#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#

# Returns the next free SIP extension number

# License
# =======
#
# Copyright (C) 2015 Bob Mottram <bob@robotics.uk.to>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

CONFIG_FILE=/etc/sipwitch.conf

extensions=()

# get the used extensions
for line in $(cat $CONFIG_FILE)
do
    if [[ "$line" == "<extension>"* ]]; then
        ext=$(echo "$line" | awk -F '>' '{print $2}' | awk -F '<' '{print $1}')
        extensions+=($ext)
    fi
    if [[ "$line" == '</provision>' ]]; then
        break
    fi
done

#echo "used extensions:"
#echo $extensions
#echo " "

# which is the first available unused extension ?
for ext in $(seq 201 299);
do
    is_used=
    for i in "${extensions[@]}"
    do
        if [[ "$i" == "$ext" ]]; then
            is_used=1
            break
        fi
    done
    if [ ! $is_used ]; then
        echo $ext;
        break
    fi
done

exit 0