#!/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)

hostcache=0
copykeyring=1
copymirrorlist=1
pacmode=-Sy

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

  Options:
    -C <config>    Use an alternate config file for pacman
    -c             Use the package cache on the host, rather than the target
    -G             Avoid copying the host's pacman keyring to the target
    -i             Prompt for package confirmation when needed (run interactively)
    -M             Avoid copying the host's mirrorlist to the target
    -U             Use pacman -U to install packages

    -h             Print this help message

pacstrap installs packages to the specified new root directory. If no packages
are given, pacstrap defaults to the "base" group.

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 ':C:cdGiMU' flag; do
  case $flag in
    C)
      pacman_config=$OPTARG
      ;;
    d)
      # retired flag. does nothing.
      ;;
    c)
      hostcache=1
      ;;
    i)
      interactive=1
      ;;
    G)
      copykeyring=0
      ;;
    M)
      copymirrorlist=0
      ;;
    U)
      pacmode=-U
      ;;
    :)
      die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
    ?)
      die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
      ;;
  esac
done
shift $(( OPTIND - 1 ))

(( $# )) || die "No root directory specified"
newroot=$1; shift
pacman_args=("${@:-base}")

if (( ! hostcache )); then
  pacman_args+=(--cachedir="$newroot/var/cache/pacman/pkg")
fi

if (( ! interactive )); then
  pacman_args+=(--noconfirm)
fi

if [[ $pacman_config ]]; then
  pacman_args+=(--config="$pacman_config")
fi

[[ -d $newroot ]] || die "%s is not a directory" "$newroot"

# create obligatory directories
msg 'Creating install root at %s' "$newroot"
mkdir -m 0755 -p "$newroot"/var/{cache/pacman/pkg,lib/pacman,log} "$newroot"/{dev,run,etc/pacman.d}
mkdir -m 1777 -p "$newroot"/tmp
mkdir -m 0555 -p "$newroot"/{sys,proc}

# mount API filesystems
chroot_setup "$newroot" || die "failed to setup chroot %s" "$newroot"

if (( copykeyring )); then
  # if there's a keyring on the host, copy it into the new root, unless it exists already
  if [[ -d /etc/pacman.d/gnupg && ! -d $newroot/etc/pacman.d/gnupg ]]; then
    cp -a /etc/pacman.d/gnupg "$newroot/etc/pacman.d/"
  fi
fi

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

if (( copymirrorlist )); then
  # install the host's mirrorlist onto the new root
  cp -a /etc/pacman.d/mirrorlist "$newroot/etc/pacman.d/"
fi

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