#!/usr/bin/env sh

#  helper script: create code trees based on git revision, with patches
#  (currently used for downloading coreboot and u-boot)
#
#	Copyright (C) 2014-2016,2020,2021,2023 Leah Rowe <info@minifree.org>
#	Copyright (C) 2022 Alper Nebi Yasak <alpernebiyasak@gmail.com>
#	Copyright (C) 2022 Ferass El Hafidi <vitali64pmemail@protonmail.com>
#
#	This program 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 3 of the License, or
#	(at your option) any later version.
#
#	This program is distributed in the hope that it will be useful,
#	but WITHOUT ANY WARRANTY; without even the implied warranty of
#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#	GNU General Public License for more details.
#
#	You should have received a copy of the GNU General Public License
#	along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

[ "x${DEBUG+set}" = 'xset' ] && set -v
set -u -e

_target=""
tree=""
rev=""
project=""
cfgsdir=""

main()
{
	rm -f ${cfgsdir}/*/seen

	printf "Downloading %s and (if available) applying patches\n" \
	    ${project}

	[ -z "${1}" ] && err "project name not specified"
	project="${1}"
	cfgsdir="resources/${project}"
	[ -d "${cfgsdir}" ] || err "unsupported project name"
	shift 1

	targets=""
	if [ $# -gt 0 ]; then
		targets=$@
	else
		for x in "${cfgsdir}/"*; do
			[ ! -d "${x}" ] && continue
			targets="${targets} ${x##*/}"
		done
	fi
	for x in ${targets}; do
		rm -f "${cfgsdir}"/*/seen
		download_for_target "${x}"
	done

	rm -f ${cfgsdir}/*/seen
}

download_for_target()
{
	_target="${1}"
	tree="undefined"
	rev="undefined"

	fetch_config "${_target}" || exit 1

	rm -f "${cfgsdir}"/*/seen

	if [ -d "${project}/${tree}" ]; then
		printf "REMARK: download/%s %s: exists. Skipping.\n" \
				${project} ${tree}
		[ "${tree}" != "${1}" ] && \
			printf "(for target: '%s}')\n" ${1}
		return 0
	fi

	fetch_from_upstream || exit 1

	prepare_new_tree "${1}" "${tree}" "${rev}" \
			|| exit 1
}

fetch_config()
{
	_target=${1}

	while true; do
		rev="undefined"
		tree="undefined"

		check_config_for_target "${_target}" || return 1

		# This is to override $rev and $tree
		. "${cfgsdir}/${_target}/target.cfg" || exit 1

		if [ "${_target}" != "${tree}" ]; then
			_target="${tree}"
			continue
		elif [ "${tree}" = "undefined" ]; then
			printf "ERROR: download/%s:"
			printf " tree name undefined for '%s\n'" \
					${project} ${_target}
			return 1
		elif [ "${rev}" = "undefined" ]; then
			printf "ERROR: download/%s:"
			printf " commit ID undefined for '%s'\n" \
					${project} ${_target}
			return 1
		else
			break
		fi
	done
}

check_config_for_target()
{
	_target=${1}

	if [ ! -f "${cfgsdir}/${_target}/target.cfg" ]; then
		printf "ERROR: download/%s: target.cfg does not" ${project}
		printf " exist for '%s'\n" ${_target}
		return 1
	elif [ -f "${cfgsdir}/${_target}/seen" ]; then
		printf "ERROR: download/%s: logical loop:" ${project}
		printf " '%s' target.cfg refers to another tree," ${_target}
		printf " which ultimately refers back to '%s'." ${_target}
		return 1
	fi
	touch "${cfgsdir}/${_target}/seen"
}

fetch_from_upstream()
{
	[ ! -d "${project}" ] && \
		mkdir -p "${project}"
	[ ! -d "${project}" ] && \
		return 1
	[ -d "${project}/${project}" ] && \
		return 0
	./fetch ${project} || \
		return 1
}

prepare_new_tree()
{
	target=${1}
	tree=${2}
	rev=${3}

	printf "Preparing %s tree: %s\n" ${project} ${tree}
	[ "${tree}" != "${target}" ] && \
		printf "(for target, %s)\n" "${target}"

	cp -R "${project}/${project}" "${project}/${tree}" || exit 1
	(
	cd "${project}/${tree}" \
		|| err "cannot cd to ${project}/${tree}"
	git reset --hard ${rev} \
		|| err "cannot reset ${project} revision for tree, ${tree}"
	git submodule update --init --checkout \
		|| err "cannot update ${project} submodules for tree, ${tree}"

	for patch in ../../"${cfgsdir}"/"${tree}"/patches/*.patch; do
		[ ! -f "${patch}" ] && \
			continue
		if ! git am "${patch}"; then
			git am --abort
			err "cannot patch ${tree}"
		fi
	done

	# extra.sh can be used for anything
	# but should *only* be a last resort
	if [ -f "../../${cfgsdir}/${tree}/extra.sh" ]; then
		"../../${cfgsdir}/${tree}/extra.sh" || \
			err "${tree} extra.sh"
	fi
	)
}

err()
{
	printf "ERROR, %s, %s\n" $0 $1 1>&2
	exit 1
}

main $@