# Locale functions
#
# Copyright (C) 2012, 2018, 2019 Patrick McDermott
#
# This file is part of opkbuild.
#
# opkbuild 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.
#
# opkbuild 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 opkbuild.  If not, see <http://www.gnu.org/licenses/>.

_OB_DEFAULT_LOCALE='en_US'
_OB_INTERNAL_TEXT_DOMAIN="libopkbuild_${LIBOPKBUILD_SHSOVERSION}"
_ob_text_domain=
_ob_builddir=
_ob_msgs_loaded=false

## @brief Get the current message domain
## @details \fBob_get_text_domain\fP() prints the currently loaded message
##          domain.
## @return Returns 0 on success.
## @stdout Prints the name of the currently loaded message domain.
## @pure yes This function has no side effects.
ob_get_text_domain()
{
	printf '%s' "${_ob_text_domain}"
	return 0
}

_ob_try_load_messages()
{
	local locale="${1}"
	shift 1 || _ob_abort
	local ms=

	if [ x"${_ob_builddir}" != x'' ]; then  # Env var set and not null
		ms="${_ob_builddir}"
		ms="${ms}/${locale}/${_ob_text_domain}.ms"
	else
		ms="${LOCALEDIR}"
		ms="${ms}/${locale}/LC_MESSAGES/${_ob_text_domain}.ms"
	fi

	# POSIX on the dot utility:
	# "If no readable file is found, a non-interactive shell shall abort"
	# So to survive an ENOENT or other error and display a more informative
	# error message before aborting, we need this eval/cat command.  This is
	# more resilient against race conditions than `[ -f "${ms}" ]` is.
	eval "$(cat "${ms}" 2>/dev/null)" || return 1
	return 0
}

## @brief Set and load the message domain
## @details \fBob_set_text_domain\fP() sets and loads the message domain for
##          future \fBob_get_msg\fP() calls.  A message domain is a catalog of
##          localized messages identified by message IDs.  Each application
##          should have its own message domain.  libopkbuild also has its own
##          message domain and temporarily switches to it when needed.
## @operand text_domain req The message domain to load.
## @return Returns 0 on success or 1 if \fItext_domain\fP is missing or invalid
##         or if the message domain cannot be loaded.
## @pure no This function sets an internal global variable and loads a message
##          catalog that sets numerous message variables.
ob_set_text_domain()
{
	local text_domain="${1}"
	shift 1 || _ob_abort

	case "${text_domain}" in *[!A-Za-z0-9_]* | '')
		return 1
	esac
	_ob_text_domain="${text_domain}"
	_ob_builddir="${OB_EXE_BUILDDIR-}"

	# Exit early if domain's messages have already been loaded.
	if eval "\${_ob_text_domain_${_ob_text_domain}_loaded:-false}"; then
		return
	fi
	eval "_ob_text_domain_${_ob_text_domain}_loaded=true"

	# Try to load the messages.
	if ! _ob_try_load_messages "${LC_MESSAGES%.*}"; then
		if ! _ob_try_load_messages "${LC_MESSAGES%_*}"; then
			if ! _ob_try_load_messages "${_OB_DEFAULT_LOCALE}"; then
				return 1
			fi
		fi
	fi

	_ob_msgs_loaded=true
	return 0
}

## @brief Get a message from the current message domain
## @details \fBob_get_msg\fP() prints a message, identified by a message ID,
##          from the currently loaded message catalog. 
##          \fBob_set_text_domain\fP() must be called first.
## @operand msgid req The ID of the message to print
## @return Returns 0 on success.
## @stdout Prints the requested message from the current message domain.
## @pure yes This function has no side effects.
ob_get_msg()
{
	local msgid="${1}"
	shift 1 || _ob_abort

	if ! ${_ob_msgs_loaded}; then
		printf '%s: Error: No text domain set\n' "${0##*/}" >&2
		_ob_abort
	fi
	eval "printf '%s' \"\${msg_${_ob_text_domain}_${msgid}}\""

	return 0
}

_ob_get_msg()
{
	local msgid="${1}"
	shift 1 || _ob_abort

	eval "printf '%s' \"\${msg_${_OB_INTERNAL_TEXT_DOMAIN}_${msgid}}\""

	return 0
}

_ob_load_internal_text_domain()
{
	# Make sure LC_MESSAGES is set.
	if [ x"${LC_MESSAGES:+set}" != x'set' ]; then
		if [ x"${LC_ALL:+set}" = x'set' ]; then
			LC_MESSAGES="${LC_ALL}"
		elif [ x"${LANG:+set}" = x'set' ]; then
			LC_MESSAGES="${LANG}"
		else
			LC_MESSAGES="${_OB_DEFAULT_LOCALE}"
		fi
	fi

	# Try to load the messages.
	_ob_text_domain="${_OB_INTERNAL_TEXT_DOMAIN}"
	_ob_builddir="${OB_LIB_BUILDDIR-}"
	if ! _ob_try_load_messages "${LC_MESSAGES%.*}"; then
		printf '%s: Error: Failed to load locale messages\n' \
			"${0##*/}" >&2
		kill 0
		exit 1  # Should never be reached, but just in case
	fi
}
__init _ob_load_internal_text_domain