#!/bin/sh

# Freetz! Web manager
# caskd
# CC0

: ${FB_ENDPOINT:-'192.168.178.1'}
: ${FB_CONFIG_PASS:-'defaultpassword'}

main() {
	for i in curl iconv md5sum cut xmlstarlet; do
		which "$i" >/dev/null || log_error "Missing dependency: $i"
	done

	log_info "Creating session"
	FB_SESSION="$(fb_auth)"
	if [ -z "$FB_SESSION" ]; then
		return "$?"
	fi

	for arg in $@; do
		case "$arg" in
			export|import) eval fb_"$arg" || return "$?";;
			*) ret="$?"; log_error "Invalid command $arg"; return "$ret";;
		esac
	done
}

log_error() {
	printf '%s\n' "$1" >&2
}

log_info() {
	printf '%s\n' "$1" >&2
}

fb_auth() {
	local \
		fb_endpoint="$FB_ENDPOINT" \
		fb_username="$FB_USERNAME" \
		fb_password="$FB_PASSWORD"

	if [ -z "$fb_password" ]; then
		log_error "Missing login password"
		return 1
	fi

	log_info "Fetching login info from $fb_endpoint"
	local login_data="$( \
		if ! curl -sSLf "http://$fb_endpoint/login_sid.lua"; then
			ret="$?"
			log_error "Failed to fetch login data"
			return "$ret"
		fi
	)"

	local auth_challange="$( \
		printf '%s' "$login_data" | \
		xmlstarlet sel -t -v '/SessionInfo/Challenge' \
	)"

	if [ -z "$auth_challange" ]; then
		log_error "Got empty challange back"
		return 1
	fi

	# If no user is given, pick the user that was last used
	if [ -z "$fb_username" ]; then
		local fb_username="$( \
			printf '%s' "$login_data" | \
			xmlstarlet sel -t -v '/SessionInfo/Users//User[@last=1]' \
		)"

		# If no user authenticated, pick the first user
		if [ -z "$fb_username" ]; then
			local fb_username="$( \
				printf '%s' "$login_data" | \
				xmlstarlet sel -t -v '/SessionInfo/Users//User[1]' \
			)"
		fi

		if [ -z "$fb_username" ]; then
			log_error "Failed to autodetect username"
			return 1
		else
			log_info "No username given, picking '$fb_username'"
		fi
	fi

	log_info "Got challange $auth_challange"
	local hashed="$( \
		printf '%s' "$auth_challange-$fb_password" | \
		iconv -f ISO8859-1 -t UTF-16LE | \
		md5sum -b | \
		cut -d' ' -f1)"

	local response="$auth_challange-$hashed"

	log_info "Sending challange response $response"
	local session_id="$( \
		curl -sSLf "http://$fb_endpoint/login_sid.lua" \
			--data-urlencode "username=$fb_username" \
			--data-urlencode "response=$response" | \
		xmlstarlet sel -t -v '/SessionInfo/SID' \
	)"

	if [ "$session_id" == "0000000000000000" ]; then
		log_error "Failed to log in"
		return 1
	fi

	printf '%s' "$session_id"
	log_info "Authenticated"
}

fb_export() {
	local \
		fb_endpoint="$FB_ENDPOINT" \
		fb_session="$FB_SESSION" \
		fb_config_pass="$FB_CONFIG_PASS"

	log_info "Exporting configuration of $fb_endpoint"
	if ! curl -\# -Lf "http://$fb_endpoint/cgi-bin/firmwarecfg" \
		-X POST \
		--form-string sid="$fb_session" \
		--form-string ImportExportPassword="$fb_config_pass" \
		--form-string ConfigExport=''
	then
		ret="$?"
		log_error "Failed to export configuration"
		return "$ret"
	fi
}

fb_import() {
	local \
		fb_endpoint="$FB_ENDPOINT" \
		fb_session="$FB_SESSION" \
		fb_config_pass="$FB_CONFIG_PASS"

	log_info "Telling Fritz! Box to load the entire configuration"
	if ! curl -sSLf "http://$fb_endpoint/data.lua" \
		-X POST \
		--form-string sid="$fb_session" \
		--form-string ImportExportPassword="$fb_config_pass" \
		--form-string cfgtakeover='all' \
		--form-string restore='' >/dev/null
	then
		ret="$?"
		log_error "Failed to set configuration restore options"
		return "$ret"
	fi

	log_info "Uploading configuration via STDIN"
	if ! curl -\# -Lf "http://$fb_endpoint/cgi-bin/firmwarecfg" \
		-X POST \
		--form-string sid="$fb_session" \
		--form-string ImportExportPassword="$fb_config_pass" \
		-F ConfigImportFile="@-;filename=config.cfg;type=application/octet-stream" >/dev/null
	then
		ret="$?"
		log_error "Failed to upload configuration"
		return "$ret"
	fi
}

main $@