#!/bin/sh

CONFIGFILE=/etc/tangorc

set -e
. /usr/share/debconf/confmodule

# summary of how this script can be called:
#        * <postinst> `configure' <most-recently-configured-version>
#        * <old-postinst> `abort-upgrade' <new version>
#        * <conflictor's-postinst> `abort-remove' `in-favour' <package>
#          <new-version>
#        * <postinst> `abort-remove'
#        * <deconfigured's-postinst> `abort-deconfigure' `in-favour'
#          <failed-install-package> <version> `removing'
#          <conflicting-package> <version>
# for details, see http://www.debian.org/doc/debian-policy/ or
# the debian-policy package

case "$1" in
       configure)

       # If the package has default file it could be sourced, so that
       # the local admin can overwrite the defaults

       [ -f "/etc/default/tango" ] && . /etc/default/tango

       # Sane defaults:

       [ -z "$SERVER_HOME" ] && SERVER_HOME=/var/lib/tango
       [ -z "$SERVER_USER" ] && SERVER_USER=tango
       [ -z "$SERVER_NAME" ] && SERVER_NAME="Tango Control System Server"
       [ -z "$SERVER_GROUP" ] && SERVER_GROUP=tango
     
       # Groups that the user will be added to, if undefined, then none.
       ADDGROUP="video"
     
       # create user to avoid running server as root
       # 1. create group if not existing
       if ! getent group | grep -q "^$SERVER_GROUP:" ; then
          echo -n "Adding group $SERVER_GROUP.."
          addgroup --quiet --system $SERVER_GROUP 2>/dev/null || true
          echo "..done"
       fi
       # 2. create homedir if not existing
       test -d $SERVER_HOME || mkdir $SERVER_HOME
       # 3. create user if not existing
       if ! getent passwd | grep -q "^$SERVER_USER:"; then
         echo -n "Adding system user $SERVER_USER.."
         adduser --quiet \
                 --system \
                 --ingroup $SERVER_GROUP \
                 --no-create-home \
		 --home /nonexistent \
                 --disabled-password \
                 $SERVER_USER 2>/dev/null || true
         echo "..done"
       fi
       # 4. adjust passwd entry
       usermod -c "$SERVER_NAME" \
               -d $SERVER_HOME   \
               -g $SERVER_GROUP  \
                  $SERVER_USER
       # 5. adjust file and directory permissions
       if ! dpkg-statoverride --list $SERVER_HOME >/dev/null
       then
           chown -R $SERVER_USER:$SERVER_GROUP $SERVER_HOME
           chmod u=rwx,g=rxs,o= $SERVER_HOME
       fi
       # 6. Add the user to the ADDGROUP group
       if test $ADDGROUP
       then
           if ! groups $SERVER_USER | cut -d: -f2 | \
              grep -qw $ADDGROUP; then
                adduser $SERVER_USER $ADDGROUP
           fi
       fi
       ;;

    abort-upgrade|abort-remove|abort-deconfigure)
    ;;
esac

# Generate config file, if it doesn't exist.
# An alternative is to copy in a template
# file from elsewhere.
if [ ! -e $CONFIGFILE ]; then
    echo "# Config file for my package" > $CONFIGFILE
    echo "TANGO_HOST=" >> $CONFIGFILE
fi

# Substitute in the values from the debconf db.
# There are obvious optimizations possible here.
# The cp before the sed ensures we do not mess up
# the config file's ownership and permissions.
db_get tango-common/tango-host
TANGO_HOST=$RET
cp -a -f $CONFIGFILE $CONFIGFILE.tmp

# If the admin deleted or commented some variables but then set
# them via debconf, (re-)add them to the conffile.
test -z "$TANGO_HOST" || grep -Eq '^ *TANGO_HOST=' $CONFIGFILE || \
    echo "TANGO_HOST=" >> $CONFIGFILE

sed -e "s/^ *TANGO_HOST=.*/TANGO_HOST=$TANGO_HOST/" \
    < $CONFIGFILE > $CONFIGFILE.tmp
mv -f $CONFIGFILE.tmp $CONFIGFILE