#!/usr/bin/env sh
# Copyright (C) 2021 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# During the release process, we need patches in the manifest, in
# vendor/replicant and vendor/replicant-release-scripts to change the
# Replicant revision.

# When the person who does the release uses a separate computer to
# build Replicant, in some cases, it makes sense to develop the patch
# locally and push them to the remote.

local_repositories="\
	../vendor_replicant-release-scripts \
	../vendor_replicant \
	../manifest \
"

. $(dirname $0)/releasevars.sh

local_tmpdir="$(mktemp -d)"

usage()
{
	echo "Usage:"
	echo "$0 <machine> <replicant_dir> apply" \
	     " # Apply patches to the remote git repositories"
	echo "$0 <machine> <replicant_dir> remove" \
	     "# Remove the last commit from the remote git repositories"
	echo "$0 <machine> <replicant_dir> reset" \
	     " # run git reset --hard on the remote git repositories"
	echo "$0 <machine> <replicant_dir> sync" \
	     "  # run repo sync on the remote git repositories"
	echo ""
	echo "Remote repositories:"
	for repository in ${local_repositories} ; do
		echo "- $(basename ${repository} | sed 's#_#/#g')/"
	done
	exit 64 # EX_USAGE in sysexits.h
}

append_raw()
{
	variable="$1"
	shift 1
	values="$@"

	if [ -z "$(eval echo \$${variable})" ] ; then
		eval "${variable}=\"${values}\""
	else
		eval "${variable}=\"\$${variable}${values}\""
	fi
}

append()
{
	variable="$1"
	shift 1
	values="$@"

	if [ -z "$(eval echo \$${variable})" ] ; then
		eval "${variable}=\"${values}\""
	else
		eval "${variable}=\"\$${variable} ${values}\""
	fi
}

remote_commands=""
queue_remote_commands()
{
	commands="$@"

	if [ -z "${remote_commands}" ] ; then
		append_raw remote_commands "${commands}"
	else
		append_raw remote_commands ";${commands}"
	fi
}

apply_remote_commands()
{
	machine="$1"

	ssh "${machine}" "${remote_commands}"
	remote_commands=""
}

patches_for_remote=""
queue_patches_for_remote()
{
	patches="$@"

	if [ -z "${patches_for_remote}" ] ; then
		append patches_for_remote "${patches}"
	else
		append patches_for_remote ";${patches}"
	fi
}

send_and_apply_patches_to_remote()
{
	machine="$1"
	replicant_dir="$2"

	remote_tmpdir="$(mktemp -d --dry-run)"

	for patch in ${patches_for_remote} ; do
		append remote_tmpsubdirs "${remote_tmpdir}/$(dirname ${patch})"
		append local_patches_paths "${local_tmpdir}/./${patch}"
		queue_remote_commands \
		    "cd;cd ${replicant_dir}/$(dirname ${patch} | sed 's#_#/#g')"
		# TODO: check if the patch is already applied
		queue_remote_commands "git am ${remote_tmpdir}/${patch}"
	done
	queue_remove_remote_temporary_files "${remote_tmpdir}"

	rsync -Rrav ${local_patches_paths} "${machine}:${remote_tmpdir}/"
	apply_remote_commands "${machine}"
	patches_for_remote=""
}

remove_local_temporary_files()
{
	tmpdirs="$@"

	for tmpdir in ${tmpdirs} ; do
		for patch in ${patches} ; do
			rm -f "${tmpdir}/${patch}"
		done

		for repository_dir in ${repositories_dirs} ; do
			rmdir "${tmpdir}/${repository_dir}/"
		done

		rmdir "${tmpdir}/"
	done
}

queue_remove_remote_temporary_files()
{
	tmpdirs="$@"

	for tmpdir in ${tmpdirs} ; do
		for patch in ${patches} ; do
			queue_remote_commands "rm -f ${tmpdir}/${patch}"
		done

		for repository_dir in ${repositories_dirs} ; do
			queue_remote_commands \
			    "rmdir ${tmpdir}/${repository_dir}/"
		done

		queue_remote_commands "rmdir ${tmpdir}/"
	done
}

apply_patches_to_remote()
{
	machine="$1"
	replicant_dir="$2"

	patches=""
	repositories_dirs=""

	for repository in ${local_repositories} ; do
		nr_patches=1
		destdir="${local_tmpdir}/$(basename ${repository})"
		mkdir -p "${destdir}/"
		append "repositories_dirs" "$(basename ${repository})"

		if is_transition_release ; then
			if [ "${repository}" = "../vendor_replicant" ] ; then
				nr_patches=2
			fi
		fi

		_patches="$(git -C ${repository} format-patch -${nr_patches})"
		for patch in ${_patches} ; do
			mv -f "${repository}/${patch}" "${destdir}/"
			append "patches" "$(basename ${repository})/${patch}"
		done
	done

	queue_patches_for_remote "${patches}"
	send_and_apply_patches_to_remote "${machine}" "${replicant_dir}"

	remove_local_temporary_files "${local_tmpdir}"
}

apply_git_reset_hard_to_remote()
{
	machine="$1"
	replicant_dir="$2"

	patches=""
	repositories_dirs=""

	for repository in ${local_repositories} ; do
		remote_git_dir="$(echo $(basename ${repository}) \
				       | sed 's#_#/#g')"
		queue_remote_commands "cd;cd ${replicant_dir}"
		queue_remote_commands "git -C ${remote_git_dir} reset --hard"
	done
	apply_remote_commands "${machine}"
}

remove_top_patches_from_remote()
{
	machine="$1"
	replicant_dir="$2"

	for repository in ${local_repositories} ; do
		remote_git_dir="$(echo $(basename ${repository}) \
				       | sed 's#_#/#g')"
		queue_remote_commands "cd;cd ${replicant_dir}"
		queue_remote_commands \
		    "GIT_EDITOR='echo noop > ' \
		    git -C ${remote_git_dir} rebase -i HEAD~1"
	done
	apply_remote_commands "${machine}"
}

repo_sync_remote_repositories()
{
	machine="$1"
	replicant_dir="$2"

	for repository in ${local_repositories} ; do
		append \
		    "remote_repositories_paths" \
		    "$(echo $(basename ${repository})| sed 's#_#/#g')"
	done

	queue_remote_commands "cd;cd ${replicant_dir}"
	# When using repo sync, repo update itself automatically. But
	# the updated repo doesn't work anymore withTrisquel 9 python3
	# version.To workaround that issue, Replicant released a
	# tarball (built with Guix) that includes a newer repo and all
	# its dependencies (including python). And to work properly we
	# need to source a script that setups the environment
	# variables to make that repo work.
	queue_remote_commands \
	    "[ -f /usr/local/bin/repo-env.sh ] && \
	    source /usr/local/bin/repo-env.sh"
	queue_remote_commands "repo sync ${remote_repositories_paths}"

	apply_remote_commands "${machine}"
}

if [ $# -ne 3 ] ; then
	usage
elif [ "$3" = "apply" ] ; then
	apply_patches_to_remote "$1" "$2"
elif [ "$3" = "remove" ] ; then
	remove_top_patches_from_remote "$1" "$2"
elif [ "$3" = "reset" ] ; then
	apply_git_reset_hard_to_remote "$1" "$2"
elif [ "$3" = "sync" ] ; then
	repo_sync_remote_repositories "$1" "$2"
fi