#!/bin/bash

usage() {
cat << EOF

Usage: ${SELF} [-d <dir>] [-p] [l|list] [d|download|da|download-all] [e|extract-config]
  options
    -d <dir>            save all downloaded files to <dir> (default ~/fw-avm/opensrc)
    -p                  prefer previously fetched ftp server content listing
  actions
    l|list              fetch content listing of AVM's ftp server
    d|download          download opensrc packages of up-to-date firmwares only (implies "list" if -p is not specified)
    da|download-all     download opensrc packages of all firmwares             (implies "list" if -p is not specified)
    e|extract-config    extract kernel .config's of all opensrc-packages in download-dir

EOF
}

#
# $1 - ftp-dir to be (recursively) listed
# ftp-dir is expected to have the following format: ftp://some.site/some/dir/
# 'ftp://' might be omitted
#
# returns ftp server content listing as string, one file per line
#
function list_ftp_dir() {
	if [ $# -ne 1 -o -z "$1" ]; then
		echo "Error[${FUNCNAME}]: ${FUNCNAME} expects exactly one non-empty parameter" >&2
		exit 1
	fi

	if ! which lftp >/dev/null 2>&1; then
		echo "Error[${FUNCNAME}]: ${FUNCNAME} requires lftp to be installed" >&2
		exit 1
	fi

	local url="${1#ftp://}"
	[ "${url: -1: 1}" != "/" ] && url="${url}/"
	if [ "${url//:\/\/}" != "${url}" ]; then
		echo "Error[${FUNCNAME}]: unsupported protocol in '${url}', only ftp:// is supported" >&2
		exit 1
	fi

	local ftp_site="${url%%/*}"
	local ftp_dir="/${url#*/}"

	local lftp_output=$(lftp -e "find ${ftp_dir}; bye" ${ftp_site})
	if [ $? != 0 ]; then
		echo "Error[${FUNCNAME}]: failed to list content of '${url}'" >&2
		exit 1
	fi

	echo "$lftp_output" | sed -r -e '/\/$/ d' -e "s,^,ftp://${ftp_site}," #-e 's, ,%20,g'
}

#
# $1 - list of URLs, one URL per line
#
# returns list of URLs of all opensrc packages, one URL per line
#
function get_opensrc_packages() {
	if [ $# -ne 1 -o -z "$1" ]; then
		echo "Error[${FUNCNAME}]: ${FUNCNAME} expects exactly one parameter" >&2
		exit 1
	fi

	echo "$1" | grep -E "/fritzbox[._]" | grep "opensrc"
}

#
# $1 - opensrc package URL
#
# returns ID of opensrc package, e.g. 7270v3.05.51
#
function get_opensrc_package_id() {
	if [ $# -ne 1 -o -z "$1" ]; then
		echo "Error[${FUNCNAME}]: ${FUNCNAME} expects exactly one parameter" >&2
		exit 1
	fi

	echo "$1" | sed -r -e 's,.*([0-9]{4})(_(sl|v[1-3]|lte))?/.*(0[4-6][.][0-9]{2})(-([0-9]{2}))?[.]tar[.]gz,\1\3.\4,'
}

#
# $1 - any string containing 04.xx, 05.[25]x, 06.xx as substring
#
function is_uptodate_firmware() {
	echo "$1" | grep -qE "(0[46][.][0-9]{2}|05[.][25][0-9])"
}

#
# $1..$* - path(s) to AVM open-source tarball(s)
#
function extract_kernel_config() {
	local opensrc_tarball=, kernel_tarball=, id=, tmp=, config=, makefile=
	for opensrc_tarball in "$@"; do
		id="$(basename "${opensrc_tarball%.tar.gz}")"

		echo -n "${id}: "

		tmp=$(mktemp -q -d /tmp/${id}-XXXXXX)
		if [ $? != 0 ]; then
			echo "failed to create temporary dir"
			shift
			continue
		fi

		echo -n "extracting opensrc-tarball ... "
		tar -C ${tmp} -xaf ${opensrc_tarball} --wildcards '*kernel*.tar.gz' >/dev/null 2>&1

		echo -n "searching for kernel sources ... "
		kernel_tarball=$(find ${tmp} -name '*kernel*.tar.gz')
		if [ -z "${kernel_tarball}" ]; then
			echo -n "not found ... assuming opensrc-tarball is kernel-tarball ... "
			kernel_tarball="${opensrc_tarball}"
		else
			echo -n "found ${kernel_tarball#${tmp}/} ... "
		fi
		echo -n "searching for .config ... "
		config=$(tar -C ${tmp} -taf ${kernel_tarball} | grep -E "[.]config$")
		if [ $? -ne 0 ]; then
			echo "failed"
		else
			makefile="${config%.config}Makefile"
			echo -n "found ${config} ... extracting ... "
			if ! tar -C ${tmp} -xaf ${kernel_tarball} ${config} ${makefile}; then
				echo "failed"
			else
				unset VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION
				cat ${tmp}/${makefile} | sed -n -r -e "s,^(VERSION|PATCHLEVEL|SUBLEVEL|EXTRAVERSION)[ \t]*=[ \t]*([^ \t]+),\1=\2,p" > ${tmp}/${makefile}.version
				source ${tmp}/${makefile}.version
				mv ${tmp}/${config} "$(dirname "${opensrc_tarball}")/.config-AVM-${id}-${VERSION}.${PATCHLEVEL}.${SUBLEVEL}${EXTRAVERSION}" && echo "done" || echo "failed"
			fi
		fi
		rm -rf ${tmp}
		shift
	done
}

#
# returns current timestamp in YYYYMMDD-HHMMSS format
#
function get_current_timestamp() {
	date +%Y%m%d-%H%M%S
}

############################################

SELF=$(basename "$0")

DL_DIR=~/fw-avm/opensrc
PREFER_PREVIOUS_LISTING=
DO_FETCH_LISTING=
DO_DOWNLOAD=
DO_EXTRACT_CONFIG=

# parse options
while getopts d:p opt; do
	case "$opt" in
		d) DL_DIR="$OPTARG" ;;
		p) PREFER_PREVIOUS_LISTING=true ;;
		*) usage >&2; exit 1 ;;
	esac
done
shift $((OPTIND-1))

# parse actions
for opt in "$@"; do
	case "$opt" in
		l|list)
			if [ -n "$PREFER_PREVIOUS_LISTING" ]; then
				echo "Error: specifying both '-p' and 'list' at the same time doesn't make sense" >&2
				usage >&2
				exit 1
			fi
			DO_FETCH_LISTING=true
			;;
		d|download)
			DO_DOWNLOAD=recent-only
			[ -z "$PREFER_PREVIOUS_LISTING" ] && DO_FETCH_LISTING=true
			;;
		da|download-all)
			DO_DOWNLOAD=all
			[ -z "$PREFER_PREVIOUS_LISTING" ] && DO_FETCH_LISTING=true
			;;
		e|extract-config)
			DO_EXTRACT_CONFIG=false ;;
		*)
			usage >&2; exit 1 ;;
	esac
done

# check if at least one action is specified
[ -n "$DO_FETCH_LISTING" -o -n "$DO_DOWNLOAD" -o -n "$DO_EXTRACT_CONFIG" ] || { usage >&2; exit 1; }

# create DL_DIR if missing
[ ! -e "$DL_DIR" ] && mkdir -p "$DL_DIR"

(
	cd "$DL_DIR" || exit 1

	# check if curl is available as early as possible
	if [ -n "$DO_DOWNLOAD" ] && ! which curl >/dev/null 2>&1; then
		echo "Error: ${SELF} requires curl to be installed" >&2
		exit 1
	fi

	# check if any previously fetched listing is available and use it if requested
	if [ -n "$PREFER_PREVIOUS_LISTING" ]; then
		listing_fn=$(ls ftp.avm.de-fritz.box-????????-??????.listing 2>/dev/null)
		if [ $? -ne 0 ]; then
			echo "No previously fetched listing found, forcing fetching of ftp server content listing"
			DO_FETCH_LISTING=true
		else
			listing_fn=$(echo "$listing_fn" | sort | tail -n 1)
			echo "Using previously fetched ftp server content listing from $listing_fn"
			listing=$(cat "$listing_fn")
		fi
	fi

	# fetch ftp server content listing and save it to a file
	if [ -n "$DO_FETCH_LISTING" ]; then
		listing="$(list_ftp_dir ftp.avm.de/fritzbox/)"
		echo "$listing" > ftp.avm.de-fritzbox-$(get_current_timestamp).listing
	fi

	# download opensrc packages, avoid redownloading of already downloaded files
	if [ -n "$DO_DOWNLOAD" ]; then
		get_opensrc_packages "$listing" | while read url; do
			id=$(get_opensrc_package_id "$url")
			if [ "$DO_DOWNLOAD" == all ] || is_uptodate_firmware "${id}"; then
				#TODO: progress bar
				curl -R -C - -o "${id}.tar.gz" "${url}"
			else
				echo "Skipping opensrc package ${url} - old firmware version"
			fi
		done
	fi

	# extract kernel .config's
	if [ -n "$DO_EXTRACT_CONFIG" ]; then
		extract_kernel_config *.tar.gz
	fi
)