#!/bin/bash

# This is the code extracted from /usr/share/lxc/templates/lxc-debian
# that comes with Ubuntu 12.10 which is responsible for downloading the
# rootfs files / packages

set -e

suggest_flush()
{
  echo <<EOF
Container upgrade failed.  The container cache may be out of date,
in which case flushing the case (see -F in the hep output) may help.
EOF
}

cleanup()
{
  rm -rf $cache/partial
  rm -rf $cache/rootfs
}

write_sourceslist()
{
  rootfs=$1
  arch=$2
  release=$3

  MIRROR=${MIRROR:-http://ftp.debian.org/debian}
  SECURITY_MIRROR=${SECURITY_MIRROR:-http://security.debian.org/debian-security}


  if [ 'sid' == "${release}" -o 'unstable' == "${release}" ]; then
    cat <<EOF > ${rootfs}/etc/apt/sources.list
# ${release}
#------------------------------------------------------------------------------
deb ${MIRROR} ${release} main contrib non-free
EOF
  else
    cat <<EOF > ${rootfs}/etc/apt/sources.list
# ${release}
#------------------------------------------------------------------------------
deb ${MIRROR} ${release} main contrib non-free

# ${release} security
#------------------------------------------------------------------------------
deb ${SECURITY_MIRROR} ${release}/updates main contrib non-free

# ${release} updates
#------------------------------------------------------------------------------
deb ${MIRROR} ${release}-updates main contrib non-free

# ${release} proposed updates
#------------------------------------------------------------------------------
deb ${MIRROR} ${release}-proposed-updates main contrib non-free
EOF
  fi
}

download_debian()
{
  cache=$1
  arch=$2
  release=$3

  packages=\
sudo,\
ifupdown,\
locales,\
libui-dialog-perl,\
dialog,\
isc-dhcp-client,\
netbase,\
net-tools,\
iproute,\
openssh-server,\
vim,\
jed,\
jed-extra,\
ssh,\
curl,\
wget,\
bash-completion,\
manpages,\
man-db,\
psmisc,\
bind9-host,\
telnet,\
mtr-tiny,\
iputils-ping,\
ca-certificates

  if [ ! -z "${ADDITIONAL_PACKAGES}" ]; then
      packages=${ADDITIONAL_PACKAGES},${packages}
  fi

  echo "installing packages: ${packages}"

  trap cleanup EXIT SIGHUP SIGINT SIGTERM
  # check the mini debian was not already downloaded
  partial=${cache}/partial-${release}-${arch}
  mkdir -p ${partial}
  if [ $? -ne 0 ]; then
      echo "Failed to create '${partial}' directory"
      return 1
  fi

  # download a mini debian into a cache
  echo "Downloading debian ${release} minimal ..."
  debootstrap \
      --variant=minbase \
      --verbose \
      --components=main,contrib,non-free \
      --arch=${arch} \
      --include=${packages} ${release} ${partial} ${MIRROR}

  if [ $? -ne 0 ]; then
      echo 'Failed to download the rootfs, aborting.'
      return 1
  fi

  echo 'Installing updates'
  write_sourceslist ${partial} ${arch} ${release}

  chroot ${partial} apt-get update
  if [ $? -ne 0 ]; then
      echo 'Failed to update the apt cache'
      return 1
  fi

  lxc-unshare -s MOUNT -- chroot ${partial} \
      apt-get dist-upgrade -y || { suggest_flush; false; }

  chroot ${partial} apt-get clean

  mv ${partial} ${cache}/rootfs
  trap EXIT
  trap SIGINT
  trap SIGTERM
  trap SIGHUP
  echo 'Download complete'
  return 0
}

declare cache=`readlink -f .` \
        arch=$1 \
        release=$2

if [ -d ${cache}/rootfs-${release}-${arch} ]; then
    echo <<EOF
The rootfs cache has been built already, please remove it if you want to update
EOF
    exit 1
fi

download_debian ${cache} ${arch} ${release}