fixup! build: use Justfile as command runner

Justfile

@@ -2,6 +2,8 @@
 
 set dotenv-load := true
 
+export PIP_REQUIRE_VIRTUALENV := "true"
+
 # === Aliases ===
 
 [private]
@@ -42,10 +44,8 @@ short_version := replace_regex(game_version, "([0-9]+).([0-9]+).[0-9]+", "$1.$2"
 build_date := `date +'%Y/%m/%d'`
 commit_hash := `git log --pretty=format:"%H" -1`
 
-# Python binaries
-python_dir := if os_family() == "windows" { "./venv/Scripts" } else { "./venv/bin" }
-python_bin := python_dir + if os_family() == "windows" { "/python.exe" } else { "/python3" }
-system_python := if os_family() == "windows" { "py.exe -3" } else { "python3" }
+# Python virtualenv
+venv_dir := justfile_directory() / "venv"
 
 # Butler binary
 butler_bin := bin_dir / "butler"
@@ -63,11 +63,11 @@ default:
 makedirs:
     @mkdir -p {{ cache_dir }} {{ bin_dir }} {{ build_dir }} {{ dist_dir }}
 
-# Setup python virtualenv
+# Python virtualenv wrapper
 [private]
-venv:
-    [ ! -d venv ] && {{ system_python }} -m venv venv || true
-    {{ python_bin }} -m pip install pre-commit==3.3.3 reuse==2.1.0 gdtoolkit==4.*
+@venv *ARGS:
+    [ ! -d {{ venv_dir }} ] && python3 -m venv {{ venv_dir }} || true
+    . {{ venv_dir }}/bin/activate && {{ ARGS }}
 
 # Download Godot
 [private]
@@ -116,16 +116,17 @@ bump-version:
     echo -e "[build_info]\npackage/version={{ game_version }}\npackage/build_date={{ build_date }}\nsource/commit={{ commit_hash }}" > override.cfg
 
 # Godot binary wrapper
-godot *ARGS: makedirs install-godot install-templates
+@godot *ARGS: makedirs install-godot install-templates
     {{ godot_bin }} {{ ARGS }}
 
 # Open the Godot editor
 editor:
     just godot --editor
 
 # Run files formatters
-fmt: venv
-    {{ python_dir }}/pre-commit run -a
+fmt:
+    just venv pip install pre-commit==3.3.3 reuse==2.1.0 gdtoolkit==4.*
+    just venv pre-commit run -a
 
 # Export game on Windows
 export-windows: bump-version install-addons import-resources
@@ -154,6 +155,7 @@ export: export-windows export-mac export-linux
 [private]
 clean-mkflower:
     rm -rf {{ main_dir }}
+    rm -rf {{ venv_dir }}
 
 # Remove files created during the export
 clean-export:
@@ -190,7 +192,7 @@ install-butler:
     fi
 
 # Bulter wrapper
-butler *ARGS: install-butler
+@butler *ARGS: install-butler
     {{ butler_bin }} {{ ARGS }}
 
 # Upload the game on Github and Itch.io