#!/usr/bin/env bash
# PiVPN: Uninstall Script

### FIXME: global: config storage, refactor all scripts to adhere to the storage
### FIXME: use variables where appropriate, reduce magic numbers by 99.9%, at least.

# Find the rows and columns. Will default to 80x24 if it can not be detected.
screen_size=$(stty size 2>/dev/null || echo 24 80)
rows=$(echo "$screen_size" | awk '{print $1}')
columns=$(echo "$screen_size" | awk '{print $2}')

# Divide by two so the dialogs take up half of the screen, which looks nice.
r=$(( rows / 2 ))
c=$(( columns / 2 ))
# Unless the screen is tiny
r=$(( r < 20 ? 20 : r ))
c=$(( c < 70 ? 70 : c ))

PKG_MANAGER="apt-get"
UPDATE_PKG_CACHE="${PKG_MANAGER} update"
dnsmasqConfig="/etc/dnsmasq.d/02-pivpn.conf"
setupVarsFile="setupVars.conf"
setupConfigDir="/etc/pivpn"
pivpnFilesDir="/usr/local/src/pivpn"
pivpnScriptDir="/opt/pivpn"

if [ -r "${setupConfigDir}/wireguard/${setupVarsFile}" ] && [ -r "${setupConfigDir}/openvpn/${setupVarsFile}" ]; then
	vpnStillExists=1

	# Two protocols have been installed, check if the script has passed
	# an argument, otherwise ask the user which one he wants to remove
	if [ $# -ge 1 ]; then
		VPN="$1"
		echo "::: Uninstalling VPN: $VPN"
	else
		chooseVPNCmd=(whiptail --backtitle "Setup PiVPN" --title "Uninstall" --separate-output --radiolist "Both OpenVPN and WireGuard are installed, choose a VPN to uninstall (press space to select):" "${r}" "${c}" 2)
		VPNChooseOptions=(WireGuard "" on
							OpenVPN "" off)

		if VPN=$("${chooseVPNCmd[@]}" "${VPNChooseOptions[@]}" 2>&1 >/dev/tty) ; then
			echo "::: Uninstalling VPN: $VPN"
			VPN="${VPN,,}"
		else
			echo "::: Cancel selected, exiting...."
			exit 1
		fi
	fi

	setupVars="${setupConfigDir}/${VPN}/${setupVarsFile}"
else
	vpnStillExists=0

	if [ -r "${setupConfigDir}/wireguard/${setupVarsFile}" ]; then
		setupVars="${setupConfigDir}/wireguard/${setupVarsFile}"
	elif [ -r "${setupConfigDir}/openvpn/${setupVarsFile}" ]; then
		setupVars="${setupConfigDir}/openvpn/${setupVarsFile}"
	fi
fi

if [ ! -f "${setupVars}" ]; then
	echo "::: Missing setup vars file!"
	exit 1
fi

# shellcheck disable=SC1090
source "${setupVars}"

### FIXME: introduce global lib
spinner(){
	local pid=$1
	local delay=0.50
	local spinstr='/-\|'
	while ps a | awk '{print $1}' | grep -q "$pid"; do
		local temp=${spinstr#?}
		printf " [%c]  " "$spinstr"
		local spinstr=$temp${spinstr%"$temp"}
		sleep $delay
		printf "\\b\\b\\b\\b\\b\\b"
	done
	printf "    \\b\\b\\b\\b"
}

removeAll(){
	# Stopping and disabling services
	echo "::: Stopping and disabling services..."

	if [ "$VPN" = "wireguard" ]; then
		systemctl stop wg-quick@wg0
		systemctl disable wg-quick@wg0 &> /dev/null
	elif [ "$VPN" = "openvpn" ]; then
		systemctl stop openvpn
		systemctl disable openvpn &> /dev/null
	fi

	# Removing firewall rules.
	echo "::: Removing firewall rules..."

	if [ "$USING_UFW" -eq 1 ]; then

    ### Ignoring SC2154, value sourced from setupVars file
		# shellcheck disable=SC2154
		ufw delete allow "${pivpnPORT}"/"${pivpnPROTO}" > /dev/null
    ### Ignoring SC2154, value sourced from setupVars file
		# shellcheck disable=SC2154
		ufw route delete allow in on "${pivpnDEV}" from "${pivpnNET}/${subnetClass}" out on "${IPv4dev}" to any > /dev/null
		ufw delete allow in on "${pivpnDEV}" to any port 53 from "${pivpnNET}/${subnetClass}" >/dev/null
		sed "/-I POSTROUTING -s ${pivpnNET}\\/${subnetClass} -o ${IPv4dev} -j MASQUERADE -m comment --comment ${VPN}-nat-rule/d" -i /etc/ufw/before.rules
		iptables -t nat -D POSTROUTING -s "${pivpnNET}/${subnetClass}" -o "${IPv4dev}" -j MASQUERADE -m comment --comment "${VPN}-nat-rule"
		ufw reload &> /dev/null

	elif [ "$USING_UFW" -eq 0 ]; then

		if [ "$INPUT_CHAIN_EDITED" -eq 1 ]; then
			iptables -D INPUT -i "${IPv4dev}" -p "${pivpnPROTO}" --dport "${pivpnPORT}" -j ACCEPT -m comment --comment "${VPN}-input-rule"
		fi

		if [ "$FORWARD_CHAIN_EDITED" -eq 1 ]; then
			iptables -D FORWARD -d "${pivpnNET}/${subnetClass}" -i "${IPv4dev}" -o "${pivpnDEV}" -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -m comment --comment "${VPN}-forward-rule"
			iptables -D FORWARD -s "${pivpnNET}/${subnetClass}" -i "${pivpnDEV}" -o "${IPv4dev}" -j ACCEPT -m comment --comment "${VPN}-forward-rule"
		fi

		iptables -t nat -D POSTROUTING -s "${pivpnNET}/${subnetClass}" -o "${IPv4dev}" -j MASQUERADE -m comment --comment "${VPN}-nat-rule"
		iptables-save > /etc/iptables/rules.v4

	fi

	# Disable IPv4 forwarding
	if [ "${vpnStillExists}" -eq 0 ]; then
		sed -i '/net.ipv4.ip_forward=1/c\#net.ipv4.ip_forward=1' /etc/sysctl.conf
		sysctl -p
	fi

	# Purge dependencies
	echo "::: Purge dependencies..."

	for i in "${INSTALLED_PACKAGES[@]}"; do
		while true; do
			read -rp "::: Do you wish to remove $i from your system? [Y/n]: " yn
			case $yn in
				[Yy]* ) if [ "${i}" = "wireguard-tools" ]; then

							# The bullseye repo may not exist if wireguard was available at the
							# time of installation.
							if [ -f /etc/apt/sources.list.d/pivpn-bullseye-repo.list ]; then
								echo "::: Removing Debian Bullseye repo..."
								rm -f /etc/apt/sources.list.d/pivpn-bullseye-repo.list
								rm -f /etc/apt/preferences.d/pivpn-limit-bullseye
								echo "::: Updating package cache..."
								${UPDATE_PKG_CACHE} &> /dev/null & spinner $!
							fi

							if [ -f /etc/systemd/system/wg-quick@.service.d/override.conf ]; then
								rm -f /etc/systemd/system/wg-quick@.service.d/override.conf
							fi

						elif [ "${i}" = "unattended-upgrades" ]; then

							rm -rf /var/log/unattended-upgrades
							rm -rf /etc/apt/apt.conf.d/*periodic
							rm -rf /etc/apt/apt.conf.d/*unattended-upgrades

						elif [ "${i}" = "openvpn" ]; then

							if [ -f /etc/apt/sources.list.d/pivpn-openvpn-repo.list ]; then
								echo "::: Removing OpenVPN software repo..."
								rm -f /etc/apt/sources.list.d/pivpn-openvpn-repo.list
								echo "::: Updating package cache..."
								${UPDATE_PKG_CACHE} &> /dev/null & spinner $!
							fi
							deluser openvpn
							rm -f /etc/rsyslog.d/30-openvpn.conf
							rm -f /etc/logrotate.d/openvpn

						fi
						printf ":::\\tRemoving %s..." "$i"; $PKG_MANAGER -y remove --purge "$i" &> /dev/null & spinner $!; printf "done!\\n";
						break
						;;
				[Nn]* ) printf ":::\\tSkipping %s\\n" "$i";
						break
						;;
				* ) printf "::: You must answer yes or no!\\n";;
			esac
		done
	done

	# Take care of any additional package cleaning
	printf "::: Auto removing remaining dependencies..."
	$PKG_MANAGER -y autoremove &> /dev/null & spinner $!; printf "done!\\n";
	printf "::: Auto cleaning remaining dependencies..."
	$PKG_MANAGER -y autoclean &> /dev/null & spinner $!; printf "done!\\n";


	if [ -f "$dnsmasqConfig" ]; then
		rm -f "$dnsmasqConfig"
		pihole restartdns
	fi

	echo ":::"
	echo "::: Removing VPN configuration files..."

	if [ "$VPN" = "wireguard" ]; then
		rm -f /etc/wireguard/wg0.conf
		rm -rf /etc/wireguard/configs
		rm -rf /etc/wireguard/keys
    ### Ignoring SC2154, value sourced from setupVars file
		# shellcheck disable=SC2154
		rm -rf "$install_home/configs"
	elif [ "$VPN" = "openvpn" ]; then
		rm -rf /var/log/*openvpn*
		rm -f /etc/openvpn/server.conf
		rm -f /etc/openvpn/crl.pem
		rm -rf /etc/openvpn/easy-rsa
		rm -rf /etc/openvpn/ccd
		rm -rf "$install_home/ovpns"
	fi

	if [ "${vpnStillExists}" -eq 0 ]; then
		echo ":::"
		echo "::: Removing pivpn system files..."
		rm -rf "${setupConfigDir}"
		rm -rf "${pivpnFilesDir}"
		rm -f /var/log/*pivpn*
		rm -f /etc/bash_completion.d/pivpn
		unlink "${pivpnScriptDir}"
		unlink /usr/local/bin/pivpn
	else
		if [[ ${VPN} == 'wireguard' ]]; then
			othervpn='openvpn'
		else
			othervpn='wireguard'
		fi

		echo ":::"
		echo "::: Other VPN ${othervpn} still present, so not"
		echo "::: removing pivpn system files"
		rm -f "${setupConfigDir}/${VPN}/${setupVarsFile}"

		# Restore single pivpn script and bash completion for the remaining VPN
		$SUDO unlink /usr/local/bin/pivpn
		$SUDO ln -s -T "${pivpnFilesDir}/scripts/${othervpn}/pivpn.sh" /usr/local/bin/pivpn
		$SUDO ln -s -T "${pivpnFilesDir}/scripts/${othervpn}/bash-completion" /etc/bash_completion.d/pivpn
		# shellcheck disable=SC1091
		. /etc/bash_completion.d/pivpn
	fi

	echo ":::"
	printf "::: Finished removing PiVPN from your system.\\n"
	printf "::: Reinstall by simply running\\n:::\\n:::\\tcurl -L https://install.pivpn.io | bash\\n:::\\n::: at any time!\\n:::\\n"
}

askreboot(){
	printf "It is \\e[1mstrongly\\e[0m recommended to reboot after un-installation.\\n"
	read -p "Would you like to reboot now? [y/n]: " -n 1 -r
	echo
	if [[ ${REPLY} =~ ^[Yy]$ ]]; then
		printf "\\nRebooting system...\\n"
		sleep 3
		shutdown -r now
	fi
}

######### SCRIPT ###########
echo "::: Preparing to remove packages, be sure that each may be safely removed depending on your operating system."
echo "::: (SAFE TO REMOVE ALL ON RASPBIAN)"
while true; do
	read -rp "::: Do you wish to completely remove PiVPN configuration and installed packages from your system? (You will be prompted for each package) [y/n]: " yn
	case $yn in
		[Yy]* ) removeAll; askreboot; break;;

		[Nn]* ) printf "::: Not removing anything, exiting...\\n"; break;;
	esac
done