#!/bin/bash
#
# Copyright (c) 2019 Clementine Computing LLC.
# 
# This file is part of PopuFare.
# 
# PopuFare is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# PopuFare is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
# 
# You should have received a copy of the GNU Affero General Public License
# along with PopuFare.  If not, see <https://www.gnu.org/licenses/>.
#

export BASEDIR="/home/bus"

. $BASEDIR/bin/common_values.sh

usage() {
	echo -e "Usage:" 1>&2
	echo -e "\t$0 line_number" 1>&2
	exit 1
}

# If the supplied line number is not numeric, complain!
#
if echo "$1" | egrep -v '^[0-9]+$' > /dev/null; then usage; fi

# Create a temporary file to hold the selected config line for disection
#
tmpfile=`mktemp /tmp/unpack_server_tmp.XXXXXX`

# Disect the server list and get the first N lines, and then the last one line of that set will be line N
#
head -n "$1" "$SERVER_LIST_FILE" | tail -n 1 > $tmpfile

# Make sure that we have the expected six fields in this line
#
if [ `cat $tmpfile | tr '\t' '\n' | wc -l` -ne 6 ]; then 
	echo "Line $1 does not contain the required 6 tab-delimited fields. Not altering server config." 1>&2; 
	rm -f $tmpfile; 
	usage; 
fi

# Extract the target username...
#
ssh_target_user="`cat $tmpfile | cut -f2`"

# Extract the target hostname...
#
ssh_target_host="`cat $tmpfile | cut -f3`"

# Now, take the username and hostname and make a ssh_target
#
ssh_target="$ssh_target_user@$ssh_target_host"

# If they pass the "smell test", we will proceed, otherwise we bail...
#
if echo "$ssh_target" | egrep -qv "$SSH_TARGET_VALIDITY_CHECK"; then
	echo "Target specified on line $1 appears to be invalid \"$ssh_target\". Not altering server config." 1>&2
	rm -f $tmpfile
	usage
fi

# If we've gotten this far, we are going to go through with it...
#

# Extract and save our description...
#
cat $tmpfile | cut -f1 > $SYNC_DESC_FILE

# Save our new sync target "user@host"...
#
echo "$ssh_target" > $SYNC_TARGET_FILE

# Extract and save our new port number...
#
cat $tmpfile | cut -f4 > $SYNC_PORT_FILE

# Here we need to first put in our target hostname, followed by a space (but no newline)
#

echo -n "$ssh_target_host " > $SYNC_KNOWN_HOSTS
# then append the 5th field (target host's public key)
#
cat $tmpfile | cut -f5 >> $SYNC_KNOWN_HOSTS

# and set the correct permissions
#
chmod $PACKAGE_SSH_MILD_FILE_PERMISSIONS $SYNC_KNOWN_HOSTS

# Here we need to put the correct preface/header on the private key

echo "-----BEGIN RSA PRIVATE KEY-----" > $SYNC_PRIVATE_KEY

# next we need to take the 6th field, and reconstitute all the spaces into newlines
#
cat $tmpfile | cut -f6 | tr ' ' '\n' >> $SYNC_PRIVATE_KEY

# add on the terminating line

echo "-----END RSA PRIVATE KEY-----" >> $SYNC_PRIVATE_KEY

# and set the correct permissions 
#
chmod $PACKAGE_SSH_STRICT_FILE_PERMISSIONS $SYNC_PRIVATE_KEY

# remove our temporary file
#
rm -f $tmpfile

# sync the secondary storage
#
sync

# and signal that we want to close any open SSH sessions and start a new one with the new server
#
abort_tunnel_and_update