#!/bin/sh
set -e
# Automatically added by dh_makeshlibs
if [ "$1" = "configure" ]; then
	ldconfig
fi
# End automatically added section


log() {
    echo "$*"
}

# try to insert mdns entries to the "hosts" line in /etc/nsswitch.conf to
# automatically enable nss-mdns support; do not change the configuration if the
# "hosts" line already references some mdns lookups
insert_mdns() {
    log "Checking NSS setup..."
    # abort if /etc/nsswitch.conf does not exist
    if ! [ -e /etc/nsswitch.conf ]; then
        log "Could not find /etc/nsswitch.conf."
        return
    fi
    perl -i -pe '
        sub insert {
            # this also splits on tab
            my @bits=split(" ", shift);
            # do not break configuration if the "hosts" line already references
            # mdns
            if (grep { $_ eq "mdns4_minimal" || $_ eq "mdns4"
                || $_ eq "mdns" || $_ eq "mdns_minimal" 
                || $_ eq "mdns6" || $_ eq "mdns6_minimal"} @bits) {
                return join " ", @bits;
            }
            # change "dns" into "mdns4_minimal [NOTFOUND=return] dns mdns4"
            return join " ", map {
                $_ eq "dns" ? ("mdns4_minimal","[NOTFOUND=return]",$_,"mdns4") : $_
            } @bits;
        }
        s/^(hosts:\s+)(.*)/$1.insert($2)/e;
    ' /etc/nsswitch.conf
}

action="$1"

if [ configure = "$action" ]; then
    if [ -z "$2" ]; then
        log "First installation detected..."
        # first install: setup the recommended configuration (unless
        # nsswitch.conf already contains mdns entries)
        insert_mdns
    else
        # upgrade
        version="$2"

        if dpkg --compare-versions "$version" lt 0.8-4.2; then
            log "Upgrade from unconfigured version detected."
            # versions prior to 0.8-4.2 did not setup nss-mdns automatically,
            # do it now
            insert_mdns
        elif dpkg --compare-versions "$version" lt 0.8-6; then
            log "Already configured version detected, skipping NSS setup."
            # versions 0.8-4.2 and 0.8-5 installed the same configuration as
            # this postinst, so nothing needs to be done
            :
        elif dpkg --compare-versions "$version" lt 0.8-6.1; then
            log "Upgrade from possibly broken version detected."
            if [ -e /etc/nsswitch.conf ]; then
                # version 0.8-6 broke the configuration in multiple ways: 1)
                # for systems which were upgraded from 0.8-4.2 or 0.8-5 to
                # 0.8-6, the hosts line will look like:
                #    hosts:          files  dns 
                # cleanup from this specially formatted line into the default
                # one:
                sed -i \
                    's/^hosts:          files  dns $/hosts:          files dns/' \
                    /etc/nsswitch.conf
                # 2) for systems which re-installed 0.8-6 or installed 0.8-6 as the
                # first version, the hosts line will look like:
                #    hosts:          files mdns_minimal dns mdns
                # cleanup from this specially formatted line into the default one:
                sed -i -r \
                    '/^hosts:/s/\<mdns_minimal dns mdns\>/dns/' \
                    /etc/nsswitch.conf
            fi

            insert_mdns
        fi
    fi
fi