#!/bin/bash

# note, this script gets piped to bash, so cant cd to current dir
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR


fai_action_arg=I
fai_reboot_arg=,reboot
case $1 in
    -h|--help)
        echo "see help from myfai-chboot"
        exit 0
        ;;
    -S)
        fai_action_arg=S
        fai_reboot_arg=
        shift
        ;;
esac

[[ $EUID == 0 ]] || exec sudo "${BASH_SOURCE}" "$@"

e() {
    echo "$*"
    if ! "$@"; then
        echo "$0: error: exit code $? from: $*"
        exit 1
    fi
}

host=$1

# assuming ipv4, or else we might need to deal with multiple addresses
# in an ipv4 + ipv6 network.
my_ip=$(ip -4 route get 8.8.8.8 | sed -nr 's,^.*src\s+(\S+).*,\1,p')
if [[ ! $my_ip || $my_ip =~ [[:space:]] ]]; then
    echo "$0: error: failed to get \$my_ip, got: $my_ip"
    exit 1
fi

if [[ $host == default ]]; then
    ip='*'
elif [[ $host == [0-9]*.[0-9]*.[0-9]*.[0-9]* ]]; then
    ip=$host/32
else
    type -t host &>/dev/null || apt-get -y install dnsutils
    ip=$(host $host | sed -rn 's/^\S+ has address //p;T;q')/32
    if [[ ! $ip || $ip =~ [[:space:]] ]]; then
        echo "$0: error: failed to get \$my_ip, got: $my_ip"
        exit 1
    fi

fi

if modprobe nfsd &>/dev/null; then
    std_arg="-u nfs://faiserver/srv/fai/config"
    # nfsv4 wont do rw with overlayfs yet
    # https://lists.uni-koeln.de/pipermail/linux-fai/2017-March/011641.html
    root_arg="$my_ip:/srv/fai/nfsroot:vers=3"
    # fai-setup without -e sets the ip to the local_ip/local_network, eg 192.168.1.3/24
    # I restrict it to one ip as simple but imperfect access control.
    sed -ri --follow-symlinks '\%^/srv/fai/%d' /etc/exports
    cat >>/etc/exports <<EOF
/srv/fai/config $ip(async,ro,no_subtree_check)
/srv/fai/nfsroot $ip(async,ro,no_subtree_check,no_root_squash)
EOF
    exportfs -ra
    systemctl start nfs-server # assumes recent os
else
    std_arg="-u http://faiserver:8080/config.tar.gz"
    root_arg="live:http://faiserver:8080/squash.img"
    /a/exe/web-conf -i -p 8080 - apache2 faiserver <<EOF
<Location />
    Deny from all
    Allow from $ip
</Location>
EOF
fi

rm -f /srv/tftp/fai/pxelinux.cfg/*
if [[ ! $1 ]]; then
    exit 0
fi


# man page doesn't explain this, but this deletes & thus disables
# all chboot systems.
e fai-chboot -${fai_action_arg}v $std_arg default # set it to default to get a val out of it next
kernel=$(fai-chboot -L '^default$' | awk '{print $3}')
default_k_args=$(fai-chboot -L '^default$' | \
                     sed -r "s/^(\S+\s+){3}(.*)/\2/")
# example of default_k_args
# initrd=initrd.img-3.16.0-4-amd64 ip=dhcp root=192.168.1.3:/srv/fai/nfsroot aufs FAI_CONFIG_SRC=nfs://faiserver/srv/fai/config FAI_ACTION=install

k_args=()
for arg in $default_k_args; do
    case $arg in
        # default root arg is /srv/fai/nfsroot
        root=*) k_args+=(root=$root_arg) ;;
        *) k_args+=($arg) ;;
    esac
done
rm -f /srv/tftp/fai/pxelinux.cfg/*
e fai-chboot -k "${k_args[*]}" -v -f verbose,sshd,createvt$fai_reboot_arg $std_arg $kernel "$host"