#!/bin/bash

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 "$@"; "$@"; }

host=$1

type -t host &>/dev/null || apt-get -y install dnsutils
gateway_if=$(ip route | sed -rn 's/^default via \S+ dev (\S+) .*/\1/p')
if [[ ! $gateway_if ]]; then
    echo "$0: failed to find gateway interface"
    exit 1
fi
# assuming ipv4, or else we might need to deal with multiple addresses
# in an ipv4 + ipv6 network.
network=$(ip -4 -o a show dev $gateway_if | sed -rn '/scope.*global/s/^(\S+\s+){3}(\S+)\s.*/\2/p')
if [[ ! $network ]]; then
    echo "$0: failed to find network"
    exit 1
fi
my_ip=${network%/*}
if [[ $host == default ]]; then
    ip=$network
else
    ip=$(host $host | sed -rn 's/^\S+ has address //p;T;q')/32
fi


# alternate way of getting my ip
#gateway_ip=$(ip route | sed -rn 's/^default via (\S+) .*/\1/p')
#my_ip=$(host faiserver $gateway_ip | sed -rn 's/^\S+ has address //p;T;q')

if modprobe nfsd &>/dev/null; then
    std_arg="-u nfs://faiserver/srv/fai/config"
    root_arg="$my_ip:/srv/fai/nfsroot"
    # 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
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"