#!/usr/bin/env bash

# Copyright (C) 2017 Andrew Robbins <contact@andrewrobbins.info>
#
# 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/>.

ARCH='arch'
CONFIG='config'
FORMAT='format'
MODMIN='modules-minimal'
PLATFORM='platform'
PREFIX='prefix'
SIZE='size'

grub_arch() {
	project_file_contents "${project}" "${CONFIGS}" "${ARCH}" "$@"
}

grub_format() {
	project_file_contents "${project}" "${CONFIGS}" "${FORMAT}" "$@"
}

grub_platform() {
	project_file_contents "${project}" "${CONFIGS}" "${PLATFORM}" "$@"
}

grub_prefix() {
	project_file_contents "${project}" "${CONFIGS}" "${PREFIX}" "$@"
}

grub_size() {
	project_file_contents "${project}" "${CONFIGS}" "${SIZE}" "$@"
}

grub_config_path() {
	project_file_path "${project}" "${CONFIGS}" "${CONFIG}" "$@"
}

grub_modmin_path() {
	project_file_path "${project}" "${CONFIGS}" "${MODMIN}" "$@"
}

grub_copy_modules() {
	local grub_module_dir="${sources_path}/grub-core"
	local keep_dir="${build_path}/$(grub_format "${target}" "$@")"

	mkdir -p "${keep_dir}"

	cp -a "${grub_module_dir}"/*.@(mod|lst) "${keep_dir}"
}

grub_build_utils() {
	(
		# If arch and/or platform files don't exist,
		# the configure script will pick a reasonable default
		local arch="$(grub_arch "${target}" "$@")"
		local platform="$(grub_platform "${target}" "$@")"

		cd "${sources_path}" || return

		if git_project_check "${repository}"; then
			./autogen.sh
		fi

		./configure --target="${arch}" --with-platform="${platform}"

		make -j"${TASKS}"
	)
}

grub_build_layout() {
	local raw_layout="${1##*/}"
	local raw_layout_path="$1"
	local grub_kbdcomp="${sources_path}/grub-kbdcomp"
	local grub_kbd_layout="${build_path}/${raw_layout}.gkb"

	"${grub_kbdcomp}" --output="${grub_kbd_layout}" "${raw_layout_path}"
}

grub_build_bootable_image() {
	local arch="$(grub_arch "${target}" "$@")"
	local format="$(grub_format "${target}" "$@")"
	local prefix="$(grub_prefix "${target}" "$@")"
	local config_path="$(grub_config_path "${target}" "$@")"

	local grub_mkimage="${sources_path}/grub-mkimage"
	local grub_module_dir="${sources_path}/grub-core"

	local grubimg="${build_path}/grub.img"
	local grub_bootimg="${grub_module_dir}/boot.img"
	local grub_bootable_img="${build_path}/grub2"

	"${grub_mkimage}" \
		--config="${config_path}" \
		--directory="${grub_module_dir}" \
		--output="${grubimg}" \
		--format="${format}" \
		--prefix="${prefix}" \
		cbfs configfile

	cat "${grub_bootimg}" "${grubimg}" > "${grub_bootable_img}"
	rm -f "${grubimg}"
}

grub_build_floppy_image() {
	local grubimg="${build_path}/grub2"
	local tempfile="${build_path}/temp.file"

	if ! ( grub_build_bootable_image "$@" ); then
		printf '\n%s\n\n' "Error: Failed to build a GRUB image" 1>&2
		return 1
	fi

	local size="$(grub_size "${target}" "$@")"

	# Pre-allocate a floppy-sized image
	# SeaBIOS requires floppy images to have a "correct" size
	if ! [[ -e "${tempfile}" ]]; then
		dd if=/dev/zero of="${tempfile}" bs=1024 count="${size:-160}"
	else
		printf '\n%s\n\n' "Error: File ${tempfile} already exists!" 1>&2
		return 1
	fi

	local -i grubimg_size="$(stat -c %s "${grubimg}")"
	local -i floppy_size="$((${size:-160} * 1024))"

	# Graft the GRUB image onto the blank floppy image
	if ((grubimg_size <= floppy_size)); then
		dd if="${grubimg}" of="${tempfile}" bs=1 conv=notrunc

		rm -f "${grubimg}"
		mv "${tempfile}" "${grubimg}"
	else
		printf '\n%s' "Error: Image ${grubimg##*/} is too large; " 1>&2
		printf '%s\n\n' "it must be less than ${size}KiB in size." 1>&2
		return 1
	fi
}

grub_build_standalone_image() {
	local arch="$(grub_arch "${target}" "$@")"
	local format="$(grub_format "${target}" "$@")"
	local prefix="$(grub_prefix "${target}" "$@")"
	local config_path="$(grub_config_path "${target}" "$@")"

	local grubimg="${build_path}/grub2"

	local grub_mkimage="${sources_path}/grub-mkimage"
	local grub_mkstandalone="${sources_path}/grub-mkstandalone"
	local grub_module_dir="${sources_path}/grub-core"

	"${grub_mkstandalone}" \
		--grub-mkimage="${grub_mkimage}" \
		--fonts='' \
		--themes='' \
		--locales='' \
		--install-modules='cbfs configfile' \
		--directory="${grub_module_dir}" \
		--format="${format}" \
		--output="${grubimg}" \
		/boot/grub/grub.cfg="${config_path}"
}