#!/bin/sh
#
# Copyright (C) 2018-2020 Ruilin Peng (Nick) <pymumu@gmail.com>.
#
# smartdns 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.
#
# smartdns 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/>.

INST_DIR=$(cd $(dirname $0);pwd)
ISWSL=1 # 1 means not WSL, 0 means wsl 

showhelp()
{
	echo "Usage: install [OPTION]"
	echo "Options:"
	echo " -i               install smartdns."
	echo " -u               uninstall smartdns."
	echo " --prefix [dir]   prefix directory."
	echo " -h               show this message."
}

start_service()
{
	if [ $ISSYSTEMD -ne 0 ]; then
		chkconfig smartdns on >/dev/null 2>&1
		service smartdns start
		return $?
	fi

	systemctl daemon-reload
	systemctl enable smartdns
	systemctl start smartdns
}

stop_service()
{
	if [ $ISSYSTEMD -ne 0 ]; then
		service smartdns stop
		chkconfig smartdns off >/dev/null 2>&1
		return 0
	fi

	systemctl stop smartdns
	systemctl disable smartdns

	return 0
}

clean_service()
{
	if [ $ISSYSTEMD -ne 0 ]; then
		return 0
	fi
	systemctl daemon-reload
}

get_systemd_path()
{
	service="`systemctl --no-legend| grep '\.service' | head -n 1 | awk '{print $1}'`"
	SERVICE_PATH="`systemctl show $service | grep FragmentPath | awk -F'=' '{print $2}'`"
	dirname $SERVICE_PATH
}

install_files()
{
	install -v -d $SMARTDNS_CONF_DIR
	if [ $? -ne 0 ]; then
		return 1
	fi

	install -v -m 0755 -t $PREFIX/usr/sbin usr/sbin/smartdns
	if [ $? -ne 0 ]; then
		return 1
	fi

	if [ -e "$PREFIX$SMARTDNS_CONF_DIR/smartdns.conf" ]; then
		cp etc/smartdns/smartdns.conf $PREFIX$SMARTDNS_CONF_DIR/smartdns.conf.pkg
	else 
		install -v -m 0640 -t  $PREFIX$SMARTDNS_CONF_DIR etc/smartdns/smartdns.conf
		if [ $? -ne 0 ]; then
			return 1
		fi
	fi

	install -v -m 0640 -t  $PREFIX/etc/default etc/default/smartdns
	if [ $? -ne 0 ]; then
		return 1
	fi
	
	install -v -m 0755 -t $SMARTDNS_INIT_DIR etc/init.d/smartdns 
	if [ $? -ne 0 ]; then
		if [ $ISSYSTEMD -ne 0 ]; then
			return 1
		fi
	fi

	if [ $ISSYSTEMD -eq 0 ]; then
		SYSTEM_UNIT_PATH="`get_systemd_path`"
		if [ -z "$SYSTEM_UNIT_PATH" ]; then
			return 1
		fi
		install -v -m 0644 -t $PREFIX$SYSTEM_UNIT_PATH systemd/smartdns.service 
		if [ $? -ne 0 ]; then
			return 1
		fi
	fi

	return 0
}

uninstall_smartdns()
{
	if [ -z "$PREFIX" ]; then
		stop_service 2>/dev/null
	fi	
	rmdir $PREFIX$SMARTDNS_CONF_DIR 2>/dev/null
	rm -f $PREFIX/usr/sbin/smartdns
	rm -f $PREFIX/etc/default/smartdns

	if [ $ISWSL -eq 0 ]; then
		sed -i '\#%sudo ALL=NOPASSWD: /etc/init.d/smartdns#d' /etc/sudoers 2>/dev/null
	fi

	if [ $ISSYSTEMD -eq 0 ]; then
		SYSTEM_UNIT_PATH="`get_systemd_path`"
		if [ ! -z "$SYSTEM_UNIT_PATH" ]; then
			rm -f $PREFIX$SYSTEM_UNIT_PATH/smartdns.service
		fi
	fi

	if [ -z "$PREFIX" ]; then
		clean_service
	fi	
}


install_smartdns()
{
	local ret

	which smartdns >/dev/null 2>&1
	if [ $? -eq 0 ]; then
		echo "Already installed."
		return 1
	fi

	install_files
	ret=$?
	if [ $ret -ne 0 ]; then
		uninstall_smartdns
		return $ret
	fi

	if [ -z "$PREFIX" ]; then
		start_service
	fi

	if [ $ISWSL -eq 0 ]; then
		grep "%sudo ALL=NOPASSWD: /etc/init.d/smartdns" /etc/sudoers >/dev/null 2>&1
		if [ $? -ne 0 ]; then
			echo "%sudo ALL=NOPASSWD: /etc/init.d/smartdns" >> /etc/sudoers
		fi
	fi

	return 0
}

init_dir()
{
	local ID=`id -u`
	if [ $ID -ne 0 ]; then
		echo "Please run as root."
		return 1
	fi

	SMARTDNS_CONF_DIR=$PREFIX/etc/smartdns
	SMARTDNS_INIT_DIR=$PREFIX/etc/init.d
	which systemctl >/dev/null 2>&1
	ISSYSTEMD="$?"
	# Running under WSL (Windows Subsystem for Linux)?
	cat /proc/version | grep Microsoft >/dev/null 2>&1; 
	if [ $? -eq 0 ]; then
		ISSYSTEMD=1
		ISWSL=0
	fi

	cd $INST_DIR
}

main()
{
	ACTION=""

	OPTS=`getopt -o iuh --long help,prefix: \
		-n  "" -- "$@"`

	if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi

	# Note the quotes around `$TEMP': they are essential!
	eval set -- "$OPTS"

	while true; do
		case "$1" in
		--prefix)
			PREFIX="$2"
			shift 2;;
		-h | --help )
			showhelp
			return 0
			shift ;;
		-i )
			ACTION="INSTALL"
			shift ;;
		-u )
			ACTION="UNINSTALL"
			shift ;;
		-- ) shift; break ;;
		* ) break ;;
  		esac
	done

	init_dir

	if [ -z "$ACTION" ]; then
		showhelp
		return 0
	elif [ "$ACTION" = "INSTALL" ]; then
		install_smartdns
		return $?
	elif [ "$ACTION" = "UNINSTALL" ]; then
		uninstall_smartdns
		return 0
	fi	

}

main $@
exit $?