#!/usr/bin/env bash
# This may be included with or without `set -euE`
# When run directly, it does `set -euE`

# Copyright (C) 2011 Joshua Ismael Haase Hernández (xihh) <hahj87@gmail.com>
# Copyright (C) 2012 Nicolás Reynolds <fauno@parabola.nu>
# Copyright (C) 2012-2014 Luke Shumaker <lukeshu@sbcglobal.net>

# For just the setup_traps() function:
#   Copyright (C) 2002-2006 Judd Vinet <jvinet@zeroflux.org>
#   Copyright (C) 2006-2010 Pacman Development Team <pacman-dev@archlinux.org>
#   Copyright (C) 2005 Aurelien Foret <orelien@chez.com>
#   Copyright (C) 2005 Christian Hamar <krics@linuxforum.hu>
#   Copyright (C) 2006 Alex Smith <alex@alex-smith.me.uk>
#   Copyright (C) 2006 Andras Voroskoi <voroskoi@frugalware.org>
#   Copyright (C) 2006 Miklos Vajna <vmiklos@frugalware.org>
#
# License: GNU GPLv2+
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

################################################################################
# Inherit most functions from devtools                                         #
################################################################################

. "$(librelib common.sh)"

################################################################################
# Own functions                                                                #
################################################################################

# Usage: panic
#
# For programming errors, bails immediately with little fanfare.
panic() {
	echo "$(_l _ 'panic: malformed call to internal function')" >&2
	exit 1
}

# Usage: print MESG [ARGS...]
#
# Like printf, but gettext-aware, and prints a trailing newline
print() {
	[[ $# -ge 1 ]] || panic
	local mesg="$(_ "$1")"
	shift
	printf -- "$mesg\n" "$@"
}

# Usage: _libremessages_html_whitespace_collapse <<<STRING
#
# Collapses whitespace on stadard I/O, similar to HTML whitespace
# collapsing, with the exception that it puts two spaces between
# sentences.  It considers newline, tab, and space to be whitespace.
	[[ $# == 0 ]] || panic

	tr '\n' '\r' | sed -r \
			   -e 's/\r/  /g' -e 's/\t/ /g' \
			   -e 's/(^|[^.!? ]) +/\1 /g' -e 's/([.!?])  +/\1  /g'
}


# Usage: prose MESG [ARGS...]
#
# Do HTML-style whitespace collapsing on the first argument, translate
# it (gettext), then word-wrap it to 75 columns.  This is useful for
# printing a paragraph of prose in --help text.
prose() {
	[[ $# -ge 1 ]] || panic
	local mesg="$(_ "$(_libremessages_html_whitespace_collapse <<<"$1")")"; shift
	printf -- "$mesg" "$@" | fmt -u
}

# Usage: bullet MESG [ARGS...]
# Like prose, but print a bullet "-" before the first line, and indent the
# remaining lines.
bullet() {
	[[ $# -ge 1 ]] || panic
	local mesg="$(_ "$(_libremessages_html_whitespace_collapse <<<"$1")")"; shift
	# Wrap the text to 71 columns; 75 (the default) minus a 4 column indent
	printf -- "$mesg" "$@" | fmt -u -w 71 | sed -e '1s/^/  - /' -e '2,$s/^/    /'
}

# Usage: flag FLAG DESCRIPTION [FLAG2 DESCRIPTION2...]
#
# Print a flag and description formatted for --help text.
#
#   ex: flag '-C <FILE>' 'Use this file instead of pacman.conf'
#
# The description is fed through gettext, the flag is not, so if part
# of the flag needs to be translated, you must do that yourself:
#
#   ex: flag "-C <$(_ FILE)>" 'Use this file instead of pacman.conf'
#
# If you want to line-break the description in the source, so it isn't
# crazy-long, feel free, it is reflowed/wrapped the same way as prose
# and bullet.  If you pass in multiple flag/description pairs at once,
# the descriptions are all alligned together.
flag() {
	[[ $# == $(($#/2*2)) ]] || panic

	local args=("$@")
	declare -i flaglen=0
	declare -i i=0
	while [[ $i -lt $# ]]; do
		if [[ ${#args[i]} -gt $flaglen ]]; then
			flaglen=${#args[$i]}
		fi
		i+=2
	done

	# Unless the $flaglen is extra-wide, the $desc should start at
	# column 16 (that is two literal-tabs).  If $flaglen is wide,
	# this should be increased in increments of 8 (that is, a
	# literal-tab).  Everything should be wrapped to 75 columns.

	# The printf-format we use has 4 spaces built into it (two at
	# the beginning, and two for a seperator).  Therefore, the
	# default indent is 16-4=12 columns.  And the width left for
	# $desc is (75-4)-indent = 71-indent.

	declare -i indent=12
	while [[ $indent -lt $flaglen ]]; do
		indent+=8
	done
	local fmt2 fmt1
	fmt2="  %-${indent}s  %s\n"
	printf -v fmt1 "  %-${indent}s  %%s\n" ''

	while [[ $# -gt 0 ]]; do
		local flag=$1
		local desc="$(_ "$(_libremessages_html_whitespace_collapse <<<"$2")")"
		shift 2

		local lines
		IFS=$'\n' lines=($(fmt -u -w $((71-indent)) <<<"$desc"))
		printf -- "$fmt2" "$flag" "${lines[0]}"
		[[ ${#lines[@]} -lt 2 ]] || printf -- "$fmt1" "${lines[@]:1}"
	done
}

# Usage: term_title MESG [ARGS...]
#
# Sets the terminal title.
term_title() {
	[[ $# -ge 1 ]] || panic
	local fmt=''
	case "$TERM" in
		screen|tmux) fmt='\ek%s\e\\';;
		xterm*|rxvt*) fmt='\e]0;%s\a';;
	esac
	printf "$fmt" "$(printf -- "$@")"
}

# Usage: setup_traps [handler]
#
# Sets up traps on TERM, HUP, QUIT and INT signals, as well as the ERR
# event, similar to makepkg.
#
# If `handler` is specified, instead of using the default handler
# (which is good for most purposes), it will call the command handler
# with the arguments:
#
#   ${handler} SIGNAL_NAME MESSAGE_FMT [MESSAGE_PARAMS...]
#
# where MESSAGE_* are printf-like stuff.
#
# This function is based on code from pacman:makepkg
setup_traps() {
	[[ $# -le 1 ]] || panic
	if [[ $# == 1 ]]; then
		eval "_libremessages_trap_exit() { $1 \"\$@\"; }"
	else
		_libremessages_trap_exit() {
			local signal=$1; shift
			echo
			error "$@"
			trap -- "$signal"
			kill "-$signal" "$$"
		}
	fi
	set -E
	for signal in TERM HUP QUIT; do
		trap "_libremessages_trap_exit $signal '%s signal caught. Exiting...' $signal" $signal
	done
	trap '_libremessages_trap_exit INT "Aborted by user! Exiting..."' INT
	trap '_libremessages_trap_exit USR1 "An unknown error has occurred. Exiting..."' ERR
}

################################################################################
# Run one of the defined functions if invoked directly                         #
################################################################################

if [[ "${0##*/}" == libremessages ]]; then
	set -euE
	"$@"
fi