#! /bin/sh
set -xeuf

. ./lib/prelude.sh

nix_url=https://nixos.org/releases/nix/nix-1.8/nix-1.8-x86_64-linux.tar.bz2
nix_sha256=52fab207b4ce4d098a12d85357d0353e972c492bab0aa9e08e1600363e76fefb
nix_find_sha1sum=86f8775bd4f0841edd4c816df861cebf509d58c3

# This is somewhat required because cloudatcost requires whitelisting
# of hosts.  If you whitelist your localhost, then leave this empty.
# cac_via=
#
# cac_key=
# cac_login=
# cac_servername=

# hostname=

main() {
  listservers=$(cac_listservers)

  listserversstatus=$(echo $listservers | jq -r .status)
  case $listserversstatus in
    ok) : ;;
    *)
      echo $0: bad listservers status: $listserversstatus >&2
      exit 1
  esac

  config=$(echo $listservers \
      | jq -r ".data|map(select(.servername == \"$cac_servername\"))[]")

  serverstatus=$(echo $config | jq -r .status)
  case $serverstatus in
    'Powered On') : ;;
    *)
      echo $0: bad server status: $serverstatus >&2
      exit 2
  esac

  template=$(echo $config | jq -r .template)
  case $template in
    'CentOS-7-64bit') infest_centos7_64bit "$config";;
    *)
      echo $0: bad template: $template >&2
      exit 3
  esac
}


cac_listservers() {
  if test -z "${cac_via-}"; then
    curl -fsS \
      "https://panel.cloudatcost.com/api/v1/listservers.php?key=$cac_key\&login=$cac_login"
  else
    ssh -q $cac_via -t curl -fsS \
      "https://panel.cloudatcost.com/api/v1/listservers.php?key=$cac_key\\&login=$cac_login"
  fi
}


infest_centos7_64bit() {
  config=$1
  address=$(echo $config | jq -r .ip)
  gateway=$(echo $config | jq -r .gateway)
  nameserver=8.8.8.8
  netmask=$(echo $config | jq -r .netmask)
  prefixLength=$(netmaskToPrefixLengh $netmask)
  RSYNC_RSH='sshpass -e ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null'
  SSHPASS=$(echo $config | jq -r .rootpass)
  export SSHPASS
  export RSYNC_RSH

  main="modules/$hostname/default.nix"
  target="root@$address"

  ./networking-configuration $cac_servername $hostname \
    > modules/$hostname/networking.nix

  echo '(
    set -xeuf
    type bzip2 || yum install -y bzip2
    type rsync || yum install -y rsync
  )' \
    | sshpass -e ssh \
        -o StrictHostKeyChecking=no \
        -o UserKnownHostsFile=/dev/null \
        "root@$address" \
        /bin/sh

  rsync_filter "$main" \
    | rsync -f '. -' -zvrlptD --delete-excluded ./ "$target":/etc/nixos/

  #
  #
  #
  echo '(
    set -xeuf
    groupadd -g 30000 nixbld || :
    for i in `seq 1 10`; do
      useradd -c "foolsgarden Nix build user $i" \
              -d /var/empty \
              -s /sbin/nologin \
              -g 30000 \
              -G 30000 \
              -l -u $(expr 30000 + $i) \
              nixbld$i || :
      rm -f /var/spool/mail/nixbld$i
    done

    #curl https://nixos.org/nix/install | sh
    nix_tar=$nix_basename.tar.bz2
    if ! echo $nix_sha256 $nix_tar | sha256sum -c; then
      curl -O -C - $nix_url || :
      if ! echo $nix_sha256 $nix_tar | sha256sum -c; then
        curl -O $nix_url || :
        if ! echo $nix_sha256 $nix_tar | sha256sum -c; then
          echo $0: cannot download $nix_url >&2
          exit 5
        fi
      fi
    fi

    if ! test -d $nix_basename; then
      tar jxf $nix_basename.tar.bz2
    fi

    nix_find=$nix_basename.find.txt
    if ! echo $nix_find_sha1sum $nix_find | sha1sum -c; then
      find $nix_basename | sort > $nix_find
      if ! echo $nix_find_sha1sum $nix_find | sha1sum -c; then
        echo $0: cannot unpack $nix_basename.tar.bz2 >&2
        # TODO we could retry
        exit 6
      fi
    fi

    mkdir -p bin
    PATH=$HOME/bin:$PATH
    export PATH

    # generate fake sudo because
    # sudo: sorry, you must have a tty to run sudo
    {
      echo "#! /bin/sh"
      echo "exec env \"\$@\""
    } > bin/sudo
    chmod +x bin/sudo

    ./$nix_basename/install

    . /root/.nix-profile/etc/profile.d/nix.sh

    nixpkgs_expr="import <nixpkgs> { system = builtins.currentSystem; }"
    nixpkgs_path=$(
      find /nix/store -mindepth 1 -maxdepth 1 -name *-nixpkgs-* -type d
    )

    for i in nixos-generate-config nixos-install; do
      nix-env \
        --arg config "{ nix.package = ($nixpkgs_expr).nix; }" \
        --arg pkgs "$nixpkgs_expr" \
        --arg modulesPath "throw \"no modulesPath\"" \
        -f $nixpkgs_path/nixpkgs/nixos/modules/installer/tools/tools.nix \
        -iA config.system.build.$i
    done

    # TODO following fail when aborted in-between
    if ! test -d /int; then
      mkdir -p /int
      mount --bind /int /mnt
    fi
    if ! test -d /mnt/boot; then
      mkdir -p /mnt/boot
      mount /dev/sda1 /mnt/boot
    fi

    mkdir -p /mnt/etc/nixos
    rsync -zvrlptD --delete-excluded /etc/nixos/ /mnt/etc/nixos/

    mkdir -m 0444 -p /mnt/var/empty

    ln -s $main /mnt/etc/nixos/configuration.nix
    nixos-install

    rsync -va --force /int/ /

    # find / -type f -mtime +1 -exec rm -v {} \; 2>&1 > rm.log
    #   ^ too aggressive, kills journal which is bad
    # shutdown -r now
    # nix-channel --add https://nixos.org/channels/nixos-unstable nixos
    # nix-channel --remove nixpkgs
    # nix-channel --update

  )' \
    | sshpass -e ssh \
        -o StrictHostKeyChecking=no \
        -o UserKnownHostsFile=/dev/null \
        "root@$address" \
        -T /usr/bin/env \
          nix_url="$nix_url" \
          nix_basename="$(basename $nix_url .tar.bz2)" \
          nix_sha256="$nix_sha256" \
          nix_find_sha1sum="$nix_find_sha1sum" \
          main="$main" \
          /bin/sh
}

netmaskToPrefixLengh() {
  binaryNetmask=$(echo $1 | sed 's/^/obase=2;/;s/\./;/g' | bc | tr -d \\n)
  binaryPrefix=$(echo $binaryNetmask | sed -n 's/^\(1*\)0*$/\1/p')
  if ! echo $binaryPrefix | grep -q .; then
    echo $0: bad netmask: $netmask >&2
    exit 4
  fi
  printf %s $binaryPrefix | tr -d 0 | wc -c
}


main "$@"