post_install_script = '''
#!/bin/bash -e
# Script based on the RPM %systemd_post scriptlet. See:
#   - https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/#_systemd
#   - https://cgit.freedesktop.org/systemd/systemd/tree/src/core/macros.systemd.in

KRILL_USER=krill
KRILL_GROUP=${KRILL_USER}
KRILL_HOME_DIR="/var/lib/krill"
KRILL_HOME_DIR_PERMS=700
KRILL_CONF="/etc/krill.conf"
KRILL_CONF_PERMS=640
KRILL_DATA="${KRILL_HOME_DIR}/data/"

if [ $EUID -ne 0 ]; then
    echo >&2 "ERROR: RTRTR postinst script must be run as root"
    exit 1
fi

create_user() {
    # https://github.com/NLnetLabs/krill/issues/908
    if ! id ${KRILL_USER} > /dev/null 2>&1; then
        # According to the CentOS 7 useradd man page:
        # --user-group causes a group by the same name as the user to be created
        # --create-home should force creation of a home dir even for a system account.
        useradd --home-dir ${KRILL_HOME_DIR} --system --create-home --user-group ${KRILL_USER}
    fi

    # Ensure that the home directory has the correct ownership
    chown -R ${KRILL_USER}:${KRILL_GROUP} ${KRILL_HOME_DIR}

    # Ensure that the home directory has the correct permissions
    chmod ${KRILL_HOME_DIR_PERMS} ${KRILL_HOME_DIR}
}

init_systemd_service() {
    systemctl preset krill.service 2>&1 || :
}

generate_password() {
    # Tries not to depend on too many other commmands
    # being installed.
    cat /dev/random | tr -dc A-Za-z0-9 | head -c 32
}

create_first_time_configuration() {
    if [ ! -f "${KRILL_CONF}" ]; then
        # generate a token for authenticating with Krill
        ADMIN_TOKEN="$(generate_password)"

        # generate a config file using our preferred filesystem locations
        # and generated admin token
        # note: we don't configure Krill to store its PID file under /var/run/
        # because that requires root privileges potentially at least once per
        # boot, and Krill doesn't drop privileges yet so when run as a non-root
        # user has no right to create the file or missing /var/run/subdir.
        # See: https://stackoverflow.com/a/28312577
        printf "%s\n" \
            "log_type = \"syslog\"" \
            "storage_uri = \"${KRILL_DATA}\"" \
            "admin_token = \"${ADMIN_TOKEN}\"" > "${KRILL_CONF}"

        # Ensure that the config file has the correct ownership
        chown ${KRILL_USER}:${KRILL_GROUP} ${KRILL_CONF}
        
        # Ensure that the config file has the correct permissions
        chmod ${KRILL_CONF_PERMS} ${KRILL_CONF}
    fi
}

if [ $1 -eq 1 ] ; then
    # Initial installation
    create_user
    init_systemd_service
    create_first_time_configuration
fi
'''

post_uninstall_script = '''
#!/bin/bash -e
# Script based on the RPM %systemd_postun scriptlet. See:
#   - https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/#_systemd
#   - https://cgit.freedesktop.org/systemd/systemd/tree/src/core/macros.systemd.in

systemctl daemon-reload >/dev/null 2>&1 || :
if [ $1 -ge 1 ] ; then
    systemctl try-restart krill.service >/dev/null 2>&1 || :
fi
'''