data"
 
-        ammo_conf_dir = Path.home() / f".local/share/ammo/{game_selection.name}"
-        ammo_mods_dir = ammo_conf_dir / "mods"
+        ammo_conf_dir = self.args.conf.resolve() / game_selection.name
+        ammo_mods_dir = (self.args.mods or ammo_conf_dir / "mods").resolve()
         ammo_conf = ammo_conf_dir / "ammo.conf"
 
         match game_selection.name:

bin/ammo

@@ -1,7 +1,37 @@
 #!/usr/bin/env python3
+import argparse
+from pathlib import Path
+
 from ammo.game_controller import GameController
 from ammo.ui import UI
 
-controller = GameController()
+parser = argparse.ArgumentParser(description="Manage mods for Bethesda games.")
+
+parser.add_argument(
+    "--downloads",
+    default=Path.home() / "Downloads",
+    metavar="PATH",
+    help="directory containing installable archives",
+    type=Path,
+)
+
+parser.add_argument(
+    "--conf",
+    default=Path.home() / ".local/share/ammo",
+    metavar="PATH",
+    help="directory containing configs for managed games",
+    type=Path,
+)
+
+parser.add_argument(
+    "--mods",
+    metavar="PATH",
+    help="directory containing mods for this session",
+    type=Path,
+)
+
+args = parser.parse_args()
+
+controller = GameController(args)
 ui = UI(controller)
 ui.repl()