#! /bin/sh -e

unset vg snapopt defdist defarch mirror scratchbase
badp=nil
while getopts "a:d:l:v:" opt; do
  case $opt in
    a) defarch=$OPTARG ;;
    d) defdist=$OPTARG ;;
    l) snapopt=$OPTARG ;;
    v) vg=$OPTARG ;;
    *) badp=t ;;
  esac
done
shift $(( $OPTIND - 1 ))
case $# in 0) badp=t ;; esac
case $badp in
  t)
    cat >&2 <<EOF
usage: $0 [-a ARCH] [-d DIST] [-l SNAPOPT] [-v VG]
	DIST-ARCH ...
EOF
    exit 1
    ;;
esac
for arg in "$@"; do
  case $arg in *-*-*) echo >&2 "$0: bad chroot name \`$arg'"; exit 1 ;; esac
done
if [ ! -d /dev/$vg/ ]; then echo >&2 "$0: no volume group \`$vg'"; exit 1; fi

: ${vg=vg-$(hostname)} ${snapopt=-L4g}
: ${defdist=$(apt-config dump |
    sed -n '/^APT::Default-Release "\(.*\)";$/s//\1/p')}
: ${defarch=$(dpkg-architecture -qDEB_HOST_ARCH_CPU)}

for i in $(set | sed -n '/^nickmap_/s/=.*//p'); do unset $i; done
while read canon aliases; do
  for alias in $aliases; do
    eval "nickmap_$canon=\"\${nickmap_$canon+\$nickmap_$canon }$alias\""
  done
done <<EOF
jessie		oldstable
stretch		stable
buster		testing
sid		unstable
EOF

cat <<EOF
### -*-conf-*- GENERATED by mkchrootconf
EOF
for arg in "$@"; do
  dist=${arg%-*} arch=${arg#*-}
  eval "nick=\$nickmap_$dist"

  cat <<EOF

[$arg]
EOF

  unset alias
  for n in $nick; do alias=${alias+$alias,}$n-$arch; done
  case $arch in
    $defarch) for n in $dist $nick; do alias=${alias+$alias,}$n; done ;;
  esac
  case $dist in
    $defdist) alias=${alias+$alias,}$arch ;;
  esac
  case ${alias+t} in
    t)
      cat <<EOF
aliases=$alias
EOF
      ;;
  esac

  case $arch in
    i386)
      cat <<EOF
personality=linux32
EOF
      ;;
    amd64)
      cat <<EOF
personality=linux
EOF
      ;;
  esac

  cat <<EOF
type=lvm-snapshot
description=Debian $dist/$arch autobuilder
device=/dev/$vg/$dist-$arch
lvm-snapshot-options=$snapopt
mount-options=-onosuid,data=writeback,barrier=0,commit=3600,noatime
location=/fs
groups=root,sbuild
root-groups=root,sbuild
source-groups=root
source-root-groups=root
profile=sbuild
EOF
done