feat(setup): per-distro package detection and install prompt

setup.py

@@ -6,32 +6,94 @@ from __future__ import annotations
 import argparse
 import filecmp
 import platform
+import shlex
 import shutil
 import subprocess
 import sys
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
 from pathlib import Path
 
 SCRIPT_DIR = Path(__file__).resolve().parent
 HOME = Path.home()
-
-# Populated now so per-distro package tracking can key off it.
-try:
-    DISTRO: str = platform.freedesktop_os_release().get("NAME", "")
-except OSError:
-    DISTRO = ""
+DISTRO: str = platform.freedesktop_os_release().get("ID", "")
 
 
-PKGS: list[str] = [
-    "alacritty",
-    "i3",
-    "i3lock",
-    "i3status",
-    "jq",
-    "lf",
-    "rofi",
-    "startx",
-    "tmux",
-    "zsh",
+class PackageManager(ABC):
+    @property
+    @abstractmethod
+    def check_cmd(self) -> list[str]: ...
+
+    @property
+    @abstractmethod
+    def install_cmd(self) -> list[str]: ...
+
+    def is_installed(self, name: str) -> bool:
+        return (
+            subprocess.run(
+                [*self.check_cmd, name],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+            ).returncode
+            == 0
+        )
+
+    def install(self, names: list[str]) -> None:
+        subprocess.run([*self.install_cmd, *names], check=True)
+
+
+class Pacman(PackageManager):
+    @property
+    def check_cmd(self) -> list[str]:
+        return ["pacman", "-Q"]
+
+    @property
+    def install_cmd(self) -> list[str]:
+        return ["sudo", "pacman", "-S", "--needed"]
+
+
+class Apt(PackageManager):
+    @property
+    def check_cmd(self) -> list[str]:
+        return ["dpkg-query", "-W", "-f=${Status}"]
+
+    @property
+    def install_cmd(self) -> list[str]:
+        return ["sudo", "apt", "install"]
+
+    def is_installed(self, name: str) -> bool:
+        r = subprocess.run(
+            [*self.check_cmd, name], capture_output=True, text=True
+        )
+        return r.returncode == 0 and r.stdout.strip() == "install ok installed"
+
+
+_apt = Apt()
+PACKAGE_MANAGERS: dict[str, PackageManager] = {
+    "arch": Pacman(),
+    "ubuntu": _apt,
+    "debian": _apt,
+}
+
+PM: PackageManager | None = PACKAGE_MANAGERS.get(DISTRO)
+
+
+@dataclass(frozen=True)
+class Pkg:
+    default_name: str
+    distro_names: dict[str, str] | None = None
+
+    def name(self, distro: str) -> str:
+        return (self.distro_names or {}).get(distro, self.default_name)
+
+
+PKGS: list[Pkg] = [
+    Pkg("foot"),
+    Pkg("jq"),
+    Pkg("lf"),
+    Pkg("tmux"),
+    Pkg("vim"),
+    Pkg("zsh"),
 ]
 
 
@@ -114,10 +176,40 @@ class Context:
         print(f"Error: {msg}", file=sys.stderr)
 
 
+def prompt_yes_no(question: str, default: bool = False) -> bool:
+    if not sys.stdin.isatty():
+        return default
+    suffix = " [Y/n] " if default else " [y/N] "
+    try:
+        answer = input(question + suffix).strip().lower()
+    except EOFError:
+        return default
+    if answer in ("y", "yes"):
+        return True
+    if answer in ("n", "no"):
+        return False
+    return default
+
+
 def check_packages_installed(ctx: Context) -> None:
-    for pkg in PKGS:
-        if shutil.which(pkg) is None:
-            ctx.error(f"missing {pkg}")
+    if PM is None:
+        ctx.error(f"don't know how to manage packages on distro {DISTRO!r}")
+        return
+
+    missing = [name for pkg in PKGS if not PM.is_installed(name := pkg.name(DISTRO))]
+    if not missing:
+        return
+
+    print(f"Missing packages: {', '.join(missing)}")
+
+    if not prompt_yes_no(f"Install with `{shlex.join([*PM.install_cmd, *missing])}`?"):
+        ctx.error(f"packages not installed: {', '.join(missing)}")
+        return
+
+    try:
+        PM.install(missing)
+    except subprocess.CalledProcessError as e:
+        ctx.error(f"package install failed (exit {e.returncode})")
 
 
 def check_terminfo(ctx: Context) -> None: