# Eggshell Compiler entry point
#
# Copyright (C) 2016  Patrick "P. J." McDermott
#
# This file is part of the Eggshell Compiler.
#
# The Eggshell Compiler 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.
#
# The Eggshell Compiler 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 the Eggshell Compiler.  If not, see
# <http://www.gnu.org/licenses/>.

set -u

usage()
{
	printf 'Usage: %s [-o <output>] <input>...\n' "${0}"
}

version()
{
	cat <<EOF
eshtrans 0.1.0
Copyright (C) 2016  Patrick "P. J." McDermott
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
EOF
}

err()
{
	local fmt="${1}"
	shift 1

	printf "eshtrans: Error: ${fmt}\n" "${@}"
}

main()
{
	local opt=
	local input=
	local output=

	output=''
	unset OPTARG
	while getopts 'V:o:' opt; do
		case "${opt}" in
			'V')
				version
				exit
				;;
			'o')
				output="${OPTARG}"
				;;
			'?')
				usage >&2
				return 1
				;;
		esac
		unset OPTARG
	done
	shift $(($OPTIND - 1))

	if [ ${#} -eq 0 ]; then
		err 'No input files'
		return 1
	fi

	if [ "x${output}" = 'x' ]; then
		for input in "${@}"; do
			output="${input%.esh}.sh"
			contents="$(cat "${input}"; printf '.')"
			contents="${contents%.}"
			sh_codegen "$(esh_parse "${input}" "${contents}")" \
				>"${output}"
		done
	else
		if [ ${#} -gt 1 ]; then
			err 'Cannot specify -o with multiple input files'
			return 1
		fi
		input="${1}"
		if [ "x${output}" = 'x-' ]; then
			contents="$(cat "${input}"; printf '.')"
			contents="${contents%.}"
			sh_codegen "$(esh_parse "${input}" "${contents}")"
		else
			contents="$(cat "${input}"; printf '.')"
			contents="${contents%.}"
			sh_codegen "$(esh_parse "${input}" "${contents}")" \
				>"${output}"
		fi
	fi
}