# pro-archman
# src/control.sh
# Functions for parsing control files.
#
# Copyright (C) 2012, 2018, 2019  Patrick McDermott
#
# This file is part of the ProteanOS Archive Manager.
#
# The ProteanOS Archive Manager 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 ProteanOS Archive Manager 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 ProteanOS Archive Manager.  If not, see
# <http://www.gnu.org/licenses/>.

_parse_control_error()
{
	file="${1}"
	line_nr="${2}"
	msg_id="${3}"
	shift 3
	local file_info=

	if [ ${line_nr} -eq 0 ]; then
		file_info="$(printf '%s' "${file}")"
	else
		file_info="$(printf '%s:%d' "${file}" "${line_nr}")"
	fi

	warn "${file_info}: $(get_msg "${msg_id}")" "${@}"

	return 0
}

parse_control()
{
	local file="${1}"
	local field_cb="${2}"
	local req_fields="${3}"
	local opt_fields="${4}"
	shift 4
	local got_fields=
	local line_nr=
	local line=
	local name=
	local value=
	local sep=

	req_fields=" $(printf '%s ' ${req_fields})"
	opt_fields=" $(printf '%s ' ${opt_fields})"
	got_fields=' '

	line_nr=0

	while IFS='' read -r line; do
		line_nr=$((${line_nr} + 1))
		case "${line}" in
			'')
				_parse_control_error "${file}" "${line_nr}" \
					'control_empty_line'
				;;
			'#'*)  # Comment.
				;;
			[!\ ]*':'*)  # "Name: Value" line.
				if [ -n "${name}" ]; then
					if ! "${field_cb}" "${name}" "${value}"
					then
						return 0
					fi
				fi
				IFS=': 	' read name value 0<<-EOF
					${line}
					EOF
				if [ -z "${name}" ]; then
					# Badly formatted control field.
					_parse_control_error "${file}" \
						"${line_nr}" 'control_bad_nv'
					continue
				fi
				case "${got_fields}" in *" ${name} "*)
					# Duplicate field.
					_parse_control_error \
						"${file}" "${line_nr}" \
						'control_duplicate_field' \
						"${name}"
					continue
				esac
				got_fields="${got_fields}${name} "
				case "${req_fields}" in *" ${name} "*)
					# Required field: remove from list.
					req_fields="${req_fields% ${name} *}$(:\
						) ${req_fields#* ${name} }"
					continue
				esac
				case "${opt_fields}" in *" ${name} "*)
					# Optional field.
					continue
				esac
				# Unknown field.
				_parse_control_error \
					"${file}" "${line_nr}" \
					'control_unknown_field' "${name}"
				;;
			' '*)  # Continuation line.
				if [ -z "${name}" ]; then
					# Expecting a "Name: Value" line.
					_parse_control_error "${file}" \
						"${line_nr}" \
						'control_found_continuation'
					continue
				fi
				value="${value}${LF}${line# }"
				;;
		esac
	done 0<<-EOF
		$(cat -- "${file}")
		EOF

	if [ -n "${name}" ]; then
		if ! "${field_cb}" "${name}" "${value}"; then
			return 0
		fi
	fi

	case "${req_fields}" in *[!\ ]*)
		# Missing required control fields.
		sep="$(get_msg 'list_item_separator')"
		req_fields="$(printf "%s${sep}" ${req_fields}; printf 'x')"
		req_fields="${req_fields%${sep}x}"
		_parse_control_error "${file}" '0' 'control_missing_fields' \
			"${req_fields}"
		return 1
	esac

	return 0
}