#!/usr/bin/env bash

# Copyright (C) 2016 Paul Kocialkowski <contact@paulk.fr>
#
# 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/>.

BUILD_SYSTEM="paper"

SOURCES="sources"
SYSTEMS="systems"
IMAGES="images"
TOOLS="tools"

ARCHIVE="tar.xz"
CHECKSUM="sha256sum"
ASC="asc"

usage() {
	printf '%s\n' "$executable [action] [projects...]" >&2

	printf '\n%s\n' 'Actions:' >&2
	printf '%s\n' '  download - Download project files' >&2
	printf '%s\n' '  sources - Download project sources' >&2
	printf '%s\n' '  verify - Verify project files' >&2
	printf '%s\n' '  extract - Extract project files' >&2
	printf '%s\n' '  prepare - Download, verify and extract project files' >&2

	printf '\n%s\n' 'Environment variables:' >&2
	printf '%s\n' '  MACHINE - Machine architecture to use' >&2
	printf '%s\n' '  DOWNLOAD_URL - Base URL to download files from' >&2
}

download() {
	local project=$1

	local ifs_save
	local prefix
	local directory
	local path
	local url

	for prefix in "$SYSTEMS/$MACHINE" "$IMAGES" "$TOOLS/$MACHINE"
	do
		ifs_save=$IFS
		IFS=$'-'

		directory=""

		for part in $project
		do
			if [ -z "$directory" ]
			then
				directory="$part"
			else
				directory="$directory-$part"
			fi

			path="$root/$prefix/$directory/$project.$ARCHIVE"
			url="$DOWNLOAD_URL/$prefix/$directory/$project.$ARCHIVE"

			if wget --quiet --spider "$url"
			then
				mkdir -p "$( dirname "$path" )"
				wget -O "$path" "$url"
				wget -O "$path.$CHECKSUM" "$url.$CHECKSUM"
				wget -O "$path.$DSIG" "$url.$DSIG"

				printf '\n%s\n' "Downloaded $project"

				return 0
			fi
		done

		IFS=$ifs_save
	done

	printf '%s\n' "Could not download $project from $DOWNLOAD_URL" >&2
	return 1
}

sources() {
	local project=$1

	local url="$DOWNLOAD_URL/$SOURCES/$project/$project.$ARCHIVE"
	local path="$root/$SOURCES/$project/$project.$ARCHIVE"

	if wget --quiet --spider "$url"
	then
		mkdir -p "$( dirname "$path" )"
		wget -O "$path" "$url"
		wget -O "$path.$CHECKSUM" "$url.$CHECKSUM"
		wget -O "$path.$DSIG" "$url.$DSIG"

		printf '\n%s\n' "Downloaded $project sources"
	else
		printf '%s\n' "Could not download $project sources from $DOWNLOAD_URL" >&2
		return 1
	fi

}

verify() {
	local project=$1

	local checksum_path
	local signature_path
	local ifs_save
	local prefix
	local directory
	local path

	for prefix in "$SYSTEMS/$MACHINE" "$IMAGES" "$TOOLS/$MACHINE"
	do
		ifs_save=$IFS
		IFS=$'-'

		directory=""

		for part in $project
		do
			if [ -z "$directory" ]
			then
				directory="$part"
			else
				directory="$directory-$part"
			fi

			path="$root/$prefix/$directory/$project.$ARCHIVE"

			if ! [ -f "$path" ]
			then
				continue
			fi

			checksum_path="$path.$CHECKSUM"
			signature_path="$path.$DSIG"

			if [ -f "$checksum_path" ]
			then
				(
					cd "$( dirname "$path" )"
					sha256sum -c "$project.$ARCHIVE.$CHECKSUM"
				)
			else
				printf '%s\n' "Could not verify $project checksum!" >&2
			fi

			if [ -f "$signature_path" ]
			then
				gpg --armor --verify "$signature_path" "$path"
			else
				printf '%s\n' "Could not verify $project signature!" >&2
			fi

			printf '\n%s\n' "Verified $project"

			return 0
		done

		IFS=$ifs_save
	done

	printf '%s\n' "Could not verify $project" >&2
	return 1
}

extract() {
	local project=$1

	local extract_path
	local ifs_save
	local prefix
	local directory
	local path

	for prefix in "$SYSTEMS/$MACHINE" "$IMAGES" "$TOOLS/$MACHINE"
	do
		ifs_save=$IFS
		IFS=$'-'

		directory=""

		for part in $project
		do
			if [ -z "$directory" ]
			then
				directory="$part"
			else
				directory="$directory-$part"
			fi

			path="$root/$prefix/$directory/$project.$ARCHIVE"

			if ! [ -f "$path" ]
			then
				continue
			fi

			if [ "$prefix" = "$SYSTEMS/$MACHINE" ]
			then
				printf '%s\n' "Skiping $project extract"
				return 0
			fi

			extract_path=$( dirname "$path" )

			tar -xf "$path" -ps -C "$extract_path"

			printf '%s\n' "Extracted $project"

			return 0
		done

		IFS=$ifs_save
	done

	printf '%s\n' "Could not extract $project" >&2
	return 1
}

requirements() {
	local requirement
	local requirement_path

	for requirement in "$@"
	do
		requirement_path=$( which "$requirement" || true )

		if [ -z "$requirement_path" ]
		then
			printf '%s\n' "Missing requirement: $requirement" >&2
			exit 1
		fi
	done
}

setup() {
	root=$(readlink -f "$( dirname "$0" )" )
	executable=$( basename "$0" )

	if [ -z "$MACHINE" ]
	then
		MACHINE=$( uname -m )
	fi

	if [ -z "$DOWNLOAD_URL" ]
	then
		printf '%s\n' 'Missing download URL' >&2
		exit 1
	fi
}

libreboot_release() {
	local action=$1
	shift

	set -e

	setup "$@"

	if [ -z "$action" ]
	then
		usage
		exit 1
	fi

	requirements "tar" "sha256sum" "gpg"

	case $action in
		"download")
			for project in "$@"
			do
				download "$project"
			done
			;;
		"sources")
			for project in "$@"
			do
				sources "$project"
			done
			;;
		"verify")
			for project in "$@"
			do
				verify "$project"
			done
			;;
		"extract")
			for project in "$@"
			do
				extract "$project"
			done
			;;
		"prepare")
			for project in "$@"
			do
				download "$project"
				verify "$project"
				extract "$project"
			done
			;;
	esac
}

libreboot_release "$@"