if [ ! "$_COMMON_SUBR" ]; then _COMMON_SUBR=1
#
# Copyright (c) 2012 Ron McDowell
# Copyright (c) 2012 Devin Teske
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
############################################################ GLOBALS

#
# Program name
#
pgm="${0##*/}"

#
# Program arguments
#
ARGC="$#"
ARGV="$@"

#
# Global exit status variables
#
SUCCESS=0
FAILURE=1

############################################################ FUNCTIONS

#
# This is an empty function by default, to use it, copy
# /usr/share/examples/bsdconfig/bsdconfigrc to $HOME/.bsdconfigrc
#
f_dprintf()
{
	: this page intentionally left blank
}

# f_err $fmt [ $opts ... ]
#
# Print a message to stderr (fd=2).
#
f_err()
{
	printf "$@" >&2
}

# f_quietly $command [ $arguments ... ]
#
# Run a command quietly (quell any output to stdout or stderr)
#
f_quietly()
{
	"$@" > /dev/null 2>&1
}

# f_have $anything ...
#
# A wrapper to the `type' built-in. Returns true if argument is a valid shell
# built-in, keyword, or externally-tracked binary, otherwise false.
#
f_have()
{
	f_quietly type "$@"
}

# f_die [ $status [ $fmt [ $opts ... ]]]
#
# Abruptly terminate due to an error optionally displaying a message in a
# dialog box using printf(1) syntax.
#
f_die()
{
	local status=$FAILURE

	# If there is at least one argument, take it as the status
	if [ $# -gt 0 ]; then
		status=$1
		shift 1 # status
	fi

	# If there are still arguments left, pass them to f_show_msg
	[ $# -gt 0 ] && f_show_msg "$@"

	# Optionally call f_clean_up() function if it exists
	f_have f_clean_up && f_clean_up

	exit $status
}

# f_interrupt
#
# Interrupt handler.
#
f_interrupt()
{
	exec 2>&1 # fix sh(1) bug where stderr gets lost within async-trap
	f_die
}

# f_show_msg $fmt [ $opts ... ]
#
# Display a message in a dialog box using printf(1) syntax.
#
f_show_msg()
{
	local msg
	msg=$( printf "$@" )

	#
	# Use f_dialog_msgbox from dialog.subr if possible, otherwise fall
	# back to dialog(1) (without options, making it obvious when using
	# un-aided system dialog).
	#
	if f_have f_dialog_msgbox; then
		f_dialog_msgbox "$msg"
	else
		dialog --msgbox "$msg" 0 0
	fi
}

# f_show_help $file
#
# Display a language help-file. Automatically takes $LANG and $LC_ALL into
# consideration when displaying $file (suffix ".$LC_ALL" or ".$LANG" will
# automatically be added prior to loading the language help-file).
#
# If a language has been requested by setting either $LANG or $LC_ALL in the
# environment and the language-specific help-file does not exist we will fall
# back to $file without-suffix.
#
# If the language help-file does not exist, an error is displayed instead.
#
f_show_help()
{
	local file="$1"
	local lang="${LANG:-$LC_ALL}"

	[ -f "$file.$lang" ] && file="$file.$lang"

	#
	# Use f_dialog_textbox from dialog.subr if possible, otherwise fall
	# back to dialog(1) (without options, making it obvious when using
	# un-aided system dialog).
	#
	if f_have f_dialog_textbox; then
		f_dialog_textbox "$file"
	else
		dialog --msgbox "$( cat "$file" 2>&1 )" 0 0
	fi
}

# f_include $file
#
# Include a shell subroutine file.
#
# If the subroutine file exists but returns error status during loading, exit
# is called and execution is prematurely terminated with the same error status.
#
f_include()
{
	local file="$1"
	. "$file" || exit $?
}

# f_include_lang $file
#
# Include a language file. Automatically takes $LANG and $LC_ALL into
# consideration when including $file (suffix ".$LC_ALL" or ".$LANG" will
# automatically by added prior to loading the language file).
#
# No error is produced if (a) a language has been requested (by setting either
# $LANG or $LC_ALL in the environment) and (b) the language file does not
# exist -- in which case we will fall back to loading $file without-suffix.
#
# If the language file exists but returns error status during loading, exit
# is called and execution is prematurely terminated with the same error status.
#
f_include_lang()
{
	local file="$1"
	local lang="${LANG:-$LC_ALL}"

	f_dprintf "lang=[$lang]"
	if [ -f "$file.$lang" ]; then
		. "$file.$lang" || exit $?
	else
		. "$file" || exit $?
	fi
}

# f_usage $file [ $key1 $value1 ... ]
#
# Display USAGE file with optional pre-processor macro definitions. The first
# argument is the template file containing the usage text to be displayed. If
# $LANG or $LC_ALL (in order of preference, respectively) is set, ".encoding"
# will automatically be appended as a suffix to the provided $file pathname.
#
# When processing $file, output begins at the first line containing that is
# (a) not a comment, (b) not empty, and (c) is not pure-whitespace. All lines
# appearing after this first-line are output, including (a) comments (b) empty
# lines, and (c) lines that are purely whitespace-only.
#
# If additional arguments appear after $file, substitutions are made while
# printing the contents of the USAGE file. The pre-processor macro syntax is in
# the style of autoconf(1), for example:
#
# 	f_usage $file "FOO" "BAR"
#
# Will cause instances of "@FOO@" appearing in $file to be replaced with the
# text "BAR" before bering printed to the screen.
#
# This function is a two-parter. Below is the awk(1) portion of the function,
# afterward is the sh(1) function which utilizes the below awk script.
#
f_usage_awk='
BEGIN { found = 0 }
{
	if ( !found && $0 ~ /^[[:space:]]*($|#)/ ) next
	found = 1
	print
}
'
f_usage()
{
	local file="$1"
	local lang="${LANG:-$LC_ALL}"

	f_dprintf "lang=[$lang]"

	shift 1 # file

	local usage
	if [ -f "$file.$lang" ]; then
		usage=$( awk "$f_usage_awk" "$file.$lang" ) || exit $FAILURE
	else
		usage=$( awk "$f_usage_awk" "$file" ) || exit $FAILURE
	fi

	while [ $# -gt 0 ]; do
		local key="$1"
		export value="$2"
		usage=$( echo "$usage" | awk \
			"{ gsub(/@$key@/, ENVIRON[\"value\"]); print }" )
		shift 2
	done

	f_err "%s\n" "$usage"

	exit $FAILURE
}

# f_index_menu_selection $file $pgm
#
# Process $file looking for $menu_selection values that correspond to $pgm.
# This function is for internationalization (i18n) mapping of the on-disk
# scriptname ($pgm) into the localized language (given language-specific
# $file). If $LANG or $LC_ALL (in orderder of preference, respectively) is set,
# ".encoding" will automatically be appended as a suffix to the provided $file
# pathname.
#
# If, within $file, multiple $menu_selection values map to $pgm, only the first
# one will be returned. If no mapping can be made, the NULL string is returned.
#
# If $file does not exist, error status is returned along with the NULL string.
#
# This function is a two-parter. Below is the awk(1) portion of the function,
# afterward is the sh(1) function which utilizes the below awk script.
#
f_index_menusel_awk='
# Variables that should be defined on the invocation line:
# 	-v pgm="program_name"
#
( $0 ~ "^menu_selection=.*\\|" pgm "\"" ) {
	sub(/\|.*/, "")
	sub(/^menu_selection="/, "")
	print
	exit
}
'
f_index_menu_selection()
{
	local file="$1" pgm="$2"
	local lang="${LANG:-$LC_ALL}"

	f_dprintf "lang=[$lang]"

	if [ -f "$file.$lang" ]; then
		awk -v pgm="$pgm" "$f_index_menusel_awk" "$file.$lang" ||
			exit $FAILURE
	elif [ -f "$file" ]; then
		awk -v pgm="$pgm" "$f_index_menusel_awk" "$file" ||
			exit $FAILURE
	else
		return $FAILURE
	fi
}

############################################################ MAIN

#
# Trap signals so we can recover gracefully
#
trap 'f_interrupt' SIGINT
trap 'f_die' SIGTERM SIGPIPE SIGXCPU SIGXFSZ \
             SIGFPE SIGTRAP SIGABRT SIGSEGV
trap '' SIGALRM SIGPROF SIGUSR1 SIGUSR2 SIGHUP SIGVTALRM

fi # ! $_COMMON_SUBR