#!/usr/bin/env bash
# vim: set autoindent smartindent ts=4 sw=4 sts=4 noet filetype=sh:
###############################################################################
## Based on instructions from:
## https://github.com/RMerl/asuswrt-merlin/wiki/Compiling-from-source-using-a-Debian-based-Linux-Distribution
## https://github.com/RMerl/asuswrt-merlin/wiki/Compile-Firmware-from-source-using-Ubuntu
###############################################################################
[[ -n "$DEBUG" ]] && set -x
pushd $(dirname $0) > /dev/null; CURRABSPATH=$(readlink -nf "$(pwd)"); popd > /dev/null
[[ -t 1 ]] && { G="\e[1;32m"; R="\e[1;31m"; Z="\e[0m"; B="\e[1;34m"; W="\e[1;37m"; Y="\e[1;33m"; }
TESTED_ON="tested on: ${W}Ubuntu 12.04 & 14.04${Z} and ${W}Debian 7.8${Z}"
REPORT_BACK="${W}Please report back${Z} about successes and failures at <https://github.com/assarbad/build-asuswrt-merlin> (e.g. by opening a ticket)"
TOOLCHAIN_BINARIES="mipsel-linux-addr2line mipsel-linux-ar mipsel-linux-as mipsel-linux-c++ mipsel-linux-cc mipsel-linux-c++filt mipsel-linux-cpp mipsel-linux-g++ mipsel-linux-gcc mipsel-linux-gcc-4.2.4 mipsel-linux-gcov mipsel-linux-gprof mipsel-linux-ld mipsel-linux-nm mipsel-linux-objcopy mipsel-linux-objdump mipsel-linux-ranlib mipsel-linux-readelf mipsel-linux-size mipsel-linux-strings mipsel-linux-strip"
INSTALL_PREREQ=""
APTI="apt-get --no-install-recommends install"
INTERACTIVE=1

help_syntax() # show a brief help screen
{
	echo -e "${W}SYNTAX:${Z} ${0##*/} [-p|--prereq] [-y|--yes] [-h|--help] <router-model> [path]\n"
	echo -e "\twhere:\n\
\t* ${W}-p, --prereq${Z} Install all the prerequisites using 'apt-get'\n\
\t  (please note that this requires you to be a sudoer)\n\
\t* ${W}-y, --yes${Z} Automatic yes to prompts\n\
\t  (assume "yes" as answer to all prompts and run non-interactively)\n\
\t* ${W}path${Z} is a directory containing the asuswrt-merlin sources\n\
\t  (default is the directory with this script: $CURRABSPATH)\n\
\t* ${W}router-model${Z} is the model name you'd pass to make\n\
\t  (e.g. rt-n66u, rt-ac66u etc, see ${W}README.md${Z})\n"
	echo -e "Variables:\n\
\t${W}USE_SUDO${Z} if set will 'install' and use tools in /opt, but requires ${W}sudo${Z}.\n\
\t${W}FORCE_UNSUPPORTED${Z} if set will proceed even if the system doesn't match prerequisites 100%.\n\
\t${W}TMUX_PANE${Z} if unset/empty will suppress logging inside a Tmux session."
}

# parse arguments
while [[ $# > 0 ]]; do
	case "$1" in
	-p|--prereq)
		INSTALL_PREREQ=1
		shift
	;;
	-y|--yes)
		INTERACTIVE=""
		shift
	;;
	-h|--help)
		help_syntax
		exit 0
	;;
	-*) echo "unknown option: $1" >&2;
		exit 1
	;;
	*)
		ROUTERMDL="${1}"
		BASEDIR="${2:-$CURRABSPATH}"
		shift; shift
	;;
	esac
done

if [[ ! -n "$INTERACTIVE" ]]; then
	APTI="$APTI -y"
	export DEBIAN_FRONTEND=noninteractive
fi

let TIME_START=$(date +%s)
CURRDATE=$(date +'%Y-%m-%dT%H-%M-%S')
_TMUX_LOG="$BASEDIR/tmux-${CURRDATE}.log"

show_time_diff()
{
	local START=$1
	local END=$2
	local MSG=$3
	[[ -n "$MSG" ]] || MSG="Runtime: %s"
	local DIFF=$((END-START))
	local DIFF_MIN=$((DIFF/60))
	local DIFF_SEC=$((DIFF%60))
	printf "$MSG\n" $(printf "%d:%02d" "$DIFF_MIN" "$DIFF_SEC")
}
fatal() # show the given error, include the help screen if requested and then exit with status 1
{
	[[ "x$1" == "xhelp" ]] && { SHOWHELP=1; shift; }
	echo -e "${R}ERROR:${Z} ${1:-<unknown>}"
	((SHOWHELP)) && help_syntax
	exit 1
}
cleanup() # turn off tmux logging if enabled before, any other common cleanup tasks will be added here
{
	if [[ -n "$TMUX_PANE" ]]; then
		echo -e "\n${Y}CLEANUP${Z}: turning off tmux logging ($_TMUX_LOG)"
		tmux pipe-pane -t $TMUX_PANE
		if [[ -f "$_TMUX_LOG" ]]; then
			sed -i.nocolor -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" "$_TMUX_LOG" && rm -f "${_TMUX_LOG}.nocolor"
			sed -i.bak -r 's#'"$BASEDIR"'#\$BASEDIR#g' "$_TMUX_LOG" && rm -f "${_TMUX_LOG}.bak"
		fi
	fi
	show_time_diff $TIME_START $(date +%s)
}
enable_tmux_logging()
{
	if [[ -n "$TMUX_PANE" ]]; then
		echo -e "${Y}NOTE:${Z} turning on tmux logging ($_TMUX_LOG)"
		tmux pipe-pane -t $TMUX_PANE "cat >> $_TMUX_LOG" && trap cleanup EXIT
	fi
}
cleanup_and_revert() # reverts parts of the effects of this script, then calls cleanup()
{
	echo -e "\n${Y}CLEANUP${Z}: extended cleanup of source tree changes"
	# Changed files will be reverted
	find "$BASEDIR" -type f -name '*.BAK-build-image'|while read fname; do
		( set -x && mv "$fname" "${fname%%.BAK-build-image}" )
	done
	# Simply remove proxy.h if we moved it there
	rm -f "$BASEDIR/release/src/router/neon/proxy.h"
	# Unlink the toolchain symlink, in case we were asked to put one
	[[ -n "$USE_SUDO" ]] && sudo unlink /opt/brcm
	cleanup
}
install_required_packages()
{
	((PREREQ_MISSING_NUM > 0)) || { echo -e "${Y}NOTE:${Z} no missing package dependencies were found."; return 0; }
	local REQ_PKGS="${REQ_PKGS[*]}"
	[[ -n "$1" ]] && REQ_PKGS="$1"
	echo -e "${W}INSTALLATION OF PREREQUISITE PACKAGES"
	echo -e     "=====================================${Z}"
	[[ $UID -eq 0 ]] || { echo -e "${Y}NOTE:${Z} This requires ${W}sudo${Z}, unless you simulate the installation only."; SUDO=sudo; }
	if [[ "$(dpkg --print-architecture)" == "amd64" ]]; then
		if [[ $(dpkg --print-foreign-architectures) =~ i386 ]]; then
			DPKG_ADD_ARCH="true"
		else
			DPKG_ADD_ARCH="dpkg --add-architecture i386"
			echo -e "${Y}NOTE:${Z} you are running a $(dpkg --print-architecture) system, but we need libelf1:i386. So we will need to run\n\t${W}${SUDO+$SUDO }${DPKG_ADD_ARCH}${Z}\n... prior to the ${W}apt-get${Z} invocation. This is just to inform you about the fact.\n"
		fi
        else
		DPKG_ADD_ARCH="true"
	fi
	echo -e "The command to be run is (beware of line breaks in overlong lines!):\n\n${W}${SUDO+$SUDO }$APTI ${Z}${REQ_PKGS}\n"
	if [[ -n $INTERACTIVE ]]; then
		echo -ne "Do you want to continue? ([${W}y${Z}]es/[${W}N${Z}]o/[${W}s${Z}]imulate)"
		read -p " " ans
		[[ $ans =~ ^[YySs]$ ]] || { echo -e "\n${Y}NOTE:${Z} aborted by user."; exit 1; }
	else
		ans=y
	fi
	if [[ $ans =~ ^[Ss]$ ]]; then
		( set -x; ${DPKG_ADD_ARCH:-true} && $APTI -s ${REQ_PKGS} )
		exit 0
	else
		( set -x; $SUDO $SHELL -c "$DPKG_ADD_ARCH && apt-get update && $APTI ${REQ_PKGS}" ) || fatal "an error occured when trying to install missing package dependencies."
		PREREQ_MISSING_NUM=0
	fi
}
check_or_fail_os_prereq()
{
	[[ -z "$FORCE_UNSUPPORTED" ]] && fatal "this script has only been ${TESTED_ON}. However, you're running ${W}$(lsb_release -si) $(lsb_release -sr) ($(lsb_release -sc))${Z}. If you'd like to try it regardless, make sure to set ${W}FORCE_UNSUPPORTED=1${Z} prior to invoking it."
}
check_runtime_requirements()
{
	# Does this look like a Debian?
	[[ -e "/etc/debian_version" ]] || fatal "this script expects a Debian flavor. It has been ${TESTED_ON}."
	[[ -n $(type -t lsb_release) ]] || fatal "${W}lsb_release{$Z} is expected to be installed. That is normally the case on Debian and Ubuntu anyway."
	OS_REL=$(lsb_release -sr|cut -d . -f 1)
	# All those packages are required according to the asuswrt-merlin docs (exceptions: I replaced g++ and make by build-essential, libncurses-dev => libncurses5-dev)
	PREREQ_PKGS=(autoconf automake bash bison build-essential bzip2 diffutils file flex gawk gcc-multilib gettext gperf groff-base libncurses5-dev libexpat1-dev libslang2 libssl-dev libtool libxml-parser-perl patch perl pkg-config python sed shtool tar texinfo unzip zlib1g zlib1g-dev)
	# Figure out the Debian flavor
	case $(lsb_release -si) in
		Debian)
			((OS_REL < 7)) && check_or_fail_os_prereq
			;;
		LinuxMint)
			echo -e "${Y}WARNING:${Z} this script should for all practical purposes run on Linux Mint >= 13 (maya), but it's possible that it doesn't. ${REPORT_BACK}."
			((OS_REL < 13)) && check_or_fail_os_prereq
			((OS_REL >= 16)) && { PREREQ_PKGS+=(automake1.11 autopoint intltool libproxy-dev); UBUNTU_EXTRAS=1; }
			;;
		Ubuntu)
			((OS_REL < 12)) && check_or_fail_os_prereq
			local UBUREL=0x$(lsb_release -sr|tr -d '.')
			# On Ubuntu 13.10 and later we check for two additional packages
			((UBUREL >= 0x1310)) && { PREREQ_PKGS+=(automake1.11 autopoint intltool libproxy-dev); UBUNTU_EXTRAS=1; }
			;;
		*)
			echo -e "${Y}WARNING:${Z} this is an ${W}unsupported Debian flavor${Z}. It is possible, even likely, that this will fail. ${REPORT_BACK}."
			;;
	esac
	# On x86_64 we also need two additional packages
	[[ "$(uname -m)" == "x86_64" ]] && PREREQ_PKGS+=(lib32z1-dev lib32stdc++6)
	# For ARM routers add libelf1
	if [[ "$ARCH" == "ARM" ]]; then
		[[ "$(dpkg --print-architecture)" == "amd64" ]] && PREREQ_PKGS+=(libelf1:i386 libxml2-dev) || PREREQ_PKGS+=(libelf1 libxml2-dev)
	fi
}
tell_missing_packages()
{
	local OTHER_ARCH_PREREQ_PKGS=()
	if [[ ${PREREQ_PKGS[*]} =~ :i386 ]] && [[ "$(dpkg --print-architecture)" == "amd64" ]]; then
		if [[ ! $(dpkg --print-foreign-architectures) =~ i386 ]]; then
			echo -e "${Y}NOTE:${Z} trying to find the list of missing packages may fail or yield an incomplete list.\n  The reason is that you require a package from a foreign architecture not installed on your system: i386.\n  You can still run this script with the ${W}--prereq${Z} option to fix missing dependencies."
			NEW_PREREQ_PKGS=()
			# Weed out packages which would cause errors
			for r in ${PREREQ_PKGS[*]}; do
				[[ $r =~ :i386 ]] && OTHER_ARCH_PREREQ_PKGS+=($r) || NEW_PREREQ_PKGS+=($r)
			done
			PREREQ_PKGS=(${NEW_PREREQ_PKGS[*]})
		fi
	fi
	# Find the packages which are already installed, so we can remove them from the list of required packages
	local INST_ALREADY=($($APTI -s ${PREREQ_PKGS[*]}|awk '/is already the newest version\.$/ {print $1}'))
	PREREQ_MISSING=($(for pkg in $(echo ""|awk -f <(cat - <<-'EOF'
		# Embedded awk script
		BEGIN {
	EOF
	for r in ${PREREQ_PKGS[*]}; do echo "  REQD[\"$r\"] = 0;"; done
	for i in ${INST_ALREADY[*]}; do echo "  INST[\"$i\"] = 0;"; done
	cat - <<-'EOF'
		}
		END {
		  for (i in INST)
		    delete REQD[i]
		  for (r in REQD)
		    printf("%s\n", r)
		}
	EOF
	)); do echo "$pkg"; done|sort -u))
	[[ ${#OTHER_ARCH_PREREQ_PKGS[@]} -gt 0 ]] && PREREQ_MISSING+=(${OTHER_ARCH_PREREQ_PKGS[*]})
	PREREQ_MISSING_NUM=${#PREREQ_MISSING[*]}
	if ((PREREQ_MISSING_NUM > 0)); then
		echo -e "${R}ERROR:${Z} ${PREREQ_MISSING_NUM} required packages are missing on your system:\n\t${Z} ${PREREQ_MISSING[*]}\n"
	fi
}
## HOOK INIT
[[ -e "${CURRABSPATH%/}/.${0##*/}rc" ]] && { source "${CURRABSPATH%/}/.${0##*/}rc" || fatal "'${CURRABSPATH%/}/.${0##*/}rc' exists but could not be sourced successfully"; }
function_exists()
{
	declare -f $1 > /dev/null 2>&1
	# use exit status from declare
}
## MAIN
[[ -n "$ROUTERMDL" ]] || fatal help "you have to ${W}give the router model${Z} to build for."
# Match the router model to find the correct base directory for make
# To find supported router models:
#   grep -hoP 'RT-(AC|N)\d+[URW]*(_V\d+)?' release/src-rt*/target.mak|sort -u
OLD_ROUTERMDL=${ROUTERMDL^^}
case ${ROUTERMDL^^} in
	# release/src-rt
	RT-N16)
		MKBASE="src-rt";;
	# release/src-rt-6.x
	RT-AC66|RT-AC66[URW])
		ROUTERMDL="RT-AC66U"
		MKBASE="src-rt-6.x";;
	RT-N66|RT-N66[URW])
		ROUTERMDL="RT-N66U"
		MKBASE="src-rt-6.x";;
	# release/src-rt-6.x.4708
	RT-AC56|RT-AC56[URW])
		ROUTERMDL="RT-AC56U"
		MKBASE="src-rt-6.x.4708";;
	RT-AC68|RT-AC68[URW])
		ROUTERMDL="RT-AC68U"
		MKBASE="src-rt-6.x.4708";;
	RT-AC68_V2|RT-AC68[URW]_V2)
		ROUTERMDL="RT-AC68U_V2"
		MKBASE="src-rt-6.x.4708";;
	RT-AC69|RT-AC69[URW])
		ROUTERMDL="RT-AC69U"
		MKBASE="src-rt-6.x.4708";;
	RT-AC87|RT-AC87[URW])
		ROUTERMDL="RT-AC87U"
		MKBASE="src-rt-6.x.4708";;
	*) # anything unmatched
		if function_exists hook_unknown_router; then
			hook_unknown_router "${ROUTERMDL}"
		else
			fatal "unrecognized router model ${W}$ROUTERMDL${Z}. Either the command line or this script needs fixing [base]."
		fi;;
esac
case ${ROUTERMDL^^} in
	RT-N16|RT-AC66U|RT-N66U)
		ARCH="MIPS";;
	RT-AC56U|RT-AC68U|RT-AC68U_V2|RT-AC69U|RT-AC87U)
		ARCH="ARM";;
	*)
		if function_exists hook_unknown_router; then
			hook_unknown_router "${ROUTERMDL}"
		else
			fatal "unrecognized router model ${W}$ROUTERMDL${Z}. Either the command line or this script needs fixing [arch]."
		fi;;
esac
enable_tmux_logging
function_exists hook_override_model && hook_override_model
[[ "${OLD_ROUTERMDL^^}" == "${ROUTERMDL^^}" ]] || { echo -e "${W}INFO${Z}: your router model choice ${W}${OLD_ROUTERMDL^^}${Z} is firmware-compatible to ${ROUTERMDL^^}. Setting target for ${W}make${Z} to ${W}${ROUTERMDL^^}${Z}."; }
unset OLD_ROUTERMDL
# Check whether this is the asuswrt-merlin source directory ...
[[ -f "$BASEDIR/README-merlin.txt" ]] || fatal help "$BASEDIR is expected to contain a file ${W}README-merlin.txt${Z}."
check_runtime_requirements
tell_missing_packages
# Did the user ask to install prerequisites instead?
[[ -n "$INSTALL_PREREQ" ]] && install_required_packages "${PREREQ_MISSING[*]}"
((PREREQ_MISSING_NUM > 0)) && fatal "can't continue because of missing packages.\n\nPlease use:\n\t${W}${0##*/} --prereq $ROUTERMDL${Z}\nor:\n\t${W}$APTI${Z} ${PREREQ_MISSING[*]}\nto install missing packages."
if [[ -n "$INTERACTIVE" ]]; then
	if [[ -n "$INSTALL_PREREQ" ]]; then
		echo -ne "\nDo you want to proceed with the firmware build now? ([${W}y${Z}]es/[${W}N${Z}]o)"
		read -p " " ans
		[[ $ans =~ ^[Yy]$ ]] || { echo -e "\n${Y}INFO:${Z} aborted by user."; exit 0; }
	fi
fi
# Special steps required on Ubuntu newer than or equal to 13.10
if [[ -n "$UBUNTU_EXTRAS" ]]; then
	echo -e "${Y}NOTE:${Z} Attempting extra fixes for Ubuntu >= 13.10 and similar"
	# fix neon missing proxy.h
	[[ -f "/usr/include/proxy.h" ]] || fatal "expected to find proxy.h from package libproxy-dev in /usr/include. It's not there, though."
	cp /usr/include/proxy.h "$BASEDIR/release/src/router/neon/" || fatal "failed to copy proxy.h into source tree" 
	# fix broken configure script for libdaemon
	( cd "$BASEDIR/release/src/router/libdaemon" && aclocal ) || fatal "failed to fix broken configure script for libdaemon"
	# fix broken configure script for libxml2
	( cd "$BASEDIR/release/src/router/libxml2" && sed -i.BAK-build-image s/^AM_C_PROTOTYPES/#AM_C_PROTOTYPES/g configure.in && aclocal ) || fatal "failed to fix broken configure script for libxml2"
	function_exists hook_ubuntu_extras && hook_ubuntu_extras
fi
# Clean up leftovers
echo -e "${Y}NOTE:${Z} removing excess files"
rm -f "$BASEDIR/release/src/router/".#preconfigure*
# Prepare the PATH environment variable and fix up hardcoded paths contained in certain files)
[[ "$ARCH" == "ARM" ]] && USE_SUDO='' # no global paths needed, so no symlinking needed
function_exists hook_pre_fixups && hook_pre_fixups
if [[ -n "$USE_SUDO" ]]; then
	echo -e "${Y}NOTE:${Z} making toolchain available in /opt"
	sudo ln -sf "$BASEDIR/tools/brcm" /opt/brcm
	export TOOLCHAIN="/opt/brcm/hndtools-mipsel-uclibc"
else
	# Cheapo version of "installing" the toolchain to /opt/brcm
	case "$ARCH" in
	ARM)
		# Instead of installing, we override some of the paths used in the build process
		export TOOLCHAIN="$BASEDIR/release/$MKBASE/toolchains/hndtools-arm-linux-2.6.36-uclibc-4.5.3" # used in preconfigure scripts
		;;
	MIPS)
		echo -e "${Y}NOTE:${Z} looking for files in which to fix hardcoded path to toolchain"
		grep -P '=\s*/opt/brcm/hndtools-mipsel-uclibc/' $(find "$BASEDIR/release/" -type f -iname '*makefile' -o -name defconfig) 2>/dev/null|cut -d : -f 1|sort -u|while read fname; do
			[[ -e "${fname}.BAK-build-image" ]] && { echo -e "${W}INFO:${Z} skipping fixup of ${fname} (prior run detected)"; continue; }
			[[ "x${fname//.BAK-build-image/}" == "x$fname" ]] || continue # skip backup files
			echo -e "Rebasing paths in: ${G}${fname}${Z}"
			sed -i.BAK-build-image 's#/opt/brcm/hndtools-mipsel-uclibc/#'"$BASEDIR/tools/brcm/hndtools-mipsel-uclibc/"'#g' "$fname" && grep --color=auto "$BASEDIR/tools/brcm/hndtools-mipsel-uclibc/" "$fname"
		done
		# Instead of installing, we override some of the paths used in the build process
		export TOOLCHAIN="$BASEDIR/tools/brcm/hndtools-mipsel-uclibc" # used in preconfigure scripts
		;;
	esac
	# Set the trap to also revert the changes we made
	trap cleanup_and_revert EXIT
fi
function_exists hook_post_fixups && hook_post_fixups
# Add the toolchain into the PATH
export PATH="$PATH:$TOOLCHAIN/bin"
# Check that the relevant tools execute from there
echo -e "${Y}NOTE:${Z} invoking each of the required programs to detect possible issues"
for i in $TOOLCHAIN_BINARIES; do
	$i --version > /dev/null 2>&1 || \
		{ function_exists hook_suppress_missing_bin && hook_suppress_missing_bin "$i" || true; [[ $? -eq 0 ]] || fatal "failed to execute $i"; }
done
# Do the make
function_exists hook_pre_clean && hook_pre_clean "$BASEDIR/release/$MKBASE"
echo -e "${Y}NOTE:${Z} running ${W}make -C release/$MKBASE clean${Z}"
make -C "$BASEDIR/release/$MKBASE" "TOOLCHAIN=$TOOLCHAIN" clean > /dev/null 2>&1
function_exists hook_pre_make && hook_pre_make "$BASEDIR/release/$MKBASE"
set -e
echo -e "${Y}NOTE:${Z} running ${W}make -C release/$MKBASE ${ROUTERMDL,,}${Z}"
make -C "$BASEDIR/release/$MKBASE" "TOOLCHAIN=$TOOLCHAIN" ${ROUTERMDL,,}
function_exists hook_post_make && hook_post_make "$BASEDIR/release/$MKBASE"
echo "Your image can be found here:"
(cd "$BASEDIR" && for i in release/$MKBASE/image/*.trx; do echo -e "\t${G}$i${Z}"; done)