#!/usr/bin/env bash
# Pi-hole: A black hole for Internet advertisements
# Network-wide ad blocking via your Raspberry Pi
# http://pi-hole.net
# Web interface settings
#
# Pi-hole 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 2 of the License, or
# (at your option) any later version.

readonly setupVars="/etc/pihole/setupVars.conf"
readonly dnsmasqconfig="/etc/dnsmasq.d/01-pihole.conf"
readonly dhcpconfig="/etc/dnsmasq.d/02-pihole-dhcp.conf"

helpFunc() {
	cat << EOM
::: Set admin options for the web interface of pihole
:::
::: Usage: pihole -a [options]
:::
::: Options:
:::  -p, password		Set web interface password, an empty input will remove any previously set password
:::  -c, celsius		Set Celsius temperature unit
:::  -f, fahrenheit		Set Fahrenheit temperature unit
:::  -k, kelvin			Set Kelvin temperature unit
:::  -h, --help			Show this help dialog
EOM
	exit 0
}

add_setting() {
	echo "${1}=${2}" >> "${setupVars}"
}

delete_setting() {
	sed -i "/${1}/d" "${setupVars}"
}

change_setting() {
	delete_setting "${1}"
	add_setting "${1}" "${2}"
}

add_dnsmasq_setting() {
	if [[ "${2}" != "" ]]; then
		echo "${1}=${2}" >> "${dnsmasqconfig}"
	else
		echo "${1}" >> "${dnsmasqconfig}"
	fi
}

delete_dnsmasq_setting() {
	sed -i "/${1}/d" "${dnsmasqconfig}"
}

SetTemperatureUnit(){

	change_setting "TEMPERATUREUNIT" "${unit}"

}

SetWebPassword(){

	if [ "${SUDO_USER}" == "www-data" ]; then
		echo "Security measure: user www-data is not allowed to change webUI password!"
		echo "Exiting"
		exit 1
	fi

	if [ "${SUDO_USER}" == "lighttpd" ]; then
		echo "Security measure: user lighttpd is not allowed to change webUI password!"
		echo "Exiting"
		exit 1
	fi

	# Set password only if there is one to be set
	if (( ${#args[2]} > 0 )) ; then
		# Compute password hash twice to avoid rainbow table vulnerability
		hash=$(echo -n ${args[2]} | sha256sum | sed 's/\s.*$//')
		hash=$(echo -n ${hash} | sha256sum | sed 's/\s.*$//')
		# Save hash to file
		change_setting "WEBPASSWORD" "${hash}"
		echo "New password set"
	else
		change_setting "WEBPASSWORD" ""
		echo "Password removed"
	fi

}

ProcessDNSSettings() {
	source "${setupVars}"

	delete_dnsmasq_setting "server="
	add_dnsmasq_setting "server" "${PIHOLE_DNS_1}"

	if [[ "${PIHOLE_DNS_2}" != "" ]]; then
		add_dnsmasq_setting "server" "${PIHOLE_DNS_2}"
	fi

	delete_dnsmasq_setting "domain-needed"

	if [[ "${DNS_FQDN_REQUIRED}" == true ]]; then
		add_dnsmasq_setting "domain-needed"
	fi

	delete_dnsmasq_setting "bogus-priv"

	if [[ "${DNS_BOGUS_PRIV}" == true ]]; then
		add_dnsmasq_setting "bogus-priv"
	fi

}

SetDNSServers(){

	# Save setting to file
	change_setting "PIHOLE_DNS_1" "${args[2]}"

	if [[ "${args[3]}" != "none" ]]; then
		change_setting "PIHOLE_DNS_2" "${args[3]}"
	else
		change_setting "PIHOLE_DNS_2" ""
	fi

	if [[ "${args[4]}" == "domain-needed" ]]; then
		change_setting "DNS_FQDN_REQUIRED" "true"
	else
		change_setting "DNS_FQDN_REQUIRED" "false"
	fi

	if [[ "${args[4]}" == "bogus-priv" || "${args[5]}" == "bogus-priv" ]]; then
		change_setting "DNS_BOGUS_PRIV" "true"
	else
		change_setting "DNS_BOGUS_PRIV" "false"
	fi

	ProcessDnsmasqSettings

	# Restart dnsmasq to load new configuration
	RestartDNS

}

SetExcludeDomains(){

	change_setting "API_EXCLUDE_DOMAINS" "${args[2]}"

}

SetExcludeClients(){

	change_setting "API_EXCLUDE_CLIENTS" "${args[2]}"

}

Reboot(){

	nohup bash -c "sleep 5; reboot" &> /dev/null </dev/null &

}

RestartDNS(){

	if [ -x "$(command -v systemctl)" ]; then
		systemctl restart dnsmasq &> /dev/null
	else
		service dnsmasq restart &> /dev/null
	fi

}

SetQueryLogOptions(){

	change_setting "API_QUERY_LOG_SHOW" "${args[2]}"

}

ProcessDHCPSettings() {

	if [[ "${DHCP_ACTIVE}" == "true" ]]; then

	source "${setupVars}"
	interface=$(grep 'PIHOLE_INTERFACE=' /etc/pihole/setupVars.conf | sed "s/.*=//")

	# Use eth0 as fallback interface
	if [ -z ${interface} ]; then
		interface="eth0"
	fi

	if [[ "${PIHOLE_DOMAIN}" == "0" ]]; then
		PIHOLE_DOMAIN="local"
		change_setting "PIHOLE_DOMAIN" "${PIHOLE_DOMAIN}"
	fi

	if [[ "${DHCP_LEASETIME}" == "0" ]]; then
		leasetime="infinite"
	elif [[ "${DHCP_LEASETIME}" == "" ]]; then
		leasetime="24h"
		change_setting "DHCP_LEASETIME" "${leasetime}"
	else
		leasetime="${DHCP_LEASETIME}h"
	fi

	# Write settings to file
	echo "###############################################################################
#  DHCP SERVER CONFIG FILE AUTOMATICALLY POPULATED BY PI-HOLE WEB INTERFACE.  #
#            ANY CHANGES MADE TO THIS FILE WILL BE LOST ON CHANGE             #
###############################################################################
dhcp-authoritative
dhcp-range=${DHCP_START},${DHCP_END},${leasetime}
dhcp-option=option:router,${DHCP_ROUTER}
dhcp-leasefile=/etc/pihole/dhcp.leases
domain=${PIHOLE_DOMAIN}
#quiet-dhcp
#quiet-dhcp6
#enable-ra
dhcp-option=option6:dns-server,[::]
dhcp-range=::100,::1ff,constructor:${interface},ra-names,slaac,${leasetime}
ra-param=*,0,0
" > "${dhcpconfig}"

	else
		rm "${dhcpconfig}"
	fi
}

EnableDHCP(){

	change_setting "DHCP_ACTIVE" "true"
	change_setting "DHCP_START" "${args[2]}"
	change_setting "DHCP_END" "${args[3]}"
	change_setting "DHCP_ROUTER" "${args[4]}"
	change_setting "DHCP_LEASETIME" "${args[5]}"
	change_setting "PIHOLE_DOMAIN" "${args[6]}"

	# Remove possible old setting from file
	delete_dnsmasq_setting "dhcp-"
	delete_dnsmasq_setting "quiet-dhcp"

	ProcessDHCPSettings

	RestartDNS
}

DisableDHCP(){

	change_setting "DHCP_ACTIVE" "false"

	# Remove possible old setting from file
	delete_dnsmasq_setting "dhcp-"
	delete_dnsmasq_setting "quiet-dhcp"

	ProcessDHCPSettings

	RestartDNS
}

SetWebUILayout(){

	change_setting "WEBUIBOXEDLAYOUT" "${args[2]}"

}

SetPrivacyMode(){

	if [[ "${args[2]}" == "true" ]] ; then
		change_setting "API_PRIVACY_MODE" "true"
	else
		change_setting "API_PRIVACY_MODE" "false"
	fi

}

ResolutionSettings() {

	typ="${args[2]}"
	state="${args[3]}"

	if [[ "${typ}" == "forward" ]]; then
		change_setting "API_GET_UPSTREAM_DNS_HOSTNAME" "${state}"
	elif [[ "${typ}" == "clients" ]]; then
		change_setting "API_GET_CLIENT_HOSTNAME" "${state}"
	fi
}

main() {

	args=("$@")

	case "${args[1]}" in
		"-p" | "password"   ) SetWebPassword;;
		"-c" | "celsius"    ) unit="C"; SetTemperatureUnit;;
		"-f" | "fahrenheit" ) unit="F"; SetTemperatureUnit;;
		"-k" | "kelvin"     ) unit="K"; SetTemperatureUnit;;
		"setdns"            ) SetDNSServers;;
		"setexcludedomains" ) SetExcludeDomains;;
		"setexcludeclients" ) SetExcludeClients;;
		"reboot"            ) Reboot;;
		"restartdns"        ) RestartDNS;;
		"setquerylog"       ) SetQueryLogOptions;;
		"enabledhcp"        ) EnableDHCP;;
		"disabledhcp"       ) DisableDHCP;;
		"layout"            ) SetWebUILayout;;
		"-h" | "--help"     ) helpFunc;;
		"privacymode"       ) SetPrivacyMode;;
		"resolve"           ) ResolutionSettings;;
		*                   ) helpFunc;;
	esac

	shift

	if [[ $# = 0 ]]; then
		helpFunc
	fi

}