#!/bin/bash

#
# Assumptions:
#  1) User has partitioned, formatted, and mounted partitions on /mnt
#  2) Network is functional
#  3) Arguments passed to the script are valid pacman targets
#  4) A valid mirror appears in /etc/pacman.d/mirrorlist
#

shopt -s extglob

m4_include(common)

declare newroot=/mnt

usage() {
  cat <<EOF
usage: ${0##*/} [options]

  Options:
    -r root        Install to 'root' (default: /mnt)
    -d             Allow installation to a non-mountpoint directory

EOF
}

if [[ -z $1 || $1 = @(-h|--help) ]]; then
  usage
  exit $(( $# ? 0 : 1 ))
fi

(( EUID == 0 )) || die 'This script must be run with root privileges'

while getopts ':dr:' flag; do
  case $flag in
    d)
      directory=1
      ;;
    r)
      newroot=$OPTARG
      ;;
    :)
      die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
    ?)
      die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
  esac
done
shift $(( OPTIND - 1 ))

if (( $# )); then
  packages=("$@")
else
  packages=('base' 'base-devel')
fi

[[ -d $newroot ]] || die "%s is not a directory" "$newroot"
if ! mountpoint -q "$newroot" && (( ! directory )); then
  die '%s is not a mountpoint!' "$newroot"
fi

# create obligatory directories
msg 'Creating install root at %s' "$newroot"
mkdir -p "$newroot/var/lib/pacman" "/$newroot"/{dev,proc,sys,run,tmp,etc}

# always call umount on quit after this point
trap 'api_fs_umount "$newroot" 2>/dev/null' EXIT

# mount API filesystems
api_fs_mount "$newroot" || die "failed to setup API filesystems in new root"

msg 'Installing packages to %s' "$newroot"
if ! pacman -r "$newroot" -Sy --noconfirm "${packages[@]}"; then
  die 'Failed to install packages to new root'
fi

# if there's a keyring on the host, copy it into the new root
[[ -d /etc/pacman.d/gnupg ]] && cp -a /etc/pacman.d/gnupg "$newroot/etc/pacman.d/"

# vim: et ts=2 sw=2 ft=sh: