# Generate a control directory with a control file and scripts
#
# Copyright (C) 2012, 2019 Patrick McDermott
#
# This file is part of opkbuild.
#
# opkbuild 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.
#
# opkbuild 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 opkbuild.  If not, see <http://www.gnu.org/licenses/>.

set -eu

gen_control()
{
	local binary="${1}"
	local version="${2}"
	local arch="${3}"
	local plat="${4}"
	local desc="${5}"
	local gen_rel="${6}"
	shift 6
	local inst_size=
	local sizes=
	local size=
	local name=
	local value=
	local homepage=

	# Calculate installed size.
	# Don't use du, since that considers the allocated size of files,
	# symbolic links, and directories (i.e. actual file sizes plus the
	# filesystem overhead on the build system).
	# See the following for more information:
	#   <http://pubs.opengroup.org/onlinepubs/9699919799/utilities/du.html>
	#   <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=630533>
	#   <https://www.gnu.org/software/coreutils/manual/html_node/du-invocation.html>
	inst_size=0
	if [ -d "${binary}.data" ]; then
		sizes="$(find "${binary}.data" -type f -exec wc -c '{}' ';' | \
			cut -d ' ' -f 1)"
		for size in ${sizes}; do
			inst_size=$((${inst_size} + ${size}))
		done
	fi
	# Convert bytes to kibibytes and round up.
	# Note: There is an inconsistency between the Debian Policy Manual and
	# opkg in the units of this field.  Debian Policy defines this field in
	# units of kibibytes:
	#   The disk space is given as the integer value of the estimated
	#   installed size in bytes, divided by 1024 and rounded up.
	# However, opkg apparently attempts to convert this value from bytes to
	# kibibytes in its determination of whether the package's data will fit
	# on the system:
	#   pkg_size_kbs = (pkg->installed_size + 1023)/1024;
	#   (from libopkg/opkg_install.c line 245)
	#   (still in upstream as of 2019-02-25, libopkg/opkg_install.c:118)
	# In other words, if a package declares an installed size of 10 KiB,
	# opkg checks for 10 MiB of available space.
	# TODO: Further investigate opkg's disk space calculation and, if
	# necessary, patch opkg and submit a bug report.
	inst_size=$(((${inst_size} + 1023) / 1024))

	mkdir -p -- "${binary}.control"

	cat >"${binary}.control/control" <<-EOF
		Package: ${binary}
		Source: ${OPK_SOURCE}
		Version: ${version}
		Architecture: ${arch}
		Platform: ${plat}
		Maintainer: $(ob_get_source_parameter 'Maintainer' | \
			tr '\n' ' ')
		EOF

	if ${gen_rel}; then
		for name in Essential Depends Recommends Suggests Pre-Depends \
				Conflicts Provides Replaces; do
			value="$(ob_get_binary_parameter "${binary}" "${name}")"
			if [ -z "${value}" ]; then
				continue
			fi
			case "${name}" in
				'Essential')
					;;
				'Depends' | 'Recommends' | \
					'Suggests' | 'Pre-Depends')
					value="$(ob_reduce_deps \
						-a "${OPK_HOST_ARCH}" \
						-p "${OPK_HOST_PLAT}" \
						-- "${value}")"
					value="$(ob_substvars "${value}" \
						"${binary}")"
					;;
				'Conflicts' | 'Provides' | 'Replaces')
					value="$(ob_reduce_deps \
						-a "${OPK_HOST_ARCH}" \
						-p "${OPK_HOST_PLAT}" \
						-u -- "${value}")"
					value="$(ob_substvars "${value}" \
						"${binary}")"
					;;
			esac
			printf '%s: %s\n' "${name}" "${value}" | \
				sed 's/[, ]*$//' \
				>>"${binary}.control/control"
		done
	fi

	cat >>"${binary}.control/control" <<-EOF
		Installed-Size: ${inst_size}
		Description:$(printf '%s' "${desc}" | sed 's/^/ /')
		EOF

	homepage="$(ob_get_source_parameter 'Homepage')"
	if [ -n "${homepage}" ]; then
		printf '%s: %s\n' 'Homepage' "${homepage}" \
			>>"${binary}.control/control"
	fi

	return 0
}

install_maintainer_scripts()
{
	local binary="${1}"
	shift 1
	local script=
	local target=

	for script in preinst postinst prerm postrm; do
		if [ -L "../${binary}.pkg/${script}" ]; then
			target="$(ls -l "../${binary}.pkg/${script}")"
			target="${target#* -> }"
			ln -s -- "${target}" "${binary}.control/${script}"
		elif [ -r "../${binary}.pkg/${script}" ]; then
			cp "../${binary}.pkg/${script}" \
				"${binary}.control/${script}"
			chmod 755 "${binary}.control/${script}"
		fi
	done

	return 0
}

gen_conffiles()
{
	local binary="${1}"
	shift 1

	if [ -d "${binary}.data/etc" ]; then
		find "${binary}.data/etc" -type f | sed "s@^${binary}.data@@" \
			>"${binary}.control/conffiles"
		if [ -z "$(head -n 1 "${binary}.control/conffiles")" ]; then
			rm -f -- "${binary}.control/conffiles"
		else
			chmod 644 "${binary}.control/conffiles"
		fi
	fi

	return 0
}

gen_md5sums()
{
	local binary="${1}"
	shift 1
	local has_data=
	local sum=
	local file=

	has_data=false
	exec 3>"${binary}.control/md5sums"
	while read -r sum file; do
		case "${file}" in '-') continue;; esac
		file="${file#${binary}.data}"
		printf '%s  %s\n' "${sum}" "${file}" >&3
		has_data=true
	done <<-EOF
		$(find "${binary}.data" -type f 2>/dev/null | sort | \
			xargs md5sum)
		EOF
	exec 3>&-

	if ! ${has_data}; then
		rm -f -- "${binary}.control/md5sums"
	else
		chmod 644 "${binary}.control/md5sums"
	fi

	return 0
}

main()
{
	local pkg=
	local arch=
	local plat=
	local desc=

	if ! ob_set_text_domain 'opkbuild'; then
		printf '%s: Error: Failed to load locale messages\n' \
			"${0##*/}" >&2
		return 1
	fi

	ob_init_package '..' || return 1

	if [ x"${OB_DO_SOURCE:+set}" = x'set' ]; then
		ob_info "$(ob_get_msg 'gen_control')" "src-${OPK_SOURCE}"
		gen_control "src-${OPK_SOURCE}" "${OPK_SOURCE_VERSION}" \
			'src' 'all' "${OPK_SOURCE} source package" 'false'
		gen_md5sums "src-${OPK_SOURCE}"
	else
		for pkg in ${OPK_PACKAGES_REDUCED}; do
			ob_info "$(ob_get_msg 'gen_control')" "${pkg}"
			ob_set_package_substvars "${pkg}"
			arch="$(ob_get_binary_parameter "${pkg}" \
				'Architecture')"
			[ x"${arch}" != x'all' ] && arch="${OPK_HOST_ARCH}"
			plat="$(ob_get_binary_parameter "${pkg}" 'Platform')"
			[ x"${plat}" != x'all' ] && plat="${OPK_HOST_PLAT}"
			desc="$(ob_get_binary_parameter "${pkg}" 'Description')"
			desc="$(ob_substvars "${desc}" "${pkg}")"
			gen_control "${pkg}" "${OPK_BINARY_VERSION}" \
				"${arch}" "${plat}" "${desc}" 'true'
			install_maintainer_scripts "${pkg}"
			gen_conffiles "${pkg}"
			gen_md5sums "${pkg}"
		done
	fi

	return 0
}