#!/bin/bash

set -e

. /usr/share/debconf/confmodule

# This is taken from the package libnss-mdns and edited to do the same thing
# but for GNS insteand of mdns. try to insert gns entries to the "hosts" line
# in /etc/nsswitch.conf to automatically enable nss-gns support; do not change
# the configuration if the "hosts" line already references some gns lookups
insert_gns() {
	echo -n "Checking NSS setup..."
	# abort if /etc/nsswitch.conf does not exist
	if ! [ -e /etc/nsswitch.conf ]; then
		echo "Could not find /etc/nsswitch.conf."
		return 1
	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 gns
			if (grep { $_ eq "gns"} @bits) {
				return join " ", @bits;
			}
			# change "dns" or "resolve", whichever comes first, into
			# "gns [NOTFOUND=return] dns"
			foreach my $bit (@bits) {
				if ($bit eq "dns") {
					$bit = "gns [NOTFOUND=return] $bit";
					last;
				}
			}
			return join " ", @bits;
		}
		s/^(hosts:\s+)(.*)/$1.insert($2)/e;
	' /etc/nsswitch.conf
	echo " done."
}

case "${1}" in
	configure)
		db_version 2.0

		db_get gnunet-systempeer/username
		_USERNAME="${RET:-gnunet}"

		db_get gnunet-systempeer/groupname
		_GROUPNAME="${RET:-gnunet}"

		db_get gnunet-systempeer/autostart
		_AUTOSTART="${RET}" # boolean

		db_get gnunet-dns/libnsswitch
		_LIBNSSWITCH="${RET}" # boolean

		db_get gnunet-user/proxy
		_PROXY="${RET}" # boolean

		db_stop

		CONFIG_FILE="/etc/default/gnunet"

		# Read default values
		GNUNET_HOME="/var/lib/gnunet"
		eval $(grep GNUNET_HOME /etc/gnunet.conf | tr -d '[:blank:]')

		# Creating gnunet group if needed
		if ! getent group ${_GROUPNAME} > /dev/null
		then
			echo -n "Creating new GNUnet group ${_GROUPNAME}:"
			addgroup --quiet --system ${_GROUPNAME}
			echo " done."
		fi

		# Creating gnunet user if needed
		if ! getent passwd ${_USERNAME} > /dev/null
		then
			echo -n "Creating new GNUnet user ${_USERNAME}:"
			adduser --quiet --system --ingroup ${_GROUPNAME} --home ${GNUNET_HOME} ${_USERNAME}
			echo " done."
		fi

		# Add a special secured group
		GNUNETDNS_GROUP="gnunetdns"

		# Creating gnunetdns group if needed
		if ! getent group ${GNUNETDNS_GROUP} > /dev/null
		then
			echo -n "Creating new secured GNUnet group ${GNUNETDNS_GROUP}:"
			addgroup --quiet --system ${GNUNETDNS_GROUP}
			echo " done."
		fi

		# Copy the libnss_gns files to the libnss directory
		if ${_LIBNSSWITCH}
		then
			echo "Editing /etc/nsswitch.conf to use GNS before DNS"
			# $2 equals the currently installed version if it exists
			if [ -z "$2" ]; then
				# first install: setup the recommended configuration (unless
				# nsswitch.conf already contains mdns entries)
				insert_gns
				if [ "$?" -gt 0 ]; then
					echo "nsswitch does not exist on this system"
				fi
			fi
			echo " done."
		fi

                # Install GNUnet configuration for all users provided non exists
		userlist=$(awk -F ':' '$3>=1000 && $3<2000 {print $1}' /etc/passwd)
		users=($userlist)
		homedirlist=$(awk -F ':' '$3>=1000 && $3<2000 {print $6}' /etc/passwd)
                homedirs=($homedirlist)

		for (( i=0; i<${#users[@]}; i++ )); do
		    usermod -aG gnunet ${users[$i]}
                    if [ -n "$i" ]  && [ -d "${homedirs[$i]}" ]; then
			            mkdir -p ${homedirs[$i]}/.config/systemd/user/

			            cat > "${homedirs[$i]}/.config/systemd/user/gnunet-user.service" << EOF
# Copyright (C) 2019 GNUnet e.V.
#
# Copying and distribution of this file, with or without modification,
# are permitted in any medium without royalty provided the copyright
# notice and this notice are preserved.  This file is offered as-is,
# without any warranty.

[Unit]
Description=Service that runs a GNUnet for the user gnunet
After=network.target

[Service]
Type=forking
ExecStart=/usr/bin/gnunet-arm -s -c ${homedirs[$i]}/.config/gnunet.conf
ExecStop=/usr/bin/gnunet-arm -e -c ${homedirs[$i]}/.config/gnunet.conf

[Install]
WantedBy=multi-user.target
EOF

			            chown "${users[$i]}":"${users[$i]}" "${homedirs[$i]}/.config/systemd/user/gnunet-user.service"
                        if [ ! -f "${homedirs[$i]}/.config/gnunet.conf" ]; then
				            mkdir -p ${homedirs[$i]}/.config/
				            cp /etc/skel/.config/gnunet.conf "${homedirs[$i]}/.config/gnunet.conf"
				            chmod 644 "${homedirs[$i]}/.config/gnunet.conf"
                        fi
                    fi
                    port=$((8000+$(id -u "${users[$i]}")))
                    gnunet-config -c "${homedirs[$i]}/.config/gnunet.conf" \
                         --section=gns-proxy \
                         --option=IMMEDIATE_START \
                         --value=YES
                    gnunet-config -c "${homedirs[$i]}/.config/gnunet.conf" \
                         --section=gns-proxy \
                         --option=OPTIONS \
 			             --value="-p $port"
				chown "${users[$i]}":"${users[$i]}" "${homedirs[$i]}/.config/gnunet.conf"
		done

                # Change the proxy settings for Firefox and Chromium if desired
		if ${_PROXY}
        then
		    mkdir -p /etc/X11/xinit/xinitrc.d/
cat > "/etc/X11/xinit/xinitrc.d/80-gnunet-user-services" << "EOF"
#!/bin/bash
systemctl --user daemon-reload
systemctl --user start gnunet-user
systemctl --user enable gnunet-user
user=$(whoami)
gnunet_proxy=$(gnunet-config -c /etc/skel/.config/gnunet.conf -s gns-proxy | grep 'IMMEDIATE_START = YES')

# Enable GNS proxy for new users informed by /etc/skel.
if [ "$gnunet_proxy" ]; then

        # Calculate user specific port
        port=$((8000+$(id -u $user)))

        gnunet-config -c $HOME/.config/gnunet.conf \
                --section=gns-proxy \
                --option=OPTIONS \
                --value="-p $port"

        # Firefox
        defaultprofile=$(ls $HOME/.mozilla/firefox/*.default)
        if [ ! "$defaultprofile" ];then
                timeout 3s firefox --headless # dirty: create profile if not existent
        fi
        for ffprofile in $HOME/.mozilla/firefox/*.*/; do
                js=$ffprofile/user.js
                if [ -f "$js" ]; then
                        sed -i '/Preferences for using the GNU Name System/d' "$js"
                        sed -i '/network.proxy.socks/d' "$js"
                        sed -i '/network.proxy.socks_port/d' "$js"
                        sed -i '/network.proxy.socks_remote_dns/d' "$js"
                        sed -i '/network.proxy.type/d' "$js"
                fi
                echo "// Preferences for using the GNU Name System" >> "$js"
                echo "user_pref(\"network.proxy.socks\", \"localhost\");" >> "$js"
                echo "user_pref(\"network.proxy.socks_port\", $port);" >> "$js"
                echo "user_pref(\"network.proxy.socks_remote_dns\", true);" >> "$js"
                echo "user_pref(\"network.proxy.type\", 1);" >> "$js"
        done

        # Chromium
        profile="$HOME/.profile"
        if [ -f "$profile" ]; then
                sed -i '/CHROMIUM_USER_FLAGS/d' "$profile"
        fi
        echo "export CHROMIUM_USER_FLAGS=--proxy-server=socks5://localhost:$port" \
                >> "$profile"
fi

# Create/Renew GNS certificate authority (CA) per user.
gnunet-gns-proxy-setup-ca
EOF
                fi

		# Update files and directories permissions.
		# Assuming default values, this *should* not be changed.
		echo -n "Updating files and directories permissions:"
		chown -R ${_USERNAME}:${_GROUPNAME} /var/log/gnunetd
		chown -R ${_USERNAME}:${_GROUPNAME} ${GNUNET_HOME}
		# Secure access to the data directory
		chmod 0700 "${GNUNET_HOME}" || true
		# Restrict access on setuid binaries
		for file in /usr/bin/gnunet-helper-exit \
			/usr/bin/gnunet-helper-nat-client \
			/usr/bin/gnunet-helper-nat-server \
			/usr/bin/gnunet-helper-transport-bluetooth \
			/usr/bin/gnunet-helper-transport-wlan \
			/usr/bin/gnunet-helper-vpn
		do
			# only do something when no setting exists
			if ! dpkg-statoverride --list $file >/dev/null 2>&1 && [ -e $file ]
			then
				chown root:${_GROUPNAME} $file
				chmod 4750 $file
			fi
		done
		if ! dpkg-statoverride --list /usr/bin/gnunet-helper-dns >/dev/null 2>&1 \
			&& [ -e /usr/bin/gnunet-helper-dns ]
		then
			chown root:${GNUNETDNS_GROUP} /usr/bin/gnunet-helper-dns
			chmod 4750 /usr/bin/gnunet-helper-dns
		fi
		if ! dpkg-statoverride --list /usr/bin/gnunet-service-dns >/dev/null 2>&1 \
			&& [ -e /usr/bin/gnunet-service-dns ]
		then
			chown ${_USERNAME}:${GNUNETDNS_GROUP} /usr/bin/gnunet-service-dns
			chmod 2750 /usr/bin/gnunet-service-dns
		fi
		echo  " done."

		# Writing new values to configuration file
		echo -n "Writing new configuration file:"
		CONFIG_NEW=$(tempfile)

cat > "${CONFIG_NEW}" <<EOF
# This file controls the behaviour of the GNUnet init script.
# It will be parsed as a shell script.
# please do not edit by hand, use 'dpkg-reconfigure gnunet-systempeer'.

GNUNET_USER=${_USERNAME}
GNUNET_GROUP=${_GROUPNAME}
GNUNET_AUTOSTART="${_AUTOSTART}"
EOF

cat > "/etc/systemd/system/gnunet.service" <<EOF
[Unit]
Description=A framework for secure peer-to-peer networking

[Service]
EnvironmentFile=/etc/default/gnunet
User=${_USERNAME}
Type=forking
ExecStart=/usr/bin/gnunet-arm -s -c /etc/gnunet.conf
ExecStop=/usr/bin/gnunet-arm -e -c /etc/gnunet.conf

[Install]
WantedBy=multi-user.target
EOF

		cp -f "${CONFIG_NEW}" "${CONFIG_FILE}"
		echo " done."

		# Cleaning
		rm -f "${CONFIG_NEW}"
		echo "All done."

		;;

	abort-upgrade|abort-remove|abort-deconfigure)

		;;

	*)
		echo "postinst called with unknown argument \`${1}'" >&2
		exit 1
		;;
esac

#DEBHELPER#

exit 0