# Main program file
#
# Copyright (C) 2013, 2014  Patrick McDermott
#
# This file is part of the ProteanOS Development Kit.
#
# The ProteanOS Development Kit 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 Development Kit 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 Development Kit.  If not, see
# <http://www.gnu.org/licenses/>.

set -eu

# Constant global variables
HT='	'
LF='
'
OPTSTRING='hV'

if [ -f "${0%/*}/.builddirstamp" ]; then
	in_place=true
	builddir="${0%/*}"
else
	in_place=false
	builddir=''
fi

unixtime()
{
	# Based on code from <https://www.etalabs.net/sh_tricks.html> by Rich
	# Felker, with whitespace added for readability.
	printf '%d' $(($(TZ=UTC0 date "+
		(
			  (%Y - 1600) * 365
			+ (%Y - 1600) / 4
			- (%Y - 1600) / 100
			+ (%Y - 1600) / 400
			+ 1%j - 1000
			- 135140
		) * 86400
		+ (1%H - 100) * 3600
		+ (1%M - 100) * 60
		+ (1%S - 100)")))
}

main()
{
	local cmd=
	local es=

	if ! load_locale; then
		return 2
	fi

	if ! get_options "${@}"; then
		cmd_help_main >&2
		return 1
	fi
	shift $((${OPTIND} - 1))

	if ${opt_h:-false}; then
		cmd='help'
	elif ${opt_V:-false}; then
		cmd='version'
	elif [ ${#} -lt 1 ]; then
		cmd_help_main >&2
		return 1
	else
		cmd="${1}"
		shift 1
	fi

	srand $((${$} + $(unixtime)))
	if ! init_vardata; then
		return 2
	fi

	case "${cmd}" in
		'help'|'version') ;;
		*)
			if ! check_uid; then
				error "$(get_msg 'uid_0_req')"
				return 1
			fi
			;;
	esac
	es=0
	run_cmd "${cmd}" "${@}" || es=${?}

	if ! fini_vardata; then
		return 2
	fi

	return ${es}
}

check_uid()
{
	local uname_s=
	local uid=

	uname_s="$( (uname -s) 2>/dev/null)" || uname_s='unknown'
	uid="$(id -u)"

	case "${uname_s}" in
		'Linux')
			if [ ${uid} -ne 0 ]; then
				return 1
			fi
			;;
	esac

	return 0
}