_os() {
  if command -v termux-setup-storage >/dev/null; then
    echo "termux"
  else
    grep '^ID=' /etc/os-release | cut -d= -f2
  fi
}

missing=()
check_apply() {
  while IFS= read -r package; do
    cmd=$(echo "$package" | cut -d\; -f1)
    pkg=$(echo "$package" | grep -Eo "$(_os):[^ ]*" || echo ":$cmd")
    pkg=$(echo "$pkg" | cut -d: -f2)
    [ -n "$pkg" ] || continue

    command -v "$cmd" >/dev/null || missing+=( "$pkg" )
  done < ~/.config/mgmt/packages

  [ ${#missing} -eq 0 ]
}

apply() {
  case "$(_os)" in
    ubuntu) manager="apt install" ;;
    arch) manager="pacman -Syu" ;;
    termux) manager="pkg install" ;;
    *) return 1 ;;
  esac

  $manager "${missing[@]}"
}